Manual de referência do GNU Guix

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GNU Guix

Esse documento descreve Guix versão 9356a8c, uma ferramenta de gerenciamento de pacotes funcional escrita para o sistema GNU.

This manual is also available in Simplified Chinese (veja GNU Guix参考手册), French (veja Manuel de référence de GNU Guix), German (veja Referenzhandbuch zu GNU Guix), Spanish (veja Manual de referencia de GNU Guix), Brazilian Portuguese (veja Manual de referência do GNU Guix), and Russian (veja Руководство GNU Guix). If you would like to translate it in your native language, consider joining Weblate (veja Traduzindo o Guix).

Sumário


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1 Introdução

GNU Guix1 é uma ferramenta de gerenciamento de pacotes e distribuição do sistema GNU. O Guix facilita a instalação, a atualização ou a remoção de pacotes de software, a reversão para um conjunto de pacotes anterior, a compilação de pacotes a partir do código-fonte e geralmente ajuda na criação e manutenção de ambientes de software.

Você pode instalar o GNU Guix sobre um sistema GNU/Linux existente, onde ele complementa as ferramentas disponíveis sem interferência (veja Instalação) ou você pode usá-lo como uma distribuição de sistema operacional independente, Guix System2. Veja Distribuição GNU.


1.1 Gerenciando software do jeito do Guix

Guix provides a command-line package management interface (veja Gerenciamento de pacote), tools to help with software development (veja Desenvolvimento), command-line utilities for more advanced usage (veja Utilitários), as well as Scheme programming interfaces (veja Interface de programação). O build daemon é responsável por compilar pacotes em nome dos usuários (veja Configurando o daemon) e por baixar binários pré-compilados de fontes autorizados (veja Substitutos).

Guix inclui definições de pacotes para muitos pacotes GNU e não-GNU, todos os quais respeitam a liberdade de computação do usuário. É extensível: os usuários podem escrever suas próprias definições de pacotes (veja Definindo pacotes) e disponibilizá-los como módulos de pacotes independentes (veja Módulos de pacote). Também é personalizável: os usuários podem derivar definições de pacotes especializados das existentes, incluindo da linha de comando (veja Opções de transformação de pacote).

Nos bastidores, a Guix implementa a disciplina gerenciamento de pacotes funcional pioneira da Nix (veja Agradecimentos). No Guix, o processo de compilação e instalação de pacotes é visto como uma função, no sentido matemático. Essa função recebe entradas, como scripts de compilação, um compilador e bibliotecas, e retorna um pacote instalado. Como uma função pura, seu resultado depende apenas de suas entradas – por exemplo, não pode fazer referência a um software ou scripts que não foram explicitamente passados como entradas. Uma função de compilação sempre produz o mesmo resultado ao passar por um determinado conjunto de entradas. Não pode alterar o ambiente do sistema em execução de qualquer forma; por exemplo, ele não pode criar, modificar ou excluir arquivos fora de seus diretórios de compilação e instalação. Isto é conseguido através da execução de processos de compilação em ambientes isolados (ou containers), onde somente suas entradas explícitas são visíveis.

O resultado das funções de compilação do pacote é mantido (cached) no sistema de arquivos, em um diretório especial chamado armazém (veja O armazém). Cada pacote é instalado em um diretório próprio no armazém – por padrão, em /gnu/store. O nome do diretório contém um hash de todas as entradas usadas para compilar esse pacote; Assim, a alteração uma entrada gera um nome de diretório diferente.

Essa abordagem é a fundação para os principais recursos do Guix: suporte para atualização transacional de pacotes e reversão, instalação por usuário e coleta de lixo de pacotes (veja Recursos).


1.2 Distribuição GNU

O Guix vem com uma distribuição do sistema GNU que consiste inteiramente de software livre3. A distribuição pode ser instalada por conta própria (veja Instalação do sistema), mas também é possível instalar o Guix como um gerenciador de pacotes em cima de um sistema GNU/Linux instalado (veja Instalação). Quando precisamos distinguir entre os dois, nos referimos à distribuição independente como Guix System.

A distribuição fornece pacotes GNU principais, como GNU libc, GCC e Binutils, além de muitos aplicativos GNU e não GNU. A lista completa de pacotes disponíveis pode ser acessada online ou executando guix package (veja Invocando guix package):

guix package --list-available

Nosso objetivo é fornecer uma distribuição prática e 100% de software livre, baseada em Linux e outras variantes do GNU, com foco na promoção e forte integração de componentes do GNU e ênfase em programas e ferramentas que ajudam os usuários a exercer essa liberdade.

Os pacotes estão atualmente disponíveis nas seguintes plataformas:

x86_64-linux

Intel/AMD x86_64 architecture, Linux-Libre kernel.

i686-linux

Intel 32-bit architecture (IA32), Linux-Libre kernel.

armhf-linux

Arquitetura ARMv7-A com hard float, Thumb-2 e NEON, usando a interface binária de aplicativos EABI hard-float (ABI) e o kernel Linux-Libre.

aarch64-linux

little-endian 64-bit ARMv8-A processors, Linux-Libre kernel.

i586-gnu

GNU/Hurd on the Intel 32-bit architecture (IA32).

This configuration is experimental and under development. The easiest way for you to give it a try is by setting up an instance of hurd-vm-service-type on your GNU/Linux machine (veja hurd-vm-service-type). Veja Contribuindo, on how to help!

mips64el-linux (unsupported)

little-endian 64-bit MIPS processors, specifically the Loongson series, n32 ABI, and Linux-Libre kernel. This configuration is no longer fully supported; in particular, there is no ongoing work to ensure that this architecture still works. Should someone decide they wish to revive this architecture then the code is still available.

powerpc-linux (unsupported)

big-endian 32-bit PowerPC processors, specifically the PowerPC G4 with AltiVec support, and Linux-Libre kernel. This configuration is not fully supported and there is no ongoing work to ensure this architecture works.

powerpc64le-linux

little-endian 64-bit Power ISA processors, Linux-Libre kernel. This includes POWER9 systems such as the RYF Talos II mainboard. This platform is available as a "technology preview": although it is supported, substitutes are not yet available from the build farm (veja Substitutos), and some packages may fail to build (veja Rastreando Bugs e Mudanças). That said, the Guix community is actively working on improving this support, and now is a great time to try it and get involved!

riscv64-linux

little-endian 64-bit RISC-V processors, specifically RV64GC, and Linux-Libre kernel. This platform is available as a "technology preview": although it is supported, substitutes are not yet available from the build farm (veja Substitutos), and some packages may fail to build (veja Rastreando Bugs e Mudanças). That said, the Guix community is actively working on improving this support, and now is a great time to try it and get involved!

Com o Guix System, você declara todos os aspectos da configuração do sistema operacional, e o Guix cuida de instanciar a configuração de maneira transacional, reproduzível e sem estado (veja Configuração do sistema). O Guix System usa o kernel Linux-libre, o sistema de inicialização Shepherd (veja Introduction em The GNU Shepherd Manual), os conhecidos utilitários do GNU e cadeia de ferramentas, bem como o ambiente gráfico ou os serviços de sistema do sua escolha.

Guix System is available on all the above platforms except mips64el-linux, powerpc-linux, powerpc64le-linux and riscv64-linux.

Para obter informações sobre como portar para outras arquiteturas ou kernels, veja Portando para uma nova plataforma.

A construção desta distribuição é um esforço cooperativo e você está convidado a participar! Veja Contribuindo, para obter informações sobre como você pode ajudar.


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2 Instalação

You can install the package management tool Guix on top of an existing GNU/Linux or GNU/Hurd system4, referred to as a foreign distro. If, instead, you want to install the complete, standalone GNU system distribution, Guix System, veja Instalação do sistema. This section is concerned only with the installation of Guix on a foreign distro.

Importante: This section only applies to systems without Guix. Following it for existing Guix installations will overwrite important system files.

Quando instalado sobre uma distro alheia. GNU Guix complementa as ferramentas disponíveis sem interferência. Seus dados residem exclusivamente em dois diretórios, geralmente /gnu/store e /var/guix; outros arquivos no seu sistema, como /etc, são deixados intactos.

Uma vez instalado, o Guix pode ser atualizado executando guix pull (veja Invocando guix pull).


2.1 Instalação de binários

This section describes how to install Guix from a self-contained tarball providing binaries for Guix and for all its dependencies. This is often quicker than installing from source, described later (veja Compilando do git).

Importante: This section only applies to systems without Guix. Following it for existing Guix installations will overwrite important system files.

Some GNU/Linux distributions, such as Debian, Ubuntu, and openSUSE provide Guix through their own package managers. The version of Guix may be older than 9356a8c but you can update it afterwards by running ‘guix pull’.

We advise system administrators who install Guix, both from the installation script or via the native package manager of their foreign distribution, to also regularly read and follow security notices, as shown by guix pull.

For Debian or derivatives such as Ubuntu or Trisquel, call:

sudo apt install guix

Likewise, on openSUSE:

sudo zypper install guix

If you are running Parabola, after enabling the pcr (Parabola Community Repo) repository, you can install Guix with:

sudo pacman -S guix

The Guix project also provides a shell script, guix-install.sh, which automates the binary installation process without use of a foreign distro package manager5. Use of guix-install.sh requires Bash, GnuPG, GNU tar, wget, and Xz.

The script guides you through the following:

  • Downloading and extracting the binary tarball
  • Setting up the build daemon
  • Making the ‘guix’ command available to non-root users
  • Configuring substitute servers

As root, run:

# cd /tmp
# wget https://git.savannah.gnu.org/cgit/guix.git/plain/etc/guix-install.sh
# chmod +x guix-install.sh
# ./guix-install.sh

The script to install Guix is also packaged in Parabola (in the pcr repository). You can install and run it with:

sudo pacman -S guix-installer
sudo guix-install.sh

Nota: By default, guix-install.sh will configure Guix to download pre-built package binaries, called substitutes (veja Substitutos), from the project’s build farms. If you choose not to permit this, Guix will build everything from source, making each installation and upgrade very expensive. Veja Confiança em binários for a discussion of why you may want to build packages from source.

To use substitutes from bordeaux.guix.gnu.org, ci.guix.gnu.org or a mirror, you must authorize them. For example,

# guix archive --authorize < \
     ~root/.config/guix/current/share/guix/bordeaux.guix.gnu.org.pub
# guix archive --authorize < \
     ~root/.config/guix/current/share/guix/ci.guix.gnu.org.pub

When you’re done installing Guix, veja Configuração de aplicativo for extra configuration you might need, and Começando for your first steps!

Nota: O tarball da instalação binária pode ser (re)produzido e verificado simplesmente executando o seguinte comando na árvore de código-fonte do Guix:

make guix-binary.system.tar.xz

... que, por sua vez, executa:

guix pack -s system --localstatedir \
  --profile-name=current-guix guix

Veja Invocando guix pack, para mais informações sobre essa ferramenta útil.

Should you eventually want to uninstall Guix, run the same script with the --uninstall flag:

./guix-install.sh --uninstall

With --uninstall, the script irreversibly deletes all the Guix files, configuration, and services.


2.2 Configurando o daemon

During installation, the build daemon that must be running to use Guix has already been set up and you can run guix commands in your terminal program, veja Começando:

guix build hello

If this runs through without error, feel free to skip this section. You should continue with the following section, Configuração de aplicativo.

However, now would be a good time to replace outdated daemon versions, tweak it, perform builds on other machines (veja Usando o recurso de descarregamento), or start it manually in special environments like “chroots” (veja Acessando um sistema existente via chroot) or WSL (not needed for WSL images created with Guix, veja wsl2-image-type). If you want to know more or optimize your system, this section is worth reading.

Operações como compilar um pacote ou executar o coletor de lixo são todas executadas por um processo especializado, o build daemon, em nome dos clientes. Apenas o daemon pode acessar o armazém e seu banco de dados associado. Assim, qualquer operação que manipule o armazém passa pelo daemon. Por exemplo, ferramentas de linha de comando como guix package e guix build se comunicam com o daemon (via chamadas de procedimento remoto) para instruir o que fazer.

The following sections explain how to prepare the build daemon’s environment. Veja Substitutos for how to allow the daemon to download pre-built binaries.


2.2.1 Configuração do ambiente de compilação

Em uma configuração multiusuário padrão, o Guix e seu daemon – o programa guix-daemon – são instalados pelo administrador do sistema; /gnu/store é de propriedade de root e guix-daemon é executado como root. Usuários desprivilegiados podem usar ferramentas Guix para criar pacotes ou acessar o armazém, e o daemon fará isso em seu nome, garantindo que o armazém seja mantido em um estado consistente e permitindo que pacotes construídos sejam compartilhados entre os usuários.

Quando guix-daemon é executado como root, você pode não querer que os próprios processos de compilação de pacotes também sejam executados como root, por razões óbvias de segurança. Para evitar isso, um conjunto especial de usuários de compilação deve ser criado para uso pelos processos de construção iniciados pelo daemon. Esses usuários de compilação não precisam ter um shell e um diretório inicial: eles serão usados apenas quando o daemon der um privilégio root nos processos de compilação. Ter vários desses usuários permite que o daemon ative processos de compilação distintos sob UIDs separados, o que garante que eles não interfiram uns com os outros - um recurso essencial, pois as compilações são consideradas funções puras (veja Introdução).

Em um sistema GNU/Linux, um conjunto de usuários de construção pode ser criado assim (usando a sintaxe Bash e os comandos shadow):

# groupadd --system guixbuild
# for i in $(seq -w 1 10);
  do
    useradd -g guixbuild -G guixbuild           \
            -d /var/empty -s $(which nologin)   \
            -c "Guix build user $i" --system    \
            guixbuilder$i;
  done

O número de usuários de compilação determina quantos trabalhos de compilação podem ser executados em paralelo, conforme especificado pela opção --max-jobs (veja --max-jobs). Para usar guix system vm e comandos relacionados, você pode precisar adicionar os usuários de compilação ao grupo kvm para que eles possam acessar /dev/kvm, usando -G guixbuild,kvm em vez de -G guixbuild (veja Invoking guix system).

The guix-daemon program may then be run as root with the following command6:

# guix-daemon --build-users-group=guixbuild

Dessa forma, o daemon inicia os processos de compilação em um chroot, sob um dos usuários guixbuilder. No GNU/Linux, por padrão, o ambiente chroot contém nada além de:

  • um diretório /dev mínimo, criado principalmente independentemente do /dev do hospedeiro7;
  • o diretório /proc; mostra apenas os processos do contêiner desde que um espaço de nome PID separado é usado;
  • /etc/passwd com uma entrada para o usuário atual e uma entrada para o usuário nobody;
  • /etc/group com uma entrada para o grupo de usuários;
  • /etc/hosts com uma entrada que mapeia localhost para 127.0.0.1;
  • um diretório /tmp com permissão de escrita.

The chroot does not contain a /home directory, and the HOME environment variable is set to the non-existent /homeless-shelter. This helps to highlight inappropriate uses of HOME in the build scripts of packages.

All this usually enough to ensure details of the environment do not influence build processes. In some exceptional cases where more control is needed—typically over the date, kernel, or CPU—you can resort to a virtual build machine (veja virtual build machines).

You can influence the directory where the daemon stores build trees via the TMPDIR environment variable. However, the build tree within the chroot is always called /tmp/guix-build-name.drv-0, where name is the derivation name—e.g., coreutils-8.24. This way, the value of TMPDIR does not leak inside build environments, which avoids discrepancies in cases where build processes capture the name of their build tree.

The daemon also honors the http_proxy and https_proxy environment variables for HTTP and HTTPS downloads it performs, be it for fixed-output derivations (veja Derivações) or for substitutes (veja Substitutos).

If you are installing Guix as an unprivileged user, it is still possible to run guix-daemon provided you pass --disable-chroot. However, build processes will not be isolated from one another, and not from the rest of the system. Thus, build processes may interfere with each other, and may access programs, libraries, and other files available on the system—making it much harder to view them as pure functions.


2.2.2 Usando o recurso de descarregamento

When desired, the build daemon can offload derivation builds to other machines running Guix, using the offload build hook8. When that feature is enabled, a list of user-specified build machines is read from /etc/guix/machines.scm; every time a build is requested, for instance via guix build, the daemon attempts to offload it to one of the machines that satisfy the constraints of the derivation, in particular its system types—e.g., x86_64-linux. A single machine can have multiple system types, either because its architecture natively supports it, via emulation (veja Transparent Emulation with QEMU), or both. Missing prerequisites for the build are copied over SSH to the target machine, which then proceeds with the build; upon success the output(s) of the build are copied back to the initial machine. The offload facility comes with a basic scheduler that attempts to select the best machine. The best machine is chosen among the available machines based on criteria such as:

  1. The availability of a build slot. A build machine can have as many build slots (connections) as the value of the parallel-builds field of its build-machine object.
  2. Its relative speed, as defined via the speed field of its build-machine object.
  3. Its load. The normalized machine load must be lower than a threshold value, configurable via the overload-threshold field of its build-machine object.
  4. Disk space availability. More than a 100 MiB must be available.

O arquivo /etc/guix/machines.scm geralmente se parece com isso:

(list (build-machine
        (name "eightysix.example.org")
        (systems (list "x86_64-linux" "i686-linux"))
        (host-key "ssh-ed25519 AAAAC3Nza…")
        (user "bob")
        (speed 2.))     ;incredibly fast!

      (build-machine
        (name "armeight.example.org")
        (systems (list "aarch64-linux"))
        (host-key "ssh-rsa AAAAB3Nza…")
        (user "alice")

        ;; Remember 'guix offload' is spawned by
        ;; 'guix-daemon' as root.
        (private-key "/root/.ssh/identity-for-guix")))

In the example above we specify a list of two build machines, one for the x86_64 and i686 architectures and one for the aarch64 architecture.

De fato, esse arquivo é – não surpreendentemente! – um arquivo de esquema que é avaliado quando o hook offload é iniciado. Seu valor de retorno deve ser uma lista de objetos de build-machine. Embora este exemplo mostre uma lista fixa de máquinas de compilação, pode-se imaginar, digamos, usando DNS-SD para retornar uma lista de possíveis máquinas de compilação descobertas na rede local (veja Guile-Avahi em Using Avahi in Guile Scheme Programs). O tipo de dados de build-machine está detalhado abaixo.

build-machine: Data Type

Esse tipo de dados representa máquinas de compilação nas quais o daemon pode descarregar compilações. Os campos importantes são:

name

O nome de host da máquina remota.

systems

The system types the remote machine supports—e.g., (list "x86_64-linux" "i686-linux").

user

The user account on the remote machine to use when connecting over SSH. Note that the SSH key pair must not be passphrase-protected, to allow non-interactive logins.

host-key

Essa deve ser a SSH chave pública do host da máquina no formato OpenSSH. Isso é usado para autenticar a máquina quando nos conectamos a ela. É uma string longa que se parece com isso:

ssh-ed25519 AAAAC3NzaC…mde+UhL hint@example.org

Se a máquina estiver executando o daemon OpenSSH, sshd, a chave do host poderá ser encontrada em um arquivo como /etc/ssh/ssh_host_ed25519_key.pub.

Se a máquina estiver executando o daemon SSH do GNU lsh, lshd, a chave do host estará em /etc/lsh/host-key.pub ou em um arquivo semelhante. Ele pode ser convertido para o formato OpenSSH usando o lsh-export-key (veja Converting keys em LSH Manual):

$ lsh-export-key --openssh < /etc/lsh/host-key.pub
ssh-rsa AAAAB3NzaC1yc2EAAAAEOp8FoQAAAQEAs1eB46LV…

Vários campos opcionais podem ser especificados:

port (padrão: 22)

O número da porta para o servidor SSH na máquina.

private-key (padrão: ~root/.ssh/id_rsa)

O arquivo de chave privada SSH a ser usado ao conectar-se à máquina, no formato OpenSSH. Esta chave não deve ser protegida com uma senha.

Observe que o valor padrão é a chave privada da usuário root. Verifique se ele existe se você usar o padrão.

compression (padrão: "zlib@openssh.com,zlib")
compression-level (padrão: 3)

Os métodos de compactação no nível SSH e o nível de compactação solicitado.

Observe que o descarregamento depende da compactação SSH para reduzir o uso da largura de banda ao transferir arquivos de e para máquinas de compilação.

daemon-socket (padrão: "/var/guix/daemon-socket/socket")

O nome do arquivo do soquete do domínio Unix guix-daemon está escutando nessa máquina.

overload-threshold (default: 0.8)

The load threshold above which a potential offload machine is disregarded by the offload scheduler. The value roughly translates to the total processor usage of the build machine, ranging from 0.0 (0%) to 1.0 (100%). It can also be disabled by setting overload-threshold to #f.

parallel-builds (padrão: 1)

O número de compilações que podem ser executadas paralelamente na máquina.

speed (padrão: 1.0)

Um “fator de velocidade relativo”. O agendador de descarregamento tenderá a preferir máquinas com um fator de velocidade mais alto.

features (padrão: '())

Uma lista de strgins que denotam recursos específicos suportados pela máquina. Um exemplo é "kvm" para máquinas que possuem os módulos KVM Linux e o suporte de hardware correspondente. As derivações podem solicitar recursos pelo nome e serão agendadas nas máquinas de compilação correspondentes.

Nota: On Guix System, instead of managing /etc/guix/machines.scm independently, you can choose to specify build machines directly in the operating-system declaration, in the build-machines field of guix-configuration. Veja build-machines field of guix-configuration.

O comando guix deve estar no caminho de pesquisa nas máquinas de compilação. Você pode verificar se este é o caso executando:

ssh build-machine guix repl --version

Há uma última coisa a fazer quando o machines.scm está em vigor. Como explicado acima, ao descarregar, os arquivos são transferidos entre os armazéns das máquinas. Para que isso funcione, primeiro você precisa gerar um par de chaves em cada máquina para permitir que o daemon exporte arquivos assinados de arquivos do armazém (veja Invocando guix archive):

# guix archive --generate-key

Nota: This key pair is not related to the SSH key pair that was previously mentioned in the description of the build-machine data type.

Cada máquina de construção deve autorizar a chave da máquina principal para que ela aceite itens do armazém que recebe do mestre:

# guix archive --authorize < master-public-key.txt

Da mesma forma, a máquina principal deve autorizar a chave de cada máquina de compilação.

Todo esse barulho com as chaves está aqui para expressar relações de confiança mútua de pares entre a máquina mestre e as de compilação. Concretamente, quando o mestre recebe arquivos de uma máquina de compilação (e vice-versa), seu daemon de compilação pode garantir que eles sejam genuínos, não tenham sido violados e que sejam assinados por uma chave autorizada.

Para testar se sua configuração está operacional, execute este comando no nó principal:

# guix offload test

This will attempt to connect to each of the build machines specified in /etc/guix/machines.scm, make sure Guix is available on each machine, attempt to export to the machine and import from it, and report any error in the process.

Se você quiser testar um arquivo de máquina diferente, basta especificá-lo na linha de comando:

# guix offload test machines-qualif.scm

Por fim, você pode testar o subconjunto das máquinas cujo nome corresponde a uma expressão regular como esta:

# guix offload test machines.scm '\.gnu\.org$'

Para exibir o carregamento atual de todos os hosts de compilação, execute este comando no nó principal:

# guix offload status

2.2.3 Suporte a SELinux

O Guix inclui um arquivo de políticas do SELinux em etc/guix-daemon.cil que pode ser instalado em um sistema em que o SELinux está ativado, para rotular os arquivos do Guix e especificar o comportamento esperado do daemon. Como o Guix System não fornece uma política básica do SELinux, a política do daemon não pode ser usada no Guix System.

2.2.3.1 Instalando a política do SELinux

Nota: The guix-install.sh binary installation script offers to perform the steps below for you (veja Instalação de binários).

Para instalar a política, execute esse comando como root:

semodule -i /var/guix/profiles/per-user/root/current-guix/share/selinux/guix-daemon.cil

Then, as root, relabel the file system, possibly after making it writable:

mount -o remount,rw /gnu/store
restorecon -R /gnu /var/guix

At this point you can start or restart guix-daemon; on a distribution that uses systemd as its service manager, you can do that with:

systemctl restart guix-daemon

Depois que a política é instalada, o sistema de arquivos foi rotulado novamente e o daemon foi reiniciado, ele deve estar em execução no contexto guix_daemon_t. Você pode confirmar isso com o seguinte comando:

ps -Zax | grep guix-daemon

Monitore os arquivos de log do SELinux enquanto executa um comando como guix build hello para se convencer de que o SELinux permite todas as operações necessárias.

2.2.3.2 Limitações

Esta política não é perfeita. Aqui está uma lista de limitações ou peculiaridades que devem ser consideradas ao implementar a política SELinux fornecida para o daemon Guix.

  1. guix_daemon_socket_t isn’t actually used. None of the socket operations involve contexts that have anything to do with guix_daemon_socket_t. It doesn’t hurt to have this unused label, but it would be preferable to define socket rules for only this label.
  2. guix gc cannot access arbitrary links to profiles. By design, the file label of the destination of a symlink is independent of the file label of the link itself. Although all profiles under $localstatedir are labelled, the links to these profiles inherit the label of the directory they are in. For links in the user’s home directory this will be user_home_t. But for links from the root user’s home directory, or /tmp, or the HTTP server’s working directory, etc, this won’t work. guix gc would be prevented from reading and following these links.
  3. O recurso do daemon de escutar conexões TCP pode não funcionar mais. Isso pode exigir regras extras, porque o SELinux trata os soquetes de rede de maneira diferente dos arquivos.
  4. Atualmente, todos os arquivos com um nome correspondente à expressão regular /gnu/store/.+-(guix-.+|profile)/bin/guix-daemon recebem o rótulo guix_daemon_exec_t; isso significa que qualquer arquivo com esse nome em qualquer perfil poderá ser executado no domínio de guix_daemon_t. Isto não é o ideal. Um invasor pode criar um pacote que forneça esse executável e convencer um usuário a instalar e executá-lo, o que o eleva ao domínio de guix_daemon_t. Nesse ponto, o SELinux não poderia impedir o acesso a arquivos permitidos para processos nesse domínio.

    You will need to relabel the store directory after all upgrades to guix-daemon, such as after running guix pull. Assuming the store is in /gnu, you can do this with restorecon -vR /gnu, or by other means provided by your operating system.

    Poderíamos gerar uma política muito mais restritiva no momento da instalação, para que apenas o nome do arquivo exato do executável guix-daemon atualmente instalado seja rotulado com guix_daemon_exec_t, em vez de usar um amplo expressão regular. A desvantagem é que o root precisaria instalar ou atualizar a política no momento da instalação sempre que o pacote Guix que fornece o executável guix-daemon em execução efetiva for atualizado.


2.3 Invocando guix-daemon

O programa guix-daemon implementa todas as funcionalidades para acessar o armazém. Isso inclui iniciar processos de compilação, executar o coletor de lixo, consultar a disponibilidade de um resultado da compilação etc. É normalmente executado como root, assim:

# guix-daemon --build-users-group=guixbuild

This daemon can also be started following the systemd “socket activation” protocol (veja make-systemd-constructor em The GNU Shepherd Manual).

Para detalhes sobre como configurá-lo, veja Configurando o daemon.

By default, guix-daemon launches build processes under different UIDs, taken from the build group specified with --build-users-group. In addition, each build process is run in a chroot environment that only contains the subset of the store that the build process depends on, as specified by its derivation (veja derivation), plus a set of specific system directories. By default, the latter contains /dev and /dev/pts. Furthermore, on GNU/Linux, the build environment is a container: in addition to having its own file system tree, it has a separate mount name space, its own PID name space, network name space, etc. This helps achieve reproducible builds (veja Recursos).

When the daemon performs a build on behalf of the user, it creates a build directory under /tmp or under the directory specified by its TMPDIR environment variable. This directory is shared with the container for the duration of the build, though within the container, the build tree is always called /tmp/guix-build-name.drv-0.

The build directory is automatically deleted upon completion, unless the build failed and the client specified --keep-failed (veja --keep-failed).

The daemon listens for connections and spawns one sub-process for each session started by a client (one of the guix sub-commands). The guix processes command allows you to get an overview of the activity on your system by viewing each of the active sessions and clients. Veja Invocando guix processes, for more information.

As seguintes opções de linha de comando são suportadas:

--build-users-group=grupo

Obtém os usuários do grupo para executar os processos de compilação (veja usuários de compilação).

--no-substitutes

Não use substitutos para compilar produtos. Ou seja, sempre crie coisas localmente, em vez de permitir downloads de binários pré-compilados (veja Substitutos).

When the daemon runs with --no-substitutes, clients can still explicitly enable substitution via the set-build-options remote procedure call (veja O armazém).

--substitute-urls=urls

Consider urls the default whitespace-separated list of substitute source URLs. When this option is omitted, ‘https://bordeaux.guix.gnu.org https://ci.guix.gnu.org’ is used.

Isso significa que os substitutos podem ser baixados de urls, desde que assinados por uma assinatura confiável (veja Substitutos).

Veja Getting Substitutes from Other Servers, for more information on how to configure the daemon to get substitutes from other servers.

--no-offload

Do not use offload builds to other machines (veja Usando o recurso de descarregamento). That is, always build things locally instead of offloading builds to remote machines.

--cache-failures

Armazena em cache as compilações que falharam. Por padrão, apenas compilações bem-sucedidas são armazenadas em cache.

Quando essa opção é usada, o guix gc --list-failures pode ser usado para consultar o conjunto de itens do armazém marcados como com falha; O guix gc --clear-failures remove os itens do armazém do conjunto de falhas em cache. Veja Invocando guix gc.

--cores=n
-c n

Usa n núcleos de CPU para compilar cada derivação; 0 significa todos disponíveis.

The default value is 0, but it may be overridden by clients, such as the --cores option of guix build (veja Invocando guix build).

The effect is to define the NIX_BUILD_CORES environment variable in the build process, which can then use it to exploit internal parallelism—for instance, by running make -j$NIX_BUILD_CORES.

--max-jobs=n
-M n

Permite no máximo n tarefas de compilação em paralelo. O valor padrão é 1. Definir como 0 significa que nenhuma compilação será executada localmente; em vez disso, o daemon descarregará as compilações (veja Usando o recurso de descarregamento) ou simplesmente falhará.

--max-silent-time=segundos

Quando o processo de compilação ou substituição permanecer em silêncio por mais de segundos, encerra-o e relata uma falha de compilação.

The default value is 3600 (one hour).

The value specified here can be overridden by clients (veja --max-silent-time).

--timeout=segundos

Da mesma forma, quando o processo de compilação ou substituição durar mais que segundos, encerra-o e relata uma falha de compilação.

The default value is 24 hours.

The value specified here can be overridden by clients (veja --timeout).

--rounds=N

Compila cada derivação n vezes seguidas e gera um erro se os resultados consecutivos da compilação não forem idênticos bit a bit. Observe que essa configuração pode ser substituída por clientes como guix build (veja Invocando guix build).

Quando usado em conjunto com --keep-failed, uma saída de comparação é mantida no armazém, sob /gnu/store/…-check. Isso facilita procurar por diferenças entre os dois resultados.

--debug

Produz uma saída de depuração.

This is useful to debug daemon start-up issues, but then it may be overridden by clients, for example the --verbosity option of guix build (veja Invocando guix build).

--chroot-directory=dir

adiciona dir ao chroot de compilação.

Isso pode alterar o resultado dos processos de compilação – por exemplo, se eles usam dependências opcionais encontradas em dir quando estão disponíveis, e não o contrário. Por esse motivo, não é recomendável fazê-lo. Em vez disso, verifique se cada derivação declara todas as entradas necessárias.

--disable-chroot

Desabilita compilações em chroot.

O uso dessa opção não é recomendado, pois, novamente, isso permitiria que os processos de compilação obtivessem acesso a dependências não declaradas. Porém, é necessário quando o guix-daemon está sendo executado em uma conta de usuário sem privilégios.

--log-compression=tipo

Compacta logs de compilação de aconrdo com tipo, que pode ser um entre gzip, bzip2 e none.

Unless --lose-logs is used, all the build logs are kept in the localstatedir. To save space, the daemon automatically compresses them with gzip by default.

--discover[=yes|no]

Whether to discover substitute servers on the local network using mDNS and DNS-SD.

This feature is still experimental. However, here are a few considerations.

  1. It might be faster/less expensive than fetching from remote servers;
  2. There are no security risks, only genuine substitutes will be used (veja Autenticação de substituto);
  3. An attacker advertising guix publish on your LAN cannot serve you malicious binaries, but they can learn what software you’re installing;
  4. Servers may serve substitute over HTTP, unencrypted, so anyone on the LAN can see what software you’re installing.

It is also possible to enable or disable substitute server discovery at run-time by running:

herd discover guix-daemon on
herd discover guix-daemon off
--disable-deduplication

Desabilita “deduplicação” automática de arquivos no armazém.

Por padrão, os arquivos adicionados ao armazém são automaticamente “deduplicados”: se um arquivo recém-adicionado for idêntico a outro encontrado no armazém, o daemon tornará o novo arquivo um link físico para o outro arquivo. Isso pode reduzir notavelmente o uso do disco, às custas de um leve aumento na carga de entrada/saída no final de um processo de criação. Esta opção desativa essa otimização.

--gc-keep-outputs[=yes|no]

Diz se o coletor de lixo (GC) deve manter as saídas de derivações vivas.

When set to yes, the GC will keep the outputs of any live derivation available in the store—the .drv files. The default is no, meaning that derivation outputs are kept only if they are reachable from a GC root. Veja Invocando guix gc, for more on GC roots.

--gc-keep-derivations[=yes|no]

Diz se o coletor de lixo (GC) deve manter as derivações correspondentes às saídas vivas.

When set to yes, as is the case by default, the GC keeps derivations—i.e., .drv files—as long as at least one of their outputs is live. This allows users to keep track of the origins of items in their store. Setting it to no saves a bit of disk space.

In this way, setting --gc-keep-derivations to yes causes liveness to flow from outputs to derivations, and setting --gc-keep-outputs to yes causes liveness to flow from derivations to outputs. When both are set to yes, the effect is to keep all the build prerequisites (the sources, compiler, libraries, and other build-time tools) of live objects in the store, regardless of whether these prerequisites are reachable from a GC root. This is convenient for developers since it saves rebuilds or downloads.

--impersonate-linux-2.6

On Linux-based systems, impersonate Linux 2.6. This means that the kernel’s uname system call will report 2.6 as the release number.

This might be helpful to build programs that (usually wrongfully) depend on the kernel version number.

--lose-logs

Do not keep build logs. By default they are kept under localstatedir/guix/log.

--system=system

Assume system as the current system type. By default it is the architecture/kernel pair found at configure time, such as x86_64-linux.

--listen=endpoint

Listen for connections on endpoint. endpoint is interpreted as the file name of a Unix-domain socket if it starts with / (slash sign). Otherwise, endpoint is interpreted as a host name or host name and port to listen to. Here are a few examples:

--listen=/gnu/var/daemon

Listen for connections on the /gnu/var/daemon Unix-domain socket, creating it if needed.

--listen=localhost

Listen for TCP connections on the network interface corresponding to localhost, on port 44146.

--listen=128.0.0.42:1234

Listen for TCP connections on the network interface corresponding to 128.0.0.42, on port 1234.

This option can be repeated multiple times, in which case guix-daemon accepts connections on all the specified endpoints. Users can tell client commands what endpoint to connect to by setting the GUIX_DAEMON_SOCKET environment variable (veja GUIX_DAEMON_SOCKET).

Nota: The daemon protocol is unauthenticated and unencrypted. Using --listen=host is suitable on local networks, such as clusters, where only trusted nodes may connect to the build daemon. In other cases where remote access to the daemon is needed, we recommend using Unix-domain sockets along with SSH.

When --listen is omitted, guix-daemon listens for connections on the Unix-domain socket located at localstatedir/guix/daemon-socket/socket.


2.4 Configuração de aplicativo

Ao usar Guix sobre uma distribuição GNU/Linux que não seja um Guix System — uma chamada distro alheia — algumas etapas adicionais são necessárias para colocar tudo no seu lugar. Aqui estão algumas delas.

2.4.1 Locales

Packages installed via Guix will not use the locale data of the host system. Instead, you must first install one of the locale packages available with Guix and then define the GUIX_LOCPATH environment variable:

$ guix install glibc-locales
$ export GUIX_LOCPATH=$HOME/.guix-profile/lib/locale

Note that the glibc-locales package contains data for all the locales supported by the GNU libc and weighs in at around 930 MiB9. If you only need a few locales, you can define your custom locales package via the make-glibc-utf8-locales procedure from the (gnu packages base) module. The following example defines a package containing the various Canadian UTF-8 locales known to the GNU libc, that weighs around 14 MiB:

(use-modules (gnu packages base))

(define my-glibc-locales
  (make-glibc-utf8-locales
   glibc
   #:locales (list "en_CA" "fr_CA" "ik_CA" "iu_CA" "shs_CA")
   #:name "glibc-canadian-utf8-locales"))

The GUIX_LOCPATH variable plays a role similar to LOCPATH (veja LOCPATH em The GNU C Library Reference Manual). There are two important differences though:

  1. GUIX_LOCPATH is honored only by the libc in Guix, and not by the libc provided by foreign distros. Thus, using GUIX_LOCPATH allows you to make sure the programs of the foreign distro will not end up loading incompatible locale data.
  2. libc suffixes each entry of GUIX_LOCPATH with /X.Y, where X.Y is the libc version—e.g., 2.22. This means that, should your Guix profile contain a mixture of programs linked against different libc version, each libc version will only try to load locale data in the right format.

This is important because the locale data format used by different libc versions may be incompatible.

2.4.2 Name Service Switch

Ao usar o Guix em uma distro alheia, nós recomendamos fortemente que o sistema use o daemon de cache de serviço de nomes da biblioteca C do GNU, nscd, que deve ouvir no soquete /var/run/nscd/socket. Caso não faça isso, os aplicativos instalados com Guix podem falhar em procurar nomes de máquina e contas de usuário, ou até mesmo travar. Os próximos parágrafos explicam o porquê.

The GNU C library implements a name service switch (NSS), which is an extensible mechanism for “name lookups” in general: host name resolution, user accounts, and more (veja Name Service Switch em The GNU C Library Reference Manual).

Being extensible, the NSS supports plugins, which provide new name lookup implementations: for example, the nss-mdns plugin allow resolution of .local host names, the nis plugin allows user account lookup using the Network information service (NIS), and so on. These extra “lookup services” are configured system-wide in /etc/nsswitch.conf, and all the programs running on the system honor those settings (veja NSS Configuration File em The GNU C Reference Manual).

When they perform a name lookup—for instance by calling the getaddrinfo function in C—applications first try to connect to the nscd; on success, nscd performs name lookups on their behalf. If the nscd is not running, then they perform the name lookup by themselves, by loading the name lookup services into their own address space and running it. These name lookup services—the libnss_*.so files—are dlopen’d, but they may come from the host system’s C library, rather than from the C library the application is linked against (the C library coming from Guix).

And this is where the problem is: if your application is linked against Guix’s C library (say, glibc 2.24) and tries to load NSS plugins from another C library (say, libnss_mdns.so for glibc 2.22), it will likely crash or have its name lookups fail unexpectedly.

Running nscd on the system, among other advantages, eliminates this binary incompatibility problem because those libnss_*.so files are loaded in the nscd process, not in applications themselves.

2.4.3 X11 Fonts

The majority of graphical applications use Fontconfig to locate and load fonts and perform X11-client-side rendering. The fontconfig package in Guix looks for fonts in $HOME/.guix-profile by default. Thus, to allow graphical applications installed with Guix to display fonts, you have to install fonts with Guix as well. Essential font packages include font-ghostscript, font-dejavu, and font-gnu-freefont.

Once you have installed or removed fonts, or when you notice an application that does not find fonts, you may need to install Fontconfig and to force an update of its font cache by running:

guix install fontconfig
fc-cache -rv

To display text written in Chinese languages, Japanese, or Korean in graphical applications, consider installing font-adobe-source-han-sans or font-wqy-zenhei. The former has multiple outputs, one per language family (veja Pacotes com múltiplas saídas). For instance, the following command installs fonts for Chinese languages:

guix install font-adobe-source-han-sans:cn

Older programs such as xterm do not use Fontconfig and instead rely on server-side font rendering. Such programs require to specify a full name of a font using XLFD (X Logical Font Description), like this:

-*-dejavu sans-medium-r-normal-*-*-100-*-*-*-*-*-1

To be able to use such full names for the TrueType fonts installed in your Guix profile, you need to extend the font path of the X server:

xset +fp $(dirname $(readlink -f ~/.guix-profile/share/fonts/truetype/fonts.dir))

After that, you can run xlsfonts (from xlsfonts package) to make sure your TrueType fonts are listed there.

2.4.4 Certificados X.509

The nss-certs package provides X.509 certificates, which allow programs to authenticate Web servers accessed over HTTPS.

Ao usar uma Guix em uma distro alheia, você pode instalar esse pacote e definir as variáveis de ambiente relevantes de forma que os pacotes saibam onde procurar por certificados. Veja Certificados X.509, para informações detalhadas.

2.4.5 Pacotes Emacs

When you install Emacs packages with Guix, the Elisp files are placed under the share/emacs/site-lisp/ directory of the profile in which they are installed. The Elisp libraries are made available to Emacs through the EMACSLOADPATH environment variable, which is set when installing Emacs itself.

Additionally, autoload definitions are automatically evaluated at the initialization of Emacs, by the Guix-specific guix-emacs-autoload-packages procedure. This procedure can be interactively invoked to have newly installed Emacs packages discovered, without having to restart Emacs. If, for some reason, you want to avoid auto-loading the Emacs packages installed with Guix, you can do so by running Emacs with the --no-site-file option (veja Init File em The GNU Emacs Manual).

Nota: Most Emacs variants are now capable of doing native compilation. The approach taken by Guix Emacs however differs greatly from the approach taken upstream.

Upstream Emacs compiles packages just-in-time and typically places shared object files in a special folder within your user-emacs-directory. These shared objects within said folder are organized in a flat hierarchy, and their file names contain two hashes to verify the original file name and contents of the source code.

Guix Emacs on the other hand prefers to compile packages ahead-of-time. Shared objects retain much of the original file name and no hashes are added to verify the original file name or the contents of the file. Crucially, this allows Guix Emacs and packages built against it to be grafted (veja grafts), but at the same time, Guix Emacs lacks the hash-based verification of source code baked into upstream Emacs. As this naming schema is trivial to exploit, we disable just-in-time compilation.

Further note, that emacs-minimal—the default Emacs for building packages—has been configured without native compilation. To natively compile your emacs packages ahead of time, use a transformation like --with-input=emacs-minimal=emacs.


2.5 Upgrading Guix

To upgrade Guix, run:

guix pull

Veja Invocando guix pull, for more information.

On a foreign distro, you can upgrade the build daemon by running:

sudo -i guix pull

followed by (assuming your distro uses the systemd service management tool):

systemctl restart guix-daemon.service

On Guix System, upgrading the daemon is achieved by reconfiguring the system (veja guix system reconfigure).


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3 Instalação do sistema

This section explains how to install Guix System on a machine. Guix, as a package manager, can also be installed on top of a running GNU/Linux system, veja Instalação.


3.1 Limitações

We consider Guix System to be ready for a wide range of “desktop” and server use cases. The reliability guarantees it provides—transactional upgrades and rollbacks, reproducibility—make it a solid foundation.

More and more system services are provided (veja Serviços).

Nevertheless, before you proceed with the installation, be aware that some services you rely on may still be missing from version 9356a8c.

More than a disclaimer, this is an invitation to report issues (and success stories!), and to join us in improving it. Veja Contribuindo, for more info.


3.2 Considerações de Hardware

GNU Guix focuses on respecting the user’s computing freedom. It builds around the kernel Linux-libre, which means that only hardware for which free software drivers and firmware exist is supported. Nowadays, a wide range of off-the-shelf hardware is supported on GNU/Linux-libre—from keyboards to graphics cards to scanners and Ethernet controllers. Unfortunately, there are still areas where hardware vendors deny users control over their own computing, and such hardware is not supported on Guix System.

One of the main areas where free drivers or firmware are lacking is WiFi devices. WiFi devices known to work include those using Atheros chips (AR9271 and AR7010), which corresponds to the ath9k Linux-libre driver, and those using Broadcom/AirForce chips (BCM43xx with Wireless-Core Revision 5), which corresponds to the b43-open Linux-libre driver. Free firmware exists for both and is available out-of-the-box on Guix System, as part of %base-firmware (veja firmware).

The installer warns you early on if it detects devices that are known not to work due to the lack of free firmware or free drivers.

The Free Software Foundation runs Respects Your Freedom (RYF), a certification program for hardware products that respect your freedom and your privacy and ensure that you have control over your device. We encourage you to check the list of RYF-certified devices.

Another useful resource is the H-Node web site. It contains a catalog of hardware devices with information about their support in GNU/Linux.


3.3 Instalação em um pendrive e em DVD

An ISO-9660 installation image that can be written to a USB stick or burnt to a DVD can be downloaded from ‘https://ftp.gnu.org/gnu/guix/guix-system-install-9356a8c.x86_64-linux.iso’, where you can replace x86_64-linux with one of:

x86_64-linux

for a GNU/Linux system on Intel/AMD-compatible 64-bit CPUs;

i686-linux

for a 32-bit GNU/Linux system on Intel-compatible CPUs.

Make sure to download the associated .sig file and to verify the authenticity of the image against it, along these lines:

$ wget https://ftp.gnu.org/gnu/guix/guix-system-install-9356a8c.x86_64-linux.iso.sig
$ gpg --verify guix-system-install-9356a8c.x86_64-linux.iso.sig

Se esse comando falhar porque você não possui a chave pública requerida, execute este comando para importá-lo:

$ wget https://sv.gnu.org/people/viewgpg.php?user_id=15145 \
      -qO - | gpg --import -

e execute novamente o comando gpg --verify.

Take note that a warning like “This key is not certified with a trusted signature!” is normal.

This image contains the tools necessary for an installation. It is meant to be copied as is to a large-enough USB stick or DVD.

Copying to a USB Stick

Insert a USB stick of 1 GiB or more into your machine, and determine its device name. Assuming that the USB stick is known as /dev/sdX, copy the image with:

dd if=guix-system-install-9356a8c.x86_64-linux.iso of=/dev/sdX status=progress
sync

Access to /dev/sdX usually requires root privileges.

Burning on a DVD

Insert a blank DVD into your machine, and determine its device name. Assuming that the DVD drive is known as /dev/srX, copy the image with:

growisofs -dvd-compat -Z /dev/srX=guix-system-install-9356a8c.x86_64-linux.iso

Access to /dev/srX usually requires root privileges.

Booting

Once this is done, you should be able to reboot the system and boot from the USB stick or DVD. The latter usually requires you to get in the BIOS or UEFI boot menu, where you can choose to boot from the USB stick. In order to boot from Libreboot, switch to the command mode by pressing the c key and type search_grub usb.

Sadly, on some machines, the installation medium cannot be properly booted and you only see a black screen after booting even after you waited for ten minutes. This may indicate that your machine cannot run Guix System; perhaps you instead want to install Guix on a foreign distro (veja Instalação de binários). But don’t give up just yet; a possible workaround is pressing the e key in the GRUB boot menu and appending nomodeset to the Linux bootline. Sometimes the black screen issue can also be resolved by connecting a different display.

Veja Installing Guix in a Virtual Machine, if, instead, you would like to install Guix System in a virtual machine (VM).


3.4 Preparando para instalação

Once you have booted, you can use the guided graphical installer, which makes it easy to get started (veja Instalação gráfica guiada). Alternatively, if you are already familiar with GNU/Linux and if you want more control than what the graphical installer provides, you can choose the “manual” installation process (veja Instalação manual).

The graphical installer is available on TTY1. You can obtain root shells on TTYs 3 to 6 by hitting ctrl-alt-f3, ctrl-alt-f4, etc. TTY2 shows this documentation and you can reach it with ctrl-alt-f2. Documentation is browsable using the Info reader commands (veja Stand-alone GNU Info). The installation system runs the GPM mouse daemon, which allows you to select text with the left mouse button and to paste it with the middle button.

Nota: Installation requires access to the Internet so that any missing dependencies of your system configuration can be downloaded. See the “Networking” section below.


3.5 Instalação gráfica guiada

The graphical installer is a text-based user interface. It will guide you, with dialog boxes, through the steps needed to install GNU Guix System.

The first dialog boxes allow you to set up the system as you use it during the installation: you can choose the language, keyboard layout, and set up networking, which will be used during the installation. The image below shows the networking dialog.

networking setup with the graphical
installer

Later steps allow you to partition your hard disk, as shown in the image below, to choose whether or not to use encrypted file systems, to enter the host name and root password, and to create an additional account, among other things.

partitioning with the graphical
installer

Note that, at any time, the installer allows you to exit the current installation step and resume at a previous step, as show in the image below.

resuming the installation process

Once you’re done, the installer produces an operating system configuration and displays it (veja Usando o sistema de configuração). At that point you can hit “OK” and installation will proceed. On success, you can reboot into the new system and enjoy. Veja Após a instalação do sistema, for what’s next!


3.6 Instalação manual

This section describes how you would “manually” install GNU Guix System on your machine. This option requires familiarity with GNU/Linux, with the shell, and with common administration tools. If you think this is not for you, consider using the guided graphical installer (veja Instalação gráfica guiada).

The installation system provides root shells on TTYs 3 to 6; press ctrl-alt-f3, ctrl-alt-f4, and so on to reach them. It includes many common tools needed to install the system, but is also a full-blown Guix System. This means that you can install additional packages, should you need it, using guix package (veja Invocando guix package).


3.6.1 Keyboard Layout, Networking, and Partitioning

Before you can install the system, you may want to adjust the keyboard layout, set up networking, and partition your target hard disk. This section will guide you through this.

3.6.1.1 Disposição do teclado

The installation image uses the US qwerty keyboard layout. If you want to change it, you can use the loadkeys command. For example, the following command selects the Dvorak keyboard layout:

loadkeys dvorak

See the files under /run/current-system/profile/share/keymaps for a list of available keyboard layouts. Run man loadkeys for more information.

3.6.1.2 Rede

Run the following command to see what your network interfaces are called:

ifconfig -a

… or, using the GNU/Linux-specific ip command:

ip address

Wired interfaces have a name starting with ‘e’; for example, the interface corresponding to the first on-board Ethernet controller is called ‘eno1’. Wireless interfaces have a name starting with ‘w’, like ‘w1p2s0’.

Conexão cabeada

To configure a wired network run the following command, substituting interface with the name of the wired interface you want to use.

ifconfig interface up

… or, using the GNU/Linux-specific ip command:

ip link set interface up
Wireless connection

To configure wireless networking, you can create a configuration file for the wpa_supplicant configuration tool (its location is not important) using one of the available text editors such as nano:

nano wpa_supplicant.conf

As an example, the following stanza can go to this file and will work for many wireless networks, provided you give the actual SSID and passphrase for the network you are connecting to:

network={
  ssid="my-ssid"
  key_mgmt=WPA-PSK
  psk="the network's secret passphrase"
}

Start the wireless service and run it in the background with the following command (substitute interface with the name of the network interface you want to use):

wpa_supplicant -c wpa_supplicant.conf -i interface -B

Run man wpa_supplicant for more information.

At this point, you need to acquire an IP address. On a network where IP addresses are automatically assigned via DHCP, you can run:

dhclient -v interface

Try to ping a server to see if networking is up and running:

ping -c 3 gnu.org

Setting up network access is almost always a requirement because the image does not contain all the software and tools that may be needed.

If you need HTTP and HTTPS access to go through a proxy, run the following command:

herd set-http-proxy guix-daemon URL

where URL is the proxy URL, for example http://example.org:8118.

If you want to, you can continue the installation remotely by starting an SSH server:

herd start ssh-daemon

Make sure to either set a password with passwd, or configure OpenSSH public key authentication before logging in.

3.6.1.3 Disk Partitioning

Unless this has already been done, the next step is to partition, and then format the target partition(s).

The installation image includes several partitioning tools, including Parted (veja Overview em GNU Parted User Manual), fdisk, and cfdisk. Run it and set up your disk with the partition layout you want:

cfdisk

If your disk uses the GUID Partition Table (GPT) format and you plan to install BIOS-based GRUB (which is the default), make sure a BIOS Boot Partition is available (veja BIOS installation em GNU GRUB manual).

If you instead wish to use EFI-based GRUB, a FAT32 EFI System Partition (ESP) is required. This partition can be mounted at /boot/efi for instance and must have the esp flag set. E.g., for parted:

parted /dev/sda set 1 esp on

Nota: Unsure whether to use EFI- or BIOS-based GRUB? If the directory /sys/firmware/efi exists in the installation image, then you should probably perform an EFI installation, using grub-efi-bootloader. Otherwise you should use the BIOS-based GRUB, known as grub-bootloader. Veja Configuração do carregador de inicialização, for more info on bootloaders.

Once you are done partitioning the target hard disk drive, you have to create a file system on the relevant partition(s)10. For the ESP, if you have one and assuming it is /dev/sda1, run:

mkfs.fat -F32 /dev/sda1

For the root file system, ext4 is the most widely used format. Other file systems, such as Btrfs, support compression, which is reported to nicely complement file deduplication that the daemon performs independently of the file system (veja deduplication).

Preferably, assign file systems a label so that you can easily and reliably refer to them in file-system declarations (veja Sistemas de arquivos). This is typically done using the -L option of mkfs.ext4 and related commands. So, assuming the target root partition lives at /dev/sda2, a file system with the label my-root can be created with:

mkfs.ext4 -L my-root /dev/sda2

If you are instead planning to encrypt the root partition, you can use the Cryptsetup/LUKS utilities to do that (see man cryptsetup for more information).

Assuming you want to store the root partition on /dev/sda2, the command sequence to format it as a LUKS partition would be along these lines:

cryptsetup luksFormat /dev/sda2
cryptsetup open /dev/sda2 my-partition
mkfs.ext4 -L my-root /dev/mapper/my-partition

Once that is done, mount the target file system under /mnt with a command like (again, assuming my-root is the label of the root file system):

mount LABEL=my-root /mnt

Also mount any other file systems you would like to use on the target system relative to this path. If you have opted for /boot/efi as an EFI mount point for example, mount it at /mnt/boot/efi now so it is found by guix system init afterwards.

Finally, if you plan to use one or more swap partitions (veja Swap Space), make sure to initialize them with mkswap. Assuming you have one swap partition on /dev/sda3, you would run:

mkswap /dev/sda3
swapon /dev/sda3

Alternatively, you may use a swap file. For example, assuming that in the new system you want to use the file /swapfile as a swap file, you would run11:

# This is 10 GiB of swap space.  Adjust "count" to change the size.
dd if=/dev/zero of=/mnt/swapfile bs=1MiB count=10240
# For security, make the file readable and writable only by root.
chmod 600 /mnt/swapfile
mkswap /mnt/swapfile
swapon /mnt/swapfile

Note that if you have encrypted the root partition and created a swap file in its file system as described above, then the encryption also protects the swap file, just like any other file in that file system.


3.6.2 Prosseguindo com a instalação

With the target partitions ready and the target root mounted on /mnt, we’re ready to go. First, run:

herd start cow-store /mnt

This makes /gnu/store copy-on-write, such that packages added to it during the installation phase are written to the target disk on /mnt rather than kept in memory. This is necessary because the first phase of the guix system init command (see below) entails downloads or builds to /gnu/store which, initially, is an in-memory file system.

Next, you have to edit a file and provide the declaration of the operating system to be installed. To that end, the installation system comes with three text editors. We recommend GNU nano (veja GNU nano Manual), which supports syntax highlighting and parentheses matching; other editors include mg (an Emacs clone), and nvi (a clone of the original BSD vi editor). We strongly recommend storing that file on the target root file system, say, as /mnt/etc/config.scm. Failing to do that, you will have lost your configuration file once you have rebooted into the newly-installed system.

Veja Usando o sistema de configuração, for an overview of the configuration file. The example configurations discussed in that section are available under /etc/configuration in the installation image. Thus, to get started with a system configuration providing a graphical display server (a “desktop” system), you can run something along these lines:

# mkdir /mnt/etc
# cp /etc/configuration/desktop.scm /mnt/etc/config.scm
# nano /mnt/etc/config.scm

You should pay attention to what your configuration file contains, and in particular:

  • Make sure the bootloader-configuration form refers to the targets you want to install GRUB on. It should mention grub-bootloader if you are installing GRUB in the legacy way, or grub-efi-bootloader for newer UEFI systems. For legacy systems, the targets field contain the names of the devices, like (list "/dev/sda"); for UEFI systems it names the paths to mounted EFI partitions, like (list "/boot/efi"); do make sure the paths are currently mounted and a file-system entry is specified in your configuration.
  • Be sure that your file system labels match the value of their respective device fields in your file-system configuration, assuming your file-system configuration uses the file-system-label procedure in its device field.
  • If there are encrypted or RAID partitions, make sure to add a mapped-devices field to describe them (veja Dispositivos mapeados).

Once you are done preparing the configuration file, the new system must be initialized (remember that the target root file system is mounted under /mnt):

guix system init /mnt/etc/config.scm /mnt

This copies all the necessary files and installs GRUB on /dev/sdX, unless you pass the --no-bootloader option. For more information, veja Invoking guix system. This command may trigger downloads or builds of missing packages, which can take some time.

Após a conclusão desse comando – e esperamos que com sucesso! – você pode executar o comando reboot e inicializar no novo sistema. A senha root no novo sistema está inicialmente vazia; as senhas de outros usuários precisam ser inicializadas executando o comando passwd como root, a menos que sua configuração especifique o contrário (veja senhas de contas de usuário). Veja Após a instalação do sistema, para o que vem a seguir!


3.7 Após a instalação do sistema

Success, you’ve now booted into Guix System! You can upgrade the system whenever you want by running:

guix pull
sudo guix system reconfigure /etc/config.scm

This builds a new system generation with the latest packages and services.

Now, veja Começando, and join us on #guix on the Libera.Chat IRC network or on guix-devel@gnu.org to share your experience!


3.8 Installing Guix in a Virtual Machine

If you’d like to install Guix System in a virtual machine (VM) or on a virtual private server (VPS) rather than on your beloved machine, this section is for you.

To boot a QEMU VM for installing Guix System in a disk image, follow these steps:

  1. First, retrieve and decompress the Guix system installation image as described previously (veja Instalação em um pendrive e em DVD).
  2. Create a disk image that will hold the installed system. To make a qcow2-formatted disk image, use the qemu-img command:
    qemu-img create -f qcow2 guix-system.img 50G
    

    The resulting file will be much smaller than 50 GB (typically less than 1 MB), but it will grow as the virtualized storage device is filled up.

  3. Boot the USB installation image in a VM:
    qemu-system-x86_64 -m 1024 -smp 1 -enable-kvm \
      -nic user,model=virtio-net-pci -boot menu=on,order=d \
      -drive file=guix-system.img \
      -drive media=cdrom,readonly=on,file=guix-system-install-9356a8c.system.iso
    

    -enable-kvm is optional, but significantly improves performance, veja Usando o Guix em uma Máquina Virtual.

  4. You’re now root in the VM, proceed with the installation process. Veja Preparando para instalação, and follow the instructions.

Once installation is complete, you can boot the system that’s on your guix-system.img image. Veja Usando o Guix em uma Máquina Virtual, for how to do that.


3.9 Compilando a imagem de instalação

The installation image described above was built using the guix system command, specifically:

guix system image -t iso9660 gnu/system/install.scm

Have a look at gnu/system/install.scm in the source tree, and see also Invoking guix system for more information about the installation image.

3.10 Building the Installation Image for ARM Boards

Many ARM boards require a specific variant of the U-Boot bootloader.

If you build a disk image and the bootloader is not available otherwise (on another boot drive etc), it’s advisable to build an image that includes the bootloader, specifically:

guix system image --system=armhf-linux -e '((@ (gnu system install) os-with-u-boot) (@ (gnu system install) installation-os) "A20-OLinuXino-Lime2")'

A20-OLinuXino-Lime2 is the name of the board. If you specify an invalid board, a list of possible boards will be printed.


4 Começando

Presumably, you’ve reached this section because either you have installed Guix on top of another distribution (veja Instalação), or you’ve installed the standalone Guix System (veja Instalação do sistema). It’s time for you to get started using Guix and this section aims to help you do that and give you a feel of what it’s like.

Guix is about installing software, so probably the first thing you’ll want to do is to actually look for software. Let’s say you’re looking for a text editor, you can run:

guix search text editor

This command shows you a number of matching packages, each time showing the package’s name, version, a description, and additional info. Once you’ve found out the one you want to use, let’s say Emacs (ah ha!), you can go ahead and install it (run this command as a regular user, no need for root privileges!):

guix install emacs

You’ve installed your first package, congrats! The package is now visible in your default profile, $HOME/.guix-profile—a profile is a directory containing installed packages. In the process, you’ve probably noticed that Guix downloaded pre-built binaries; or, if you explicitly chose to not use pre-built binaries, then probably Guix is still building software (veja Substitutos, for more info).

Unless you’re using Guix System, the guix install command must have printed this hint:

hint: Consider setting the necessary environment variables by running:

     GUIX_PROFILE="$HOME/.guix-profile"
     . "$GUIX_PROFILE/etc/profile"

Alternately, see `guix package --search-paths -p "$HOME/.guix-profile"'.

Indeed, you must now tell your shell where emacs and other programs installed with Guix are to be found. Pasting the two lines above will do just that: it will add $HOME/.guix-profile/bin—which is where the installed package is—to the PATH environment variable. You can paste these two lines in your shell so they take effect right away, but more importantly you should add them to ~/.bash_profile (or equivalent file if you do not use Bash) so that environment variables are set next time you spawn a shell. You only need to do this once and other search paths environment variables will be taken care of similarly—e.g., if you eventually install python and Python libraries, GUIX_PYTHONPATH will be defined.

You can go on installing packages at your will. To list installed packages, run:

guix package --list-installed

To remove a package, you would unsurprisingly run guix remove. A distinguishing feature is the ability to roll back any operation you made—installation, removal, upgrade—by simply typing:

guix package --roll-back

This is because each operation is in fact a transaction that creates a new generation. These generations and the difference between them can be displayed by running:

guix package --list-generations

Now you know the basics of package management!

Indo além: Veja Gerenciamento de pacote, for more about package management. You may like declarative package management with guix package --manifest, managing separate profiles with --profile, deleting old generations, collecting garbage, and other nifty features that will come in handy as you become more familiar with Guix. If you are a developer, veja Desenvolvimento for additional tools. And if you’re curious, veja Recursos, to peek under the hood.

You can also manage the configuration of your entire home environment—your user “dot files”, services, and packages—using Guix Home. Veja Home Configuration, to learn more about it!

Once you’ve installed a set of packages, you will want to periodically upgrade them to the latest and greatest version. To do that, you will first pull the latest revision of Guix and its package collection:

guix pull

The end result is a new guix command, under ~/.config/guix/current/bin. Unless you’re on Guix System, the first time you run guix pull, be sure to follow the hint that the command prints and, similar to what we saw above, paste these two lines in your terminal and .bash_profile:

GUIX_PROFILE="$HOME/.config/guix/current"
. "$GUIX_PROFILE/etc/profile"

You must also instruct your shell to point to this new guix:

hash guix

At this point, you’re running a brand new Guix. You can thus go ahead and actually upgrade all the packages you previously installed:

guix upgrade

As you run this command, you will see that binaries are downloaded (or perhaps some packages are built), and eventually you end up with the upgraded packages. Should one of these upgraded packages not be to your liking, remember you can always roll back!

You can display the exact revision of Guix you’re currently using by running:

guix describe

The information it displays is all it takes to reproduce the exact same Guix, be it at a different point in time or on a different machine.

Indo além: Veja Invocando guix pull, for more information. Veja Canais, on how to specify additional channels to pull packages from, how to replicate Guix, and more. You may also find time-machine handy (veja Invoking guix time-machine).

If you installed Guix System, one of the first things you’ll want to do is to upgrade your system. Once you’ve run guix pull to get the latest Guix, you can upgrade the system like this:

sudo guix system reconfigure /etc/config.scm

Upon completion, the system runs the latest versions of its software packages. Just like for packages, you can always roll back to a previous generation of the whole system. Veja Começando, to learn how to manage your system.

Now you know enough to get started!

Resources: The rest of this manual provides a reference for all things Guix. Here are some additional resources you may find useful:

  • Veja The GNU Guix Cookbook, for a list of “how-to” style of recipes for a variety of applications.
  • The GNU Guix Reference Card lists in two pages most of the commands and options you’ll ever need.
  • The web site contains instructional videos covering topics such as everyday use of Guix, how to get help, and how to become a contributor.
  • Veja Documentação, to learn how to access documentation on your computer.

We hope you will enjoy Guix as much as the community enjoys building it!


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5 Gerenciamento de pacote

The purpose of GNU Guix is to allow users to easily install, upgrade, and remove software packages, without having to know about their build procedures or dependencies. Guix also goes beyond this obvious set of features.

This chapter describes the main features of Guix, as well as the package management tools it provides. Along with the command-line interface described below (veja guix package), you may also use the Emacs-Guix interface (veja The Emacs-Guix Reference Manual), after installing emacs-guix package (run M-x guix-help command to start with it):

guix install emacs-guix

5.1 Recursos

Here we assume you’ve already made your first steps with Guix (veja Começando) and would like to get an overview about what’s going on under the hood.

When using Guix, each package ends up in the package store, in its own directory—something that resembles /gnu/store/xxx-package-1.2, where xxx is a base32 string.

Instead of referring to these directories, users have their own profile, which points to the packages that they actually want to use. These profiles are stored within each user’s home directory, at $HOME/.guix-profile.

For example, alice installs GCC 4.7.2. As a result, /home/alice/.guix-profile/bin/gcc points to /gnu/store/…-gcc-4.7.2/bin/gcc. Now, on the same machine, bob had already installed GCC 4.8.0. The profile of bob simply continues to point to /gnu/store/…-gcc-4.8.0/bin/gcc—i.e., both versions of GCC coexist on the same system without any interference.

The guix package command is the central tool to manage packages (veja Invocando guix package). It operates on the per-user profiles, and can be used with normal user privileges.

The command provides the obvious install, remove, and upgrade operations. Each invocation is actually a transaction: either the specified operation succeeds, or nothing happens. Thus, if the guix package process is terminated during the transaction, or if a power outage occurs during the transaction, then the user’s profile remains in its previous state, and remains usable.

In addition, any package transaction may be rolled back. So, if, for example, an upgrade installs a new version of a package that turns out to have a serious bug, users may roll back to the previous instance of their profile, which was known to work well. Similarly, the global system configuration on Guix is subject to transactional upgrades and roll-back (veja Começando).

All packages in the package store may be garbage-collected. Guix can determine which packages are still referenced by user profiles, and remove those that are provably no longer referenced (veja Invocando guix gc). Users may also explicitly remove old generations of their profile so that the packages they refer to can be collected.

Guix takes a purely functional approach to package management, as described in the introduction (veja Introdução). Each /gnu/store package directory name contains a hash of all the inputs that were used to build that package—compiler, libraries, build scripts, etc. This direct correspondence allows users to make sure a given package installation matches the current state of their distribution. It also helps maximize build reproducibility: thanks to the isolated build environments that are used, a given build is likely to yield bit-identical files when performed on different machines (veja container).

This foundation allows Guix to support transparent binary/source deployment. When a pre-built binary for a /gnu/store item is available from an external source—a substitute, Guix just downloads it and unpacks it; otherwise, it builds the package from source, locally (veja Substitutos). Because build results are usually bit-for-bit reproducible, users do not have to trust servers that provide substitutes: they can force a local build and challenge providers (veja Invocando guix challenge).

Control over the build environment is a feature that is also useful for developers. The guix shell command allows developers of a package to quickly set up the right development environment for their package, without having to manually install the dependencies of the package into their profile (veja Invoking guix shell).

All of Guix and its package definitions is version-controlled, and guix pull allows you to “travel in time” on the history of Guix itself (veja Invocando guix pull). This makes it possible to replicate a Guix instance on a different machine or at a later point in time, which in turn allows you to replicate complete software environments, while retaining precise provenance tracking of the software.


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5.2 Invocando guix package

The guix package command is the tool that allows users to install, upgrade, and remove packages, as well as rolling back to previous configurations. These operations work on a user profile—a directory of installed packages. Each user has a default profile in $HOME/.guix-profile. The command operates only on the user’s own profile, and works with normal user privileges (veja Recursos). Its syntax is:

guix package opções

Primarily, options specifies the operations to be performed during the transaction. Upon completion, a new profile is created, but previous generations of the profile remain available, should the user want to roll back.

For example, to remove lua and install guile and guile-cairo in a single transaction:

guix package -r lua -i guile guile-cairo

For your convenience, we also provide the following aliases:

  • guix search is an alias for guix package -s,
  • guix install is an alias for guix package -i,
  • guix remove is an alias for guix package -r,
  • guix upgrade is an alias for guix package -u,
  • and guix show is an alias for guix package --show=.

These aliases are less expressive than guix package and provide fewer options, so in some cases you’ll probably want to use guix package directly.

guix package also supports a declarative approach whereby the user specifies the exact set of packages to be available and passes it via the --manifest option (veja --manifest).

For each user, a symlink to the user’s default profile is automatically created in $HOME/.guix-profile. This symlink always points to the current generation of the user’s default profile. Thus, users can add $HOME/.guix-profile/bin to their PATH environment variable, and so on. If you are not using Guix System, consider adding the following lines to your ~/.bash_profile (veja Bash Startup Files em The GNU Bash Reference Manual) so that newly-spawned shells get all the right environment variable definitions:

GUIX_PROFILE="$HOME/.guix-profile" ; \
source "$GUIX_PROFILE/etc/profile"

In a multi-user setup, user profiles are stored in a place registered as a garbage-collector root, which $HOME/.guix-profile points to (veja Invocando guix gc). That directory is normally localstatedir/guix/profiles/per-user/user, where localstatedir is the value passed to configure as --localstatedir, and user is the user name. The per-user directory is created when guix-daemon is started, and the user sub-directory is created by guix package.

The options can be among the following:

--install=package
-i package

Install the specified packages.

Each package may specify a simple package name, such as guile, optionally followed by an at-sign and version number, such as guile@3.0.7 or simply guile@3.0. In the latter case, the newest version prefixed by 3.0 is selected.

If no version number is specified, the newest available version will be selected. In addition, such a package specification may contain a colon, followed by the name of one of the outputs of the package, as in gcc:doc or binutils@2.22:lib (veja Pacotes com múltiplas saídas).

Packages with a corresponding name (and optionally version) are searched for among the GNU distribution modules (veja Módulos de pacote).

Alternatively, a package can directly specify a store file name such as /gnu/store/...-guile-3.0.7, as produced by, e.g., guix build.

Sometimes packages have propagated inputs: these are dependencies that automatically get installed along with the required package (veja propagated-inputs in package objects, for information about propagated inputs in package definitions).

An example is the GNU MPC library: its C header files refer to those of the GNU MPFR library, which in turn refer to those of the GMP library. Thus, when installing MPC, the MPFR and GMP libraries also get installed in the profile; removing MPC also removes MPFR and GMP—unless they had also been explicitly installed by the user.

Besides, packages sometimes rely on the definition of environment variables for their search paths (see explanation of --search-paths below). Any missing or possibly incorrect environment variable definitions are reported here.

--install-from-expression=exp
-e exp

Install the package exp evaluates to.

exp must be a Scheme expression that evaluates to a <package> object. This option is notably useful to disambiguate between same-named variants of a package, with expressions such as (@ (gnu packages commencement) guile-final).

Note that this option installs the first output of the specified package, which may be insufficient when needing a specific output of a multiple-output package.

--install-from-file=file
-f arquivo

Install the package that the code within file evaluates to.

As an example, file might contain a definition like this (veja Definindo pacotes):

(use-modules (guix)
             (guix build-system gnu)
             (guix licenses))

(package
  (name "hello")
  (version "2.10")
  (source (origin
            (method url-fetch)
            (uri (string-append "mirror://gnu/hello/hello-" version
                                ".tar.gz"))
            (sha256
             (base32
              "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i"))))
  (build-system gnu-build-system)
  (synopsis "Hello, GNU world: An example GNU package")
  (description "Guess what GNU Hello prints!")
  (home-page "http://www.gnu.org/software/hello/")
  (license gpl3+))

Developers may find it useful to include such a guix.scm file in the root of their project source tree that can be used to test development snapshots and create reproducible development environments (veja Invoking guix shell).

The file may also contain a JSON representation of one or more package definitions. Running guix package -f on hello.json with the following contents would result in installing the package greeter after building myhello:

[
  {
    "name": "myhello",
    "version": "2.10",
    "source": "mirror://gnu/hello/hello-2.10.tar.gz",
    "build-system": "gnu",
    "arguments": {
      "tests?": false
    },
    "home-page": "https://www.gnu.org/software/hello/",
    "synopsis": "Hello, GNU world: An example GNU package",
    "description": "GNU Hello prints a greeting.",
    "license": "GPL-3.0+",
    "native-inputs": ["gettext"]
  },
  {
    "name": "greeter",
    "version": "1.0",
    "source": "mirror://gnu/hello/hello-2.10.tar.gz",
    "build-system": "gnu",
    "arguments": {
      "test-target": "foo",
      "parallel-build?": false
    },
    "home-page": "https://example.com/",
    "synopsis": "Greeter using GNU Hello",
    "description": "This is a wrapper around GNU Hello.",
    "license": "GPL-3.0+",
    "inputs": ["myhello", "hello"]
  }
]
--remove=package
-r pacote

Remove the specified packages.

As for --install, each package may specify a version number and/or output name in addition to the package name. For instance, ‘-r glibc:debug’ would remove the debug output of glibc.

--upgrade[=regexp …]
-u [regexp …]

Upgrade all the installed packages. If one or more regexps are specified, upgrade only installed packages whose name matches a regexp. Also see the --do-not-upgrade option below.

Note that this upgrades package to the latest version of packages found in the distribution currently installed. To update your distribution, you should regularly run guix pull (veja Invocando guix pull).

When upgrading, package transformations that were originally applied when creating the profile are automatically re-applied (veja Opções de transformação de pacote). For example, assume you first installed Emacs from the tip of its development branch with:

guix install emacs-next --with-branch=emacs-next=master

Next time you run guix upgrade, Guix will again pull the tip of the Emacs development branch and build emacs-next from that checkout.

Note that transformation options such as --with-branch and --with-source depend on external state; it is up to you to ensure that they work as expected. You can also discard a transformations that apply to a package by running:

guix install package
--do-not-upgrade[=regexp …]

When used together with the --upgrade option, do not upgrade any packages whose name matches a regexp. For example, to upgrade all packages in the current profile except those containing the substring “emacs”:

$ guix package --upgrade . --do-not-upgrade emacs
--manifest=arquivo
-m arquivo

Create a new generation of the profile from the manifest object returned by the Scheme code in file. This option can be repeated several times, in which case the manifests are concatenated.

This allows you to declare the profile’s contents rather than constructing it through a sequence of --install and similar commands. The advantage is that file can be put under version control, copied to different machines to reproduce the same profile, and so on.

file must return a manifest object, which is roughly a list of packages:

(use-package-modules guile emacs)

(packages->manifest
 (list emacs
       guile-2.0
       ;; Usa uma saída de pacote específica.
       (list guile-2.0 "debug")))

Veja Writing Manifests, for information on how to write a manifest. Veja --export-manifest, to learn how to obtain a manifest file from an existing profile.

--roll-back

Roll back to the previous generation of the profile—i.e., undo the last transaction.

When combined with options such as --install, roll back occurs before any other actions.

When rolling back from the first generation that actually contains installed packages, the profile is made to point to the zeroth generation, which contains no files apart from its own metadata.

After having rolled back, installing, removing, or upgrading packages overwrites previous future generations. Thus, the history of the generations in a profile is always linear.

--switch-generation=padrão
-S padrão

Switch to a particular generation defined by pattern.

pattern may be either a generation number or a number prefixed with “+” or “-”. The latter means: move forward/backward by a specified number of generations. For example, if you want to return to the latest generation after --roll-back, use --switch-generation=+1.

The difference between --roll-back and --switch-generation=-1 is that --switch-generation will not make a zeroth generation, so if a specified generation does not exist, the current generation will not be changed.

--search-paths[=tipo]

Report environment variable definitions, in Bash syntax, that may be needed in order to use the set of installed packages. These environment variables are used to specify search paths for files used by some of the installed packages.

For example, GCC needs the CPATH and LIBRARY_PATH environment variables to be defined so it can look for headers and libraries in the user’s profile (veja Environment Variables em Using the GNU Compiler Collection (GCC)). If GCC and, say, the C library are installed in the profile, then --search-paths will suggest setting these variables to profile/include and profile/lib, respectively (veja Search Paths, for info on search path specifications associated with packages.)

The typical use case is to define these environment variables in the shell:

$ eval $(guix package --search-paths)

kind may be one of exact, prefix, or suffix, meaning that the returned environment variable definitions will either be exact settings, or prefixes or suffixes of the current value of these variables. When omitted, kind defaults to exact.

This option can also be used to compute the combined search paths of several profiles. Consider this example:

$ guix package -p foo -i guile
$ guix package -p bar -i guile-json
$ guix package -p foo -p bar --search-paths

The last command above reports about the GUILE_LOAD_PATH variable, even though, taken individually, neither foo nor bar would lead to that recommendation.

--profile=perfil
-p perfil

Use profile instead of the user’s default profile.

profile must be the name of a file that will be created upon completion. Concretely, profile will be a mere symbolic link (“symlink”) pointing to the actual profile where packages are installed:

$ guix install hello -p ~/code/my-profile
…
$ ~/code/my-profile/bin/hello
Hello, world!

All it takes to get rid of the profile is to remove this symlink and its siblings that point to specific generations:

$ rm ~/code/my-profile ~/code/my-profile-*-link
--list-profiles

List all the user’s profiles:

$ guix package --list-profiles
/home/charlie/.guix-profile
/home/charlie/code/my-profile
/home/charlie/code/devel-profile
/home/charlie/tmp/test

When running as root, list all the profiles of all the users.

--allow-collisions

Allow colliding packages in the new profile. Use at your own risk!

By default, guix package reports as an error collisions in the profile. Collisions happen when two or more different versions or variants of a given package end up in the profile.

--bootstrap

Use the bootstrap Guile to build the profile. This option is only useful to distribution developers.

In addition to these actions, guix package supports the following options to query the current state of a profile, or the availability of packages:

--search=regexp
-s regexp

List the available packages whose name, synopsis, or description matches regexp (in a case-insensitive fashion), sorted by relevance. Print all the metadata of matching packages in recutils format (veja GNU recutils databases em GNU recutils manual).

This allows specific fields to be extracted using the recsel command, for instance:

$ guix package -s malloc | recsel -p name,version,relevance
name: jemalloc
version: 4.5.0
relevance: 6

name: glibc
version: 2.25
relevance: 1

name: libgc
version: 7.6.0
relevance: 1

Similarly, to show the name of all the packages available under the terms of the GNU LGPL version 3:

$ guix package -s "" | recsel -p name -e 'license ~ "LGPL 3"'
name: elfutils

name: gmp
…

It is also possible to refine search results using several -s flags to guix package, or several arguments to guix search. For example, the following command returns a list of board games (this time using the guix search alias):

$ guix search '\<board\>' game | recsel -p name
name: gnubg
…

If we were to omit -s game, we would also get software packages that deal with printed circuit boards; removing the angle brackets around board would further add packages that have to do with keyboards.

And now for a more elaborate example. The following command searches for cryptographic libraries, filters out Haskell, Perl, Python, and Ruby libraries, and prints the name and synopsis of the matching packages:

$ guix search crypto library | \
    recsel -e '! (name ~ "^(ghc|perl|python|ruby)")' -p name,synopsis

Veja Selection Expressions em GNU recutils manual, for more information on selection expressions for recsel -e.

--show=package

Show details about package, taken from the list of available packages, in recutils format (veja GNU recutils databases em GNU recutils manual).

$ guix package --show=guile | recsel -p name,version
name: guile
version: 3.0.5

name: guile
version: 3.0.2

name: guile
version: 2.2.7
…

You may also specify the full name of a package to only get details about a specific version of it (this time using the guix show alias):

$ guix show guile@3.0.5 | recsel -p name,version
name: guile
version: 3.0.5
--list-installed[=regexp]
-I [regexp]

List the currently installed packages in the specified profile, with the most recently installed packages shown last. When regexp is specified, list only installed packages whose name matches regexp.

For each installed package, print the following items, separated by tabs: the package name, its version string, the part of the package that is installed (for instance, out for the default output, include for its headers, etc.), and the path of this package in the store.

--list-available[=regexp]
-A [regexp]

List packages currently available in the distribution for this system (veja Distribuição GNU). When regexp is specified, list only available packages whose name matches regexp.

For each package, print the following items separated by tabs: its name, its version string, the parts of the package (veja Pacotes com múltiplas saídas), and the source location of its definition.

--list-generations[=padrão]
-l [padrão]

Return a list of generations along with their creation dates; for each generation, show the installed packages, with the most recently installed packages shown last. Note that the zeroth generation is never shown.

For each installed package, print the following items, separated by tabs: the name of a package, its version string, the part of the package that is installed (veja Pacotes com múltiplas saídas), and the location of this package in the store.

When pattern is used, the command returns only matching generations. Valid patterns include:

  • Integers and comma-separated integers. Both patterns denote generation numbers. For instance, --list-generations=1 returns the first one.

    And --list-generations=1,8,2 outputs three generations in the specified order. Neither spaces nor trailing commas are allowed.

  • Ranges. --list-generations=2..9 prints the specified generations and everything in between. Note that the start of a range must be smaller than its end.

    It is also possible to omit the endpoint. For example, --list-generations=2.., returns all generations starting from the second one.

  • Durations. You can also get the last N days, weeks, or months by passing an integer along with the first letter of the duration. For example, --list-generations=20d lists generations that are up to 20 days old.
--delete-generations[=pattern]
-d [pattern]

When pattern is omitted, delete all generations except the current one.

This command accepts the same patterns as --list-generations. When pattern is specified, delete the matching generations. When pattern specifies a duration, generations older than the specified duration match. For instance, --delete-generations=1m deletes generations that are more than one month old.

If the current generation matches, it is not deleted. Also, the zeroth generation is never deleted.

Note that deleting generations prevents rolling back to them. Consequently, this command must be used with care.

--export-manifest

Write to standard output a manifest suitable for --manifest corresponding to the chosen profile(s).

This option is meant to help you migrate from the “imperative” operating mode—running guix install, guix upgrade, etc.—to the declarative mode that --manifest offers.

Be aware that the resulting manifest approximates what your profile actually contains; for instance, depending on how your profile was created, it can refer to packages or package versions that are not exactly what you specified.

Keep in mind that a manifest is purely symbolic: it only contains package names and possibly versions, and their meaning varies over time. If you wish to “pin” channels to the revisions that were used to build the profile(s), see --export-channels below.

--export-channels

Write to standard output the list of channels used by the chosen profile(s), in a format suitable for guix pull --channels or guix time-machine --channels (veja Canais).

Together with --export-manifest, this option provides information allowing you to replicate the current profile (veja Replicating Guix).

However, note that the output of this command approximates what was actually used to build this profile. In particular, a single profile might have been built from several different revisions of the same channel. In that case, --export-manifest chooses the last one and writes the list of other revisions in a comment. If you really need to pick packages from different channel revisions, you can use inferiors in your manifest to do so (veja Inferiores).

Together with --export-manifest, this is a good starting point if you are willing to migrate from the “imperative” model to the fully declarative model consisting of a manifest file along with a channels file pinning the exact channel revision(s) you want.

Finally, since guix package may actually start build processes, it supports all the common build options (veja Opções de compilação comum). It also supports package transformation options, such as --with-source, and preserves them across upgrades (veja Opções de transformação de pacote).


5.3 Substitutos

Guix supports transparent source/binary deployment, which means that it can either build things locally, or download pre-built items from a server, or both. We call these pre-built items substitutes—they are substitutes for local build results. In many cases, downloading a substitute is much faster than building things locally.

Substitutes can be anything resulting from a derivation build (veja Derivações). Of course, in the common case, they are pre-built package binaries, but source tarballs, for instance, which also result from derivation builds, can be available as substitutes.


5.3.1 Official Substitute Servers

bordeaux.guix.gnu.org and ci.guix.gnu.org are both front-ends to official build farms that build packages from Guix continuously for some architectures, and make them available as substitutes. These are the default source of substitutes; which can be overridden by passing the --substitute-urls option either to guix-daemon (veja guix-daemon --substitute-urls) or to client tools such as guix package (veja client --substitute-urls option).

Substitute URLs can be either HTTP or HTTPS. HTTPS is recommended because communications are encrypted; conversely, using HTTP makes all communications visible to an eavesdropper, who could use the information gathered to determine, for instance, whether your system has unpatched security vulnerabilities.

Substitutes from the official build farms are enabled by default when using Guix System (veja Distribuição GNU). However, they are disabled by default when using Guix on a foreign distribution, unless you have explicitly enabled them via one of the recommended installation steps (veja Instalação). The following paragraphs describe how to enable or disable substitutes for the official build farm; the same procedure can also be used to enable substitutes for any other substitute server.


5.3.2 Autorização de servidor substituto

To allow Guix to download substitutes from bordeaux.guix.gnu.org, ci.guix.gnu.org or a mirror, you must add the relevant public key to the access control list (ACL) of archive imports, using the guix archive command (veja Invocando guix archive). Doing so implies that you trust the substitute server to not be compromised and to serve genuine substitutes.

Nota: If you are using Guix System, you can skip this section: Guix System authorizes substitutes from bordeaux.guix.gnu.org and ci.guix.gnu.org by default.

The public keys for each of the project maintained substitute servers are installed along with Guix, in prefix/share/guix/, where prefix is the installation prefix of Guix. If you installed Guix from source, make sure you checked the GPG signature of guix-9356a8c.tar.gz, which contains this public key file. Then, you can run something like this:

# guix archive --authorize < prefix/share/guix/bordeaux.guix.gnu.org.pub
# guix archive --authorize < prefix/share/guix/ci.guix.gnu.org.pub

Once this is in place, the output of a command like guix build should change from something like:

$ guix build emacs --dry-run
The following derivations would be built:
   /gnu/store/yr7bnx8xwcayd6j95r2clmkdl1qh688w-emacs-24.3.drv
   /gnu/store/x8qsh1hlhgjx6cwsjyvybnfv2i37z23w-dbus-1.6.4.tar.gz.drv
   /gnu/store/1ixwp12fl950d15h2cj11c73733jay0z-alsa-lib-1.0.27.1.tar.bz2.drv
   /gnu/store/nlma1pw0p603fpfiqy7kn4zm105r5dmw-util-linux-2.21.drv
…

to something like:

$ guix build emacs --dry-run
112.3 MB would be downloaded:
   /gnu/store/pk3n22lbq6ydamyymqkkz7i69wiwjiwi-emacs-24.3
   /gnu/store/2ygn4ncnhrpr61rssa6z0d9x22si0va3-libjpeg-8d
   /gnu/store/71yz6lgx4dazma9dwn2mcjxaah9w77jq-cairo-1.12.16
   /gnu/store/7zdhgp0n1518lvfn8mb96sxqfmvqrl7v-libxrender-0.9.7
…

The text changed from “The following derivations would be built” to “112.3 MB would be downloaded”. This indicates that substitutes from the configured substitute servers are usable and will be downloaded, when possible, for future builds.

The substitute mechanism can be disabled globally by running guix-daemon with --no-substitutes (veja Invocando guix-daemon). It can also be disabled temporarily by passing the --no-substitutes option to guix package, guix build, and other command-line tools.


5.3.3 Getting Substitutes from Other Servers

Guix can look up and fetch substitutes from several servers. This is useful when you are using packages from additional channels for which the official server does not have substitutes but another server provides them. Another situation where this is useful is when you would prefer to download from your organization’s substitute server, resorting to the official server only as a fallback or dismissing it altogether.

You can give Guix a list of substitute server URLs and it will check them in the specified order. You also need to explicitly authorize the public keys of substitute servers to instruct Guix to accept the substitutes they sign.

On Guix System, this is achieved by modifying the configuration of the guix service. Since the guix service is part of the default lists of services, %base-services and %desktop-services, you can use modify-services to change its configuration and add the URLs and substitute keys that you want (veja modify-services).

As an example, suppose you want to fetch substitutes from guix.example.org and to authorize the signing key of that server, in addition to the default bordeaux.guix.gnu.org and ci.guix.gnu.org. The resulting operating system configuration will look something like:

(operating-system
  ;; …
  (services
    ;; Assume we're starting from '%desktop-services'.  Replace it
    ;; with the list of services you're actually using.
    (modify-services %desktop-services
      (guix-service-type config =>
                        (guix-configuration
                          (inherit config)
                          (substitute-urls
                            (append (list "https://guix.example.org")
                                    %default-substitute-urls))
                          (authorized-keys
                            (append (list (local-file "./key.pub"))
                                    %default-authorized-guix-keys)))))))

This assumes that the file key.pub contains the signing key of guix.example.org. With this change in place in your operating system configuration file (say /etc/config.scm), you can reconfigure and restart the guix-daemon service or reboot so the changes take effect:

$ sudo guix system reconfigure /etc/config.scm
$ sudo herd restart guix-daemon

If you’re running Guix on a “foreign distro”, you would instead take the following steps to get substitutes from additional servers:

  1. Edit the service configuration file for guix-daemon; when using systemd, this is normally /etc/systemd/system/guix-daemon.service. Add the --substitute-urls option on the guix-daemon command line and list the URLs of interest (veja guix-daemon --substitute-urls):
    … --substitute-urls='https://guix.example.org https://bordeaux.guix.gnu.org https://ci.guix.gnu.org'
    
  2. Restart the daemon. For systemd, it goes like this:
    systemctl daemon-reload
    systemctl restart guix-daemon.service
    
  3. Authorize the key of the new server (veja Invocando guix archive):
    guix archive --authorize < key.pub
    

    Again this assumes key.pub contains the public key that guix.example.org uses to sign substitutes.

Now you’re all set! Substitutes will be preferably taken from https://guix.example.org, using bordeaux.guix.gnu.org then ci.guix.gnu.org as fallback options. Of course you can list as many substitute servers as you like, with the caveat that substitute lookup can be slowed down if too many servers need to be contacted.

Troubleshooting: To diagnose problems, you can run guix weather. For example, running:

guix weather coreutils

not only tells you which of the currently-configured servers has substitutes for the coreutils package, it also reports whether one of these servers is unauthorized. Veja Invocando guix weather, for more information.

Note that there are also situations where one may want to add the URL of a substitute server without authorizing its key. Veja Autenticação de substituto, to understand this fine point.


5.3.4 Autenticação de substituto

Guix detects and raises an error when attempting to use a substitute that has been tampered with. Likewise, it ignores substitutes that are not signed, or that are not signed by one of the keys listed in the ACL.

There is one exception though: if an unauthorized server provides substitutes that are bit-for-bit identical to those provided by an authorized server, then the unauthorized server becomes eligible for downloads. For example, assume we have chosen two substitute servers with this option:

--substitute-urls="https://a.example.org https://b.example.org"

If the ACL contains only the key for ‘b.example.org’, and if ‘a.example.org’ happens to serve the exact same substitutes, then Guix will download substitutes from ‘a.example.org’ because it comes first in the list and can be considered a mirror of ‘b.example.org’. In practice, independent build machines usually produce the same binaries, thanks to bit-reproducible builds (see below).

When using HTTPS, the server’s X.509 certificate is not validated (in other words, the server is not authenticated), contrary to what HTTPS clients such as Web browsers usually do. This is because Guix authenticates substitute information itself, as explained above, which is what we care about (whereas X.509 certificates are about authenticating bindings between domain names and public keys).


5.3.5 Configurações de proxy

Substitutes are downloaded over HTTP or HTTPS. The http_proxy and https_proxy environment variables can be set in the environment of guix-daemon and are honored for downloads of substitutes. Note that the value of those environment variables in the environment where guix build, guix package, and other client commands are run has absolutely no effect.


5.3.6 Falha na substituição

Even when a substitute for a derivation is available, sometimes the substitution attempt will fail. This can happen for a variety of reasons: the substitute server might be offline, the substitute may recently have been deleted, the connection might have been interrupted, etc.

When substitutes are enabled and a substitute for a derivation is available, but the substitution attempt fails, Guix will attempt to build the derivation locally depending on whether or not --fallback was given (veja common build option --fallback). Specifically, if --fallback was omitted, then no local build will be performed, and the derivation is considered to have failed. However, if --fallback was given, then Guix will attempt to build the derivation locally, and the success or failure of the derivation depends on the success or failure of the local build. Note that when substitutes are disabled or no substitute is available for the derivation in question, a local build will always be performed, regardless of whether or not --fallback was given.

To get an idea of how many substitutes are available right now, you can try running the guix weather command (veja Invocando guix weather). This command provides statistics on the substitutes provided by a server.


5.3.7 Confiança em binários

Today, each individual’s control over their own computing is at the mercy of institutions, corporations, and groups with enough power and determination to subvert the computing infrastructure and exploit its weaknesses. While using substitutes can be convenient, we encourage users to also build on their own, or even run their own build farm, such that the project run substitute servers are less of an interesting target. One way to help is by publishing the software you build using guix publish so that others have one more choice of server to download substitutes from (veja Invocando guix publish).

Guix has the foundations to maximize build reproducibility (veja Recursos). In most cases, independent builds of a given package or derivation should yield bit-identical results. Thus, through a diverse set of independent package builds, we can strengthen the integrity of our systems. The guix challenge command aims to help users assess substitute servers, and to assist developers in finding out about non-deterministic package builds (veja Invocando guix challenge). Similarly, the --check option of guix build allows users to check whether previously-installed substitutes are genuine by rebuilding them locally (veja guix build --check).

In the future, we want Guix to have support to publish and retrieve binaries to/from other users, in a peer-to-peer fashion. If you would like to discuss this project, join us on guix-devel@gnu.org.


5.4 Pacotes com múltiplas saídas

Often, packages defined in Guix have a single output—i.e., the source package leads to exactly one directory in the store. When running guix install glibc, one installs the default output of the GNU libc package; the default output is called out, but its name can be omitted as shown in this command. In this particular case, the default output of glibc contains all the C header files, shared libraries, static libraries, Info documentation, and other supporting files.

Sometimes it is more appropriate to separate the various types of files produced from a single source package into separate outputs. For instance, the GLib C library (used by GTK+ and related packages) installs more than 20 MiB of reference documentation as HTML pages. To save space for users who do not need it, the documentation goes to a separate output, called doc. To install the main GLib output, which contains everything but the documentation, one would run:

guix install glib

The command to install its documentation is:

guix install glib:doc

While the colon syntax works for command-line specification of package outputs, it will not work when using a package variable in Scheme code. For example, to add the documentation of glib to the globally installed packages of an operating-system (see operating-system Reference), a list of two items, the first one being the package variable and the second one the name of the output to select (a string), must be used instead:

(use-modules (gnu packages glib))
;; glib-with-documentation is the Guile symbol for the glib package
(operating-system
 ...
 (packages
  (append
   (list (list glib-with-documentation "doc"))
         %base-packages)))

Some packages install programs with different “dependency footprints”. For instance, the WordNet package installs both command-line tools and graphical user interfaces (GUIs). The former depend solely on the C library, whereas the latter depend on Tcl/Tk and the underlying X libraries. In this case, we leave the command-line tools in the default output, whereas the GUIs are in a separate output. This allows users who do not need the GUIs to save space. The guix size command can help find out about such situations (veja Invocando guix size). guix graph can also be helpful (veja Invocando guix graph).

There are several such multiple-output packages in the GNU distribution. Other conventional output names include lib for libraries and possibly header files, bin for stand-alone programs, and debug for debugging information (veja Instalando arquivos de depuração). The outputs of a package are listed in the third column of the output of guix package --list-available (veja Invocando guix package).


5.5 Invocando guix locate

There’s so much free software out there that sooner or later, you will need to search for packages. The guix search command that we’ve seen before (veja Invocando guix package) lets you search by keywords:

guix search video editor

Sometimes, you instead want to find which package provides a given file, and this is where guix locate comes in. Here is how you can find which package provides the ls command:

$ guix locate ls
coreutils@9.1       /gnu/store/…-coreutils-9.1/bin/ls

Of course the command works for any file, not just commands:

$ guix locate unistr.h
icu4c@71.1          /gnu/store/…/include/unicode/unistr.h
libunistring@1.0    /gnu/store/…/include/unistr.h

You may also specify glob patterns with wildcards. For example, here is how you would search for packages providing .service files:

$ guix locate -g '*.service'
man-db@2.11.1        …/lib/systemd/system/man-db.service
wpa-supplicant@2.10  …/system-services/fi.w1.wpa_supplicant1.service

The guix locate command relies on a database that maps file names to package names. By default, it automatically creates that database if it does not exist yet by traversing packages available locally, which can take a few minutes (depending on the size of your store and the speed of your storage device).

Nota: For now, guix locate builds its database based on purely local knowledge—meaning that you will not find packages that never reached your store. Eventually it will support downloading a pre-built database so you can potentially find more packages.

By default, guix locate first tries to look for a system-wide database, usually under /var/cache/guix/locate; if it does not exist or is too old, it falls back to the per-user database, by default under ~/.cache/guix/locate. On a multi-user system, administrators may want to periodically update the system-wide database so that all users can benefit from it, for instance by setting up package-database-service-type (veja package-database-service-type).

The general syntax is:

guix locate [options…] file

... where file is the name of a file to search for (specifically, the “base name” of the file: files whose parent directories are called file are not matched).

The available options are as follows:

--glob
-g

Interpret file… as glob patterns—patterns that may include wildcards, such as ‘*.scm’ to denote all files ending in ‘.scm’.

--stats

Display database statistics.

--update
-u

Update the file database.

By default, the database is automatically updated when it is too old.

--clear

Clear the database and re-populate it.

This option lets you start anew, ensuring old data is removed from the database, which also avoids having an endlessly growing database. By default guix locate automatically does that periodically, though infrequently.

--database=file

Use file as the database, creating it if necessary.

By default, guix locate picks the database under ~/.cache/guix or /var/cache/guix, whichever is the most recent one.

--method=method
-m method

Use method to select the set of packages to index. Possible values are:

manifests

This is the default method: it works by traversing profiles on the machine and recording packages it encounters—packages you or other users of the machine installed, directly or indirectly. It is fast but it can miss other packages available in the store but not referred to by any profile.

armazém

This is a slower but more exhaustive method: it checks among all the existing packages those that are available in the store and records them.


5.6 Invocando guix gc

Packages that are installed, but not used, may be garbage-collected. The guix gc command allows users to explicitly run the garbage collector to reclaim space from the /gnu/store directory. It is the only way to remove files from /gnu/store—removing files or directories manually may break it beyond repair!

The garbage collector has a set of known roots: any file under /gnu/store reachable from a root is considered live and cannot be deleted; any other file is considered dead and may be deleted. The set of garbage collector roots (“GC roots” for short) includes default user profiles; by default, the symlinks under /var/guix/gcroots represent these GC roots. New GC roots can be added with guix build --root, for example (veja Invocando guix build). The guix gc --list-roots command lists them.

Prior to running guix gc --collect-garbage to make space, it is often useful to remove old generations from user profiles; that way, old package builds referenced by those generations can be reclaimed. This is achieved by running guix package --delete-generations (veja Invocando guix package).

Our recommendation is to run a garbage collection periodically, or when you are short on disk space. For instance, to guarantee that at least 5 GB are available on your disk, simply run:

guix gc -F 5G

It is perfectly safe to run as a non-interactive periodic job (veja Execução de trabalho agendado, for how to set up such a job). Running guix gc with no arguments will collect as much garbage as it can, but that is often inconvenient: you may find yourself having to rebuild or re-download software that is “dead” from the GC viewpoint but that is necessary to build other pieces of software—e.g., the compiler tool chain.

The guix gc command has three modes of operation: it can be used to garbage-collect any dead files (the default), to delete specific files (the --delete option), to print garbage-collector information, or for more advanced queries. The garbage collection options are as follows:

--collect-garbage[=min]
-C [min]

Collect garbage—i.e., unreachable /gnu/store files and sub-directories. This is the default operation when no option is specified.

When min is given, stop once min bytes have been collected. min may be a number of bytes, or it may include a unit as a suffix, such as MiB for mebibytes and GB for gigabytes (veja size specifications em GNU Coreutils).

When min is omitted, collect all the garbage.

--free-space=free
-F free

Collect garbage until free space is available under /gnu/store, if possible; free denotes storage space, such as 500MiB, as described above.

When free or more is already available in /gnu/store, do nothing and exit immediately.

--delete-generations[=duração]
-d [duration]

Before starting the garbage collection process, delete all the generations older than duration, for all the user profiles and home environment generations; when run as root, this applies to all the profiles of all the users.

For example, this command deletes all the generations of all your profiles that are older than 2 months (except generations that are current), and then proceeds to free space until at least 10 GiB are available:

guix gc -d 2m -F 10G
--delete
-D

Attempt to delete all the store files and directories specified as arguments. This fails if some of the files are not in the store, or if they are still live.

--list-failures

List store items corresponding to cached build failures.

This prints nothing unless the daemon was started with --cache-failures (veja --cache-failures).

--list-roots

List the GC roots owned by the user; when run as root, list all the GC roots.

--list-busy

List store items in use by currently running processes. These store items are effectively considered GC roots: they cannot be deleted.

--clear-failures

Remove the specified store items from the failed-build cache.

Again, this option only makes sense when the daemon is started with --cache-failures. Otherwise, it does nothing.

--list-dead

Show the list of dead files and directories still present in the store—i.e., files and directories no longer reachable from any root.

--list-live

Show the list of live store files and directories.

In addition, the references among existing store files can be queried:

--references
--referrers

List the references (respectively, the referrers) of store files given as arguments.

--requisites
-R

List the requisites of the store files passed as arguments. Requisites include the store files themselves, their references, and the references of these, recursively. In other words, the returned list is the transitive closure of the store files.

Veja Invocando guix size, for a tool to profile the size of the closure of an element. Veja Invocando guix graph, for a tool to visualize the graph of references.

--derivers

Return the derivation(s) leading to the given store items (veja Derivações).

For example, this command:

guix gc --derivers $(guix package -I ^emacs$ | cut -f4)

returns the .drv file(s) leading to the emacs package installed in your profile.

Note that there may be zero matching .drv files, for instance because these files have been garbage-collected. There can also be more than one matching .drv due to fixed-output derivations.

Lastly, the following options allow you to check the integrity of the store and to control disk usage.

--verify[=options]

Verify the integrity of the store.

By default, make sure that all the store items marked as valid in the database of the daemon actually exist in /gnu/store.

When provided, options must be a comma-separated list containing one or more of contents and repair.

When passing --verify=contents, the daemon computes the content hash of each store item and compares it against its hash in the database. Hash mismatches are reported as data corruptions. Because it traverses all the files in the store, this command can take a long time, especially on systems with a slow disk drive.

Using --verify=repair or --verify=contents,repair causes the daemon to try to repair corrupt store items by fetching substitutes for them (veja Substitutos). Because repairing is not atomic, and thus potentially dangerous, it is available only to the system administrator. A lightweight alternative, when you know exactly which items in the store are corrupt, is guix build --repair (veja Invocando guix build).

--optimize

Optimize the store by hard-linking identical files—this is deduplication.

The daemon performs deduplication after each successful build or archive import, unless it was started with --disable-deduplication (veja --disable-deduplication). Thus, this option is primarily useful when the daemon was running with --disable-deduplication.

--vacuum-database

Guix uses an sqlite database to keep track of the items in (veja O armazém). Over time it is possible that the database may grow to a large size and become fragmented. As a result, one may wish to clear the freed space and join the partially used pages in the database left behind from removed packages or after running the garbage collector. Running sudo guix gc --vacuum-database will lock the database and VACUUM the store, defragmenting the database and purging freed pages, unlocking the database when it finishes.


5.7 Invocando guix pull

Packages are installed or upgraded to the latest version available in the distribution currently available on your local machine. To update that distribution, along with the Guix tools, you must run guix pull: the command downloads the latest Guix source code and package descriptions, and deploys it. Source code is downloaded from a Git repository, by default the official GNU Guix repository, though this can be customized. guix pull ensures that the code it downloads is authentic by verifying that commits are signed by Guix developers.

Specifically, guix pull downloads code from the channels (veja Canais) specified by one of the following, in this order:

  1. the --channels option;
  2. the user’s ~/.config/guix/channels.scm file, unless -q is passed;
  3. the system-wide /etc/guix/channels.scm file, unless -q is passed (on Guix System, this file can be declared in the operating system configuration, veja channels field of guix-configuration);
  4. the built-in default channels specified in the %default-channels variable.

On completion, guix package will use packages and package versions from this just-retrieved copy of Guix. Not only that, but all the Guix commands and Scheme modules will also be taken from that latest version. New guix sub-commands added by the update also become available.

Any user can update their Guix copy using guix pull, and the effect is limited to the user who ran guix pull. For instance, when user root runs guix pull, this has no effect on the version of Guix that user alice sees, and vice versa.

The result of running guix pull is a profile available under ~/.config/guix/current containing the latest Guix.

The --list-generations or -l option lists past generations produced by guix pull, along with details about their provenance:

$ guix pull -l
Generation 1	Jun 10 2018 00:18:18
  guix 65956ad
    repository URL: https://git.savannah.gnu.org/git/guix.git
    branch: origin/master
    commit: 65956ad3526ba09e1f7a40722c96c6ef7c0936fe

Generation 2	Jun 11 2018 11:02:49
  guix e0cc7f6
    repository URL: https://git.savannah.gnu.org/git/guix.git
    branch: origin/master
    commit: e0cc7f669bec22c37481dd03a7941c7d11a64f1d

Generation 3	Jun 13 2018 23:31:07	(current)
  guix 844cc1c
    repository URL: https://git.savannah.gnu.org/git/guix.git
    branch: origin/master
    commit: 844cc1c8f394f03b404c5bb3aee086922373490c

Veja guix describe, for other ways to describe the current status of Guix.

This ~/.config/guix/current profile works exactly like the profiles created by guix package (veja Invocando guix package). That is, you can list generations, roll back to the previous generation—i.e., the previous Guix—and so on:

$ guix pull --roll-back
switched from generation 3 to 2
$ guix pull --delete-generations=1
deleting /var/guix/profiles/per-user/charlie/current-guix-1-link

You can also use guix package (veja Invocando guix package) to manage the profile by naming it explicitly:

$ guix package -p ~/.config/guix/current --roll-back
switched from generation 3 to 2
$ guix package -p ~/.config/guix/current --delete-generations=1
deleting /var/guix/profiles/per-user/charlie/current-guix-1-link

The guix pull command is usually invoked with no arguments, but it supports the following options:

--url=url
--commit=commit
--branch=ramo

Download code for the guix channel from the specified url, at the given commit (a valid Git commit ID represented as a hexadecimal string or the name of a tag), or branch.

These options are provided for convenience, but you can also specify your configuration in the ~/.config/guix/channels.scm file or using the --channels option (see below).

--channels=file
-C arquivo

Read the list of channels from file instead of ~/.config/guix/channels.scm or /etc/guix/channels.scm. file must contain Scheme code that evaluates to a list of channel objects. Veja Canais, for more information.

--no-channel-files
-q

Inhibit loading of the user and system channel files, ~/.config/guix/channels.scm and /etc/guix/channels.scm.

--news
-N

Display news written by channel authors for their users for changes made since the previous generation (veja Writing Channel News). When --details is passed, additionally display new and upgraded packages.

You can view that information for previous generations with guix pull -l.

--list-generations[=padrão]
-l [padrão]

List all the generations of ~/.config/guix/current or, if pattern is provided, the subset of generations that match pattern. The syntax of pattern is the same as with guix package --list-generations (veja Invocando guix package).

By default, this prints information about the channels used in each revision as well as the corresponding news entries. If you pass --details, it will also print the list of packages added and upgraded in each generation compared to the previous one.

--details

Instruct --list-generations or --news to display more information about the differences between subsequent generations—see above.

--roll-back

Roll back to the previous generation of ~/.config/guix/current—i.e., undo the last transaction.

--switch-generation=padrão
-S padrão

Switch to a particular generation defined by pattern.

pattern may be either a generation number or a number prefixed with “+” or “-”. The latter means: move forward/backward by a specified number of generations. For example, if you want to return to the latest generation after --roll-back, use --switch-generation=+1.

--delete-generations[=pattern]
-d [pattern]

When pattern is omitted, delete all generations except the current one.

This command accepts the same patterns as --list-generations. When pattern is specified, delete the matching generations. When pattern specifies a duration, generations older than the specified duration match. For instance, --delete-generations=1m deletes generations that are more than one month old.

If the current generation matches, it is not deleted.

Note that deleting generations prevents rolling back to them. Consequently, this command must be used with care.

Veja Invocando guix describe, for a way to display information about the current generation only.

--profile=perfil
-p perfil

Use profile instead of ~/.config/guix/current.

--dry-run
-n

Show which channel commit(s) would be used and what would be built or substituted but do not actually do it.

--allow-downgrades

Allow pulling older or unrelated revisions of channels than those currently in use.

By default, guix pull protects against so-called “downgrade attacks” whereby the Git repository of a channel would be reset to an earlier or unrelated revision of itself, potentially leading you to install older, known-vulnerable versions of software packages.

Nota: Make sure you understand its security implications before using --allow-downgrades.

--disable-authentication

Allow pulling channel code without authenticating it.

By default, guix pull authenticates code downloaded from channels by verifying that its commits are signed by authorized developers, and raises an error if this is not the case. This option instructs it to not perform any such verification.

Nota: Make sure you understand its security implications before using --disable-authentication.

--system=system
-s sistema

Attempt to build for system—e.g., i686-linux—instead of the system type of the build host.

--bootstrap

Use the bootstrap Guile to build the latest Guix. This option is only useful to Guix developers.

The channel mechanism allows you to instruct guix pull which repository and branch to pull from, as well as additional repositories containing package modules that should be deployed. Veja Canais, for more information.

In addition, guix pull supports all the common build options (veja Opções de compilação comum).


5.8 Invoking guix time-machine

The guix time-machine command provides access to other revisions of Guix, for example to install older versions of packages, or to reproduce a computation in an identical environment. The revision of Guix to be used is defined by a commit or by a channel description file created by guix describe (veja Invocando guix describe).

Let’s assume that you want to travel to those days of November 2020 when version 1.2.0 of Guix was released and, once you’re there, run the guile of that time:

guix time-machine --commit=v1.2.0 -- \
  environment -C --ad-hoc guile -- guile

The command above fetches Guix 1.2.0 (and possibly other channels specified by your channels.scm configuration files—see below) and runs its guix environment command to spawn an environment in a container running guile (guix environment has since been subsumed by guix shell; veja Invoking guix shell). It’s like driving a DeLorean12! The first guix time-machine invocation can be expensive: it may have to download or even build a large number of packages; the result is cached though and subsequent commands targeting the same commit are almost instantaneous.

As for guix pull, in the absence of any options, time-machine fetches the latest commits of the channels specified in ~/.config/guix/channels.scm, /etc/guix/channels.scm, or the default channels; the -q option lets you ignore these configuration files. The command:

guix time-machine -q -- build hello

will thus build the package hello as defined in the main branch of Guix, without any additional channel, which is in general a newer revision of Guix than you have installed. Time travel works in both directions!

Nota: The history of Guix is immutable and guix time-machine provides the exact same software as they are in a specific Guix revision. Naturally, no security fixes are provided for old versions of Guix or its channels. A careless use of guix time-machine opens the door to security vulnerabilities. Veja --allow-downgrades.

guix time-machine raises an error when attempting to travel to commits older than “v0.16.0” (commit ‘4a0b87f0’), dated Dec. 2018. This is one of the oldest commits supporting the channel mechanism that makes “time travel” possible.

Nota: Although it should technically be possible to travel to such an old commit, the ease to do so will largely depend on the availability of binary substitutes. When traveling to a distant past, some packages may not easily build from source anymore. One such example are old versions of OpenSSL whose tests would fail after a certain date. This particular problem can be worked around by running a virtual build machine with its clock set to the right time (veja Virtual Build Machines).

The general syntax is:

guix time-machine options… -- command arg

where command and arg… are passed unmodified to the guix command of the specified revision. The options that define this revision are the same as for guix pull (veja Invocando guix pull):

--url=url
--commit=commit
--branch=ramo

Use the guix channel from the specified url, at the given commit (a valid Git commit ID represented as a hexadecimal string or the name of a tag), or branch.

--channels=file
-C arquivo

Read the list of channels from file. file must contain Scheme code that evaluates to a list of channel objects. Veja Canais for more information.

--no-channel-files
-q

Inhibit loading of the user and system channel files, ~/.config/guix/channels.scm and /etc/guix/channels.scm.

Thus, guix time-machine -q is equivalent to the following Bash command, using the “process substitution” syntax (veja Process Substitution em The GNU Bash Reference Manual):

guix time-machine -C <(echo %default-channels) …

Note that guix time-machine can trigger builds of channels and their dependencies, and these are controlled by the standard build options (veja Opções de compilação comum).


5.9 Inferiores

Nota: The functionality described here is a “technology preview” as of version 9356a8c. As such, the interface is subject to change.

Sometimes you might need to mix packages from the revision of Guix you’re currently running with packages available in a different revision of Guix. Guix inferiors allow you to achieve that by composing different Guix revisions in arbitrary ways.

Technically, an “inferior” is essentially a separate Guix process connected to your main Guix process through a REPL (veja Invocando guix repl). The (guix inferior) module allows you to create inferiors and to communicate with them. It also provides a high-level interface to browse and manipulate the packages that an inferior provides—inferior packages.

When combined with channels (veja Canais), inferiors provide a simple way to interact with a separate revision of Guix. For example, let’s assume you want to install in your profile the current guile package, along with the guile-json as it existed in an older revision of Guix—perhaps because the newer guile-json has an incompatible API and you want to run your code against the old API. To do that, you could write a manifest for use by guix package --manifest (veja Writing Manifests); in that manifest, you would create an inferior for that old Guix revision you care about, and you would look up the guile-json package in the inferior:

(use-modules (guix inferior) (guix channels)
             (srfi srfi-1))   ;for 'first'

(define channels
  ;; This is the old revision from which we want to
  ;; extract guile-json.
  (list (channel
         (name 'guix)
         (url "https://git.savannah.gnu.org/git/guix.git")
         (commit
          "65956ad3526ba09e1f7a40722c96c6ef7c0936fe"))))

(define inferior
  ;; An inferior representing the above revision.
  (inferior-for-channels channels))

;; Now create a manifest with the current "guile" package
;; and the old "guile-json" package.
(packages->manifest
 (list (first (lookup-inferior-packages inferior "guile-json"))
       (specification->package "guile")))

On its first run, guix package --manifest might have to build the channel you specified before it can create the inferior; subsequent runs will be much faster because the Guix revision will be cached.

The (guix inferior) module provides the following procedures to open an inferior:

Procedure: inferior-for-channels channels [#:cache-directory] [#:ttl]

Return an inferior for channels, a list of channels. Use the cache at cache-directory, where entries can be reclaimed after ttl seconds. This procedure opens a new connection to the build daemon.

As a side effect, this procedure may build or substitute binaries for channels, which can take time.

Procedure: open-inferior directory [#:command "bin/guix"]

Open the inferior Guix in directory, running directory/command repl or equivalent. Return #f if the inferior could not be launched.

The procedures listed below allow you to obtain and manipulate inferior packages.

Procedure: inferior-packages inferior

Return the list of packages known to inferior.

Procedure: lookup-inferior-packages inferior name [version]

Return the sorted list of inferior packages matching name in inferior, with highest version numbers first. If version is true, return only packages with a version number prefixed by version.

Procedure: inferior-package? obj

Return true if obj is an inferior package.

Procedure: inferior-package-name package
Procedure: inferior-package-version package
Procedure: inferior-package-synopsis package
Procedure: inferior-package-description package
Procedure: inferior-package-home-page package
Procedure: inferior-package-location package
Procedure: inferior-package-inputs package
Procedure: inferior-package-native-inputs package
Procedure: inferior-package-propagated-inputs package
Procedure: inferior-package-transitive-propagated-inputs package
Procedure: inferior-package-native-search-paths package
Procedure: inferior-package-transitive-native-search-paths package
Procedure: inferior-package-search-paths package

These procedures are the counterpart of package record accessors (veja package Reference). Most of them work by querying the inferior package comes from, so the inferior must still be live when you call these procedures.

Inferior packages can be used transparently like any other package or file-like object in G-expressions (veja Expressões-G). They are also transparently handled by the packages->manifest procedure, which is commonly used in manifests (veja the --manifest option of guix package). Thus you can insert an inferior package pretty much anywhere you would insert a regular package: in manifests, in the packages field of your operating-system declaration, and so on.


5.10 Invocando guix describe

Often you may want to answer questions like: “Which revision of Guix am I using?” or “Which channels am I using?” This is useful information in many situations: if you want to replicate an environment on a different machine or user account, if you want to report a bug or to determine what change in the channels you are using caused it, or if you want to record your system state for reproducibility purposes. The guix describe command answers these questions.

When run from a guix pulled guix, guix describe displays the channel(s) that it was built from, including their repository URL and commit IDs (veja Canais):

$ guix describe
Generation 10	Sep 03 2018 17:32:44	(current)
  guix e0fa68c
    repository URL: https://git.savannah.gnu.org/git/guix.git
    branch: master
    commit: e0fa68c7718fffd33d81af415279d6ddb518f727

If you’re familiar with the Git version control system, this is similar in spirit to git describe; the output is also similar to that of guix pull --list-generations, but limited to the current generation (veja the --list-generations option). Because the Git commit ID shown above unambiguously refers to a snapshot of Guix, this information is all it takes to describe the revision of Guix you’re using, and also to replicate it.

To make it easier to replicate Guix, guix describe can also be asked to return a list of channels instead of the human-readable description above:

$ guix describe -f channels
(list (channel
        (name 'guix)
        (url "https://git.savannah.gnu.org/git/guix.git")
        (commit
          "e0fa68c7718fffd33d81af415279d6ddb518f727")
        (introduction
          (make-channel-introduction
            "9edb3f66fd807b096b48283debdcddccfea34bad"
            (openpgp-fingerprint
              "BBB0 2DDF 2CEA F6A8 0D1D  E643 A2A0 6DF2 A33A 54FA")))))

You can save this to a file and feed it to guix pull -C on some other machine or at a later point in time, which will instantiate this exact Guix revision (veja the -C option). From there on, since you’re able to deploy the same revision of Guix, you can just as well replicate a complete software environment. We humbly think that this is awesome, and we hope you’ll like it too!

The details of the options supported by guix describe are as follows:

--format=format
-f format

Produce output in the specified format, one of:

human

produce human-readable output;

channels

produce a list of channel specifications that can be passed to guix pull -C or installed as ~/.config/guix/channels.scm (veja Invocando guix pull);

channels-sans-intro

like channels, but omit the introduction field; use it to produce a channel specification suitable for Guix version 1.1.0 or earlier—the introduction field has to do with channel authentication (veja Channel Authentication) and is not supported by these older versions;

json

produce a list of channel specifications in JSON format;

recutils

produce a list of channel specifications in Recutils format.

--list-formats

Display available formats for --format option.

--profile=perfil
-p perfil

Display information about profile.


5.11 Invocando guix archive

The guix archive command allows users to export files from the store into a single archive, and to later import them on a machine that runs Guix. In particular, it allows store files to be transferred from one machine to the store on another machine.

Nota: If you’re looking for a way to produce archives in a format suitable for tools other than Guix, veja Invocando guix pack.

To export store files as an archive to standard output, run:

guix archive --export options specifications...

specifications may be either store file names or package specifications, as for guix package (veja Invocando guix package). For instance, the following command creates an archive containing the gui output of the git package and the main output of emacs:

guix archive --export git:gui /gnu/store/...-emacs-24.3 > great.nar

If the specified packages are not built yet, guix archive automatically builds them. The build process may be controlled with the common build options (veja Opções de compilação comum).

To transfer the emacs package to a machine connected over SSH, one would run:

guix archive --export -r emacs | ssh the-machine guix archive --import

Similarly, a complete user profile may be transferred from one machine to another like this:

guix archive --export -r $(readlink -f ~/.guix-profile) | \
  ssh the-machine guix archive --import

However, note that, in both examples, all of emacs and the profile as well as all of their dependencies are transferred (due to -r), regardless of what is already available in the store on the target machine. The --missing option can help figure out which items are missing from the target store. The guix copy command simplifies and optimizes this whole process, so this is probably what you should use in this case (veja Invocando guix copy).

Each store item is written in the normalized archive or nar format (described below), and the output of guix archive --export (and input of guix archive --import) is a nar bundle.

The nar format is comparable in spirit to ‘tar’, but with differences that make it more appropriate for our purposes. First, rather than recording all Unix metadata for each file, the nar format only mentions the file type (regular, directory, or symbolic link); Unix permissions and owner/group are dismissed. Second, the order in which directory entries are stored always follows the order of file names according to the C locale collation order. This makes archive production fully deterministic.

That nar bundle format is essentially the concatenation of zero or more nars along with metadata for each store item it contains: its file name, references, corresponding derivation, and a digital signature.

When exporting, the daemon digitally signs the contents of the archive, and that digital signature is appended. When importing, the daemon verifies the signature and rejects the import in case of an invalid signature or if the signing key is not authorized.

The main options are:

--export

Export the specified store files or packages (see below). Write the resulting archive to the standard output.

Dependencies are not included in the output, unless --recursive is passed.

-r
--recursive

When combined with --export, this instructs guix archive to include dependencies of the given items in the archive. Thus, the resulting archive is self-contained: it contains the closure of the exported store items.

--import

Read an archive from the standard input, and import the files listed therein into the store. Abort if the archive has an invalid digital signature, or if it is signed by a public key not among the authorized keys (see --authorize below).

--missing

Read a list of store file names from the standard input, one per line, and write on the standard output the subset of these files missing from the store.

--generate-key[=parameters]

Generate a new key pair for the daemon. This is a prerequisite before archives can be exported with --export. This operation is usually instantaneous but it can take time if the system’s entropy pool needs to be refilled. On Guix System, guix-service-type takes care of generating this key pair the first boot.

The generated key pair is typically stored under /etc/guix, in signing-key.pub (public key) and signing-key.sec (private key, which must be kept secret). When parameters is omitted, an ECDSA key using the Ed25519 curve is generated, or, for Libgcrypt versions before 1.6.0, it is a 4096-bit RSA key. Alternatively, parameters can specify genkey parameters suitable for Libgcrypt (veja gcry_pk_genkey em The Libgcrypt Reference Manual).

--authorize

Authorize imports signed by the public key passed on standard input. The public key must be in “s-expression advanced format”—i.e., the same format as the signing-key.pub file.

The list of authorized keys is kept in the human-editable file /etc/guix/acl. The file contains “advanced-format s-expressions” and is structured as an access-control list in the Simple Public-Key Infrastructure (SPKI).

--extract=directory
-x directory

Read a single-item archive as served by substitute servers (veja Substitutos) and extract it to directory. This is a low-level operation needed in only very narrow use cases; see below.

For example, the following command extracts the substitute for Emacs served by bordeaux.guix.gnu.org to /tmp/emacs:

$ wget -O - \
  https://bordeaux.guix.gnu.org/nar/gzip/…-emacs-24.5 \
  | gunzip | guix archive -x /tmp/emacs

Single-item archives are different from multiple-item archives produced by guix archive --export; they contain a single store item, and they do not embed a signature. Thus this operation does no signature verification and its output should be considered unsafe.

The primary purpose of this operation is to facilitate inspection of archive contents coming from possibly untrusted substitute servers (veja Invocando guix challenge).

--list
-t

Read a single-item archive as served by substitute servers (veja Substitutos) and print the list of files it contains, as in this example:

$ wget -O - \
  https://bordeaux.guix.gnu.org/nar/lzip/…-emacs-26.3 \
  | lzip -d | guix archive -t

6 Canais

Guix and its package collection are updated by running guix pull. By default guix pull downloads and deploys Guix itself from the official GNU Guix repository. This can be customized by providing a file specifying the set of channels to pull from (veja Invocando guix pull). A channel specifies the URL and branch of a Git repository to be deployed, and guix pull can be instructed to pull from one or more channels. In other words, channels can be used to customize and to extend Guix, as we will see below. Guix is able to take into account security concerns and deal with authenticated updates.


6.1 Specifying Additional Channels

You can specify additional channels to pull from. To use a channel, write ~/.config/guix/channels.scm to instruct guix pull to pull from it in addition to the default Guix channel(s):

;; Add variant packages to those Guix provides.
(cons (channel
        (name 'variant-packages)
        (url "https://example.org/variant-packages.git"))
      %default-channels)

Note that the snippet above is (as always!) Scheme code; we use cons to add a channel the list of channels that the variable %default-channels is bound to (veja cons and lists em GNU Guile Reference Manual). With this file in place, guix pull builds not only Guix but also the package modules from your own repository. The result in ~/.config/guix/current is the union of Guix with your own package modules:

$ guix describe
Generation 19	Aug 27 2018 16:20:48
  guix d894ab8
    repository URL: https://git.savannah.gnu.org/git/guix.git
    branch: master
    commit: d894ab8e9bfabcefa6c49d9ba2e834dd5a73a300
  variant-packages dd3df5e
    repository URL: https://example.org/variant-packages.git
    branch: master
    commit: dd3df5e2c8818760a8fc0bd699e55d3b69fef2bb

The output of guix describe above shows that we’re now running Generation 19 and that it includes both Guix and packages from the variant-packages channel (veja Invocando guix describe).


6.2 Using a Custom Guix Channel

The channel called guix specifies where Guix itself—its command-line tools as well as its package collection—should be downloaded. For instance, suppose you want to update from another copy of the Guix repository at example.org, and specifically the super-hacks branch, you can write in ~/.config/guix/channels.scm this specification:

;; Tell 'guix pull' to use another repo.
(list (channel
        (name 'guix)
        (url "https://example.org/another-guix.git")
        (branch "super-hacks")))

From there on, guix pull will fetch code from the super-hacks branch of the repository at example.org. The authentication concern is addressed below (veja Channel Authentication).

Note that you can specify a local directory on the url field above if the channel that you intend to use resides on a local file system. However, in this case guix checks said directory for ownership before any further processing. This means that if the user is not the directory owner, but wants to use it as their default, they will then need to set it as a safe directory in their global git configuration file. Otherwise, guix will refuse to even read it. Supposing your system-wide local directory is at /src/guix.git, you would then create a git configuration file at ~/.gitconfig with the following contents:

[safe]
        directory = /src/guix.git

This also applies to the root user unless when called with sudo by the directory owner.


6.3 Replicating Guix

The guix describe command shows precisely which commits were used to build the instance of Guix we’re using (veja Invocando guix describe). We can replicate this instance on another machine or at a different point in time by providing a channel specification “pinned” to these commits that looks like this:

;; Deploy specific commits of my channels of interest.
(list (channel
       (name 'guix)
       (url "https://git.savannah.gnu.org/git/guix.git")
       (commit "6298c3ffd9654d3231a6f25390b056483e8f407c"))
      (channel
       (name 'variant-packages)
       (url "https://example.org/variant-packages.git")
       (commit "dd3df5e2c8818760a8fc0bd699e55d3b69fef2bb")))

To obtain this pinned channel specification, the easiest way is to run guix describe and to save its output in the channels format in a file, like so:

guix describe -f channels > channels.scm

The resulting channels.scm file can be passed to the -C option of guix pull (veja Invocando guix pull) or guix time-machine (veja Invoking guix time-machine), as in this example:

guix time-machine -C channels.scm -- shell python -- python3

Given the channels.scm file, the command above will always fetch the exact same Guix instance, then use that instance to run the exact same Python (veja Invoking guix shell). On any machine, at any time, it ends up running the exact same binaries, bit for bit.

Pinned channels address a problem similar to “lock files” as implemented by some deployment tools—they let you pin and reproduce a set of packages. In the case of Guix though, you are effectively pinning the entire package set as defined at the given channel commits; in fact, you are pinning all of Guix, including its core modules and command-line tools. You’re also getting strong guarantees that you are, indeed, obtaining the exact same software.

This gives you super powers, allowing you to track the provenance of binary artifacts with very fine grain, and to reproduce software environments at will—some sort of “meta reproducibility” capabilities, if you will. Veja Inferiores, for another way to take advantage of these super powers.


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6.4 Customizing the System-Wide Guix

If you’re running Guix System or building system images with it, maybe you will want to customize the system-wide guix it provides—specifically, /run/current-system/profile/bin/guix. For example, you might want to provide additional channels or to pin its revision.

This can be done using the guix-for-channels procedure, which returns a package for the given channels, and using it as part of your operating system configuration, as in this example:

(use-modules (gnu packages package-management)
             (guix channels))

(define my-channels
  ;; Channels that should be available to
  ;; /run/current-system/profile/bin/guix.
  (append
   (list (channel
          (name 'guix-science)
          (url "https://github.com/guix-science/guix-science")
          (branch "master")))
   %default-channels))

(operating-system
  ;; …
  (services
    ;; Change the package used by 'guix-service-type'.
    (modify-services %base-services
      (guix-service-type
       config => (guix-configuration
                  (inherit config)
                  (channels my-channels)
                  (guix (guix-for-channels my-channels)))))))

The resulting operating system will have both the guix and the guix-science channels visible by default. The channels field of guix-configuration above further ensures that /etc/guix/channels.scm, which is used by guix pull, specifies the same set of channels (veja channels field of guix-configuration).

The (gnu packages package-management) module exports the guix-for-channels procedure, described below.

Procedure: guix-for-channels channels

Return a package corresponding to channels.

The result is a “regular” package, which can be used in guix-configuration as shown above or in any other place that expects a package.


6.5 Channel Authentication

The guix pull and guix time-machine commands authenticate the code retrieved from channels: they make sure each commit that is fetched is signed by an authorized developer. The goal is to protect from unauthorized modifications to the channel that would lead users to run malicious code.

As a user, you must provide a channel introduction in your channels file so that Guix knows how to authenticate its first commit. A channel specification, including its introduction, looks something along these lines:

(channel
  (name 'some-channel)
  (url "https://example.org/some-channel.git")
  (introduction
   (make-channel-introduction
    "6f0d8cc0d88abb59c324b2990bfee2876016bb86"
    (openpgp-fingerprint
     "CABB A931 C0FF EEC6 900D  0CFB 090B 1199 3D9A EBB5"))))

The specification above shows the name and URL of the channel. The call to make-channel-introduction above specifies that authentication of this channel starts at commit 6f0d8cc…, which is signed by the OpenPGP key with fingerprint CABB A931….

For the main channel, called guix, you automatically get that information from your Guix installation. For other channels, include the channel introduction provided by the channel authors in your channels.scm file. Make sure you retrieve the channel introduction from a trusted source since that is the root of your trust.

If you’re curious about the authentication mechanics, read on!


6.6 Channels with Substitutes

When running guix pull, Guix will first compile the definitions of every available package. This is an expensive operation for which substitutes (veja Substitutos) may be available. The following snippet in channels.scm will ensure that guix pull uses the latest commit with available substitutes for the package definitions: this is done by querying the continuous integration server at https://ci.guix.gnu.org.

(use-modules (guix ci))

(list (channel-with-substitutes-available
       %default-guix-channel
       "https://ci.guix.gnu.org"))

Note that this does not mean that all the packages that you will install after running guix pull will have available substitutes. It only ensures that guix pull will not try to compile package definitions. This is particularly useful when using machines with limited resources.


6.7 Creating a Channel

Let’s say you have a bunch of custom package variants or personal packages that you think would make little sense to contribute to the Guix project, but would like to have these packages transparently available to you at the command line. By creating a channel, you can use and publish such a package collection. This involves the following steps:

  1. A channel lives in a Git repository so the first step, when creating a channel, is to create its repository:
    mkdir my-channel
    cd my-channel
    git init
    
  2. The next step is to create files containing package modules (veja Módulos de pacote), each of which will contain one or more package definitions (veja Definindo pacotes). A channel can provide things other than packages, such as build systems or services; we’re using packages as it’s the most common use case.

    For example, Alice might want to provide a module called (alice packages greetings) that will provide her favorite “hello world” implementations. To do that Alice will create a directory corresponding to that module name.

    mkdir -p alice/packages
    $EDITOR alice/packages/greetings.scm
    git add alice/packages/greetings.scm
    

    You can name your package modules however you like; the main constraint to keep in mind is to avoid name clashes with other package collections, which is why our hypothetical Alice wisely chose the (alice packages …) name space.

    Note that you can also place modules in a sub-directory of the repository; veja Package Modules in a Sub-directory, for more info on that.

  3. With this first module in place, the next step is to test the packages it provides. This can be done with guix build, which needs to be told to look for modules in the Git checkout. For example, assuming (alice packages greetings) provides a package called hi-from-alice, Alice will run this command from the Git checkout:
    guix build -L. hi-from-alice
    

    ... where -L. adds the current directory to Guile’s load path (veja Load Paths em GNU Guile Reference Manual).

  4. It might take Alice a few iterations to obtain satisfying package definitions. Eventually Alice will commit this file:
    git commit
    

    As a channel author, consider bundling authentication material with your channel so that users can authenticate it. Veja Channel Authentication, and Specifying Channel Authorizations, for info on how to do it.

  5. To use Alice’s channel, anyone can now add it to their channel file (veja Specifying Additional Channels) and run guix pull (veja Invocando guix pull):
    $EDITOR ~/.config/guix/channels.scm
    guix pull
    

    Guix will now behave as if the root directory of that channel’s Git repository had been permanently added to the Guile load path. In this example, (alice packages greetings) will automatically be found by the guix command.

Voilà!

Aviso: Before you publish your channel, we would like to share a few words of caution:

  • Before publishing a channel, please consider contributing your package definitions to Guix proper (veja Contribuindo). Guix as a project is open to free software of all sorts, and packages in Guix proper are readily available to all Guix users and benefit from the project’s quality assurance process.
  • Package modules and package definitions are Scheme code that uses various programming interfaces (APIs). We, Guix developers, never change APIs gratuitously, but we do not commit to freezing APIs either. When you maintain package definitions outside Guix, we consider that the compatibility burden is on you.
  • Corollary: if you’re using an external channel and that channel breaks, please report the issue to the channel authors, not to the Guix project.

You’ve been warned! Having said this, we believe external channels are a practical way to exert your freedom to augment Guix’ package collection and to share your improvements, which are basic tenets of free software. Please email us at guix-devel@gnu.org if you’d like to discuss this.


6.8 Package Modules in a Sub-directory

As a channel author, you may want to keep your channel modules in a sub-directory. If your modules are in the sub-directory guix, you must add a meta-data file .guix-channel that contains:

(channel
  (version 0)
  (directory "guix"))

The modules must be underneath the specified directory, as the directory changes Guile’s load-path. For example, if .guix-channel has (directory "base"), then a module defined as (define-module (gnu packages fun)) must be located at base/gnu/packages/fun.scm.

Doing this allows for only parts of a repository to be used as a channel, as Guix expects valid Guile modules when pulling. For instance, guix deploy machine configuration files are not valid Guile modules, and treating them as such would make guix pull fail.


6.9 Declaring Channel Dependencies

Channel authors may decide to augment a package collection provided by other channels. They can declare their channel to be dependent on other channels in a meta-data file .guix-channel, which is to be placed in the root of the channel repository.

The meta-data file should contain a simple S-expression like this:

(channel
 (version 0)
 (dependencies
  (channel
   (name some-collection)
   (url "https://example.org/first-collection.git")

   ;; The 'introduction' bit below is optional: you would
   ;; provide it for dependencies that can be authenticated.
   (introduction
    (channel-introduction
      (version 0)
      (commit "a8883b58dc82e167c96506cf05095f37c2c2c6cd")
      (signer "CABB A931 C0FF EEC6 900D  0CFB 090B 1199 3D9A EBB5"))))
  (channel
   (name some-other-collection)
   (url "https://example.org/second-collection.git")
   (branch "testing"))))

In the above example this channel is declared to depend on two other channels, which will both be fetched automatically. The modules provided by the channel will be compiled in an environment where the modules of all these declared channels are available.

For the sake of reliability and maintainability, you should avoid dependencies on channels that you don’t control, and you should aim to keep the number of dependencies to a minimum.


6.10 Specifying Channel Authorizations

As we saw above, Guix ensures the source code it pulls from channels comes from authorized developers. As a channel author, you need to specify the list of authorized developers in the .guix-authorizations file in the channel’s Git repository. The authentication rule is simple: each commit must be signed by a key listed in the .guix-authorizations file of its parent commit(s)13 The .guix-authorizations file looks like this:

;; Example '.guix-authorizations' file.

(authorizations
 (version 0)               ;current file format version

 (("AD17 A21E F8AE D8F1 CC02  DBD9 F8AE D8F1 765C 61E3"
   (name "alice"))
  ("2A39 3FFF 68F4 EF7A 3D29  12AF 68F4 EF7A 22FB B2D5"
   (name "bob"))
  ("CABB A931 C0FF EEC6 900D  0CFB 090B 1199 3D9A EBB5"
   (name "charlie"))))

Each fingerprint is followed by optional key/value pairs, as in the example above. Currently these key/value pairs are ignored.

This authentication rule creates a chicken-and-egg issue: how do we authenticate the first commit? Related to that: how do we deal with channels whose repository history contains unsigned commits and lack .guix-authorizations? And how do we fork existing channels?

Channel introductions answer these questions by describing the first commit of a channel that should be authenticated. The first time a channel is fetched with guix pull or guix time-machine, the command looks up the introductory commit and verifies that it is signed by the specified OpenPGP key. From then on, it authenticates commits according to the rule above. Authentication fails if the target commit is neither a descendant nor an ancestor of the introductory commit.

Additionally, your channel must provide all the OpenPGP keys that were ever mentioned in .guix-authorizations, stored as .key files, which can be either binary or “ASCII-armored”. By default, those .key files are searched for in the branch named keyring but you can specify a different branch name in .guix-channel like so:

(channel
  (version 0)
  (keyring-reference "my-keyring-branch"))

To summarize, as the author of a channel, there are three things you have to do to allow users to authenticate your code:

  1. Export the OpenPGP keys of past and present committers with gpg --export and store them in .key files, by default in a branch named keyring (we recommend making it an orphan branch).
  2. Introduce an initial .guix-authorizations in the channel’s repository. Do that in a signed commit (veja Confirmar acesso, for information on how to sign Git commits.)
  3. Advertise the channel introduction, for instance on your channel’s web page. The channel introduction, as we saw above, is the commit/key pair—i.e., the commit that introduced .guix-authorizations, and the fingerprint of the OpenPGP used to sign it.

Before pushing to your public Git repository, you can run guix git authenticate to verify that you did sign all the commits you are about to push with an authorized key:

guix git authenticate commit signer

where commit and signer are your channel introduction. Veja Invoking guix git authenticate, for details.

Publishing a signed channel requires discipline: any mistake, such as an unsigned commit or a commit signed by an unauthorized key, will prevent users from pulling from your channel—well, that’s the whole point of authentication! Pay attention to merges in particular: merge commits are considered authentic if and only if they are signed by a key present in the .guix-authorizations file of both branches.


6.11 Primary URL

Channel authors can indicate the primary URL of their channel’s Git repository in the .guix-channel file, like so:

(channel
  (version 0)
  (url "https://example.org/guix.git"))

This allows guix pull to determine whether it is pulling code from a mirror of the channel; when that is the case, it warns the user that the mirror might be stale and displays the primary URL. That way, users cannot be tricked into fetching code from a stale mirror that does not receive security updates.

This feature only makes sense for authenticated repositories, such as the official guix channel, for which guix pull ensures the code it fetches is authentic.


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6.12 Writing Channel News

Channel authors may occasionally want to communicate to their users information about important changes in the channel. You’d send them all an email, but that’s not convenient.

Instead, channels can provide a news file; when the channel users run guix pull, that news file is automatically read and guix pull --news can display the announcements that correspond to the new commits that have been pulled, if any.

To do that, channel authors must first declare the name of the news file in their .guix-channel file:

(channel
  (version 0)
  (news-file "etc/news.txt"))

The news file itself, etc/news.txt in this example, must look something like this:

(channel-news
  (version 0)
  (entry (tag "the-bug-fix")
         (title (en "Fixed terrible bug")
                (fr "Oh la la"))
         (body (en "@emph{Good news}!  It's fixed!")
               (eo "Certe ĝi pli bone funkcias nun!")))
  (entry (commit "bdcabe815cd28144a2d2b4bc3c5057b051fa9906")
         (title (en "Added a great package")
                (ca "Què vol dir guix?"))
         (body (en "Don't miss the @code{hello} package!"))))

While the news file is using the Scheme syntax, avoid naming it with a .scm extension or else it will get picked up when building the channel and yield an error since it is not a valid module. Alternatively, you can move the channel module to a subdirectory and store the news file in another directory.

The file consists of a list of news entries. Each entry is associated with a commit or tag: it describes changes made in this commit, possibly in preceding commits as well. Users see entries only the first time they obtain the commit the entry refers to.

The title field should be a one-line summary while body can be arbitrarily long, and both can contain Texinfo markup (veja Overview em GNU Texinfo). Both the title and body are a list of language tag/message tuples, which allows guix pull to display news in the language that corresponds to the user’s locale.

If you want to translate news using a gettext-based workflow, you can extract translatable strings with xgettext (veja xgettext Invocation em GNU Gettext Utilities). For example, assuming you write news entries in English first, the command below creates a PO file containing the strings to translate:

xgettext -o news.po -l scheme -ken etc/news.txt

To sum up, yes, you could use your channel as a blog. But beware, this is not quite what your users might expect.


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7 Desenvolvimento

If you are a software developer, Guix provides tools that you should find helpful—independently of the language you’re developing in. This is what this chapter is about.

The guix shell command provides a convenient way to set up one-off software environments, be it for development purposes or to run a command without installing it in your profile. The guix pack command allows you to create application bundles that can be easily distributed to users who do not run Guix.


7.1 Invoking guix shell

The purpose of guix shell is to make it easy to create one-off software environments, without changing one’s profile. It is typically used to create development environments; it is also a convenient way to run applications without “polluting” your profile.

Nota: The guix shell command was recently introduced to supersede guix environment (veja Invocando guix environment). If you are familiar with guix environment, you will notice that it is similar but also—we hope!—more convenient.

The general syntax is:

guix shell [options] [package…]

The following example creates an environment containing Python and NumPy, building or downloading any missing package, and runs the python3 command in that environment:

guix shell python python-numpy -- python3

Note that it is necessary to include the main python package in this command even if it is already installed into your environment. This is so that the shell environment knows to set PYTHONPATH and other related variables. The shell environment cannot check the previously installed environment, because then it would be non-deterministic. This is true for most libraries: their corresponding language package should be included in the shell invocation.

Nota: guix shell can be also be used as a script interpreter, also known as shebang. Here is an example self-contained Python script making use of this feature:

#!/usr/bin/env -S guix shell python python-numpy -- python3
import numpy
print("This is numpy", numpy.version.version)

You may pass any guix shell option, but there’s one caveat: the Linux kernel has a limit of 127 bytes on shebang length.

Development environments can be created as in the example below, which spawns an interactive shell containing all the dependencies and environment variables needed to work on Inkscape:

guix shell --development inkscape

Exiting the shell places the user back in the original environment before guix shell was invoked. The next garbage collection (veja Invocando guix gc) may clean up packages that were installed in the environment and that are no longer used outside of it.

As an added convenience, guix shell will try to do what you mean when it is invoked interactively without any other arguments as in:

guix shell

If it finds a manifest.scm in the current working directory or any of its parents, it uses this manifest as though it was given via --manifest. Likewise, if it finds a guix.scm in the same directories, it uses it to build a development profile as though both --development and --file were present. In either case, the file will only be loaded if the directory it resides in is listed in ~/.config/guix/shell-authorized-directories. This provides an easy way to define, share, and enter development environments.

By default, the shell session or command runs in an augmented environment, where the new packages are added to search path environment variables such as PATH. You can, instead, choose to create an isolated environment containing nothing but the packages you asked for. Passing the --pure option clears environment variable definitions found in the parent environment14; passing --container goes one step further by spawning a container isolated from the rest of the system:

guix shell --container emacs gcc-toolchain

The command above spawns an interactive shell in a container where nothing but emacs, gcc-toolchain, and their dependencies is available. The container lacks network access and shares no files other than the current working directory with the surrounding environment. This is useful to prevent access to system-wide resources such as /usr/bin on foreign distros.

This --container option can also prove useful if you wish to run a security-sensitive application, such as a web browser, in an isolated environment. For example, the command below launches Ungoogled-Chromium in an isolated environment, which:

  • shares network access with the host
  • inherits host’s environment variables DISPLAY and XAUTHORITY
  • has access to host’s authentication records from the XAUTHORITY file
  • has no information about host’s current directory
guix shell --container --network --no-cwd ungoogled-chromium \
  --preserve='^XAUTHORITY$' --expose="${XAUTHORITY}" \
  --preserve='^DISPLAY$' -- chromium

guix shell defines the GUIX_ENVIRONMENT variable in the shell it spawns; its value is the file name of the profile of this environment. This allows users to, say, define a specific prompt for development environments in their .bashrc (veja Bash Startup Files em The GNU Bash Reference Manual):

if [ -n "$GUIX_ENVIRONMENT" ]
then
    export PS1="\u@\h \w [dev]\$ "
fi

... or to browse the profile:

$ ls "$GUIX_ENVIRONMENT/bin"

The available options are summarized below.

--check

Set up the environment and check whether the shell would clobber environment variables. It’s a good idea to use this option the first time you run guix shell for an interactive session to make sure your setup is correct.

For example, if the shell modifies the PATH environment variable, report it since you would get a different environment than what you asked for.

Such problems usually indicate that the shell startup files are unexpectedly modifying those environment variables. For example, if you are using Bash, make sure that environment variables are set or modified in ~/.bash_profile and not in ~/.bashrc—the former is sourced only by log-in shells. Veja Bash Startup Files em The GNU Bash Reference Manual, for details on Bash start-up files.

--development
-D

Cause guix shell to include in the environment the dependencies of the following package rather than the package itself. This can be combined with other packages. For instance, the command below starts an interactive shell containing the build-time dependencies of GNU Guile, plus Autoconf, Automake, and Libtool:

guix shell -D guile autoconf automake libtool
--expression=expr
-e expr

Create an environment for the package or list of packages that expr evaluates to.

For example, running:

guix shell -D -e '(@ (gnu packages maths) petsc-openmpi)'

starts a shell with the environment for this specific variant of the PETSc package.

Running:

guix shell -e '(@ (gnu) %base-packages)'

starts a shell with all the base system packages available.

The above commands only use the default output of the given packages. To select other outputs, two element tuples can be specified:

guix shell -e '(list (@ (gnu packages bash) bash) "include")'

Veja package->development-manifest, for information on how to write a manifest for the development environment of a package.

--file=file
-f arquivo

Create an environment containing the package or list of packages that the code within file evaluates to.

As an example, file might contain a definition like this (veja Definindo pacotes):

(use-modules (guix)
             (gnu packages gdb)
             (gnu packages autotools)
             (gnu packages texinfo))

;; Augment the package definition of GDB with the build tools
;; needed when developing GDB (and which are not needed when
;; simply installing it.)
(package
  (inherit gdb)
  (native-inputs (modify-inputs (package-native-inputs gdb)
                   (prepend autoconf-2.69 automake texinfo))))

With the file above, you can enter a development environment for GDB by running:

guix shell -D -f gdb-devel.scm
--manifest=arquivo
-m arquivo

Create an environment for the packages contained in the manifest object returned by the Scheme code in file. This option can be repeated several times, in which case the manifests are concatenated.

This is similar to the same-named option in guix package (veja --manifest) and uses the same manifest files.

Veja Writing Manifests, for information on how to write a manifest. See --export-manifest below on how to obtain a first manifest.

--export-manifest

Write to standard output a manifest suitable for --manifest corresponding to given command-line options.

This is a way to “convert” command-line arguments into a manifest. For example, imagine you are tired of typing long lines and would like to get a manifest equivalent to this command line:

guix shell -D guile git emacs emacs-geiser emacs-geiser-guile

Just add --export-manifest to the command line above:

guix shell --export-manifest \
  -D guile git emacs emacs-geiser emacs-geiser-guile

... and you get a manifest along these lines:

(concatenate-manifests
  (list (specifications->manifest
          (list "git"
                "emacs"
                "emacs-geiser"
                "emacs-geiser-guile"))
        (package->development-manifest
          (specification->package "guile"))))

You can store it into a file, say manifest.scm, and from there pass it to guix shell or indeed pretty much any guix command:

guix shell -m manifest.scm

Voilà, you’ve converted a long command line into a manifest! That conversion process honors package transformation options (veja Opções de transformação de pacote) so it should be lossless.

--profile=perfil
-p perfil

Create an environment containing the packages installed in profile. Use guix package (veja Invocando guix package) to create and manage profiles.

--pure

Unset existing environment variables when building the new environment, except those specified with --preserve (see below). This has the effect of creating an environment in which search paths only contain package inputs.

--preserve=regexp
-E regexp

When used alongside --pure, preserve the environment variables matching regexp—in other words, put them on a “white list” of environment variables that must be preserved. This option can be repeated several times.

guix shell --pure --preserve=^SLURM openmpi … \
  -- mpirun …

This example runs mpirun in a context where the only environment variables defined are PATH, environment variables whose name starts with ‘SLURM’, as well as the usual “precious” variables (HOME, USER, etc.).

--search-paths

Display the environment variable definitions that make up the environment.

--system=system
-s sistema

Attempt to build for system—e.g., i686-linux.

--container
-C

Run command within an isolated container. The current working directory outside the container is mapped inside the container. Additionally, unless overridden with --user, a dummy home directory is created that matches the current user’s home directory, and /etc/passwd is configured accordingly.

The spawned process runs as the current user outside the container. Inside the container, it has the same UID and GID as the current user, unless --user is passed (see below).

--network
-N

For containers, share the network namespace with the host system. Containers created without this flag only have access to the loopback device.

--link-profile
-P

For containers, link the environment profile to ~/.guix-profile within the container and set GUIX_ENVIRONMENT to that. This is equivalent to making ~/.guix-profile a symlink to the actual profile within the container. Linking will fail and abort the environment if the directory already exists, which will certainly be the case if guix shell was invoked in the user’s home directory.

Certain packages are configured to look in ~/.guix-profile for configuration files and data;15 --link-profile allows these programs to behave as expected within the environment.

--user=user
-u usuário

For containers, use the username user in place of the current user. The generated /etc/passwd entry within the container will contain the name user, the home directory will be /home/user, and no user GECOS data will be copied. Furthermore, the UID and GID inside the container are 1000. user need not exist on the system.

Additionally, any shared or exposed path (see --share and --expose respectively) whose target is within the current user’s home directory will be remapped relative to /home/USER; this includes the automatic mapping of the current working directory.

# will expose paths as /home/foo/wd, /home/foo/test, and /home/foo/target
cd $HOME/wd
guix shell --container --user=foo \
     --expose=$HOME/test \
     --expose=/tmp/target=$HOME/target

While this will limit the leaking of user identity through home paths and each of the user fields, this is only one useful component of a broader privacy/anonymity solution—not one in and of itself.

--no-cwd

For containers, the default behavior is to share the current working directory with the isolated container and immediately change to that directory within the container. If this is undesirable, --no-cwd will cause the current working directory to not be automatically shared and will change to the user’s home directory within the container instead. See also --user.

--expose=fonte[=alvo]
--share=fonte[=alvo]

For containers, --expose (resp. --share) exposes the file system source from the host system as the read-only (resp. writable) file system target within the container. If target is not specified, source is used as the target mount point in the container.

The example below spawns a Guile REPL in a container in which the user’s home directory is accessible read-only via the /exchange directory:

guix shell --container --expose=$HOME=/exchange guile -- guile
--symlink=spec
-S spec

For containers, create the symbolic links specified by spec, as documented in pack-symlink-option.

--emulate-fhs
-F

When used with --container, emulate a Filesystem Hierarchy Standard (FHS) configuration within the container, providing /bin, /lib, and other directories and files specified by the FHS.

As Guix deviates from the FHS specification, this option sets up the container to more closely mimic that of other GNU/Linux distributions. This is useful for reproducing other development environments, testing, and using programs which expect the FHS specification to be followed. With this option, the container will include a version of glibc that will read /etc/ld.so.cache within the container for the shared library cache (contrary to glibc in regular Guix usage) and set up the expected FHS directories: /bin, /etc, /lib, and /usr from the container’s profile.

--nesting
-W

When used with --container, provide Guix inside the container and arrange so that it can interact with the build daemon that runs outside the container. This is useful if you want, within your isolated container, to create other containers, as in this sample session:

$ guix shell -CW coreutils
[env]$ guix shell -C guile -- guile -c '(display "hello!\n")'
hello!
[env]$ exit

The session above starts a container with coreutils programs available in PATH. From there, we spawn guix shell to create a nested container that provides nothing but Guile.

Another example is evaluating a guix.scm file that is untrusted, as shown here:

guix shell -CW -- guix build -f guix.scm

The guix build command as executed above can only access the current directory.

Under the hood, the -W option does several things:

  • mapeie o socket do daemon (por padrão, /var/guix/daemon-socket/socket) dentro do contêiner;
  • map the whole store (by default /gnu/store) inside the container such that store items made available by nested guix invocations are visible;
  • add the currently-used guix command to the profile in the container, such that guix describe returns the same state inside and outside the container;
  • share the cache (by default ~/.cache/guix) with the host, to speed up operations such as guix time-machine and guix shell.
--rebuild-cache

In most cases, guix shell caches the environment so that subsequent uses are instantaneous. Least-recently used cache entries are periodically removed. The cache is also invalidated, when using --file or --manifest, anytime the corresponding file is modified.

The --rebuild-cache forces the cached environment to be refreshed. This is useful when using --file or --manifest and the guix.scm or manifest.scm file has external dependencies, or if its behavior depends, say, on environment variables.

--root=arquivo
-r arquivo

Make file a symlink to the profile for this environment, and register it as a garbage collector root.

This is useful if you want to protect your environment from garbage collection, to make it “persistent”.

When this option is omitted, guix shell caches profiles so that subsequent uses of the same environment are instantaneous—this is comparable to using --root except that guix shell takes care of periodically removing the least-recently used garbage collector roots.

In some cases, guix shell does not cache profiles—e.g., if transformation options such as --with-latest are used. In those cases, the environment is protected from garbage collection only for the duration of the guix shell session. This means that next time you recreate the same environment, you could have to rebuild or re-download packages.

Veja Invocando guix gc, for more on GC roots.

guix shell also supports all of the common build options that guix build supports (veja Opções de compilação comum) as well as package transformation options (veja Opções de transformação de pacote).


7.2 Invocando guix environment

The purpose of guix environment is to assist in creating development environments.

Deprecation warning: The guix environment command is deprecated in favor of guix shell, which performs similar functions but is more convenient to use. Veja Invoking guix shell.

Being deprecated, guix environment is slated for eventual removal, but the Guix project is committed to keeping it until May 1st, 2023. Please get in touch with us at guix-devel@gnu.org if you would like to discuss it.

The general syntax is:

guix environment options package

The following example spawns a new shell set up for the development of GNU Guile:

guix environment guile

If the needed dependencies are not built yet, guix environment automatically builds them. The environment of the new shell is an augmented version of the environment that guix environment was run in. It contains the necessary search paths for building the given package added to the existing environment variables. To create a “pure” environment, in which the original environment variables have been unset, use the --pure option16.

Exiting from a Guix environment is the same as exiting from the shell, and will place the user back in the old environment before guix environment was invoked. The next garbage collection (veja Invocando guix gc) will clean up packages that were installed from within the environment and are no longer used outside of it.

guix environment defines the GUIX_ENVIRONMENT variable in the shell it spawns; its value is the file name of the profile of this environment. This allows users to, say, define a specific prompt for development environments in their .bashrc (veja Bash Startup Files em The GNU Bash Reference Manual):

if [ -n "$GUIX_ENVIRONMENT" ]
then
    export PS1="\u@\h \w [dev]\$ "
fi

... or to browse the profile:

$ ls "$GUIX_ENVIRONMENT/bin"

Additionally, more than one package may be specified, in which case the union of the inputs for the given packages are used. For example, the command below spawns a shell where all of the dependencies of both Guile and Emacs are available:

guix environment guile emacs

Sometimes an interactive shell session is not desired. An arbitrary command may be invoked by placing the -- token to separate the command from the rest of the arguments:

guix environment guile -- make -j4

In other situations, it is more convenient to specify the list of packages needed in the environment. For example, the following command runs python from an environment containing Python 3 and NumPy:

guix environment --ad-hoc python-numpy python -- python3

Furthermore, one might want the dependencies of a package and also some additional packages that are not build-time or runtime dependencies, but are useful when developing nonetheless. Because of this, the --ad-hoc flag is positional. Packages appearing before --ad-hoc are interpreted as packages whose dependencies will be added to the environment. Packages appearing after are interpreted as packages that will be added to the environment directly. For example, the following command creates a Guix development environment that additionally includes Git and strace:

guix environment --pure guix --ad-hoc git strace

Sometimes it is desirable to isolate the environment as much as possible, for maximal purity and reproducibility. In particular, when using Guix on a host distro that is not Guix System, it is desirable to prevent access to /usr/bin and other system-wide resources from the development environment. For example, the following command spawns a Guile REPL in a “container” where only the store and the current working directory are mounted:

guix environment --ad-hoc --container guile -- guile

Nota: The --container option requires Linux-libre 3.19 or newer.

Another typical use case for containers is to run security-sensitive applications such as a web browser. To run Eolie, we must expose and share some files and directories; we include nss-certs and expose /etc/ssl/certs/ for HTTPS authentication; finally we preserve the DISPLAY environment variable since containerized graphical applications won’t display without it.

guix environment --preserve='^DISPLAY$' --container --network \
  --expose=/etc/machine-id \
  --expose=/etc/ssl/certs/ \
  --share=$HOME/.local/share/eolie/=$HOME/.local/share/eolie/ \
  --ad-hoc eolie nss-certs dbus --  eolie

The available options are summarized below.

--check

Set up the environment and check whether the shell would clobber environment variables. Veja --check, for more info.

--root=arquivo
-r arquivo

Make file a symlink to the profile for this environment, and register it as a garbage collector root.

This is useful if you want to protect your environment from garbage collection, to make it “persistent”.

When this option is omitted, the environment is protected from garbage collection only for the duration of the guix environment session. This means that next time you recreate the same environment, you could have to rebuild or re-download packages. Veja Invocando guix gc, for more on GC roots.

--expression=expr
-e expr

Create an environment for the package or list of packages that expr evaluates to.

For example, running:

guix environment -e '(@ (gnu packages maths) petsc-openmpi)'

starts a shell with the environment for this specific variant of the PETSc package.

Running:

guix environment --ad-hoc -e '(@ (gnu) %base-packages)'

starts a shell with all the base system packages available.

The above commands only use the default output of the given packages. To select other outputs, two element tuples can be specified:

guix environment --ad-hoc -e '(list (@ (gnu packages bash) bash) "include")'
--load=arquivo
-l arquivo

Create an environment for the package or list of packages that the code within file evaluates to.

As an example, file might contain a definition like this (veja Definindo pacotes):

(use-modules (guix)
             (gnu packages gdb)
             (gnu packages autotools)
             (gnu packages texinfo))

;; Augment the package definition of GDB with the build tools
;; needed when developing GDB (and which are not needed when
;; simply installing it.)
(package
  (inherit gdb)
  (native-inputs (modify-inputs (package-native-inputs gdb)
                   (prepend autoconf-2.69 automake texinfo))))
--manifest=arquivo
-m arquivo

Create an environment for the packages contained in the manifest object returned by the Scheme code in file. This option can be repeated several times, in which case the manifests are concatenated.

This is similar to the same-named option in guix package (veja --manifest) and uses the same manifest files.

Veja guix shell --export-manifest, for information on how to “convert” command-line options into a manifest.

--ad-hoc

Include all specified packages in the resulting environment, as if an ad hoc package were defined with them as inputs. This option is useful for quickly creating an environment without having to write a package expression to contain the desired inputs.

For instance, the command:

guix environment --ad-hoc guile guile-sdl -- guile

runs guile in an environment where Guile and Guile-SDL are available.

Note that this example implicitly asks for the default output of guile and guile-sdl, but it is possible to ask for a specific output—e.g., glib:bin asks for the bin output of glib (veja Pacotes com múltiplas saídas).

This option may be composed with the default behavior of guix environment. Packages appearing before --ad-hoc are interpreted as packages whose dependencies will be added to the environment, the default behavior. Packages appearing after are interpreted as packages that will be added to the environment directly.

--profile=perfil
-p perfil

Create an environment containing the packages installed in profile. Use guix package (veja Invocando guix package) to create and manage profiles.

--pure

Unset existing environment variables when building the new environment, except those specified with --preserve (see below). This has the effect of creating an environment in which search paths only contain package inputs.

--preserve=regexp
-E regexp

When used alongside --pure, preserve the environment variables matching regexp—in other words, put them on a “white list” of environment variables that must be preserved. This option can be repeated several times.

guix environment --pure --preserve=^SLURM --ad-hoc openmpi … \
  -- mpirun …

This example runs mpirun in a context where the only environment variables defined are PATH, environment variables whose name starts with ‘SLURM’, as well as the usual “precious” variables (HOME, USER, etc.).

--search-paths

Display the environment variable definitions that make up the environment.

--system=system
-s sistema

Attempt to build for system—e.g., i686-linux.

--container
-C

Run command within an isolated container. The current working directory outside the container is mapped inside the container. Additionally, unless overridden with --user, a dummy home directory is created that matches the current user’s home directory, and /etc/passwd is configured accordingly.

The spawned process runs as the current user outside the container. Inside the container, it has the same UID and GID as the current user, unless --user is passed (see below).

--network
-N

For containers, share the network namespace with the host system. Containers created without this flag only have access to the loopback device.

--link-profile
-P

For containers, link the environment profile to ~/.guix-profile within the container and set GUIX_ENVIRONMENT to that. This is equivalent to making ~/.guix-profile a symlink to the actual profile within the container. Linking will fail and abort the environment if the directory already exists, which will certainly be the case if guix environment was invoked in the user’s home directory.

Certain packages are configured to look in ~/.guix-profile for configuration files and data;17 --link-profile allows these programs to behave as expected within the environment.

--user=user
-u usuário

For containers, use the username user in place of the current user. The generated /etc/passwd entry within the container will contain the name user, the home directory will be /home/user, and no user GECOS data will be copied. Furthermore, the UID and GID inside the container are 1000. user need not exist on the system.

Additionally, any shared or exposed path (see --share and --expose respectively) whose target is within the current user’s home directory will be remapped relative to /home/USER; this includes the automatic mapping of the current working directory.

# will expose paths as /home/foo/wd, /home/foo/test, and /home/foo/target
cd $HOME/wd
guix environment --container --user=foo \
     --expose=$HOME/test \
     --expose=/tmp/target=$HOME/target

While this will limit the leaking of user identity through home paths and each of the user fields, this is only one useful component of a broader privacy/anonymity solution—not one in and of itself.

--no-cwd

For containers, the default behavior is to share the current working directory with the isolated container and immediately change to that directory within the container. If this is undesirable, --no-cwd will cause the current working directory to not be automatically shared and will change to the user’s home directory within the container instead. See also --user.

--expose=fonte[=alvo]
--share=fonte[=alvo]

For containers, --expose (resp. --share) exposes the file system source from the host system as the read-only (resp. writable) file system target within the container. If target is not specified, source is used as the target mount point in the container.

The example below spawns a Guile REPL in a container in which the user’s home directory is accessible read-only via the /exchange directory:

guix environment --container --expose=$HOME=/exchange --ad-hoc guile -- guile
--emulate-fhs
-F

For containers, emulate a Filesystem Hierarchy Standard (FHS) configuration within the container, see the official specification. As Guix deviates from the FHS specification, this option sets up the container to more closely mimic that of other GNU/Linux distributions. This is useful for reproducing other development environments, testing, and using programs which expect the FHS specification to be followed. With this option, the container will include a version of glibc which will read /etc/ld.so.cache within the container for the shared library cache (contrary to glibc in regular Guix usage) and set up the expected FHS directories: /bin, /etc, /lib, and /usr from the container’s profile.

guix environment also supports all of the common build options that guix build supports (veja Opções de compilação comum) as well as package transformation options (veja Opções de transformação de pacote).


7.3 Invocando guix pack

Occasionally you want to pass software to people who are not (yet!) lucky enough to be using Guix. You’d tell them to run guix package -i something, but that’s not possible in this case. This is where guix pack comes in.

Nota: If you are looking for ways to exchange binaries among machines that already run Guix, veja Invocando guix copy, Invocando guix publish, and Invocando guix archive.

The guix pack command creates a shrink-wrapped pack or software bundle: it creates a tarball or some other archive containing the binaries of the software you’re interested in, and all its dependencies. The resulting archive can be used on any machine that does not have Guix, and people can run the exact same binaries as those you have with Guix. The pack itself is created in a bit-reproducible fashion, so anyone can verify that it really contains the build results that you pretend to be shipping.

For example, to create a bundle containing Guile, Emacs, Geiser, and all their dependencies, you can run:

$ guix pack guile emacs emacs-geiser
…
/gnu/store/…-pack.tar.gz

The result here is a tarball containing a /gnu/store directory with all the relevant packages. The resulting tarball contains a profile with the three packages of interest; the profile is the same as would be created by guix package -i. It is this mechanism that is used to create Guix’s own standalone binary tarball (veja Instalação de binários).

Users of this pack would have to run /gnu/store/…-profile/bin/guile to run Guile, which you may find inconvenient. To work around it, you can create, say, a /opt/gnu/bin symlink to the profile:

guix pack -S /opt/gnu/bin=bin guile emacs emacs-geiser

That way, users can happily type /opt/gnu/bin/guile and enjoy.

What if the recipient of your pack does not have root privileges on their machine, and thus cannot unpack it in the root file system? In that case, you will want to use the --relocatable option (see below). This option produces relocatable binaries, meaning they can be placed anywhere in the file system hierarchy: in the example above, users can unpack your tarball in their home directory and directly run ./opt/gnu/bin/guile.

Alternatively, you can produce a pack in the Docker image format using the following command:

guix pack -f docker -S /bin=bin guile guile-readline

The result is a tarball that can be passed to the docker load command, followed by docker run:

docker load < file
docker run -ti guile-guile-readline /bin/guile

where file is the image returned by guix pack, and guile-guile-readline is its “image tag”. See the Docker documentation for more information.

Yet another option is to produce a SquashFS image with the following command:

guix pack -f squashfs bash guile emacs emacs-geiser

The result is a SquashFS file system image that can either be mounted or directly be used as a file system container image with the Singularity container execution environment, using commands like singularity shell or singularity exec.

Several command-line options allow you to customize your pack:

--format=format
-f format

Produce a pack in the given format.

The available formats are:

tarball

This is the default format. It produces a tarball containing all the specified binaries and symlinks.

docker

This produces a tarball that follows the Docker Image Specification. By default, the “repository name” as it appears in the output of the docker images command is computed from package names passed on the command line or in the manifest file. Alternatively, the “repository name” can also be configured via the --image-tag option. Refer to --help-docker-format for more information on such advanced options.

squashfs

This produces a SquashFS image containing all the specified binaries and symlinks, as well as empty mount points for virtual file systems like procfs.

Nota: Singularity requires you to provide /bin/sh in the image. For that reason, guix pack -f squashfs always implies -S /bin=bin. Thus, your guix pack invocation must always start with something like:

guix pack -f squashfs bash …

If you forget the bash (or similar) package, singularity run and singularity exec will fail with an unhelpful “no such file or directory” message.

deb

This produces a Debian archive (a package with the ‘.deb’ file extension) containing all the specified binaries and symbolic links, that can be installed on top of any dpkg-based GNU(/Linux) distribution. Advanced options can be revealed via the --help-deb-format option. They allow embedding control files for more fine-grained control, such as activating specific triggers or providing a maintainer configure script to run arbitrary setup code upon installation.

guix pack -f deb -C xz -S /usr/bin/hello=bin/hello hello

Nota: Because archives produced with guix pack contain a collection of store items and because each dpkg package must not have conflicting files, in practice that means you likely won’t be able to install more than one such archive on a given system. You can nonetheless pack as many Guix packages as you want in one such archive.

Aviso: dpkg will assume ownership of any files contained in the pack that it does not know about. It is unwise to install Guix-produced ‘.deb’ files on a system where /gnu/store is shared by other software, such as a Guix installation or other, non-deb packs.

rpm

This produces an RPM archive (a package with the ‘.rpm’ file extension) containing all the specified binaries and symbolic links, that can be installed on top of any RPM-based GNU/Linux distribution. The RPM format embeds checksums for every file it contains, which the rpm command uses to validate the integrity of the archive.

Advanced RPM-related options are revealed via the --help-rpm-format option. These options allow embedding maintainer scripts that can run before or after the installation of the RPM archive, for example.

The RPM format supports relocatable packages via the --prefix option of the rpm command, which can be handy to install an RPM package to a specific prefix.

guix pack -f rpm -R -C xz -S /usr/bin/hello=bin/hello hello
sudo rpm --install --prefix=/opt /gnu/store/...-hello.rpm

Nota: Contrary to Debian packages, conflicting but identical files in RPM packages can be installed simultaneously, which means multiple guix pack-produced RPM packages can usually be installed side by side without any problem.

Aviso: rpm assumes ownership of any files contained in the pack, which means it will remove /gnu/store upon uninstalling a Guix-generated RPM package, unless the RPM package was installed with the --prefix option of the rpm command. It is unwise to install Guix-produced ‘.rpm’ packages on a system where /gnu/store is shared by other software, such as a Guix installation or other, non-rpm packs.

--relocatable
-R

Produce relocatable binaries—i.e., binaries that can be placed anywhere in the file system hierarchy and run from there.

When this option is passed once, the resulting binaries require support for user namespaces in the kernel Linux; when passed twice18, relocatable binaries fall to back to other techniques if user namespaces are unavailable, and essentially work anywhere—see below for the implications.

For example, if you create a pack containing Bash with:

guix pack -RR -S /mybin=bin bash

... you can copy that pack to a machine that lacks Guix, and from your home directory as a normal user, run:

tar xf pack.tar.gz
./mybin/sh

In that shell, if you type ls /gnu/store, you’ll notice that /gnu/store shows up and contains all the dependencies of bash, even though the machine actually lacks /gnu/store altogether! That is probably the simplest way to deploy Guix-built software on a non-Guix machine.

Nota: By default, relocatable binaries rely on the user namespace feature of the kernel Linux, which allows unprivileged users to mount or change root. Old versions of Linux did not support it, and some GNU/Linux distributions turn it off.

To produce relocatable binaries that work even in the absence of user namespaces, pass --relocatable or -R twice. In that case, binaries will try user namespace support and fall back to another execution engine if user namespaces are not supported. The following execution engines are supported:

default

Try user namespaces and fall back to PRoot if user namespaces are not supported (see below).

performance

Try user namespaces and fall back to Fakechroot if user namespaces are not supported (see below).

userns

Run the program through user namespaces and abort if they are not supported.

proot

Run through PRoot. The PRoot program provides the necessary support for file system virtualization. It achieves that by using the ptrace system call on the running program. This approach has the advantage to work without requiring special kernel support, but it incurs run-time overhead every time a system call is made.

fakechroot

Run through Fakechroot. Fakechroot virtualizes file system accesses by intercepting calls to C library functions such as open, stat, exec, and so on. Unlike PRoot, it incurs very little overhead. However, it does not always work: for example, some file system accesses made from within the C library are not intercepted, and file system accesses made via direct syscalls are not intercepted either, leading to erratic behavior.

When running a wrapped program, you can explicitly request one of the execution engines listed above by setting the GUIX_EXECUTION_ENGINE environment variable accordingly.

--entry-point=command

Use command as the entry point of the resulting pack, if the pack format supports it—currently docker and squashfs (Singularity) support it. command must be relative to the profile contained in the pack.

The entry point specifies the command that tools like docker run or singularity run automatically start by default. For example, you can do:

guix pack -f docker --entry-point=bin/guile guile

The resulting pack can easily be loaded and docker run with no extra arguments will spawn bin/guile:

docker load -i pack.tar.gz
docker run image-id
--entry-point-argument=command
-A command

Use command as an argument to entry point of the resulting pack. This option is only valid in conjunction with --entry-point and can appear multiple times on the command line.

guix pack -f docker --entry-point=bin/guile --entry-point-argument="--help" guile
--max-layers=n

Specifies the maximum number of Docker image layers allowed when building an image.

guix pack -f docker --max-layers=100 guile

This option allows you to limit the number of layers in a Docker image. Docker images are comprised of multiple layers, and each layer adds to the overall size and complexity of the image. By setting a maximum number of layers, you can control the following effects:

  • Disk Usage: Increasing the number of layers can help optimize the disk space required to store multiple images built with a similar package graph.
  • Pulling: When transferring images between different nodes or systems, having more layers can reduce the time required to pull the image.
--expression=expr
-e expr

Consider the package expr evaluates to.

This has the same purpose as the same-named option in guix build (veja --expression in guix build).

--manifest=arquivo
-m arquivo

Use the packages contained in the manifest object returned by the Scheme code in file. This option can be repeated several times, in which case the manifests are concatenated.

This has a similar purpose as the same-named option in guix package (veja --manifest) and uses the same manifest files. It allows you to define a collection of packages once and use it both for creating profiles and for creating archives for use on machines that do not have Guix installed. Note that you can specify either a manifest file or a list of packages, but not both.

Veja Writing Manifests, for information on how to write a manifest. Veja guix shell --export-manifest, for information on how to “convert” command-line options into a manifest.

--system=system
-s sistema

Attempt to build for system—e.g., i686-linux—instead of the system type of the build host.

--target=triplet

Cross-build for triplet, which must be a valid GNU triplet, such as "aarch64-linux-gnu" (veja GNU configuration triplets em Autoconf).

--compression=tool
-C tool

Compress the resulting tarball using tool—one of gzip, zstd, bzip2, xz, lzip, or none for no compression.

--symlink=spec
-S spec

Add the symlinks specified by spec to the pack. This option can appear several times.

spec has the form source=target, where source is the symlink that will be created and target is the symlink target.

For instance, -S /opt/gnu/bin=bin creates a /opt/gnu/bin symlink pointing to the bin sub-directory of the profile.

--save-provenance

Save provenance information for the packages passed on the command line. Provenance information includes the URL and commit of the channels in use (veja Canais).

Provenance information is saved in the /gnu/store/…-profile/manifest file in the pack, along with the usual package metadata—the name and version of each package, their propagated inputs, and so on. It is useful information to the recipient of the pack, who then knows how the pack was (supposedly) obtained.

This option is not enabled by default because, like timestamps, provenance information contributes nothing to the build process. In other words, there is an infinity of channel URLs and commit IDs that can lead to the same pack. Recording such “silent” metadata in the output thus potentially breaks the source-to-binary bitwise reproducibility property.

--root=arquivo
-r arquivo

Make file a symlink to the resulting pack, and register it as a garbage collector root.

--localstatedir
--profile-name=name

Include the “local state directory”, /var/guix, in the resulting pack, and notably the /var/guix/profiles/per-user/root/name profile—by default name is guix-profile, which corresponds to ~root/.guix-profile.

/var/guix contains the store database (veja O armazém) as well as garbage-collector roots (veja Invocando guix gc). Providing it in the pack means that the store is “complete” and manageable by Guix; not providing it pack means that the store is “dead”: items cannot be added to it or removed from it after extraction of the pack.

One use case for this is the Guix self-contained binary tarball (veja Instalação de binários).

--derivation
-d

Print the name of the derivation that builds the pack.

--bootstrap

Use the bootstrap binaries to build the pack. This option is only useful to Guix developers.

In addition, guix pack supports all the common build options (veja Opções de compilação comum) and all the package transformation options (veja Opções de transformação de pacote).


7.4 The GCC toolchain

If you need a complete toolchain for compiling and linking C or C++ source code, use the gcc-toolchain package. This package provides a complete GCC toolchain for C/C++ development, including GCC itself, the GNU C Library (headers and binaries, plus debugging symbols in the debug output), Binutils, and a linker wrapper.

The wrapper’s purpose is to inspect the -L and -l switches passed to the linker, add corresponding -rpath arguments, and invoke the actual linker with this new set of arguments. You can instruct the wrapper to refuse to link against libraries not in the store by setting the GUIX_LD_WRAPPER_ALLOW_IMPURITIES environment variable to no.

The package gfortran-toolchain provides a complete GCC toolchain for Fortran development. For other languages, please use ‘guix search gcc toolchain’ (veja Invoking guix package).


7.5 Invoking guix git authenticate

The guix git authenticate command authenticates a Git checkout following the same rule as for channels (veja channel authentication). That is, starting from a given commit, it ensures that all subsequent commits are signed by an OpenPGP key whose fingerprint appears in the .guix-authorizations file of its parent commit(s).

You will find this command useful if you maintain a channel. But in fact, this authentication mechanism is useful in a broader context, so you might want to use it for Git repositories that have nothing to do with Guix.

The general syntax is:

guix git authenticate commit signer [options…]

By default, this command authenticates the Git checkout in the current directory; it outputs nothing and exits with exit code zero on success and non-zero on failure. commit above denotes the first commit where authentication takes place, and signer is the OpenPGP fingerprint of public key used to sign commit. Together, they form a channel introduction (veja channel introduction). On your first successful run, the introduction is recorded in the .git/config file of your checkout, allowing you to omit them from subsequent invocations:

guix git authenticate [options…]

Should you have branches that require different introductions, you can specify them directly in .git/config. For example, if the branch called personal-fork has a different introduction than other branches, you can extend .git/config along these lines:

[guix "authentication-personal-fork"]
	introduction-commit = cabba936fd807b096b48283debdcddccfea3900d
	introduction-signer = C0FF EECA BBA9 E6A8 0D1D  E643 A2A0 6DF2 A33A 54FA
	keyring = keyring

The first run also attempts to install pre-push and post-merge hooks, such that guix git authenticate is invoked as soon as you run git push, git pull, and related commands; it does not overwrite preexisting hooks though.

The command-line options described below allow you to fine-tune the process.

--repository=directory
-r directory

Open the Git repository in directory instead of the current directory.

--keyring=reference
-k reference

Load OpenPGP keyring from reference, the reference of a branch such as origin/keyring or my-keyring. The branch must contain OpenPGP public keys in .key files, either in binary form or “ASCII-armored”. By default the keyring is loaded from the branch named keyring.

--end=commit

Authenticate revisions up to commit.

--stats

Display commit signing statistics upon completion.

--cache-key=key

Previously-authenticated commits are cached in a file under ~/.cache/guix/authentication. This option forces the cache to be stored in file key in that directory.

--historical-authorizations=file

By default, any commit whose parent commit(s) lack the .guix-authorizations file is considered inauthentic. In contrast, this option considers the authorizations in file for any commit that lacks .guix-authorizations. The format of file is the same as that of .guix-authorizations (veja .guix-authorizations format).


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8 Interface de programação

GNU Guix provides several Scheme programming interfaces (APIs) to define, build, and query packages. The first interface allows users to write high-level package definitions. These definitions refer to familiar packaging concepts, such as the name and version of a package, its build system, and its dependencies. These definitions can then be turned into concrete build actions.

Build actions are performed by the Guix daemon, on behalf of users. In a standard setup, the daemon has write access to the store—the /gnu/store directory—whereas users do not. The recommended setup also has the daemon perform builds in chroots, under specific build users, to minimize interference with the rest of the system.

Lower-level APIs are available to interact with the daemon and the store. To instruct the daemon to perform a build action, users actually provide it with a derivation. A derivation is a low-level representation of the build actions to be taken, and the environment in which they should occur—derivations are to package definitions what assembly is to C programs. The term “derivation” comes from the fact that build results derive from them.

This chapter describes all these APIs in turn, starting from high-level package definitions. Veja Source Tree Structure, for a more general overview of the source code.


8.1 Módulos de pacote

From a programming viewpoint, the package definitions of the GNU distribution are provided by Guile modules in the (gnu packages …) name space19 (veja Guile modules em GNU Guile Reference Manual). For instance, the (gnu packages emacs) module exports a variable named emacs, which is bound to a <package> object (veja Definindo pacotes).

The (gnu packages …) module name space is automatically scanned for packages by the command-line tools. For instance, when running guix install emacs, all the (gnu packages …) modules are scanned until one that exports a package object whose name is emacs is found. This package search facility is implemented in the (gnu packages) module.

Users can store package definitions in modules with different names—e.g., (my-packages emacs)20. There are two ways to make these package definitions visible to the user interfaces:

  1. By adding the directory containing your package modules to the search path with the -L flag of guix package and other commands (veja Opções de compilação comum), or by setting the GUIX_PACKAGE_PATH environment variable described below.
  2. By defining a channel and configuring guix pull so that it pulls from it. A channel is essentially a Git repository containing package modules. Veja Canais, for more information on how to define and use channels.

GUIX_PACKAGE_PATH works similarly to other search path variables:

Environment Variable: GUIX_PACKAGE_PATH

This is a colon-separated list of directories to search for additional package modules. Directories listed in this variable take precedence over the own modules of the distribution.

The distribution is fully bootstrapped and self-contained: each package is built based solely on other packages in the distribution. The root of this dependency graph is a small set of bootstrap binaries, provided by the (gnu packages bootstrap) module. For more information on bootstrapping, veja Inicializando.


8.2 Definindo pacotes

The high-level interface to package definitions is implemented in the (guix packages) and (guix build-system) modules. As an example, the package definition, or recipe, for the GNU Hello package looks like this:

(define-module (gnu packages hello)
  #:use-module (guix packages)
  #:use-module (guix download)
  #:use-module (guix build-system gnu)
  #:use-module (guix licenses)
  #:use-module (gnu packages gawk))

(define-public hello
  (package
    (name "hello")
    (version "2.10")
    (source (origin
              (method url-fetch)
              (uri (string-append "mirror://gnu/hello/hello-" version
                                  ".tar.gz"))
              (sha256
               (base32
                "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i"))))
    (build-system gnu-build-system)
    (arguments '(#:configure-flags '("--enable-silent-rules")))
    (inputs (list gawk))
    (synopsis "Hello, GNU world: An example GNU package")
    (description "Guess what GNU Hello prints!")
    (home-page "https://www.gnu.org/software/hello/")
    (license gpl3+)))

Without being a Scheme expert, the reader may have guessed the meaning of the various fields here. This expression binds the variable hello to a <package> object, which is essentially a record (veja Scheme records em GNU Guile Reference Manual). This package object can be inspected using procedures found in the (guix packages) module; for instance, (package-name hello) returns—surprise!—"hello".

With luck, you may be able to import part or all of the definition of the package you are interested in from another repository, using the guix import command (veja Invoking guix import).

In the example above, hello is defined in a module of its own, (gnu packages hello). Technically, this is not strictly necessary, but it is convenient to do so: all the packages defined in modules under (gnu packages …) are automatically known to the command-line tools (veja Módulos de pacote).

There are a few points worth noting in the above package definition:

  • The source field of the package is an <origin> object (veja origin Reference, for the complete reference). Here, the url-fetch method from (guix download) is used, meaning that the source is a file to be downloaded over FTP or HTTP.

    The mirror://gnu prefix instructs url-fetch to use one of the GNU mirrors defined in (guix download).

    The sha256 field specifies the expected SHA256 hash of the file being downloaded. It is mandatory, and allows Guix to check the integrity of the file. The (base32 …) form introduces the base32 representation of the hash. You can obtain this information with guix download (veja Invocando guix download) and guix hash (veja Invocando guix hash).

    When needed, the origin form can also have a patches field listing patches to be applied, and a snippet field giving a Scheme expression to modify the source code.

  • The build-system field specifies the procedure to build the package (veja Sistemas de compilação). Here, gnu-build-system represents the familiar GNU Build System, where packages may be configured, built, and installed with the usual ./configure && make && make check && make install command sequence.

    When you start packaging non-trivial software, you may need tools to manipulate those build phases, manipulate files, and so on. Veja Build Utilities, for more on this.

  • The arguments field specifies options for the build system (veja Sistemas de compilação). Here it is interpreted by gnu-build-system as a request run configure with the --enable-silent-rules flag.

    What about these quote (') characters? They are Scheme syntax to introduce a literal list; ' is synonymous with quote. Sometimes you’ll also see ` (a backquote, synonymous with quasiquote) and , (a comma, synonymous with unquote). Veja quoting em GNU Guile Reference Manual, for details. Here the value of the arguments field is a list of arguments passed to the build system down the road, as with apply (veja apply em GNU Guile Reference Manual).

    The hash-colon (#:) sequence defines a Scheme keyword (veja Keywords em GNU Guile Reference Manual), and #:configure-flags is a keyword used to pass a keyword argument to the build system (veja Coding With Keywords em GNU Guile Reference Manual).

  • The inputs field specifies inputs to the build process—i.e., build-time or run-time dependencies of the package. Here, we add an input, a reference to the gawk variable; gawk is itself bound to a <package> object.

    Note that GCC, Coreutils, Bash, and other essential tools do not need to be specified as inputs here. Instead, gnu-build-system takes care of ensuring that they are present (veja Sistemas de compilação).

    However, any other dependencies need to be specified in the inputs field. Any dependency not specified here will simply be unavailable to the build process, possibly leading to a build failure.

Veja package Reference, for a full description of possible fields.

Indo além: Intimidated by the Scheme language or curious about it? The Cookbook has a short section to get started that recaps some of the things shown above and explains the fundamentals. Veja A Scheme Crash Course em GNU Guix Cookbook, for more information.

Once a package definition is in place, the package may actually be built using the guix build command-line tool (veja Invocando guix build), troubleshooting any build failures you encounter (veja Depurando falhas de compilação). You can easily jump back to the package definition using the guix edit command (veja Invocando guix edit). Veja Diretrizes de empacotamento, for more information on how to test package definitions, and Invocando guix lint, for information on how to check a definition for style conformance. Lastly, veja Canais, for information on how to extend the distribution by adding your own package definitions in a “channel”.

Finally, updating the package definition to a new upstream version can be partly automated by the guix refresh command (veja Invocando guix refresh).

Behind the scenes, a derivation corresponding to the <package> object is first computed by the package-derivation procedure. That derivation is stored in a .drv file under /gnu/store. The build actions it prescribes may then be realized by using the build-derivations procedure (veja O armazém).

Procedure: package-derivation store package [system]

Return the <derivation> object of package for system (veja Derivações).

package must be a valid <package> object, and system must be a string denoting the target system type—e.g., "x86_64-linux" for an x86_64 Linux-based GNU system. store must be a connection to the daemon, which operates on the store (veja O armazém).

Similarly, it is possible to compute a derivation that cross-builds a package for some other system:

Procedure: package-cross-derivation store package target [system]

Return the <derivation> object of package cross-built from system to target.

target must be a valid GNU triplet denoting the target hardware and operating system, such as "aarch64-linux-gnu" (veja Specifying Target Triplets em Autoconf).

Once you have package definitions, you can easily define variants of those packages. Veja Defining Package Variants, for more on that.


8.2.1 package Reference

This section summarizes all the options available in package declarations (veja Definindo pacotes).

Data Type: package

This is the data type representing a package recipe.

name

The name of the package, as a string.

version

The version of the package, as a string. Veja Números de versão, for guidelines.

source

An object telling how the source code for the package should be acquired. Most of the time, this is an origin object, which denotes a file fetched from the Internet (veja origin Reference). It can also be any other “file-like” object such as a local-file, which denotes a file from the local file system (veja local-file).

build-system

The build system that should be used to build the package (veja Sistemas de compilação).

arguments (default: '())

The arguments that should be passed to the build system (veja Sistemas de compilação). This is a list, typically containing sequential keyword-value pairs, as in this example:

(package
  (name "example")
  ;; several fields omitted
  (arguments
    (list #:tests? #f                     ;skip tests
          #:make-flags #~'("VERBOSE=1")   ;pass flags to 'make'
          #:configure-flags #~'("--enable-frobbing"))))

The exact set of supported keywords depends on the build system (veja Sistemas de compilação), but you will find that almost all of them honor #:configure-flags, #:make-flags, #:tests?, and #:phases. The #:phases keyword in particular lets you modify the set of build phases for your package (veja Build Phases).

The REPL has dedicated commands to interactively inspect values of some of these arguments, as a convenient debugging aid (veja Using Guix Interactively).

Compatibility Note: Until version 1.3.0, the arguments field would typically use quote (') or quasiquote (`) and no G-expressions, like so:

(package
  ;; several fields omitted
  (arguments   ;old-style quoted arguments
   '(#:tests? #f
     #:configure-flags '("--enable-frobbing"))))

To convert from that style to the one shown above, you can run guix style -S arguments package (veja Invoking guix style).

inputs (default: '())
native-inputs (default: '())
propagated-inputs (default: '())

These fields list dependencies of the package. Each element of these lists is either a package, origin, or other “file-like object” (veja Expressões-G); to specify the output of that file-like object that should be used, pass a two-element list where the second element is the output (veja Pacotes com múltiplas saídas, for more on package outputs). For example, the list below specifies three inputs:

(list libffi libunistring
      `(,glib "bin"))      ;the "bin" output of GLib

In the example above, the "out" output of libffi and libunistring is used.

Compatibility Note: Until version 1.3.0, input lists were a list of tuples, where each tuple has a label for the input (a string) as its first element, a package, origin, or derivation as its second element, and optionally the name of the output thereof that should be used, which defaults to "out". For example, the list below is equivalent to the one above, but using the old input style:

;; Old input style (deprecated).
`(("libffi" ,libffi)
  ("libunistring" ,libunistring)
  ("glib:bin" ,glib "bin"))  ;the "bin" output of GLib

This style is now deprecated; it is still supported but support will be removed in a future version. It should not be used for new package definitions. Veja Invoking guix style, on how to migrate to the new style.

The distinction between native-inputs and inputs is necessary when considering cross-compilation. When cross-compiling, dependencies listed in inputs are built for the target architecture; conversely, dependencies listed in native-inputs are built for the architecture of the build machine.

native-inputs is typically used to list tools needed at build time, but not at run time, such as Autoconf, Automake, pkg-config, Gettext, or Bison. guix lint can report likely mistakes in this area (veja Invocando guix lint).

Lastly, propagated-inputs is similar to inputs, but the specified packages will be automatically installed to profiles (veja the role of profiles in Guix) alongside the package they belong to (veja guix package, for information on how guix package deals with propagated inputs).

For example this is necessary when packaging a C/C++ library that needs headers of another library to compile, or when a pkg-config file refers to another one via its Requires field.

Another example where propagated-inputs is useful is for languages that lack a facility to record the run-time search path akin to the RUNPATH of ELF files; this includes Guile, Python, Perl, and more. When packaging libraries written in those languages, ensure they can find library code they depend on at run time by listing run-time dependencies in propagated-inputs rather than inputs.

outputs (default: '("out"))

The list of output names of the package. Veja Pacotes com múltiplas saídas, for typical uses of additional outputs.

native-search-paths (default: '())
search-paths (default: '())

A list of search-path-specification objects describing search-path environment variables honored by the package. Veja Search Paths, for more on search path specifications.

As for inputs, the distinction between native-search-paths and search-paths only matters when cross-compiling. In a cross-compilation context, native-search-paths applies exclusively to native inputs whereas search-paths applies only to host inputs.

Packages such as cross-compilers care about target inputs—for instance, our (modified) GCC cross-compiler has CROSS_C_INCLUDE_PATH in search-paths, which allows it to pick .h files for the target system and not those of native inputs. For the majority of packages though, only native-search-paths makes sense.

replacement (default: #f)

This must be either #f or a package object that will be used as a replacement for this package. Veja grafts, for details.

synopsis

A one-line description of the package.

description

A more elaborate description of the package, as a string in Texinfo syntax.

license

The license of the package; a value from (guix licenses), or a list of such values.

página inicial

The URL to the home-page of the package, as a string.

supported-systems (default: %supported-systems)

The list of systems supported by the package, as strings of the form architecture-kernel, for example "x86_64-linux".

location (default: source location of the package form)

The source location of the package. It is useful to override this when inheriting from another package, in which case this field is not automatically corrected.

Macro: this-package

When used in the lexical scope of a package field definition, this identifier resolves to the package being defined.

The example below shows how to add a package as a native input of itself when cross-compiling:

(package
  (name "guile")
  ;; ...

  ;; When cross-compiled, Guile, for example, depends on
  ;; a native version of itself.  Add it here.
  (native-inputs (if (%current-target-system)
                     (list this-package)
                     '())))

It is an error to refer to this-package outside a package definition.

The following helper procedures are provided to help deal with package inputs.

Procedure: lookup-package-input package name
Procedure: lookup-package-native-input package name
Procedure: lookup-package-propagated-input package name
Procedure: lookup-package-direct-input package name

Look up name among package’s inputs (or native, propagated, or direct inputs). Return it if found, #f otherwise.

name is the name of a package depended on. Here’s how you might use it:

(use-modules (guix packages) (gnu packages base))

(lookup-package-direct-input coreutils "gmp")
 #<package gmp@6.2.1 …>

In this example we obtain the gmp package that is among the direct inputs of coreutils.

Sometimes you will want to obtain the list of inputs needed to develop a package—all the inputs that are visible when the package is compiled. This is what the package-development-inputs procedure returns.

Procedure: package-development-inputs package [system] [#:target #f]

Return the list of inputs required by package for development purposes on system. When target is true, return the inputs needed to cross-compile package from system to target, where target is a triplet such as "aarch64-linux-gnu".

Note that the result includes both explicit inputs and implicit inputs—inputs automatically added by the build system (veja Sistemas de compilação). Let us take the hello package to illustrate that:

(use-modules (gnu packages base) (guix packages))

hello
 #<package hello@2.10 gnu/packages/base.scm:79 7f585d4f6790>

(package-direct-inputs hello)
 ()

(package-development-inputs hello)
 (("source" ) ("tar" #<package tar@1.32 …>) )

In this example, package-direct-inputs returns the empty list, because hello has zero explicit dependencies. Conversely, package-development-inputs includes inputs implicitly added by gnu-build-system that are required to build hello: tar, gzip, GCC, libc, Bash, and more. To visualize it, guix graph hello would show you explicit inputs, whereas guix graph -t bag hello would include implicit inputs (veja Invocando guix graph).

Because packages are regular Scheme objects that capture a complete dependency graph and associated build procedures, it is often useful to write procedures that take a package and return a modified version thereof according to some parameters. Below are a few examples.

Procedure: package-with-c-toolchain package toolchain

Return a variant of package that uses toolchain instead of the default GNU C/C++ toolchain. toolchain must be a list of inputs (label/package tuples) providing equivalent functionality, such as the gcc-toolchain package.

The example below returns a variant of the hello package built with GCC 10.x and the rest of the GNU tool chain (Binutils and the GNU C Library) instead of the default tool chain:

(let ((toolchain (specification->package "gcc-toolchain@10")))
  (package-with-c-toolchain hello `(("toolchain" ,toolchain))))

The build tool chain is part of the implicit inputs of packages—it’s usually not listed as part of the various “inputs” fields and is instead pulled in by the build system. Consequently, this procedure works by changing the build system of package so that it pulls in toolchain instead of the defaults. Sistemas de compilação, for more on build systems.


8.2.2 origin Reference

This section documents origins. An origin declaration specifies data that must be “produced”—downloaded, usually—and whose content hash is known in advance. Origins are primarily used to represent the source code of packages (veja Definindo pacotes). For that reason, the origin form allows you to declare patches to apply to the original source code as well as code snippets to modify it.

Data Type: origin

This is the data type representing a source code origin.

uri

An object containing the URI of the source. The object type depends on the method (see below). For example, when using the url-fetch method of (guix download), the valid uri values are: a URL represented as a string, or a list thereof.

method

A monadic procedure that handles the given URI. The procedure must accept at least three arguments: the value of the uri field and the hash algorithm and hash value specified by the hash field. It must return a store item or a derivation in the store monad (veja A mônada do armazém); most methods return a fixed-output derivation (veja Derivações).

Commonly used methods include url-fetch, which fetches data from a URL, and git-fetch, which fetches data from a Git repository (see below).

sha256

A bytevector containing the SHA-256 hash of the source. This is equivalent to providing a content-hash SHA256 object in the hash field described below.

hash (masc.)

The content-hash object of the source—see below for how to use content-hash.

You can obtain this information using guix download (veja Invocando guix download) or guix hash (veja Invocando guix hash).

file-name (default: #f)

The file name under which the source code should be saved. When this is #f, a sensible default value will be used in most cases. In case the source is fetched from a URL, the file name from the URL will be used. For version control checkouts, it is recommended to provide the file name explicitly because the default is not very descriptive.

patches (default: '())

A list of file names, origins, or file-like objects (veja file-like objects) pointing to patches to be applied to the source.

This list of patches must be unconditional. In particular, it cannot depend on the value of %current-system or %current-target-system.

snippet (default: #f)

A G-expression (veja Expressões-G) or S-expression that will be run in the source directory. This is a convenient way to modify the source, sometimes more convenient than a patch.

patch-flags (default: '("-p1"))

A list of command-line flags that should be passed to the patch command.

patch-inputs (default: #f)

Input packages or derivations to the patching process. When this is #f, the usual set of inputs necessary for patching are provided, such as GNU Patch.

modules (default: '())

A list of Guile modules that should be loaded during the patching process and while running the code in the snippet field.

patch-guile (default: #f)

The Guile package that should be used in the patching process. When this is #f, a sensible default is used.

Data Type: content-hash value [algorithm]

Construct a content hash object for the given algorithm, and with value as its hash value. When algorithm is omitted, assume it is sha256.

value can be a literal string, in which case it is base32-decoded, or it can be a bytevector.

The following forms are all equivalent:

(content-hash "05zxkyz9bv3j9h0xyid1rhvh3klhsmrpkf3bcs6frvlgyr2gwilj")
(content-hash "05zxkyz9bv3j9h0xyid1rhvh3klhsmrpkf3bcs6frvlgyr2gwilj"
              sha256)
(content-hash (base32
               "05zxkyz9bv3j9h0xyid1rhvh3klhsmrpkf3bcs6frvlgyr2gwilj"))
(content-hash (base64 "kkb+RPaP7uyMZmu4eXPVkM4BN8yhRd8BTHLslb6f/Rc=")
              sha256)

Technically, content-hash is currently implemented as a macro. It performs sanity checks at macro-expansion time, when possible, such as ensuring that value has the right size for algorithm.

As we have seen above, how exactly the data an origin refers to is retrieved is determined by its method field. The (guix download) module provides the most common method, url-fetch, described below.

Procedure: url-fetch url hash-algo hash [name] [#:executable? #f]

Return a fixed-output derivation that fetches data from url (a string, or a list of strings denoting alternate URLs), which is expected to have hash hash of type hash-algo (a symbol). By default, the file name is the base name of URL; optionally, name can specify a different file name. When executable? is true, make the downloaded file executable.

When one of the URL starts with mirror://, then its host part is interpreted as the name of a mirror scheme, taken from %mirror-file.

Alternatively, when URL starts with file://, return the corresponding file name in the store.

Likewise, the (guix git-download) module defines the git-fetch origin method, which fetches data from a Git version control repository, and the git-reference data type to describe the repository and revision to fetch.

Procedure: git-fetch ref hash-algo hash

Return a fixed-output derivation that fetches ref, a <git-reference> object. The output is expected to have recursive hash hash of type hash-algo (a symbol). Use name as the file name, or a generic name if #f.

Procedure: git-fetch/lfs ref hash-algo hash

This is a variant of the git-fetch procedure that supports the Git LFS (Large File Storage) extension. This may be useful to pull some binary test data to run the test suite of a package, for example.

Data Type: git-reference

This data type represents a Git reference for git-fetch to retrieve.

url

The URL of the Git repository to clone.

commit

This string denotes either the commit to fetch (a hexadecimal string), or the tag to fetch. You can also use a “short” commit ID or a git describe style identifier such as v1.0.1-10-g58d7909c97.

recursive? (default: #f)

This Boolean indicates whether to recursively fetch Git sub-modules.

The example below denotes the v2.10 tag of the GNU Hello repository:

(git-reference
  (url "https://git.savannah.gnu.org/git/hello.git")
  (commit "v2.10"))

This is equivalent to the reference below, which explicitly names the commit:

(git-reference
  (url "https://git.savannah.gnu.org/git/hello.git")
  (commit "dc7dc56a00e48fe6f231a58f6537139fe2908fb9"))

For Mercurial repositories, the module (guix hg-download) defines the hg-fetch origin method and hg-reference data type for support of the Mercurial version control system.

Procedure: hg-fetch ref hash-algo hash [name]

Return a fixed-output derivation that fetches ref, a <hg-reference> object. The output is expected to have recursive hash hash of type hash-algo (a symbol). Use name as the file name, or a generic name if #f.

Data Type: hg-reference

This data type represents a Mercurial reference for hg-fetch to retrieve.

url

The URL of the Mercurial repository to clone.

changeset

This string denotes changeset to fetch.

For Subversion repositories, the module (guix svn-download) defines the svn-fetch origin method and svn-reference data type for support of the Subversion version control system.

Procedure: svn-fetch ref hash-algo hash [name]

Return a fixed-output derivation that fetches ref, a <svn-reference> object. The output is expected to have recursive hash hash of type hash-algo (a symbol). Use name as the file name, or a generic name if #f.

Data Type: svn-reference

This data type represents a Subversion reference for svn-fetch to retrieve.

url

The URL of the Subversion repository to clone.

revision

This string denotes revision to fetch specified as a number.

recursive? (default: #f)

This Boolean indicates whether to recursively fetch Subversion “externals”.

user-name (default: #f)

The name of an account that has read-access to the repository, if the repository isn’t public.

password (default: #f)

Password to access the Subversion repository, if required.

For Bazaar repositories, the module (guix bzr-download) defines the bzr-fetch origin method and bzr-reference data type for support of the Bazaar version control system.

Procedure: bzr-fetch ref hash-algo hash [name]

Return a fixed-output derivation that fetches ref, a <bzr-reference> object. The output is expected to have recursive hash hash of type hash-algo (a symbol). Use name as the file name, or a generic name if #f.

Data Type: bzr-reference

This data type represents a Bazaar reference for bzr-fetch to retrieve.

url

The URL of the Bazaar repository to clone.

revision

This string denotes revision to fetch specified as a number.

For CVS repositories, the module (guix cvs-download) defines the cvs-fetch origin method and cvs-reference data type for support of the Concurrent Versions System (CVS).

Procedure: cvs-fetch ref hash-algo hash [name]

Return a fixed-output derivation that fetches ref, a <cvs-reference> object. The output is expected to have recursive hash hash of type hash-algo (a symbol). Use name as the file name, or a generic name if #f.

Data Type: cvs-reference

This data type represents a CVS reference for cvs-fetch to retrieve.

root-directory

The CVS root directory.

modulo

Module to fetch.

revision

Revision to fetch.

The example below denotes a version of gnu-standards to fetch:

(cvs-reference
  (root-directory ":pserver:anonymous@cvs.savannah.gnu.org:/sources/gnustandards")
  (module "gnustandards")
  (revision "2020-11-25"))

8.3 Defining Package Variants

One of the nice things with Guix is that, given a package definition, you can easily derive variants of that package—for a different upstream version, with different dependencies, different compilation options, and so on. Some of these custom packages can be defined straight from the command line (veja Opções de transformação de pacote). This section describes how to define package variants in code. This can be useful in “manifests” (veja Writing Manifests) and in your own package collection (veja Creating a Channel), among others!

As discussed earlier, packages are first-class objects in the Scheme language. The (guix packages) module provides the package construct to define new package objects (veja package Reference). The easiest way to define a package variant is using the inherit keyword together with package. This allows you to inherit from a package definition while overriding the fields you want.

For example, given the hello variable, which contains a definition for the current version of GNU Hello, here’s how you would define a variant for version 2.2 (released in 2006, it’s vintage!):

(use-modules (gnu packages base))    ;for 'hello'

(define hello-2.2
  (package
    (inherit hello)
    (version "2.2")
    (source (origin
              (method url-fetch)
              (uri (string-append "mirror://gnu/hello/hello-" version
                                  ".tar.gz"))
              (sha256
               (base32
                "0lappv4slgb5spyqbh6yl5r013zv72yqg2pcl30mginf3wdqd8k9"))))))

The example above corresponds to what the --with-version or --with-source package transformations option do. Essentially hello-2.2 preserves all the fields of hello, except version and source, which it overrides. Note that the original hello variable is still there, in the (gnu packages base) module, unchanged. When you define a custom package like this, you are really adding a new package definition; the original one remains available.

You can just as well define variants with a different set of dependencies than the original package. For example, the default gdb package depends on guile, but since that is an optional dependency, you can define a variant that removes that dependency like so:

(use-modules (gnu packages gdb))   ;for 'gdb'

(define gdb-sans-guile
  (package
    (inherit gdb)
    (inputs (modify-inputs (package-inputs gdb)
              (delete "guile")))))

The modify-inputs form above removes the "guile" package from the inputs field of gdb. The modify-inputs macro is a helper that can prove useful anytime you want to remove, add, or replace package inputs.

Macro: modify-inputs inputs clauses

Modify the given package inputs, as returned by package-inputs & co., according to the given clauses. Each clause must have one of the following forms:

(delete name…)

Delete from the inputs packages with the given names (strings).

(prepend package…)

Add packages to the front of the input list.

(append package…)

Add packages to the end of the input list.

(replace name replacement)

Replace the package called name with replacement.

The example below removes the GMP and ACL inputs of Coreutils and adds libcap to the front of the input list:

(modify-inputs (package-inputs coreutils)
  (delete "gmp" "acl")
  (prepend libcap))

The example below replaces the guile package from the inputs of guile-redis with guile-2.2:

(modify-inputs (package-inputs guile-redis)
  (replace "guile" guile-2.2))

The last type of clause is append, to add inputs at the back of the list.

In some cases, you may find it useful to write functions (“procedures”, in Scheme parlance) that return a package based on some parameters. For example, consider the luasocket library for the Lua programming language. We want to create luasocket packages for major versions of Lua. One way to do that is to define a procedure that takes a Lua package and returns a luasocket package that depends on it:

(define (make-lua-socket name lua)
  ;; Return a luasocket package built with LUA.
  (package
    (name name)
    (version "3.0")
    ;; several fields omitted
    (inputs (list lua))
    (synopsis "Socket library for Lua")))

(define-public lua5.1-socket
  (make-lua-socket "lua5.1-socket" lua-5.1))

(define-public lua5.2-socket
  (make-lua-socket "lua5.2-socket" lua-5.2))

Here we have defined packages lua5.1-socket and lua5.2-socket by calling make-lua-socket with different arguments. Veja Procedures em GNU Guile Reference Manual, for more info on procedures. Having top-level public definitions for these two packages means that they can be referred to from the command line (veja Módulos de pacote).

These are pretty simple package variants. As a convenience, the (guix transformations) module provides a high-level interface that directly maps to the more sophisticated package transformation options (veja Opções de transformação de pacote):

Procedure: options->transformation opts

Return a procedure that, when passed an object to build (package, derivation, etc.), applies the transformations specified by opts and returns the resulting objects. opts must be a list of symbol/string pairs such as:

((with-branch . "guile-gcrypt=master")
 (without-tests . "libgcrypt"))

Each symbol names a transformation and the corresponding string is an argument to that transformation.

For instance, a manifest equivalent to this command:

guix build guix \
  --with-branch=guile-gcrypt=master \
  --with-debug-info=zlib

... would look like this:

(use-modules (guix transformations))

(define transform
  ;; The package transformation procedure.
  (options->transformation
   '((with-branch . "guile-gcrypt=master")
     (with-debug-info . "zlib"))))

(packages->manifest
 (list (transform (specification->package "guix"))))

The options->transformation procedure is convenient, but it’s perhaps also not as flexible as you may like. How is it implemented? The astute reader probably noticed that most package transformation options go beyond the superficial changes shown in the first examples of this section: they involve input rewriting, whereby the dependency graph of a package is rewritten by replacing specific inputs by others.

Dependency graph rewriting, for the purposes of swapping packages in the graph, is what the package-input-rewriting procedure in (guix packages) implements.

Procedure: package-input-rewriting replacements [rewrite-name] [#:deep? #t]

Return a procedure that, when passed a package, replaces its direct and indirect dependencies, including implicit inputs when deep? is true, according to replacements. replacements is a list of package pairs; the first element of each pair is the package to replace, and the second one is the replacement.

Optionally, rewrite-name is a one-argument procedure that takes the name of a package and returns its new name after rewrite.

Consider this example:

(define libressl-instead-of-openssl
  ;; This is a procedure to replace OPENSSL by LIBRESSL,
  ;; recursively.
  (package-input-rewriting `((,openssl . ,libressl))))

(define git-with-libressl
  (libressl-instead-of-openssl git))

Here we first define a rewriting procedure that replaces openssl with libressl. Then we use it to define a variant of the git package that uses libressl instead of openssl. This is exactly what the --with-input command-line option does (veja --with-input).

The following variant of package-input-rewriting can match packages to be replaced by name rather than by identity.

Procedure: package-input-rewriting/spec replacements [#:deep? #t]

Return a procedure that, given a package, applies the given replacements to all the package graph, including implicit inputs unless deep? is false.

replacements is a list of spec/procedures pair; each spec is a package specification such as "gcc" or "guile@2", and each procedure takes a matching package and returns a replacement for that package. Matching packages that have the hidden? property set are not replaced.

The example above could be rewritten this way:

(define libressl-instead-of-openssl
  ;; Replace all the packages called "openssl" with LibreSSL.
  (package-input-rewriting/spec `(("openssl" . ,(const libressl)))))

The key difference here is that, this time, packages are matched by spec and not by identity. In other words, any package in the graph that is called openssl will be replaced.

A more generic procedure to rewrite a package dependency graph is package-mapping: it supports arbitrary changes to nodes in the graph.

Procedure: package-mapping proc [cut?] [#:deep? #f]

Return a procedure that, given a package, applies proc to all the packages depended on and returns the resulting package. The procedure stops recursion when cut? returns true for a given package. When deep? is true, proc is applied to implicit inputs as well.

Tips: Understanding what a variant really looks like can be difficult as one starts combining the tools shown above. There are several ways to inspect a package before attempting to build it that can prove handy:

  • You can inspect the package interactively at the REPL, for instance to view its inputs, the code of its build phases, or its configure flags (veja Using Guix Interactively).
  • When rewriting dependencies, guix graph can often help visualize the changes that are made (veja Invocando guix graph).

8.4 Writing Manifests

guix commands let you specify package lists on the command line. This is convenient, but as the command line becomes longer and less trivial, it quickly becomes more convenient to have that package list in what we call a manifest. A manifest is some sort of a “bill of materials” that defines a package set. You would typically come up with a code snippet that builds the manifest, store it in a file, say manifest.scm, and then pass that file to the -m (or --manifest) option that many guix commands support. For example, here’s what a manifest for a simple package set might look like:

;; Manifest for three packages.
(specifications->manifest '("gcc-toolchain" "make" "git"))

Once you have that manifest, you can pass it, for example, to guix package to install just those three packages to your profile (veja -m option of guix package):

guix package -m manifest.scm

... or you can pass it to guix shell (veja -m option of guix shell) to spawn an ephemeral environment:

guix shell -m manifest.scm

... or you can pass it to guix pack in pretty much the same way (veja -m option of guix pack). You can store the manifest under version control, share it with others so they can easily get set up, etc.

But how do you write your first manifest? To get started, maybe you’ll want to write a manifest that mirrors what you already have in a profile. Rather than start from a blank page, guix package can generate a manifest for you (veja guix package --export-manifest):

# Write to 'manifest.scm' a manifest corresponding to the
# default profile, ~/.guix-profile.
guix package --export-manifest > manifest.scm

Or maybe you’ll want to “translate” command-line arguments into a manifest. In that case, guix shell can help (veja guix shell --export-manifest):

# Write a manifest for the packages specified on the command line.
guix shell --export-manifest gcc-toolchain make git > manifest.scm

In both cases, the --export-manifest option tries hard to generate a faithful manifest; in particular, it takes package transformation options into account (veja Opções de transformação de pacote).

Nota: Manifests are symbolic: they refer to packages of the channels currently in use (veja Canais). In the example above, gcc-toolchain might refer to version 11 today, but it might refer to version 13 two years from now.

If you want to “pin” your software environment to specific package versions and variants, you need an additional piece of information: the list of channel revisions in use, as returned by guix describe. Veja Replicating Guix, for more information.

Once you’ve obtained your first manifest, perhaps you’ll want to customize it. Since your manifest is code, you now have access to all the Guix programming interfaces!

Let’s assume you want a manifest to deploy a custom variant of GDB, the GNU Debugger, that does not depend on Guile, together with another package. Building on the example seen in the previous section (veja Defining Package Variants), you can write a manifest along these lines:

(use-modules (guix packages)
             (gnu packages gdb)               ;for 'gdb'
             (gnu packages version-control))  ;for 'git'

;; Define a variant of GDB without a dependency on Guile.
(define gdb-sans-guile
  (package
    (inherit gdb)
    (inputs (modify-inputs (package-inputs gdb)
              (delete "guile")))))

;; Return a manifest containing that one package plus Git.
(packages->manifest (list gdb-sans-guile git))

Note that in this example, the manifest directly refers to the gdb and git variables, which are bound to a package object (veja package Reference), instead of calling specifications->manifest to look up packages by name as we did before. The use-modules form at the top lets us access the core package interface (veja Definindo pacotes) and the modules that define gdb and git (veja Módulos de pacote). Seamlessly, we’re weaving all this together—the possibilities are endless, unleash your creativity!

The data type for manifests as well as supporting procedures are defined in the (guix profiles) module, which is automatically available to code passed to -m. The reference follows.

Data Type: manifest

Data type representing a manifest.

It currently has one field:

entries

This must be a list of manifest-entry records—see below.

Data Type: manifest-entry

Data type representing a manifest entry. A manifest entry contains essential metadata: a name and version string, the object (usually a package) for that entry, the desired output (veja Pacotes com múltiplas saídas), and a number of optional pieces of information detailed below.

Most of the time, you won’t build a manifest entry directly; instead, you will pass a package to package->manifest-entry, described below. In some unusual cases though, you might want to create manifest entries for things that are not packages, as in this example:

;; Manually build a single manifest entry for a non-package object.
(let ((hello (program-file "hello" #~(display "Hi!"))))
  (manifest-entry
    (name "foo")
    (version "42")
    (item
     (computed-file "hello-directory"
                     #~(let ((bin (string-append #$output "/bin")))
                         (mkdir #$output) (mkdir bin)
                          (symlink #$hello
                                   (string-append bin "/hello")))))))

The available fields are the following:

name
version

Name and version string for this entry.

item

A package or other file-like object (veja file-like objects).

output (default: "out")

Output of item to use, in case item has multiple outputs (veja Pacotes com múltiplas saídas).

dependencies (default: '())

List of manifest entries this entry depends on. When building a profile, dependencies are added to the profile.

Typically, the propagated inputs of a package (veja propagated-inputs) end up having a corresponding manifest entry in among the dependencies of the package’s own manifest entry.

search-paths (default: '())

The list of search path specifications honored by this entry (veja Search Paths).

properties (default: '())

List of symbol/value pairs. When building a profile, those properties get serialized.

This can be used to piggyback additional metadata—e.g., the transformations applied to a package (veja Opções de transformação de pacote).

parent (default: (delay #f))

A promise pointing to the “parent” manifest entry.

This is used as a hint to provide context when reporting an error related to a manifest entry coming from a dependencies field.

Procedure: concatenate-manifests lst

Concatenate the manifests listed in lst and return the resulting manifest.

Procedure: package->manifest-entry package [output] [#:properties]

Return a manifest entry for the output of package package, where output defaults to "out", and with the given properties. By default properties is the empty list or, if one or more package transformations were applied to package, it is an association list representing those transformations, suitable as an argument to options->transformation (veja options->transformation).

The code snippet below builds a manifest with an entry for the default output and the send-email output of the git package:

(use-modules (gnu packages version-control))

(manifest (list (package->manifest-entry git)
                (package->manifest-entry git "send-email")))
Procedure: packages->manifest packages

Return a list of manifest entries, one for each item listed in packages. Elements of packages can be either package objects or package/string tuples denoting a specific output of a package.

Using this procedure, the manifest above may be rewritten more concisely:

(use-modules (gnu packages version-control))

(packages->manifest (list git `(,git "send-email")))
Procedure: package->development-manifest package [system] [#:target]

Return a manifest for the development inputs of package for system, optionally when cross-compiling to target. Development inputs include both explicit and implicit inputs of package.

Like the -D option of guix shell (veja guix shell -D), the resulting manifest describes the environment in which one can develop package. For example, suppose you’re willing to set up a development environment for Inkscape, with the addition of Git for version control; you can describe that “bill of materials” with the following manifest:

(use-modules (gnu packages inkscape)          ;for 'inkscape'
             (gnu packages version-control))  ;for 'git'

(concatenate-manifests
 (list (package->development-manifest inkscape)
       (packages->manifest (list git))))

In this example, the development manifest that package->development-manifest returns includes the compiler (GCC), the many supporting libraries (Boost, GLib, GTK, etc.), and a couple of additional development tools—these are the dependencies guix show inkscape lists.

Last, the (gnu packages) module provides higher-level facilities to build manifests. In particular, it lets you look up packages by name—see below.

Procedure: specifications->manifest specs

Given specs, a list of specifications such as "emacs@25.2" or "guile:debug", return a manifest. Specs have the format that command-line tools such as guix install and guix package understand (veja Invocando guix package).

As an example, it lets you rewrite the Git manifest that we saw earlier like this:

(specifications->manifest '("git" "git:send-email"))

Notice that we do not need to worry about use-modules, importing the right set of modules, and referring to the right variables. Instead, we directly refer to packages in the same way as on the command line, which can often be more convenient.


8.5 Sistemas de compilação

Each package definition specifies a build system and arguments for that build system (veja Definindo pacotes). This build-system field represents the build procedure of the package, as well as implicit dependencies of that build procedure.

Build systems are <build-system> objects. The interface to create and manipulate them is provided by the (guix build-system) module, and actual build systems are exported by specific modules.

Under the hood, build systems first compile package objects to bags. A bag is like a package, but with less ornamentation—in other words, a bag is a lower-level representation of a package, which includes all the inputs of that package, including some that were implicitly added by the build system. This intermediate representation is then compiled to a derivation (veja Derivações). The package-with-c-toolchain is an example of a way to change the implicit inputs that a package’s build system pulls in (veja package-with-c-toolchain).

Build systems accept an optional list of arguments. In package definitions, these are passed via the arguments field (veja Definindo pacotes). They are typically keyword arguments (veja keyword arguments in Guile em GNU Guile Reference Manual). The value of these arguments is usually evaluated in the build stratum—i.e., by a Guile process launched by the daemon (veja Derivações).

The main build system is gnu-build-system, which implements the standard build procedure for GNU and many other packages. It is provided by the (guix build-system gnu) module.

Variável: gnu-build-system

gnu-build-system represents the GNU Build System, and variants thereof (veja configuration and makefile conventions em GNU Coding Standards).

In a nutshell, packages using it are configured, built, and installed with the usual ./configure && make && make check && make install command sequence. In practice, a few additional steps are often needed. All these steps are split up in separate phases. Veja Build Phases, for more info on build phases and ways to customize them.

In addition, this build system ensures that the “standard” environment for GNU packages is available. This includes tools such as GCC, libc, Coreutils, Bash, Make, Diffutils, grep, and sed (see the (guix build-system gnu) module for a complete list). We call these the implicit inputs of a package, because package definitions do not have to mention them.

This build system supports a number of keyword arguments, which can be passed via the arguments field of a package. Here are some of the main parameters:

#:phases

This argument specifies build-side code that evaluates to an alist of build phases. Veja Build Phases, for more information.

#:configure-flags

This is a list of flags (strings) passed to the configure script. Veja Definindo pacotes, for an example.

#:make-flags

This list of strings contains flags passed as arguments to make invocations in the build, check, and install phases.

#:out-of-source?

This Boolean, #f by default, indicates whether to run builds in a build directory separate from the source tree.

When it is true, the configure phase creates a separate build directory, changes to that directory, and runs the configure script from there. This is useful for packages that require it, such as glibc.

#:tests?

This Boolean, #t by default, indicates whether the check phase should run the package’s test suite.

#:test-target

This string, "check" by default, gives the name of the makefile target used by the check phase.

#:parallel-build?
#:parallel-tests?

These Boolean values specify whether to build, respectively run the test suite, in parallel, with the -j flag of make. When they are true, make is passed -jn, where n is the number specified as the --cores option of guix-daemon or that of the guix client command (veja --cores).

#:validate-runpath?

This Boolean, #t by default, determines whether to “validate” the RUNPATH of ELF binaries (.so shared libraries as well as executables) previously installed by the install phase. Veja the validate-runpath phase, for details.

#:substituível?

This Boolean, #t by default, tells whether the package outputs should be substitutable—i.e., whether users should be able to obtain substitutes for them instead of building locally (veja Substitutos).

#:allowed-references
#:disallowed-references

When true, these arguments must be a list of dependencies that must not appear among the references of the build results. If, upon build completion, some of these references are retained, the build process fails.

This is useful to ensure that a package does not erroneously keep a reference to some of it build-time inputs, in cases where doing so would, for example, unnecessarily increase its size (veja Invocando guix size).

Most other build systems support these keyword arguments.

Other <build-system> objects are defined to support other conventions and tools used by free software packages. They inherit most of gnu-build-system, and differ mainly in the set of inputs implicitly added to the build process, and in the list of phases executed. Some of these build systems are listed below.

Variável: agda-build-system

This variable is exported by (guix build-system agda). It implements a build procedure for Agda libraries.

It adds agda to the set of inputs. A different Agda can be specified with the #:agda key.

The #:plan key is a list of cons cells (regexp . parameters), where regexp is a regexp that should match the .agda files to build, and parameters is an optional list of parameters that will be passed to agda when type-checking it.

When the library uses Haskell to generate a file containing all imports, the convenience #:gnu-and-haskell? can be set to #t to add ghc and the standard inputs of gnu-build-system to the input list. You will still need to manually add a phase or tweak the 'build phase, as in the definition of agda-stdlib.

Variável: ant-build-system

This variable is exported by (guix build-system ant). It implements the build procedure for Java packages that can be built with Ant build tool.

It adds both ant and the Java Development Kit (JDK) as provided by the icedtea package to the set of inputs. Different packages can be specified with the #:ant and #:jdk parameters, respectively.

When the original package does not provide a suitable Ant build file, the parameter #:jar-name can be used to generate a minimal Ant build file build.xml with tasks to build the specified jar archive. In this case the parameter #:source-dir can be used to specify the source sub-directory, defaulting to “src”.

The #:main-class parameter can be used with the minimal ant buildfile to specify the main class of the resulting jar. This makes the jar file executable. The #:test-include parameter can be used to specify the list of junit tests to run. It defaults to (list "**/*Test.java"). The #:test-exclude can be used to disable some tests. It defaults to (list "**/Abstract*.java"), because abstract classes cannot be run as tests.

The parameter #:build-target can be used to specify the Ant task that should be run during the build phase. By default the “jar” task will be run.

Variável: android-ndk-build-system

This variable is exported by (guix build-system android-ndk). It implements a build procedure for Android NDK (native development kit) packages using a Guix-specific build process.

The build system assumes that packages install their public interface (header) files to the subdirectory include of the out output and their libraries to the subdirectory lib the out output.

It’s also assumed that the union of all the dependencies of a package has no conflicting files.

For the time being, cross-compilation is not supported - so right now the libraries and header files are assumed to be host tools.

Variável: asdf-build-system/source
Variável: asdf-build-system/sbcl
Variável: asdf-build-system/ecl

These variables, exported by (guix build-system asdf), implement build procedures for Common Lisp packages using “ASDF”. ASDF is a system definition facility for Common Lisp programs and libraries.

The asdf-build-system/source system installs the packages in source form, and can be loaded using any common lisp implementation, via ASDF. The others, such as asdf-build-system/sbcl, install binary systems in the format which a particular implementation understands. These build systems can also be used to produce executable programs, or lisp images which contain a set of packages pre-loaded.

The build system uses naming conventions. For binary packages, the package name should be prefixed with the lisp implementation, such as sbcl- for asdf-build-system/sbcl.

Additionally, the corresponding source package should be labeled using the same convention as Python packages (veja Módulos Python), using the cl- prefix.

In order to create executable programs and images, the build-side procedures build-program and build-image can be used. They should be called in a build phase after the create-asdf-configuration phase, so that the system which was just built can be used within the resulting image. build-program requires a list of Common Lisp expressions to be passed as the #:entry-program argument.

By default, all the .asd files present in the sources are read to find system definitions. The #:asd-files parameter can be used to specify the list of .asd files to read. Furthermore, if the package defines a system for its tests in a separate file, it will be loaded before the tests are run if it is specified by the #:test-asd-file parameter. If it is not set, the files <system>-tests.asd, <system>-test.asd, tests.asd, and test.asd will be tried if they exist.

If for some reason the package must be named in a different way than the naming conventions suggest, or if several systems must be compiled, the #:asd-systems parameter can be used to specify the list of system names.

Variável: cargo-build-system

This variable is exported by (guix build-system cargo). It supports builds of packages using Cargo, the build tool of the Rust programming language.

It adds rustc and cargo to the set of inputs. A different Rust package can be specified with the #:rust parameter.

Regular cargo dependencies should be added to the package definition similarly to other packages; those needed only at build time to native-inputs, others to inputs. If you need to add source-only crates then you should add them to via the #:cargo-inputs parameter as a list of name and spec pairs, where the spec can be a package or a source definition. Note that the spec must evaluate to a path to a gzipped tarball which includes a Cargo.toml file at its root, or it will be ignored. Similarly, cargo dev-dependencies should be added to the package definition via the #:cargo-development-inputs parameter.

In its configure phase, this build system will make any source inputs specified in the #:cargo-inputs and #:cargo-development-inputs parameters available to cargo. It will also remove an included Cargo.lock file to be recreated by cargo during the build phase. The package phase will run cargo package to create a source crate for future use. The install phase installs the binaries defined by the crate. Unless install-source? #f is defined it will also install a source crate repository of itself and unpacked sources, to ease in future hacking on rust packages.

Variável: chicken-build-system

This variable is exported by (guix build-system chicken). It builds CHICKEN Scheme modules, also called “eggs” or “extensions”. CHICKEN generates C source code, which then gets compiled by a C compiler, in this case GCC.

This build system adds chicken to the package inputs, as well as the packages of gnu-build-system.

The build system can’t (yet) deduce the egg’s name automatically, so just like with go-build-system and its #:import-path, you should define #:egg-name in the package’s arguments field.

For example, if you are packaging the srfi-1 egg:

(arguments '(#:egg-name "srfi-1"))

Egg dependencies must be defined in propagated-inputs, not inputs because CHICKEN doesn’t embed absolute references in compiled eggs. Test dependencies should go to native-inputs, as usual.

Variável: copy-build-system

This variable is exported by (guix build-system copy). It supports builds of simple packages that don’t require much compiling, mostly just moving files around.

It adds much of the gnu-build-system packages to the set of inputs. Because of this, the copy-build-system does not require all the boilerplate code often needed for the trivial-build-system.

To further simplify the file installation process, an #:install-plan argument is exposed to let the packager specify which files go where. The install plan is a list of (source target [filters]). filters are optional.

  • When source matches a file or directory without trailing slash, install it to target.
    • If target has a trailing slash, install source basename beneath target.
    • Otherwise install source as target.
  • When source is a directory with a trailing slash, or when filters are used, the trailing slash of target is implied with the same meaning as above.
    • Without filters, install the full source content to target.
    • With filters among #:include, #:include-regexp, #:exclude, #:exclude-regexp, only select files are installed depending on the filters. Each filters is specified by a list of strings.
      • With #:include, install all the files which the path suffix matches at least one of the elements in the given list.
      • With #:include-regexp, install all the files which the subpaths match at least one of the regular expressions in the given list.
      • The #:exclude and #:exclude-regexp filters are the complement of their inclusion counterpart. Without #:include flags, install all files but those matching the exclusion filters. If both inclusions and exclusions are specified, the exclusions are done on top of the inclusions.
    • When a package has multiple outputs, the #:output argument can be used to specify which output label the files should be installed to.

    In all cases, the paths relative to source are preserved within target.

Examples:

  • ("foo/bar" "share/my-app/"): Install bar to share/my-app/bar.
  • ("foo/bar" "share/my-app/baz"): Install bar to share/my-app/baz.
  • ("foo/" "share/my-app"): Install the content of foo inside share/my-app, e.g., install foo/sub/file to share/my-app/sub/file.
  • ("foo/" "share/my-app" #:include ("sub/file")): Install only foo/sub/file to share/my-app/sub/file.
  • ("foo/sub" "share/my-app" #:include ("file")): Install foo/sub/file to share/my-app/file.
  • ("foo/doc" "share/my-app/doc" #:output "doc"): Install "foo/doc" to "share/my-app/doc" within the "doc" output.
Variável: vim-build-system

This variable is exported by (guix build-system vim). It is an extension of the copy-build-system, installing Vim and Neovim plugins into locations where these two text editors know to find their plugins, using their packpaths.

Packages which are prefixed with vim- will be installed in Vim’s packpath, while those prefixed with neovim- will be installed in Neovim’s packpath. If there is a doc directory with the plugin then helptags will be generated automatically.

There are a couple of keywords added with the vim-build-system:

  • With plugin-name it is possible to set the name of the plugin. While by default this is set to the name and version of the package, it is often more helpful to set this to name which the upstream author calls their plugin. This is the name used for :packadd from inside Vim.
  • With install-plan it is possible to augment the built-in install-plan of the vim-build-system. This is particularly helpful if you have files which should be installed in other locations. For more information about using the install-plan, see the copy-build-system (veja copy-build-system).
  • With #:vim it is possible to add this package to Vim’s packpath, in addition to if it is added automatically because of the vim- prefix in the package’s name.
  • With #:neovim it is possible to add this package to Neovim’s packpath, in addition to if it is added automatically because of the neovim- prefix in the package’s name.
  • With #:mode it is possible to adjust the path which the plugin is installed into. By default the plugin is installed into start and other options are available, including opt. Adding a plugin into opt will mean you will need to run, for example, :packadd foo to load the foo plugin from inside of Vim.
Variável: clojure-build-system

This variable is exported by (guix build-system clojure). It implements a simple build procedure for Clojure packages using plain old compile in Clojure. Cross-compilation is not supported yet.

It adds clojure, icedtea and zip to the set of inputs. Different packages can be specified with the #:clojure, #:jdk and #:zip parameters, respectively.

A list of source directories, test directories and jar names can be specified with the #:source-dirs, #:test-dirs and #:jar-names parameters, respectively. Compile directory and main class can be specified with the #:compile-dir and #:main-class parameters, respectively. Other parameters are documented below.

This build system is an extension of ant-build-system, but with the following phases changed:

build

This phase calls compile in Clojure to compile source files and runs jar to create jars from both source files and compiled files according to the include list and exclude list specified in #:aot-include and #:aot-exclude, respectively. The exclude list has priority over the include list. These lists consist of symbols representing Clojure libraries or the special keyword #:all representing all Clojure libraries found under the source directories. The parameter #:omit-source? decides if source should be included into the jars.

marcar

This phase runs tests according to the include list and exclude list specified in #:test-include and #:test-exclude, respectively. Their meanings are analogous to that of #:aot-include and #:aot-exclude, except that the special keyword #:all now stands for all Clojure libraries found under the test directories. The parameter #:tests? decides if tests should be run.

instalar

This phase installs all jars built previously.

Apart from the above, this build system also contains an additional phase:

install-doc

This phase installs all top-level files with base name matching %doc-regex. A different regex can be specified with the #:doc-regex parameter. All files (recursively) inside the documentation directories specified in #:doc-dirs are installed as well.

Variável: cmake-build-system

This variable is exported by (guix build-system cmake). It implements the build procedure for packages using the CMake build tool.

It automatically adds the cmake package to the set of inputs. Which package is used can be specified with the #:cmake parameter.

The #:configure-flags parameter is taken as a list of flags passed to the cmake command. The #:build-type parameter specifies in abstract terms the flags passed to the compiler; it defaults to "RelWithDebInfo" (short for “release mode with debugging information”), which roughly means that code is compiled with -O2 -g, as is the case for Autoconf-based packages by default.

Variável: composer-build-system

This variable is exported by (guix build-system composer). It implements the build procedure for packages using Composer, the PHP package manager.

It automatically adds the php package to the set of inputs. Which package is used can be specified with the #:php parameter.

The #:test-target parameter is used to control which script is run for the tests. By default, the test script is run if it exists. If the script does not exist, the build system will run phpunit from the source directory, assuming there is a phpunit.xml file.

Variável: dune-build-system

This variable is exported by (guix build-system dune). It supports builds of packages using Dune, a build tool for the OCaml programming language. It is implemented as an extension of the ocaml-build-system which is described below. As such, the #:ocaml and #:findlib parameters can be passed to this build system.

It automatically adds the dune package to the set of inputs. Which package is used can be specified with the #:dune parameter.

There is no configure phase because dune packages typically don’t need to be configured. The #:build-flags parameter is taken as a list of flags passed to the dune command during the build.

The #:jbuild? parameter can be passed to use the jbuild command instead of the more recent dune command while building a package. Its default value is #f.

The #:package parameter can be passed to specify a package name, which is useful when a package contains multiple packages and you want to build only one of them. This is equivalent to passing the -p argument to dune.

Variável: elm-build-system

This variable is exported by (guix build-system elm). It implements a build procedure for Elm packages similar to ‘elm install’.

The build system adds an Elm compiler package to the set of inputs. The default compiler package (currently elm-sans-reactor) can be overridden using the #:elm argument. Additionally, Elm packages needed by the build system itself are added as implicit inputs if they are not already present: to suppress this behavior, use the #:implicit-elm-package-inputs? argument, which is primarily useful for bootstrapping.

The "dependencies" and "test-dependencies" in an Elm package’s elm.json file correspond to propagated-inputs and inputs, respectively.

Elm requires a particular structure for package names: veja Elm Packages for more details, including utilities provided by (guix build-system elm).

There are currently a few noteworthy limitations to elm-build-system:

  • The build system is focused on packages in the Elm sense of the word: Elm projects which declare { "type": "package" } in their elm.json files. Using elm-build-system to build Elm applications (which declare { "type": "application" }) is possible, but requires ad-hoc modifications to the build phases. For examples, see the definitions of the elm-todomvc example application and the elm package itself (because the front-end for the ‘elm reactor’ command is an Elm application).
  • Elm supports multiple versions of a package coexisting simultaneously under ELM_HOME, but this does not yet work well with elm-build-system. This limitation primarily affects Elm applications, because they specify exact versions for their dependencies, whereas Elm packages specify supported version ranges. As a workaround, the example applications mentioned above use the patch-application-dependencies procedure provided by (guix build elm-build-system) to rewrite their elm.json files to refer to the package versions actually present in the build environment. Alternatively, Guix package transformations (veja Defining Package Variants) could be used to rewrite an application’s entire dependency graph.
  • We are not yet able to run tests for Elm projects because neither elm-test-rs nor the Node.js-based elm-test runner has been packaged for Guix yet.
Variável: go-build-system

This variable is exported by (guix build-system go). It implements a build procedure for Go packages using the standard Go build mechanisms.

The user is expected to provide a value for the key #:import-path and, in some cases, #:unpack-path. The import path corresponds to the file system path expected by the package’s build scripts and any referring packages, and provides a unique way to refer to a Go package. It is typically based on a combination of the package source code’s remote URI and file system hierarchy structure. In some cases, you will need to unpack the package’s source code to a different directory structure than the one indicated by the import path, and #:unpack-path should be used in such cases.

Packages that provide Go libraries should install their source code into the built output. The key #:install-source?, which defaults to #t, controls whether or not the source code is installed. It can be set to #f for packages that only provide executable files.

Packages can be cross-built, and if a specific architecture or operating system is desired then the keywords #:goarch and #:goos can be used to force the package to be built for that architecture and operating system. The combinations known to Go can be found in their documentation.

The key #:go can be used to specify the Go compiler package with which to build the package.

Variável: glib-or-gtk-build-system

This variable is exported by (guix build-system glib-or-gtk). It is intended for use with packages making use of GLib or GTK+.

This build system adds the following two phases to the ones defined by gnu-build-system:

glib-or-gtk-wrap

The phase glib-or-gtk-wrap ensures that programs in bin/ are able to find GLib “schemas” and GTK+ modules. This is achieved by wrapping the programs in launch scripts that appropriately set the XDG_DATA_DIRS and GTK_PATH environment variables.

It is possible to exclude specific package outputs from that wrapping process by listing their names in the #:glib-or-gtk-wrap-excluded-outputs parameter. This is useful when an output is known not to contain any GLib or GTK+ binaries, and where wrapping would gratuitously add a dependency of that output on GLib and GTK+.

glib-or-gtk-compile-schemas

The phase glib-or-gtk-compile-schemas makes sure that all GSettings schemas of GLib are compiled. Compilation is performed by the glib-compile-schemas program. It is provided by the package glib:bin which is automatically imported by the build system. The glib package providing glib-compile-schemas can be specified with the #:glib parameter.

Both phases are executed after the install phase.

Variável: guile-build-system

This build system is for Guile packages that consist exclusively of Scheme code and that are so lean that they don’t even have a makefile, let alone a configure script. It compiles Scheme code using guild compile (veja Compilation em GNU Guile Reference Manual) and installs the .scm and .go files in the right place. It also installs documentation.

This build system supports cross-compilation by using the --target option of ‘guild compile’.

Packages built with guile-build-system must provide a Guile package in their native-inputs field.

Variável: julia-build-system

This variable is exported by (guix build-system julia). It implements the build procedure used by julia packages, which essentially is similar to running ‘julia -e 'using Pkg; Pkg.add(package)'’ in an environment where JULIA_LOAD_PATH contains the paths to all Julia package inputs. Tests are run by calling /test/runtests.jl.

The Julia package name and uuid is read from the file Project.toml. These values can be overridden by passing the argument #:julia-package-name (which must be correctly capitalized) or #:julia-package-uuid.

Julia packages usually manage their binary dependencies via JLLWrappers.jl, a Julia package that creates a module (named after the wrapped library followed by _jll.jl.

To add the binary path _jll.jl packages, you need to patch the files under src/wrappers/, replacing the call to the macro JLLWrappers.@generate_wrapper_header, adding as a second argument containing the store path the binary.

As an example, in the MbedTLS Julia package, we add a build phase (veja Build Phases) to insert the absolute file name of the wrapped MbedTLS package:

(add-after 'unpack 'override-binary-path
  (lambda* (#:key inputs #:allow-other-keys)
    (for-each (lambda (wrapper)
                (substitute* wrapper
                  (("generate_wrapper_header.*")
                   (string-append
                    "generate_wrapper_header(\"MbedTLS\", \""
                    (assoc-ref inputs "mbedtls") "\")\n"))))
              ;; There's a Julia file for each platform, override them all.
              (find-files "src/wrappers/" "\\.jl$"))))

Some older packages that aren’t using Project.toml yet, will require this file to be created, too. It is internally done if the arguments #:julia-package-name and #:julia-package-uuid are provided.

Variável: maven-build-system

This variable is exported by (guix build-system maven). It implements a build procedure for Maven packages. Maven is a dependency and lifecycle management tool for Java. A user of Maven specifies dependencies and plugins in a pom.xml file that Maven reads. When Maven does not have one of the dependencies or plugins in its repository, it will download them and use them to build the package.

The maven build system ensures that maven will not try to download any dependency by running in offline mode. Maven will fail if a dependency is missing. Before running Maven, the pom.xml (and subprojects) are modified to specify the version of dependencies and plugins that match the versions available in the guix build environment. Dependencies and plugins must be installed in the fake maven repository at lib/m2, and are symlinked into a proper repository before maven is run. Maven is instructed to use that repository for the build and installs built artifacts there. Changed files are copied to the lib/m2 directory of the package output.

You can specify a pom.xml file with the #:pom-file argument, or let the build system use the default pom.xml file in the sources.

In case you need to specify a dependency’s version manually, you can use the #:local-packages argument. It takes an association list where the key is the groupId of the package and its value is an association list where the key is the artifactId of the package and its value is the version you want to override in the pom.xml.

Some packages use dependencies or plugins that are not useful at runtime nor at build time in Guix. You can alter the pom.xml file to remove them using the #:exclude argument. Its value is an association list where the key is the groupId of the plugin or dependency you want to remove, and the value is a list of artifactId you want to remove.

You can override the default jdk and maven packages with the corresponding argument, #:jdk and #:maven.

The #:maven-plugins argument is a list of maven plugins used during the build, with the same format as the inputs fields of the package declaration. Its default value is (default-maven-plugins) which is also exported.

Variável: minetest-mod-build-system

This variable is exported by (guix build-system minetest). It implements a build procedure for Minetest mods, which consists of copying Lua code, images and other resources to the location Minetest searches for mods. The build system also minimises PNG images and verifies that Minetest can load the mod without errors.

Variável: minify-build-system

This variable is exported by (guix build-system minify). It implements a minification procedure for simple JavaScript packages.

It adds uglify-js to the set of inputs and uses it to compress all JavaScript files in the src directory. A different minifier package can be specified with the #:uglify-js parameter, but it is expected that the package writes the minified code to the standard output.

When the input JavaScript files are not all located in the src directory, the parameter #:javascript-files can be used to specify a list of file names to feed to the minifier.

Variável: mozilla-build-system

This variable is exported by (guix build-system mozilla). It sets the --target and --host configuration flags to what software developed by Mozilla expects – due to historical reasons, Mozilla software expects --host to be the system that is cross-compiled from and --target to be the system that is cross-compiled to, contrary to the standard Autotools conventions.

Variável: ocaml-build-system

This variable is exported by (guix build-system ocaml). It implements a build procedure for OCaml packages, which consists of choosing the correct set of commands to run for each package. OCaml packages can expect many different commands to be run. This build system will try some of them.

When the package has a setup.ml file present at the top-level, it will run ocaml setup.ml -configure, ocaml setup.ml -build and ocaml setup.ml -install. The build system will assume that this file was generated by OASIS and will take care of setting the prefix and enabling tests if they are not disabled. You can pass configure and build flags with the #:configure-flags and #:build-flags. The #:test-flags key can be passed to change the set of flags used to enable tests. The #:use-make? key can be used to bypass this system in the build and install phases.

When the package has a configure file, it is assumed that it is a hand-made configure script that requires a different argument format than in the gnu-build-system. You can add more flags with the #:configure-flags key.

When the package has a Makefile file (or #:use-make? is #t), it will be used and more flags can be passed to the build and install phases with the #:make-flags key.

Finally, some packages do not have these files and use a somewhat standard location for its build system. In that case, the build system will run ocaml pkg/pkg.ml or ocaml pkg/build.ml and take care of providing the path to the required findlib module. Additional flags can be passed via the #:build-flags key. Install is taken care of by opam-installer. In this case, the opam package must be added to the native-inputs field of the package definition.

Note that most OCaml packages assume they will be installed in the same directory as OCaml, which is not what we want in guix. In particular, they will install .so files in their module’s directory, which is usually fine because it is in the OCaml compiler directory. In guix though, these libraries cannot be found and we use CAML_LD_LIBRARY_PATH. This variable points to lib/ocaml/site-lib/stubslibs and this is where .so libraries should be installed.

Variável: python-build-system

This variable is exported by (guix build-system python). It implements the more or less standard build procedure used by Python packages, which consists in running python setup.py build and then python setup.py install --prefix=/gnu/store/….

For packages that install stand-alone Python programs under bin/, it takes care of wrapping these programs so that their GUIX_PYTHONPATH environment variable points to all the Python libraries they depend on.

Which Python package is used to perform the build can be specified with the #:python parameter. This is a useful way to force a package to be built for a specific version of the Python interpreter, which might be necessary if the package is only compatible with a single interpreter version.

By default guix calls setup.py under control of setuptools, much like pip does. Some packages are not compatible with setuptools (and pip), thus you can disable this by setting the #:use-setuptools? parameter to #f.

If a "python" output is available, the package is installed into it instead of the default "out" output. This is useful for packages that include a Python package as only a part of the software, and thus want to combine the phases of python-build-system with another build system. Python bindings are a common usecase.

Variável: pyproject-build-system

This is a variable exported by guix build-system pyproject. It is based on python-build-system, and adds support for pyproject.toml and PEP 517. It also supports a variety of build backends and test frameworks.

The API is slightly different from python-build-system:

  • #:use-setuptools? and #:test-target is removed.
  • #:build-backend is added. It defaults to #false and will try to guess the appropriate backend based on pyproject.toml.
  • #:test-backend is added. It defaults to #false and will guess an appropriate test backend based on what is available in package inputs.
  • #:test-flags is added. The default is '(). These flags are passed as arguments to the test command. Note that flags for verbose output is always enabled on supported backends.

It is considered “experimental” in that the implementation details are not set in stone yet, however users are encouraged to try it for new Python projects (even those using setup.py). The API is subject to change, but any breaking changes in the Guix channel will be dealt with.

Eventually this build system will be deprecated and merged back into python-build-system, probably some time in 2024.

Variável: perl-build-system

This variable is exported by (guix build-system perl). It implements the standard build procedure for Perl packages, which either consists in running perl Build.PL --prefix=/gnu/store/…, followed by Build and Build install; or in running perl Makefile.PL PREFIX=/gnu/store/…, followed by make and make install, depending on which of Build.PL or Makefile.PL is present in the package distribution. Preference is given to the former if both Build.PL and Makefile.PL exist in the package distribution. This preference can be reversed by specifying #t for the #:make-maker? parameter.

The initial perl Makefile.PL or perl Build.PL invocation passes flags specified by the #:make-maker-flags or #:module-build-flags parameter, respectively.

Which Perl package is used can be specified with #:perl.

Variável: renpy-build-system

This variable is exported by (guix build-system renpy). It implements the more or less standard build procedure used by Ren’py games, which consists of loading #:game once, thereby creating bytecode for it.

It further creates a wrapper script in bin/ and a desktop entry in share/applications, both of which can be used to launch the game.

Which Ren’py package is used can be specified with #:renpy. Games can also be installed in outputs other than “out” by using #:output.

Variável: qt-build-system

This variable is exported by (guix build-system qt). It is intended for use with applications using Qt or KDE.

This build system adds the following two phases to the ones defined by cmake-build-system:

check-setup

The phase check-setup prepares the environment for running the checks as commonly used by Qt test programs. For now this only sets some environment variables: QT_QPA_PLATFORM=offscreen, DBUS_FATAL_WARNINGS=0 and CTEST_OUTPUT_ON_FAILURE=1.

This phase is added before the check phase. It’s a separate phase to ease adjusting if necessary.

qt-wrap

The phase qt-wrap searches for Qt5 plugin paths, QML paths and some XDG in the inputs and output. In case some path is found, all programs in the output’s bin/, sbin/, libexec/ and lib/libexec/ directories are wrapped in scripts defining the necessary environment variables.

It is possible to exclude specific package outputs from that wrapping process by listing their names in the #:qt-wrap-excluded-outputs parameter. This is useful when an output is known not to contain any Qt binaries, and where wrapping would gratuitously add a dependency of that output on Qt, KDE, or such.

This phase is added after the install phase.

Variável: r-build-system

This variable is exported by (guix build-system r). It implements the build procedure used by R packages, which essentially is little more than running ‘R CMD INSTALL --library=/gnu/store/…’ in an environment where R_LIBS_SITE contains the paths to all R package inputs. Tests are run after installation using the R function tools::testInstalledPackage.

Variável: rakudo-build-system

This variable is exported by (guix build-system rakudo). It implements the build procedure used by Rakudo for Perl6 packages. It installs the package to /gnu/store/…/NAME-VERSION/share/perl6 and installs the binaries, library files and the resources, as well as wrap the files under the bin/ directory. Tests can be skipped by passing #f to the tests? parameter.

Which rakudo package is used can be specified with rakudo. Which perl6-tap-harness package used for the tests can be specified with #:prove6 or removed by passing #f to the with-prove6? parameter. Which perl6-zef package used for tests and installing can be specified with #:zef or removed by passing #f to the with-zef? parameter.

Variável: rebar-build-system

This variable is exported by (guix build-system rebar). It implements a build procedure around rebar3, a build system for programs written in the Erlang language.

It adds both rebar3 and the erlang to the set of inputs. Different packages can be specified with the #:rebar and #:erlang parameters, respectively.

This build system is based on gnu-build-system, but with the following phases changed:

unpack

This phase, after unpacking the source like the gnu-build-system does, checks for a file contents.tar.gz at the top-level of the source. If this file exists, it will be unpacked, too. This eases handling of package hosted at https://hex.pm/, the Erlang and Elixir package repository.

bootstrap
configure

There are no bootstrap and configure phase because erlang packages typically don’t need to be configured.

build

This phase runs rebar3 compile with the flags listed in #:rebar-flags.

marcar

Unless #:tests? #f is passed, this phase runs rebar3 eunit, or some other target specified with #:test-target, with the flags listed in #:rebar-flags,

instalar

This installs the files created in the default profile, or some other profile specified with #:install-profile.

Variável: texlive-build-system

This variable is exported by (guix build-system texlive). It is used to build TeX packages in batch mode with a specified engine. The build system sets the TEXINPUTS variable to find all TeX source files in the inputs.

By default it tries to run luatex on all .ins files, and if it fails to find any, on all .dtx files. A different engine and format can be specified with, respectively, the #:tex-engine and #:tex-format arguments. Different build targets can be specified with the #:build-targets argument, which expects a list of file names.

It also generates font metrics (i.e., .tfm files) out of Metafont files whenever possible. Likewise, it can also create TeX formats (i.e., .fmt files) listed in the #:create-formats argument, and generate a symbolic link from bin/ directory to any script located in texmf-dist/scripts/, provided its file name is listed in #:link-scripts argument.

The build system adds texlive-bin from (gnu packages tex) to the native inputs. It can be overridden with the #:texlive-bin argument.

The package texlive-latex-bin, from the same module, contains most of the tools for building TeX Live packages; for convenience, it is also added by default to the native inputs. However, this can be troublesome when building a dependency of texlive-latex-bin itself. In this particular situation, the #:texlive-latex-bin? argument should be set to #f.

Variável: ruby-build-system

This variable is exported by (guix build-system ruby). It implements the RubyGems build procedure used by Ruby packages, which involves running gem build followed by gem install.

The source field of a package that uses this build system typically references a gem archive, since this is the format that Ruby developers use when releasing their software. The build system unpacks the gem archive, potentially patches the source, runs the test suite, repackages the gem, and installs it. Additionally, directories and tarballs may be referenced to allow building unreleased gems from Git or a traditional source release tarball.

Which Ruby package is used can be specified with the #:ruby parameter. A list of additional flags to be passed to the gem command can be specified with the #:gem-flags parameter.

Variável: waf-build-system

This variable is exported by (guix build-system waf). It implements a build procedure around the waf script. The common phases—configure, build, and install—are implemented by passing their names as arguments to the waf script.

The waf script is executed by the Python interpreter. Which Python package is used to run the script can be specified with the #:python parameter.

Variável: zig-build-system

This variable is exported by (guix build-system zig). It implements the build procedures for the Zig build system (zig build command).

Selecting this build system adds zig to the package inputs, in addition to the packages of gnu-build-system.

There is no configure phase because Zig packages typically do not need to be configured. The #:zig-build-flags parameter is a list of flags that are passed to the zig command during the build. The #:zig-test-flags parameter is a list of flags that are passed to the zig test command during the check phase. The default compiler package can be overridden with the #:zig argument.

The optional zig-release-type parameter declares the type of release. Possible values are: safe, fast, or small. The default value is #f, which causes the release flag to be omitted from the zig command. That results in a debug build.

Variável: scons-build-system

This variable is exported by (guix build-system scons). It implements the build procedure used by the SCons software construction tool. This build system runs scons to build the package, scons test to run tests, and then scons install to install the package.

Additional flags to be passed to scons can be specified with the #:scons-flags parameter. The default build and install targets can be overridden with #:build-targets and #:install-targets respectively. The version of Python used to run SCons can be specified by selecting the appropriate SCons package with the #:scons parameter.

Variável: haskell-build-system

This variable is exported by (guix build-system haskell). It implements the Cabal build procedure used by Haskell packages, which involves running runhaskell Setup.hs configure --prefix=/gnu/store/… and runhaskell Setup.hs build. Instead of installing the package by running runhaskell Setup.hs install, to avoid trying to register libraries in the read-only compiler store directory, the build system uses runhaskell Setup.hs copy, followed by runhaskell Setup.hs register. In addition, the build system generates the package documentation by running runhaskell Setup.hs haddock, unless #:haddock? #f is passed. Optional Haddock parameters can be passed with the help of the #:haddock-flags parameter. If the file Setup.hs is not found, the build system looks for Setup.lhs instead.

Which Haskell compiler is used can be specified with the #:haskell parameter which defaults to ghc.

Variável: dub-build-system

This variable is exported by (guix build-system dub). It implements the Dub build procedure used by D packages, which involves running dub build and dub run. Installation is done by copying the files manually.

Which D compiler is used can be specified with the #:ldc parameter which defaults to ldc.

Variável: emacs-build-system

This variable is exported by (guix build-system emacs). It implements an installation procedure similar to the packaging system of Emacs itself (veja Packages em The GNU Emacs Manual).

It first creates the package-autoloads.el file, then it byte compiles all Emacs Lisp files. Differently from the Emacs packaging system, the Info documentation files are moved to the standard documentation directory and the dir file is deleted. The Elisp package files are installed directly under share/emacs/site-lisp.

Variável: font-build-system

This variable is exported by (guix build-system font). It implements an installation procedure for font packages where upstream provides pre-compiled TrueType, OpenType, etc. font files that merely need to be copied into place. It copies font files to standard locations in the output directory.

Variável: meson-build-system

This variable is exported by (guix build-system meson). It implements the build procedure for packages that use Meson as their build system.

It adds both Meson and Ninja to the set of inputs, and they can be changed with the parameters #:meson and #:ninja if needed.

This build system is an extension of gnu-build-system, but with the following phases changed to some specific for Meson:

configure

The phase runs meson with the flags specified in #:configure-flags. The flag --buildtype is always set to debugoptimized unless something else is specified in #:build-type.

build

The phase runs ninja to build the package in parallel by default, but this can be changed with #:parallel-build?.

marcar

The phase runs ‘meson test’ with a base set of options that cannot be overridden. This base set of options can be extended via the #:test-options argument, for example to select or skip a specific test suite.

instalar

The phase runs ninja install and can not be changed.

Apart from that, the build system also adds the following phases:

fix-runpath

This phase ensures that all binaries can find the libraries they need. It searches for required libraries in subdirectories of the package being built, and adds those to RUNPATH where needed. It also removes references to libraries left over from the build phase by meson, such as test dependencies, that aren’t actually required for the program to run.

glib-or-gtk-wrap

This phase is the phase provided by glib-or-gtk-build-system, and it is not enabled by default. It can be enabled with #:glib-or-gtk?.

glib-or-gtk-compile-schemas

This phase is the phase provided by glib-or-gtk-build-system, and it is not enabled by default. It can be enabled with #:glib-or-gtk?.

Variável: linux-module-build-system

linux-module-build-system allows building Linux kernel modules.

This build system is an extension of gnu-build-system, but with the following phases changed:

configure

This phase configures the environment so that the Linux kernel’s Makefile can be used to build the external kernel module.

build

This phase uses the Linux kernel’s Makefile in order to build the external kernel module.

instalar

This phase uses the Linux kernel’s Makefile in order to install the external kernel module.

It is possible and useful to specify the Linux kernel to use for building the module (in the arguments form of a package using the linux-module-build-system, use the key #:linux to specify it).

Variável: node-build-system

This variable is exported by (guix build-system node). It implements the build procedure used by Node.js, which implements an approximation of the npm install command, followed by an npm test command.

Which Node.js package is used to interpret the npm commands can be specified with the #:node parameter which defaults to node.

Variável: tree-sitter-build-system

This variable is exported by (guix build-system tree-sitter). It implements procedures to compile grammars for the Tree-sitter parsing library. It essentially runs tree-sitter generate to translate grammar.js grammars to JSON and then to C. Which it then compiles to native code.

Tree-sitter packages may support multiple grammars, so this build system supports a #:grammar-directories keyword to specify a list of locations where a grammar.js file may be found.

Grammars sometimes depend on each other, such as C++ depending on C and TypeScript depending on JavaScript. You may use inputs to declare such dependencies.

Lastly, for packages that do not need anything as sophisticated, a “trivial” build system is provided. It is trivial in the sense that it provides basically no support: it does not pull any implicit inputs, and does not have a notion of build phases.

Variável: trivial-build-system

This variable is exported by (guix build-system trivial).

This build system requires a #:builder argument. This argument must be a Scheme expression that builds the package output(s)—as with build-expression->derivation (veja build-expression->derivation).

Variável: channel-build-system

This variable is exported by (guix build-system channel).

This build system is meant primarily for internal use. A package using this build system must have a channel specification as its source field (veja Canais); alternatively, its source can be a directory name, in which case an additional #:commit argument must be supplied to specify the commit being built (a hexadecimal string).

Optionally, a #:channels argument specifying additional channels can be provided.

The resulting package is a Guix instance of the given channel(s), similar to how guix time-machine would build it.


8.6 Build Phases

Almost all package build systems implement a notion build phases: a sequence of actions that the build system executes, when you build the package, leading to the installed byproducts in the store. A notable exception is the “bare-bones” trivial-build-system (veja Sistemas de compilação).

As discussed in the previous section, those build systems provide a standard list of phases. For gnu-build-system, the main build phases are the following:

set-paths

Define search path environment variables for all the input packages, including PATH (veja Search Paths).

unpack

Unpack the source tarball, and change the current directory to the extracted source tree. If the source is actually a directory, copy it to the build tree, and enter that directory.

patch-source-shebangs

Patch shebangs encountered in source files so they refer to the right store file names. For instance, this changes #!/bin/sh to #!/gnu/store/…-bash-4.3/bin/sh.

configure

Run the configure script with a number of default options, such as --prefix=/gnu/store/…, as well as the options specified by the #:configure-flags argument.

build

Run make with the list of flags specified with #:make-flags. If the #:parallel-build? argument is true (the default), build with make -j.

marcar

Run make check, or some other target specified with #:test-target, unless #:tests? #f is passed. If the #:parallel-tests? argument is true (the default), run make check -j.

instalar

Run make install with the flags listed in #:make-flags.

patch-shebangs

Patch shebangs on the installed executable files.

strip

Strip debugging symbols from ELF files (unless #:strip-binaries? is false), copying them to the debug output when available (veja Instalando arquivos de depuração).

validate-runpath

Validate the RUNPATH of ELF binaries, unless #:validate-runpath? is false (veja Sistemas de compilação).

This validation step consists in making sure that all the shared libraries needed by an ELF binary, which are listed as DT_NEEDED entries in its PT_DYNAMIC segment, appear in the DT_RUNPATH entry of that binary. In other words, it ensures that running or using those binaries will not result in a “file not found” error at run time. Veja -rpath em The GNU Linker, for more information on RUNPATH.

Other build systems have similar phases, with some variations. For example, cmake-build-system has same-named phases but its configure phases runs cmake instead of ./configure. Others, such as python-build-system, have a wholly different list of standard phases. All this code runs on the build side: it is evaluated when you actually build the package, in a dedicated build process spawned by the build daemon (veja Invocando guix-daemon).

Build phases are represented as association lists or “alists” (veja Association Lists em GNU Guile Reference Manual) where each key is a symbol for the name of the phase and the associated value is a procedure that accepts an arbitrary number of arguments. By convention, those procedures receive information about the build in the form of keyword parameters, which they can use or ignore.

For example, here is how (guix build gnu-build-system) defines %standard-phases, the variable holding its alist of build phases21:

;; The build phases of 'gnu-build-system'.

(define* (unpack #:key source #:allow-other-keys)
  ;; Extract the source tarball.
  (invoke "tar" "xvf" source))

(define* (configure #:key outputs #:allow-other-keys)
  ;; Run the 'configure' script.  Install to output "out".
  (let ((out (assoc-ref outputs "out")))
    (invoke "./configure"
            (string-append "--prefix=" out))))

(define* (build #:allow-other-keys)
  ;; Compile.
  (invoke "make"))

(define* (check #:key (test-target "check") (tests? #true)
                #:allow-other-keys)
  ;; Run the test suite.
  (if tests?
      (invoke "make" test-target)
      (display "test suite not run\n")))

(define* (install #:allow-other-keys)
  ;; Install files to the prefix 'configure' specified.
  (invoke "make" "install"))

(define %standard-phases
  ;; The list of standard phases (quite a few are omitted
  ;; for brevity).  Each element is a symbol/procedure pair.
  (list (cons 'unpack unpack)
        (cons 'configure configure)
        (cons 'build build)
        (cons 'check check)
        (cons 'install install)))

This shows how %standard-phases is defined as a list of symbol/procedure pairs (veja Pairs em GNU Guile Reference Manual). The first pair associates the unpack procedure with the unpack symbol—a name; the second pair defines the configure phase similarly, and so on. When building a package that uses gnu-build-system with its default list of phases, those phases are executed sequentially. You can see the name of each phase started and completed in the build log of packages that you build.

Let’s now look at the procedures themselves. Each one is defined with define*: #:key lists keyword parameters the procedure accepts, possibly with a default value, and #:allow-other-keys specifies that other keyword parameters are ignored (veja Optional Arguments em GNU Guile Reference Manual).

The unpack procedure honors the source parameter, which the build system uses to pass the file name of the source tarball (or version control checkout), and it ignores other parameters. The configure phase only cares about the outputs parameter, an alist mapping package output names to their store file name (veja Pacotes com múltiplas saídas). It extracts the file name of for out, the default output, and passes it to ./configure as the installation prefix, meaning that make install will eventually copy all the files in that directory (veja configuration and makefile conventions em GNU Coding Standards). build and install ignore all their arguments. check honors the test-target argument, which specifies the name of the Makefile target to run tests; it prints a message and skips tests when tests? is false.

The list of phases used for a particular package can be changed with the #:phases parameter of the build system. Changing the set of build phases boils down to building a new alist of phases based on the %standard-phases alist described above. This can be done with standard alist procedures such as alist-delete (veja SRFI-1 Association Lists em GNU Guile Reference Manual); however, it is more convenient to do so with modify-phases (veja modify-phases).

Here is an example of a package definition that removes the configure phase of %standard-phases and inserts a new phase before the build phase, called set-prefix-in-makefile:

(define-public example
  (package
    (name "example")
    ;; other fields omitted
    (build-system gnu-build-system)
    (arguments
     (list
      #:phases
      #~(modify-phases %standard-phases
          (delete 'configure)
          (add-before 'build 'set-prefix-in-makefile
            (lambda* (#:key inputs #:allow-other-keys)
              ;; Modify the makefile so that its
              ;; 'PREFIX' variable points to #$output and
              ;; 'XMLLINT' points to the correct path.
              (substitute* "Makefile"
                (("PREFIX =.*")
                 (string-append "PREFIX = " #$output "\n"))
                (("XMLLINT =.*")
                 (string-append "XMLLINT = "
                                (search-input-file inputs "/bin/xmllint")
                                "\n"))))))))))

The new phase that is inserted is written as an anonymous procedure, introduced with lambda*; it looks for the xmllint executable under a /bin directory among the package’s inputs (veja package Reference). It also honors the outputs parameter we have seen before. Veja Build Utilities, for more about the helpers used by this phase, and for more examples of modify-phases.

Tip: You can inspect the code associated with a package’s #:phases argument interactively, at the REPL (veja Using Guix Interactively).

Keep in mind that build phases are code evaluated at the time the package is actually built. This explains why the whole modify-phases expression above is quoted (it comes after the ' or apostrophe): it is staged for later execution. Veja Expressões-G, for an explanation of code staging and the code strata involved.


8.7 Build Utilities

As soon as you start writing non-trivial package definitions (veja Definindo pacotes) or other build actions (veja Expressões-G), you will likely start looking for helpers for “shell-like” actions—creating directories, copying and deleting files recursively, manipulating build phases, and so on. The (guix build utils) module provides such utility procedures.

Most build systems load (guix build utils) (veja Sistemas de compilação). Thus, when writing custom build phases for your package definitions, you can usually assume those procedures are in scope.

When writing G-expressions, you can import (guix build utils) on the “build side” using with-imported-modules and then put it in scope with the use-modules form (veja Using Guile Modules em GNU Guile Reference Manual):

(with-imported-modules '((guix build utils))  ;import it
  (computed-file "empty-tree"
                 #~(begin
                     ;; Put it in scope.
                     (use-modules (guix build utils))

                     ;; Happily use its 'mkdir-p' procedure.
                     (mkdir-p (string-append #$output "/a/b/c")))))

The remainder of this section is the reference for most of the utility procedures provided by (guix build utils).

8.7.1 Dealing with Store File Names

This section documents procedures that deal with store file names.

Procedure: %store-directory

Return the directory name of the store.

Procedure: store-file-name? file

Return true if file is in the store.

Procedure: strip-store-file-name file

Strip the /gnu/store and hash from file, a store file name. The result is typically a "package-version" string.

Procedure: package-name->name+version name

Given name, a package name like "foo-0.9.1b", return two values: "foo" and "0.9.1b". When the version part is unavailable, name and #f are returned. The first hyphen followed by a digit is considered to introduce the version part.

8.7.2 File Types

The procedures below deal with files and file types.

Procedure: directory-exists? dir

Return #t if dir exists and is a directory.

Procedure: executable-file? file

Return #t if file exists and is executable.

Return #t if file is a symbolic link (aka. a “symlink”).

Procedure: elf-file? file
Procedure: ar-file? file
Procedure: gzip-file? file

Return #t if file is, respectively, an ELF file, an ar archive (such as a .a static library), or a gzip file.

Procedure: reset-gzip-timestamp file [#:keep-mtime? #t]

If file is a gzip file, reset its embedded timestamp (as with gzip --no-name) and return true. Otherwise return #f. When keep-mtime? is true, preserve file’s modification time.

8.7.3 File Manipulation

The following procedures and macros help create, modify, and delete files. They provide functionality comparable to common shell utilities such as mkdir -p, cp -r, rm -r, and sed. They complement Guile’s extensive, but low-level, file system interface (veja POSIX em GNU Guile Reference Manual).

Macro: with-directory-excursion directory body …

Run body with directory as the process’s current directory.

Essentially, this macro changes the current directory to directory before evaluating body, using chdir (veja Processes em GNU Guile Reference Manual). It changes back to the initial directory when the dynamic extent of body is left, be it via normal procedure return or via a non-local exit such as an exception.

Procedure: mkdir-p dir

Create directory dir and all its ancestors.

Procedure: install-file file directory

Create directory if it does not exist and copy file in there under the same name.

Procedure: make-file-writable file

Make file writable for its owner.

Procedure: copy-recursively source destination [#:log (current-output-port)] [#:follow-symlinks? #f]  [#:copy-file

copy-file] [#:keep-mtime? #f] [#:keep-permissions? #t] [#:select? (const #t)] Copy source directory to destination. Follow symlinks if follow-symlinks? is true; otherwise, just preserve them. Call copy-file to copy regular files. Call select?, taking two arguments, file and stat, for each entry in source, where file is the entry’s absolute file name and stat is the result of lstat (or stat if follow-symlinks? is true); exclude entries for which select? does not return true. When keep-mtime? is true, keep the modification time of the files in source on those of destination. When keep-permissions? is true, preserve file permissions. Write verbose output to the log port.

Procedure: delete-file-recursively dir [#:follow-mounts? #f]

Delete dir recursively, like rm -rf, without following symlinks. Don’t follow mount points either, unless follow-mounts? is true. Report but ignore errors.

Macro: substitute* file ((regexp match-var…) body…) … Substitute regexp in

file by the string returned by body. body is evaluated with each match-var bound to the corresponding positional regexp sub-expression. For example:

(substitute* file
  (("hello")
   "good morning\n")
  (("foo([a-z]+)bar(.*)$" all letters end)
   (string-append "baz" letters end)))

Here, anytime a line of file contains hello, it is replaced by good morning. Anytime a line of file matches the second regexp, all is bound to the complete match, letters is bound to the first sub-expression, and end is bound to the last one.

When one of the match-var is _, no variable is bound to the corresponding match substring.

Alternatively, file may be a list of file names, in which case they are all subject to the substitutions.

Be careful about using $ to match the end of a line; by itself it won’t match the terminating newline of a line. For example, to match a whole line ending with a backslash, one needs a regex like "(.*)\\\\\n$".

8.7.5 Program Invocation

You’ll find handy procedures to spawn processes in this module, essentially convenient wrappers around Guile’s system* (veja system* em GNU Guile Reference Manual).

Procedure: invoke program args…

Invoke program with the given args. Raise an &invoke-error exception if the exit code is non-zero; otherwise return #t.

The advantage compared to system* is that you do not need to check the return value. This reduces boilerplate in shell-script-like snippets for instance in package build phases.

Procedure: invoke-error? c

Return true if c is an &invoke-error condition.

Procedure: invoke-error-program c
Procedure: invoke-error-arguments c
Procedure: invoke-error-exit-status c
Procedure: invoke-error-term-signal c
Procedure: invoke-error-stop-signal c

Access specific fields of c, an &invoke-error condition.

Procedure: report-invoke-error c [port]

Report to port (by default the current error port) about c, an &invoke-error condition, in a human-friendly way.

Typical usage would look like this:

(use-modules (srfi srfi-34) ;for 'guard'
             (guix build utils))

(guard (c ((invoke-error? c)
           (report-invoke-error c)))
  (invoke "date" "--imaginary-option"))

-| command "date" "--imaginary-option" failed with status 1
Procedure: invoke/quiet program args…

Invoke program with args and capture program’s standard output and standard error. If program succeeds, print nothing and return the unspecified value; otherwise, raise a &message error condition that includes the status code and the output of program.

Here’s an example:

(use-modules (srfi srfi-34) ;for 'guard'
             (srfi srfi-35) ;for 'message-condition?'
             (guix build utils))

(guard (c ((message-condition? c)
           (display (condition-message c))))
  (invoke/quiet "date")  ;all is fine
  (invoke/quiet "date" "--imaginary-option"))

-| 'date --imaginary-option' exited with status 1; output follows:

    date: unrecognized option '--imaginary-option'
    Try 'date --help' for more information.

8.7.6 Build Phases

The (guix build utils) also contains tools to manipulate build phases as used by build systems (veja Sistemas de compilação). Build phases are represented as association lists or “alists” (veja Association Lists em GNU Guile Reference Manual) where each key is a symbol naming the phase and the associated value is a procedure (veja Build Phases).

Guile core and the (srfi srfi-1) module both provide tools to manipulate alists. The (guix build utils) module complements those with tools written with build phases in mind.

Macro: modify-phases phases clause…

Modify phases sequentially as per each clause, which may have one of the following forms:

(delete old-phase-name)
(replace old-phase-name new-phase)
(add-before old-phase-name new-phase-name new-phase)
(add-after old-phase-name new-phase-name new-phase)

Where every phase-name above is an expression evaluating to a symbol, and new-phase an expression evaluating to a procedure.

The example below is taken from the definition of the grep package. It adds a phase to run after the install phase, called fix-egrep-and-fgrep. That phase is a procedure (lambda* is for anonymous procedures) that takes a #:outputs keyword argument and ignores extra keyword arguments (veja Optional Arguments em GNU Guile Reference Manual, for more on lambda* and optional and keyword arguments.) The phase uses substitute* to modify the installed egrep and fgrep scripts so that they refer to grep by its absolute file name:

(modify-phases %standard-phases
  (add-after 'install 'fix-egrep-and-fgrep
    ;; Patch 'egrep' and 'fgrep' to execute 'grep' via its
    ;; absolute file name instead of searching for it in $PATH.
    (lambda* (#:key outputs #:allow-other-keys)
      (let* ((out (assoc-ref outputs "out"))
             (bin (string-append out "/bin")))
        (substitute* (list (string-append bin "/egrep")
                           (string-append bin "/fgrep"))
          (("^exec grep")
           (string-append "exec " bin "/grep")))))))

In the example below, phases are modified in two ways: the standard configure phase is deleted, presumably because the package does not have a configure script or anything similar, and the default install phase is replaced by one that manually copies the executable files to be installed:

(modify-phases %standard-phases
  (delete 'configure)      ;no 'configure' script
  (replace 'install
    (lambda* (#:key outputs #:allow-other-keys)
      ;; The package's Makefile doesn't provide an "install"
      ;; rule so do it by ourselves.
      (let ((bin (string-append (assoc-ref outputs "out")
                                "/bin")))
        (install-file "footswitch" bin)
        (install-file "scythe" bin)))))

8.7.7 Wrappers

It is not unusual for a command to require certain environment variables to be set for proper functioning, typically search paths (veja Search Paths). Failing to do that, the command might fail to find files or other commands it relies on, or it might pick the “wrong” ones—depending on the environment in which it runs. Examples include:

  • a shell script that assumes all the commands it uses are in PATH;
  • a Guile program that assumes all its modules are in GUILE_LOAD_PATH and GUILE_LOAD_COMPILED_PATH;
  • a Qt application that expects to find certain plugins in QT_PLUGIN_PATH.

For a package writer, the goal is to make sure commands always work the same rather than depend on some external settings. One way to achieve that is to wrap commands in a thin script that sets those environment variables, thereby ensuring that those run-time dependencies are always found. The wrapper would be used to set PATH, GUILE_LOAD_PATH, or QT_PLUGIN_PATH in the examples above.

To ease that task, the (guix build utils) module provides a couple of helpers to wrap commands.

Procedure: wrap-program program [#:sh sh] [#:rest variables]

Make a wrapper for program. variables should look like this:

'(variable delimiter position list-of-directories)

where delimiter is optional. : will be used if delimiter is not given.

For example, this call:

(wrap-program "foo"
              '("PATH" ":" = ("/gnu/.../bar/bin"))
              '("CERT_PATH" suffix ("/gnu/.../baz/certs"
                                    "/qux/certs")))

will copy foo to .foo-real and create the file foo with the following contents:

#!location/of/bin/bash
export PATH="/gnu/.../bar/bin"
export CERT_PATH="$CERT_PATH${CERT_PATH:+:}/gnu/.../baz/certs:/qux/certs"
exec -a $0 location/of/.foo-real "$@"

If program has previously been wrapped by wrap-program, the wrapper is extended with definitions for variables. If it is not, sh will be used as the interpreter.

Procedure: wrap-script program [#:guile guile] [#:rest variables]

Wrap the script program such that variables are set first. The format of variables is the same as in the wrap-program procedure. This procedure differs from wrap-program in that it does not create a separate shell script. Instead, program is modified directly by prepending a Guile script, which is interpreted as a comment in the script’s language.

Special encoding comments as supported by Python are recreated on the second line.

Note that this procedure can only be used once per file as Guile scripts are not supported.


8.8 Search Paths

Many programs and libraries look for input data in a search path, a list of directories: shells like Bash look for executables in the command search path, a C compiler looks for .h files in its header search path, the Python interpreter looks for .py files in its search path, the spell checker has a search path for dictionaries, and so on.

Search paths can usually be defined or overridden via environment variables (veja Environment Variables em The GNU C Library Reference Manual). For example, the search paths mentioned above can be changed by defining the PATH, C_INCLUDE_PATH, PYTHONPATH (or GUIX_PYTHONPATH), and DICPATH environment variables—you know, all these something-PATH variables that you need to get right or things “won’t be found”.

You may have noticed from the command line that Guix “knows” which search path environment variables should be defined, and how. When you install packages in your default profile, the file ~/.guix-profile/etc/profile is created, which you can “source” from the shell to set those variables. Likewise, if you ask guix shell to create an environment containing Python and NumPy, a Python library, and if you pass it the --search-paths option, it will tell you about PATH and GUIX_PYTHONPATH (veja Invoking guix shell):

$ guix shell python python-numpy --pure --search-paths
export PATH="/gnu/store/…-profile/bin"
export GUIX_PYTHONPATH="/gnu/store/…-profile/lib/python3.9/site-packages"

When you omit --search-paths, it defines these environment variables right away, such that Python can readily find NumPy:

$ guix shell python python-numpy -- python3
Python 3.9.6 (default, Jan  1 1970, 00:00:01)
[GCC 10.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import numpy
>>> numpy.version.version
'1.20.3'

For this to work, the definition of the python package declares the search path it cares about and its associated environment variable, GUIX_PYTHONPATH. It looks like this:

(package
  (name "python")
  (version "3.9.9")
  ;; some fields omitted...
  (native-search-paths
   (list (search-path-specification
          (variable "GUIX_PYTHONPATH")
          (files (list "lib/python/3.9/site-packages"))))))

What this native-search-paths field says is that, when the python package is used, the GUIX_PYTHONPATH environment variable must be defined to include all the lib/python/3.9/site-packages sub-directories encountered in its environment. (The native- bit means that, if we are in a cross-compilation environment, only native inputs may be added to the search path; veja search-paths.) In the NumPy example above, the profile where python appears contains exactly one such sub-directory, and GUIX_PYTHONPATH is set to that. When there are several lib/python/3.9/site-packages—this is the case in package build environments—they are all added to GUIX_PYTHONPATH, separated by colons (:).

Nota: Notice that GUIX_PYTHONPATH is specified as part of the definition of the python package, and not as part of that of python-numpy. This is because this environment variable “belongs” to Python, not NumPy: Python actually reads the value of that variable and honors it.

Corollary: if you create a profile that does not contain python, GUIX_PYTHONPATH will not be defined, even if it contains packages that provide .py files:

$ guix shell python-numpy --search-paths --pure
export PATH="/gnu/store/…-profile/bin"

This makes a lot of sense if we look at this profile in isolation: no software in this profile would read GUIX_PYTHONPATH.

Of course, there are many variations on that theme: some packages honor more than one search path, some use separators other than colon, some accumulate several directories in their search path, and so on. A more complex example is the search path of libxml2: the value of the XML_CATALOG_FILES environment variable is space-separated, it must contain a list of catalog.xml files (not directories), which are to be found in xml sub-directories—nothing less. The search path specification looks like this:

(search-path-specification
 (variable "XML_CATALOG_FILES")
 (separator " ")
 (files '("xml"))
 (file-pattern "^catalog\\.xml$")
 (file-type 'regular))

Worry not, search path specifications are usually not this tricky.

The (guix search-paths) module defines the data type of search path specifications and a number of helper procedures. Below is the reference of search path specifications.

Data Type: search-path-specification

The data type for search path specifications.

variable

The name of the environment variable for this search path (a string).

files

The list of sub-directories (strings) that should be added to the search path.

separator (default: ":")

The string used to separate search path components.

As a special case, a separator value of #f specifies a “single-component search path”—in other words, a search path that cannot contain more than one element. This is useful in some cases, such as the SSL_CERT_DIR variable (honored by OpenSSL, cURL, and a few other packages) or the ASPELL_DICT_DIR variable (honored by the GNU Aspell spell checker), both of which must point to a single directory.

file-type (default: 'directory)

The type of file being matched—'directory or 'regular, though it can be any symbol returned by stat:type (veja stat em GNU Guile Reference Manual).

In the XML_CATALOG_FILES example above, we would match regular files; in the Python example, we would match directories.

file-pattern (default: #f)

This must be either #f or a regular expression specifying files to be matched within the sub-directories specified by the files field.

Again, the XML_CATALOG_FILES example shows a situation where this is needed.

Some search paths are not tied by a single package but to many packages. To reduce duplications, some of them are pre-defined in (guix search-paths).

Variável: $SGML_CATALOG_FILES
Variável: $XML_CATALOG_FILES

These two search paths indicate where the TR9401 catalog22 or XML catalog files can be found.

Variável: $SSL_CERT_DIR
Variável: $SSL_CERT_FILE

These two search paths indicate where X.509 certificates can be found (veja Certificados X.509).

These pre-defined search paths can be used as in the following example:

(package
  (name "curl")
  ;; some fields omitted ...
  (native-search-paths (list $SSL_CERT_DIR $SSL_CERT_FILE)))

How do you turn search path specifications on one hand and a bunch of directories on the other hand in a set of environment variable definitions? That’s the job of evaluate-search-paths.

Procedure: evaluate-search-paths search-paths directories [getenv]

Evaluate search-paths, a list of search-path specifications, for directories, a list of directory names, and return a list of specification/value pairs. Use getenv to determine the current settings and report only settings not already effective.

The (guix profiles) provides a higher-level helper procedure, load-profile, that sets the environment variables of a profile.


8.9 O armazém

Conceptually, the store is the place where derivations that have been built successfully are stored—by default, /gnu/store. Sub-directories in the store are referred to as store items or sometimes store paths. The store has an associated database that contains information such as the store paths referred to by each store path, and the list of valid store items—results of successful builds. This database resides in localstatedir/guix/db, where localstatedir is the state directory specified via --localstatedir at configure time, usually /var.

The store is always accessed by the daemon on behalf of its clients (veja Invocando guix-daemon). To manipulate the store, clients connect to the daemon over a Unix-domain socket, send requests to it, and read the result—these are remote procedure calls, or RPCs.

Nota: Users must never modify files under /gnu/store directly. This would lead to inconsistencies and break the immutability assumptions of Guix’s functional model (veja Introdução).

Veja guix gc --verify, for information on how to check the integrity of the store and attempt recovery from accidental modifications.

The (guix store) module provides procedures to connect to the daemon, and to perform RPCs. These are described below. By default, open-connection, and thus all the guix commands, connect to the local daemon or to the URI specified by the GUIX_DAEMON_SOCKET environment variable.

Environment Variable: GUIX_DAEMON_SOCKET

When set, the value of this variable should be a file name or a URI designating the daemon endpoint. When it is a file name, it denotes a Unix-domain socket to connect to. In addition to file names, the supported URI schemes are:

file
unix

These are for Unix-domain sockets. file:///var/guix/daemon-socket/socket is equivalent to /var/guix/daemon-socket/socket.

guix

These URIs denote connections over TCP/IP, without encryption nor authentication of the remote host. The URI must specify the host name and optionally a port number (by default port 44146 is used):

guix://master.guix.example.org:1234

This setup is suitable on local networks, such as clusters, where only trusted nodes may connect to the build daemon at master.guix.example.org.

The --listen option of guix-daemon can be used to instruct it to listen for TCP connections (veja --listen).

ssh

These URIs allow you to connect to a remote daemon over SSH. This feature requires Guile-SSH (veja Requisitos) and a working guile binary in PATH on the destination machine. It supports public key and GSSAPI authentication. A typical URL might look like this:

ssh://charlie@guix.example.org:22

As for guix copy, the usual OpenSSH client configuration files are honored (veja Invocando guix copy).

Additional URI schemes may be supported in the future.

Nota: The ability to connect to remote build daemons is considered experimental as of 9356a8c. Please get in touch with us to share any problems or suggestions you may have (veja Contribuindo).

Procedure: open-connection [uri] [#:reserve-space? #t]

Connect to the daemon over the Unix-domain socket at uri (a string). When reserve-space? is true, instruct it to reserve a little bit of extra space on the file system so that the garbage collector can still operate should the disk become full. Return a server object.

file defaults to %default-socket-path, which is the normal location given the options that were passed to configure.

Procedure: close-connection server

Close the connection to server.

Variável: current-build-output-port

This variable is bound to a SRFI-39 parameter, which refers to the port where build and error logs sent by the daemon should be written.

Procedures that make RPCs all take a server object as their first argument.

Procedure: valid-path? server path

Return #t when path designates a valid store item and #f otherwise (an invalid item may exist on disk but still be invalid, for instance because it is the result of an aborted or failed build).

A &store-protocol-error condition is raised if path is not prefixed by the store directory (/gnu/store).

Procedure: add-text-to-store server name text [references]

Add text under file name in the store, and return its store path. references is the list of store paths referred to by the resulting store path.

Procedure: build-derivations store derivations [mode]

Build derivations, a list of <derivation> objects, .drv file names, or derivation/output pairs, using the specified mode(build-mode normal) by default.

Note that the (guix monads) module provides a monad as well as monadic versions of the above procedures, with the goal of making it more convenient to work with code that accesses the store (veja A mônada do armazém).

This section is currently incomplete.


8.10 Derivações

Low-level build actions and the environment in which they are performed are represented by derivations. A derivation contains the following pieces of information:

  • The outputs of the derivation—derivations produce at least one file or directory in the store, but may produce more.
  • The inputs of the derivation—i.e., its build-time dependencies—which may be other derivations or plain files in the store (patches, build scripts, etc.).
  • The system type targeted by the derivation—e.g., x86_64-linux.
  • The file name of a build script in the store, along with the arguments to be passed.
  • A list of environment variables to be defined.

Derivations allow clients of the daemon to communicate build actions to the store. They exist in two forms: as an in-memory representation, both on the client- and daemon-side, and as files in the store whose name end in .drv—these files are referred to as derivation paths. Derivations paths can be passed to the build-derivations procedure to perform the build actions they prescribe (veja O armazém).

Operations such as file downloads and version-control checkouts for which the expected content hash is known in advance are modeled as fixed-output derivations. Unlike regular derivations, the outputs of a fixed-output derivation are independent of its inputs—e.g., a source code download produces the same result regardless of the download method and tools being used.

The outputs of derivations—i.e., the build results—have a set of references, as reported by the references RPC or the guix gc --references command (veja Invocando guix gc). References are the set of run-time dependencies of the build results. References are a subset of the inputs of the derivation; this subset is automatically computed by the build daemon by scanning all the files in the outputs.

The (guix derivations) module provides a representation of derivations as Scheme objects, along with procedures to create and otherwise manipulate derivations. The lowest-level primitive to create a derivation is the derivation procedure:

Procedure: derivation store name builder args [#:outputs '("out")] [#:hash #f] [#:hash-algo #f]  [#:recursive? #f]

[#:inputs ’()] [#:env-vars ’()]  [#:system (%current-system)] [#:references-graphs #f]  [#:allowed-references #f] [#:disallowed-references #f]  [#:leaked-env-vars #f] [#:local-build? #f]  [#:substitutable? #t] [#:properties ’()] Build a derivation with the given arguments, and return the resulting <derivation> object.

When hash and hash-algo are given, a fixed-output derivation is created—i.e., one whose result is known in advance, such as a file download. If, in addition, recursive? is true, then that fixed output may be an executable file or a directory and hash must be the hash of an archive containing this output.

When references-graphs is true, it must be a list of file name/store path pairs. In that case, the reference graph of each store path is exported in the build environment in the corresponding file, in a simple text format.

When allowed-references is true, it must be a list of store items or outputs that the derivation’s output may refer to. Likewise, disallowed-references, if true, must be a list of things the outputs may not refer to.

When leaked-env-vars is true, it must be a list of strings denoting environment variables that are allowed to “leak” from the daemon’s environment to the build environment. This is only applicable to fixed-output derivations—i.e., when hash is true. The main use is to allow variables such as http_proxy to be passed to derivations that download files.

When local-build? is true, declare that the derivation is not a good candidate for offloading and should rather be built locally (veja Usando o recurso de descarregamento). This is the case for small derivations where the costs of data transfers would outweigh the benefits.

When substitutable? is false, declare that substitutes of the derivation’s output should not be used (veja Substitutos). This is useful, for instance, when building packages that capture details of the host CPU instruction set.

properties must be an association list describing “properties” of the derivation. It is kept as-is, uninterpreted, in the derivation.

Here’s an example with a shell script as its builder, assuming store is an open connection to the daemon, and bash points to a Bash executable in the store:

(use-modules (guix utils)
             (guix store)
             (guix derivations))

(let ((builder   ; add the Bash script to the store
        (add-text-to-store store "my-builder.sh"
                           "echo hello world > $out\n" '())))
  (derivation store "foo"
              bash `("-e" ,builder)
              #:inputs `((,bash) (,builder))
              #:env-vars '(("HOME" . "/homeless"))))
 #<derivation /gnu/store/…-foo.drv => /gnu/store/…-foo>

As can be guessed, this primitive is cumbersome to use directly. A better approach is to write build scripts in Scheme, of course! The best course of action for that is to write the build code as a “G-expression”, and to pass it to gexp->derivation. For more information, veja Expressões-G.

Once upon a time, gexp->derivation did not exist and constructing derivations with build code written in Scheme was achieved with build-expression->derivation, documented below. This procedure is now deprecated in favor of the much nicer gexp->derivation.

Procedure: build-expression->derivation store name exp [#:system (%current-system)] [#:inputs '()]  [#:outputs '("out")] [#:hash

#f] [#:hash-algo #f]  [#:recursive? #f] [#:env-vars ’()] [#:modules ’()]  [#:references-graphs #f] [#:allowed-references #f]  [#:disallowed-references #f]  [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f] Return a derivation that executes Scheme expression exp as a builder for derivation name. inputs must be a list of (name drv-path sub-drv) tuples; when sub-drv is omitted, "out" is assumed. modules is a list of names of Guile modules from the current search path to be copied in the store, compiled, and made available in the load path during the execution of exp—e.g., ((guix build utils) (guix build gnu-build-system)).

exp is evaluated in an environment where %outputs is bound to a list of output/path pairs, and where %build-inputs is bound to a list of string/output-path pairs made from inputs. Optionally, env-vars is a list of string pairs specifying the name and value of environment variables visible to the builder. The builder terminates by passing the result of exp to exit; thus, when exp returns #f, the build is considered to have failed.

exp is built using guile-for-build (a derivation). When guile-for-build is omitted or is #f, the value of the %guile-for-build fluid is used instead.

See the derivation procedure for the meaning of references-graphs, allowed-references, disallowed-references, local-build?, and substitutable?.

Here’s an example of a single-output derivation that creates a directory containing one file:

(let ((builder '(let ((out (assoc-ref %outputs "out")))
                  (mkdir out)    ; create /gnu/store/…-goo
                  (call-with-output-file (string-append out "/test")
                    (lambda (p)
                      (display '(hello guix) p))))))
  (build-expression->derivation store "goo" builder))

 #<derivation /gnu/store/…-goo.drv => …>

8.11 A mônada do armazém

The procedures that operate on the store described in the previous sections all take an open connection to the build daemon as their first argument. Although the underlying model is functional, they either have side effects or depend on the current state of the store.

The former is inconvenient: the connection to the build daemon has to be carried around in all those functions, making it impossible to compose functions that do not take that parameter with functions that do. The latter can be problematic: since store operations have side effects and/or depend on external state, they have to be properly sequenced.

This is where the (guix monads) module comes in. This module provides a framework for working with monads, and a particularly useful monad for our uses, the store monad. Monads are a construct that allows two things: associating “context” with values (in our case, the context is the store), and building sequences of computations (here computations include accesses to the store). Values in a monad—values that carry this additional context—are called monadic values; procedures that return such values are called monadic procedures.

Consider this “normal” procedure:

(define (sh-symlink store)
  ;; Return a derivation that symlinks the 'bash' executable.
  (let* ((drv (package-derivation store bash))
         (out (derivation->output-path drv))
         (sh  (string-append out "/bin/bash")))
    (build-expression->derivation store "sh"
                                  `(symlink ,sh %output))))

Using (guix monads) and (guix gexp), it may be rewritten as a monadic function:

(define (sh-symlink)
  ;; Same, but return a monadic value.
  (mlet %store-monad ((drv (package->derivation bash)))
    (gexp->derivation "sh"
                      #~(symlink (string-append #$drv "/bin/bash")
                                 #$output))))

There are several things to note in the second version: the store parameter is now implicit and is “threaded” in the calls to the package->derivation and gexp->derivation monadic procedures, and the monadic value returned by package->derivation is bound using mlet instead of plain let.

As it turns out, the call to package->derivation can even be omitted since it will take place implicitly, as we will see later (veja Expressões-G):

(define (sh-symlink)
  (gexp->derivation "sh"
                    #~(symlink (string-append #$bash "/bin/bash")
                               #$output)))

Calling the monadic sh-symlink has no effect. As someone once said, “you exit a monad like you exit a building on fire: by running”. So, to exit the monad and get the desired effect, one must use run-with-store:

(run-with-store (open-connection) (sh-symlink))
 /gnu/store/...-sh-symlink

Note that the (guix monad-repl) module extends the Guile REPL with new “commands” to make it easier to deal with monadic procedures: run-in-store, and enter-store-monad (veja Using Guix Interactively). The former is used to “run” a single monadic value through the store:

scheme@(guile-user)> ,run-in-store (package->derivation hello)
$1 = #<derivation /gnu/store/…-hello-2.9.drv => …>

The latter enters a recursive REPL, where all the return values are automatically run through the store:

scheme@(guile-user)> ,enter-store-monad
store-monad@(guile-user) [1]> (package->derivation hello)
$2 = #<derivation /gnu/store/…-hello-2.9.drv => …>
store-monad@(guile-user) [1]> (text-file "foo" "Hello!")
$3 = "/gnu/store/…-foo"
store-monad@(guile-user) [1]> ,q
scheme@(guile-user)>

Note that non-monadic values cannot be returned in the store-monad REPL.

Other meta-commands are available at the REPL, such as ,build to build a file-like object (veja Using Guix Interactively).

The main syntactic forms to deal with monads in general are provided by the (guix monads) module and are described below.

Macro: with-monad monad body …

Evaluate any >>= or return forms in body as being in monad.

Macro: return val

Return a monadic value that encapsulates val.

Macro: >>= mval mproc …

Bind monadic value mval, passing its “contents” to monadic procedures mproc23. There can be one mproc or several of them, as in this example:

(run-with-state
    (with-monad %state-monad
      (>>= (return 1)
           (lambda (x) (return (+ 1 x)))
           (lambda (x) (return (* 2 x)))))
  'some-state)

 4
 some-state
Macro: mlet monad ((var mval) …) body …
Macro: mlet* monad ((var mval) …) body …

Bind the variables var to the monadic values mval in body, which is a sequence of expressions. As with the bind operator, this can be thought of as “unpacking” the raw, non-monadic value “contained” in mval and making var refer to that raw, non-monadic value within the scope of the body. The form (var -> val) binds var to the “normal” value val, as per let. The binding operations occur in sequence from left to right. The last expression of body must be a monadic expression, and its result will become the result of the mlet or mlet* when run in the monad.

mlet* is to mlet what let* is to let (veja Local Bindings em GNU Guile Reference Manual).

Macro: mbegin monad mexp …

Bind mexp and the following monadic expressions in sequence, returning the result of the last expression. Every expression in the sequence must be a monadic expression.

This is akin to mlet, except that the return values of the monadic expressions are ignored. In that sense, it is analogous to begin, but applied to monadic expressions.

Macro: mwhen condition mexp0 mexp* …

When condition is true, evaluate the sequence of monadic expressions mexp0..mexp* as in an mbegin. When condition is false, return *unspecified* in the current monad. Every expression in the sequence must be a monadic expression.

Macro: munless condition mexp0 mexp* …

When condition is false, evaluate the sequence of monadic expressions mexp0..mexp* as in an mbegin. When condition is true, return *unspecified* in the current monad. Every expression in the sequence must be a monadic expression.

The (guix monads) module provides the state monad, which allows an additional value—the state—to be threaded through monadic procedure calls.

Variável: %state-monad

The state monad. Procedures in the state monad can access and change the state that is threaded.

Consider the example below. The square procedure returns a value in the state monad. It returns the square of its argument, but also increments the current state value:

(define (square x)
  (mlet %state-monad ((count (current-state)))
    (mbegin %state-monad
      (set-current-state (+ 1 count))
      (return (* x x)))))

(run-with-state (sequence %state-monad (map square (iota 3))) 0)
 (0 1 4)
 3

When “run” through %state-monad, we obtain that additional state value, which is the number of square calls.

Monadic Procedure: current-state

Return the current state as a monadic value.

Monadic Procedure: set-current-state value

Set the current state to value and return the previous state as a monadic value.

Monadic Procedure: state-push value

Push value to the current state, which is assumed to be a list, and return the previous state as a monadic value.

Monadic Procedure: state-pop

Pop a value from the current state and return it as a monadic value. The state is assumed to be a list.

Procedure: run-with-state mval [state]

Run monadic value mval starting with state as the initial state. Return two values: the resulting value, and the resulting state.

The main interface to the store monad, provided by the (guix store) module, is as follows.

Variável: %store-monad

The store monad—an alias for %state-monad.

Values in the store monad encapsulate accesses to the store. When its effect is needed, a value of the store monad must be “evaluated” by passing it to the run-with-store procedure (see below).

Procedure: run-with-store store mval [#:guile-for-build] [#:system (%current-system)] Run mval, a monadic

value in the store monad, in store, an open store connection.

Monadic Procedure: text-file name text [references]

Return as a monadic value the absolute file name in the store of the file containing text, a string. references is a list of store items that the resulting text file refers to; it defaults to the empty list.

Monadic Procedure: binary-file name data [references]

Return as a monadic value the absolute file name in the store of the file containing data, a bytevector. references is a list of store items that the resulting binary file refers to; it defaults to the empty list.

Monadic Procedure: interned-file file [name] [#:recursive? #t] [#:select? (const #t)] Return the name of file once

interned in the store. Use name as its store name, or the basename of file if name is omitted.

When recursive? is true, the contents of file are added recursively; if file designates a flat file and recursive? is true, its contents are added, and its permission bits are kept.

When recursive? is true, call (select? file stat) for each directory entry, where file is the entry’s absolute file name and stat is the result of lstat; exclude entries for which select? does not return true.

The example below adds a file to the store, under two different names:

(run-with-store (open-connection)
  (mlet %store-monad ((a (interned-file "README"))
                      (b (interned-file "README" "LEGU-MIN")))
    (return (list a b))))

 ("/gnu/store/rwm…-README" "/gnu/store/44i…-LEGU-MIN")

The (guix packages) module exports the following package-related monadic procedures:

Monadic Procedure: package-file package [file] [#:system (%current-system)] [#:target #f]  [#:output "out"] Return as a

monadic value in the absolute file name of file within the output directory of package. When file is omitted, return the name of the output directory of package. When target is true, use it as a cross-compilation target triplet.

Note that this procedure does not build package. Thus, the result might or might not designate an existing file. We recommend not using this procedure unless you know what you are doing.

Monadic Procedure: package->derivation package [system]
Monadic Procedure: package->cross-derivation package target [system] Monadic version of package-derivation and

package-cross-derivation (veja Definindo pacotes).


8.12 Expressões-G

So we have “derivations”, which represent a sequence of build actions to be performed to produce an item in the store (veja Derivações). These build actions are performed when asking the daemon to actually build the derivations; they are run by the daemon in a container (veja Invocando guix-daemon).

It should come as no surprise that we like to write these build actions in Scheme. When we do that, we end up with two strata of Scheme code24: the “host code”—code that defines packages, talks to the daemon, etc.—and the “build code”—code that actually performs build actions, such as making directories, invoking make, and so on (veja Build Phases).

To describe a derivation and its build actions, one typically needs to embed build code inside host code. It boils down to manipulating build code as data, and the homoiconicity of Scheme—code has a direct representation as data—comes in handy for that. But we need more than the normal quasiquote mechanism in Scheme to construct build expressions.

The (guix gexp) module implements G-expressions, a form of S-expressions adapted to build expressions. G-expressions, or gexps, consist essentially of three syntactic forms: gexp, ungexp, and ungexp-splicing (or simply: #~, #$, and #$@), which are comparable to quasiquote, unquote, and unquote-splicing, respectively (veja quasiquote em GNU Guile Reference Manual). However, there are major differences:

  • Gexps are meant to be written to a file and run or manipulated by other processes.
  • When a high-level object such as a package or derivation is unquoted inside a gexp, the result is as if its output file name had been introduced.
  • Gexps carry information about the packages or derivations they refer to, and these dependencies are automatically added as inputs to the build processes that use them.

This mechanism is not limited to package and derivation objects: compilers able to “lower” other high-level objects to derivations or files in the store can be defined, such that these objects can also be inserted into gexps. For example, a useful type of high-level objects that can be inserted in a gexp is “file-like objects”, which make it easy to add files to the store and to refer to them in derivations and such (see local-file and plain-file below).

To illustrate the idea, here is an example of a gexp:

(define build-exp
  #~(begin
      (mkdir #$output)
      (chdir #$output)
      (symlink (string-append #$coreutils "/bin/ls")
               "list-files")))

This gexp can be passed to gexp->derivation; we obtain a derivation that builds a directory containing exactly one symlink to /gnu/store/…-coreutils-8.22/bin/ls:

(gexp->derivation "the-thing" build-exp)

As one would expect, the "/gnu/store/…-coreutils-8.22" string is substituted to the reference to the coreutils package in the actual build code, and coreutils is automatically made an input to the derivation. Likewise, #$output (equivalent to (ungexp output)) is replaced by a string containing the directory name of the output of the derivation.

In a cross-compilation context, it is useful to distinguish between references to the native build of a package—that can run on the host—versus references to cross builds of a package. To that end, the #+ plays the same role as #$, but is a reference to a native package build:

(gexp->derivation "vi"
   #~(begin
       (mkdir #$output)
       (mkdir (string-append #$output "/bin"))
       (system* (string-append #+coreutils "/bin/ln")
                "-s"
                (string-append #$emacs "/bin/emacs")
                (string-append #$output "/bin/vi")))
   #:target "aarch64-linux-gnu")

In the example above, the native build of coreutils is used, so that ln can actually run on the host; but then the cross-compiled build of emacs is referenced.

Another gexp feature is imported modules: sometimes you want to be able to use certain Guile modules from the “host environment” in the gexp, so those modules should be imported in the “build environment”. The with-imported-modules form allows you to express that:

(let ((build (with-imported-modules '((guix build utils))
               #~(begin
                   (use-modules (guix build utils))
                   (mkdir-p (string-append #$output "/bin"))))))
  (gexp->derivation "empty-dir"
                    #~(begin
                        #$build
                        (display "success!\n")
                        #t)))

In this example, the (guix build utils) module is automatically pulled into the isolated build environment of our gexp, such that (use-modules (guix build utils)) works as expected.

Usually you want the closure of the module to be imported—i.e., the module itself and all the modules it depends on—rather than just the module; failing to do that, attempts to use the module will fail because of missing dependent modules. The source-module-closure procedure computes the closure of a module by looking at its source file headers, which comes in handy in this case:

(use-modules (guix modules))   ;for 'source-module-closure'

(with-imported-modules (source-module-closure
                         '((guix build utils)
                           (gnu build image)))
  (gexp->derivation "something-with-vms"
                    #~(begin
                        (use-modules (guix build utils)
                                     (gnu build image))
                        )))

In the same vein, sometimes you want to import not just pure-Scheme modules, but also “extensions” such as Guile bindings to C libraries or other “full-blown” packages. Say you need the guile-json package available on the build side, here’s how you would do it:

(use-modules (gnu packages guile))  ;for 'guile-json'

(with-extensions (list guile-json)
  (gexp->derivation "something-with-json"
                    #~(begin
                        (use-modules (json))
                        )))

The syntactic form to construct gexps is summarized below.

Macro: #~exp
Macro: (gexp exp)

Return a G-expression containing exp. exp may contain one or more of the following forms:

#$obj
(ungexp obj)

Introduce a reference to obj. obj may have one of the supported types, for example a package or a derivation, in which case the ungexp form is replaced by its output file name—e.g., "/gnu/store/…-coreutils-8.22.

If obj is a list, it is traversed and references to supported objects are substituted similarly.

If obj is another gexp, its contents are inserted and its dependencies are added to those of the containing gexp.

If obj is another kind of object, it is inserted as is.

#$obj:saída
(ungexp obj saída)

This is like the form above, but referring explicitly to the output of obj—this is useful when obj produces multiple outputs (veja Pacotes com múltiplas saídas).

Sometimes a gexp unconditionally refers to the "out" output, but the user of that gexp would still like to insert a reference to another output. The gexp-input procedure aims to address that. Veja gexp-input.

#+obj
#+obj:output
(ungexp-native obj)
(ungexp-native obj output)

Same as ungexp, but produces a reference to the native build of obj when used in a cross compilation context.

#$output[:saída]
(ungexp output [saída])

Insert a reference to derivation output output, or to the main output when output is omitted.

This only makes sense for gexps passed to gexp->derivation.

#$@lst
(ungexp-splicing lst)

Like the above, but splices the contents of lst inside the containing list.

#+@lst
(ungexp-native-splicing lst)

Like the above, but refers to native builds of the objects listed in lst.

G-expressions created by gexp or #~ are run-time objects of the gexp? type (see below).

Macro: with-imported-modules modules body…

Mark the gexps defined in body… as requiring modules in their execution environment.

Each item in modules can be the name of a module, such as (guix build utils), or it can be a module name, followed by an arrow, followed by a file-like object:

`((guix build utils)
  (guix gcrypt)
  ((guix config) => ,(scheme-file "config.scm"
                                  #~(define-module ))))

In the example above, the first two modules are taken from the search path, and the last one is created from the given file-like object.

This form has lexical scope: it has an effect on the gexps directly defined in body…, but not on those defined, say, in procedures called from body….

Macro: with-extensions extensions body…

Mark the gexps defined in body… as requiring extensions in their build and execution environment. extensions is typically a list of package objects such as those defined in the (gnu packages guile) module.

Concretely, the packages listed in extensions are added to the load path while compiling imported modules in body…; they are also added to the load path of the gexp returned by body….

Procedure: gexp? obj

Return #t if obj is a G-expression.

G-expressions are meant to be written to disk, either as code building some derivation, or as plain files in the store. The monadic procedures below allow you to do that (veja A mônada do armazém, for more information about monads).

Monadic Procedure: gexp->derivation name exp [#:system (%current-system)] [#:target #f] [#:graft? #t]  [#:hash #f]

[#:hash-algo #f]  [#:recursive? #f] [#:env-vars ’()] [#:modules ’()]  [#:module-path %load-path]  [#:effective-version "2.2"]  [#:references-graphs #f] [#:allowed-references #f]  [#:disallowed-references #f]  [#:leaked-env-vars #f]  [#:script-name (string-append name "-builder")]  [#:deprecation-warnings #f]  [#:local-build? #f] [#:substitutable? #t]  [#:properties ’()] [#:guile-for-build #f] Return a derivation name that runs exp (a gexp) with guile-for-build (a derivation) on system; exp is stored in a file called script-name. When target is true, it is used as the cross-compilation target triplet for packages referred to by exp.

modules is deprecated in favor of with-imported-modules. Its meaning is to make modules available in the evaluation context of exp; modules is a list of names of Guile modules searched in module-path to be copied in the store, compiled, and made available in the load path during the execution of exp—e.g., ((guix build utils) (guix build gnu-build-system)).

effective-version determines the string to use when adding extensions of exp (see with-extensions) to the search path—e.g., "2.2".

graft? determines whether packages referred to by exp should be grafted when applicable.

When references-graphs is true, it must be a list of tuples of one of the following forms:

(file-name obj)
(file-name obj output)
(file-name gexp-input)
(file-name store-item)

The right-hand-side of each element of references-graphs is automatically made an input of the build process of exp. In the build environment, each file-name contains the reference graph of the corresponding item, in a simple text format.

allowed-references must be either #f or a list of output names and packages. In the latter case, the list denotes store items that the result is allowed to refer to. Any reference to another store item will lead to a build error. Similarly for disallowed-references, which can list items that must not be referenced by the outputs.

deprecation-warnings determines whether to show deprecation warnings while compiling modules. It can be #f, #t, or 'detailed.

The other arguments are as for derivation (veja Derivações).

The local-file, plain-file, computed-file, program-file, and scheme-file procedures below return file-like objects. That is, when unquoted in a G-expression, these objects lead to a file in the store. Consider this G-expression:

#~(system* #$(file-append glibc "/sbin/nscd") "-f"
           #$(local-file "/tmp/my-nscd.conf"))

The effect here is to “intern” /tmp/my-nscd.conf by copying it to the store. Once expanded, for instance via gexp->derivation, the G-expression refers to that copy under /gnu/store; thus, modifying or removing the file in /tmp does not have any effect on what the G-expression does. plain-file can be used similarly; it differs in that the file content is directly passed as a string.

Procedure: local-file file [name] [#:recursive? #f] [#:select? (const #t)]

Return an object representing local file file to add to the store; this object can be used in a gexp. If file is a literal string denoting a relative file name, it is looked up relative to the source file where it appears; if file is not a literal string, it is looked up relative to the current working directory at run time. file will be added to the store under name–by default the base name of file.

When recursive? is true, the contents of file are added recursively; if file designates a flat file and recursive? is true, its contents are added, and its permission bits are kept.

When recursive? is true, call (select? file stat) for each directory entry, where file is the entry’s absolute file name and stat is the result of lstat; exclude entries for which select? does not return true.

file can be wrapped in the assume-valid-file-name syntactic keyword. When this is done, there will not be a warning when local-file is used with a non-literal path. The path is still looked up relative to the current working directory at run time. Wrapping is done like this:

(define alice-key-file-path "alice.pub")
;; ...
(local-file (assume-valid-file-name alice-key-file-path))

file can be wrapped in the assume-source-relative-file-name syntactic keyword. When this is done, the file name will be looked up relative to the source file where it appears even when it is not a string literal.

This is the declarative counterpart of the interned-file monadic procedure (veja interned-file).

Procedure: plain-file name content

Return an object representing a text file called name with the given content (a string or a bytevector) to be added to the store.

This is the declarative counterpart of text-file.

Procedure: computed-file name gexp [#:local-build? #t] [#:options '()]

Return an object representing the store item name, a file or directory computed by gexp. When local-build? is true (the default), the derivation is built locally. options is a list of additional arguments to pass to gexp->derivation.

This is the declarative counterpart of gexp->derivation.

Monadic Procedure: gexp->script name exp [#:guile (default-guile)] [#:module-path %load-path]  [#:system

(%current-system)] [#:target #f] Return an executable script name that runs exp using guile, with exp’s imported modules in its search path. Look up exp’s modules in module-path.

The example below builds a script that simply invokes the ls command:

(use-modules (guix gexp) (gnu packages base))

(gexp->script "list-files"
              #~(execl #$(file-append coreutils "/bin/ls")
                       "ls"))

When “running” it through the store (veja run-with-store), we obtain a derivation that produces an executable file /gnu/store/…-list-files along these lines:

#!/gnu/store/…-guile-2.0.11/bin/guile -ds
!#
(execl "/gnu/store/…-coreutils-8.22"/bin/ls" "ls")
Procedure: program-file name exp [#:guile #f] [#:module-path %load-path]

Return an object representing the executable store item name that runs gexp. guile is the Guile package used to execute that script. Imported modules of gexp are looked up in module-path.

This is the declarative counterpart of gexp->script.

Monadic Procedure: gexp->file name exp [#:set-load-path? #t] [#:module-path %load-path]  [#:splice? #f]  [#:guile

(default-guile)] Return a derivation that builds a file name containing exp. When splice? is true, exp is considered to be a list of expressions that will be spliced in the resulting file.

When set-load-path? is true, emit code in the resulting file to set %load-path and %load-compiled-path to honor exp’s imported modules. Look up exp’s modules in module-path.

The resulting file holds references to all the dependencies of exp or a subset thereof.

Procedure: scheme-file name exp [#:splice? #f] [#:guile #f] [#:set-load-path? #t] Return an object representing the Scheme

file name that contains exp. guile is the Guile package used to produce that file.

This is the declarative counterpart of gexp->file.

Monadic Procedure: text-file* name text

Return as a monadic value a derivation that builds a text file containing all of text. text may list, in addition to strings, objects of any type that can be used in a gexp: packages, derivations, local file objects, etc. The resulting store file holds references to all these.

This variant should be preferred over text-file anytime the file to create will reference items from the store. This is typically the case when building a configuration file that embeds store file names, like this:

(define (profile.sh)
  ;; Return the name of a shell script in the store that
  ;; initializes the 'PATH' environment variable.
  (text-file* "profile.sh"
              "export PATH=" coreutils "/bin:"
              grep "/bin:" sed "/bin\n"))

In this example, the resulting /gnu/store/…-profile.sh file will reference coreutils, grep, and sed, thereby preventing them from being garbage-collected during its lifetime.

Procedure: mixed-text-file name text …

Return an object representing store file name containing text. text is a sequence of strings and file-like objects, as in:

(mixed-text-file "profile"
                 "export PATH=" coreutils "/bin:" grep "/bin")

This is the declarative counterpart of text-file*.

Procedure: file-union name files

Return a <computed-file> that builds a directory containing all of files. Each item in files must be a two-element list where the first element is the file name to use in the new directory, and the second element is a gexp denoting the target file. Here’s an example:

(file-union "etc"
            `(("hosts" ,(plain-file "hosts"
                                    "127.0.0.1 localhost"))
              ("bashrc" ,(plain-file "bashrc"
                                     "alias ls='ls --color=auto'"))))

This yields an etc directory containing these two files.

Procedure: directory-union name things

Return a directory that is the union of things, where things is a list of file-like objects denoting directories. For example:

(directory-union "guile+emacs" (list guile emacs))

yields a directory that is the union of the guile and emacs packages.

Procedure: file-append obj suffix …

Return a file-like object that expands to the concatenation of obj and suffix, where obj is a lowerable object and each suffix is a string.

As an example, consider this gexp:

(gexp->script "run-uname"
              #~(system* #$(file-append coreutils
                                        "/bin/uname")))

The same effect could be achieved with:

(gexp->script "run-uname"
              #~(system* (string-append #$coreutils
                                        "/bin/uname")))

There is one difference though: in the file-append case, the resulting script contains the absolute file name as a string, whereas in the second case, the resulting script contains a (string-append …) expression to construct the file name at run time.

Macro: let-system system body…
Macro: let-system (system target) body…

Bind system to the currently targeted system—e.g., "x86_64-linux"—within body.

In the second case, additionally bind target to the current cross-compilation target—a GNU triplet such as "arm-linux-gnueabihf"—or #f if we are not cross-compiling.

let-system is useful in the occasional case where the object spliced into the gexp depends on the target system, as in this example:

#~(system*
   #+(let-system system
       (cond ((string-prefix? "armhf-" system)
              (file-append qemu "/bin/qemu-system-arm"))
             ((string-prefix? "x86_64-" system)
              (file-append qemu "/bin/qemu-system-x86_64"))
             (else
              (error "dunno!"))))
   "-net" "user" #$image)
Macro: with-parameters ((parameter value) …) exp

This macro is similar to the parameterize form for dynamically-bound parameters (veja Parameters em GNU Guile Reference Manual). The key difference is that it takes effect when the file-like object returned by exp is lowered to a derivation or store item.

A typical use of with-parameters is to force the system in effect for a given object:

(with-parameters ((%current-system "i686-linux"))
  coreutils)

The example above returns an object that corresponds to the i686 build of Coreutils, regardless of the current value of %current-system.

Procedure: gexp-input obj [output] [#:native? #f]

Return a gexp input record for the given output of file-like object obj, with #:native? determining whether this is a native reference (as with ungexp-native) or not.

This procedure is helpful when you want to pass a reference to a specific output of an object to some procedure that may not know about that output. For example, assume you have this procedure, which takes one file-like object:

(define (make-symlink target)
  (computed-file "the-symlink"
                 #~(symlink #$target #$output)))

Here make-symlink can only ever refer to the default output of target—the "out" output (veja Pacotes com múltiplas saídas). To have it refer to, say, the "lib" output of the hwloc package, you can call it like so:

(make-symlink (gexp-input hwloc "lib"))

You can also compose it like any other file-like object:

(make-symlink
  (file-append (gexp-input hwloc "lib") "/lib/libhwloc.so"))

Of course, in addition to gexps embedded in “host” code, there are also modules containing build tools. To make it clear that they are meant to be used in the build stratum, these modules are kept in the (guix build …) name space.

Internally, high-level objects are lowered, using their compiler, to either derivations or store items. For instance, lowering a package yields a derivation, and lowering a plain-file yields a store item. This is achieved using the lower-object monadic procedure.

Monadic Procedure: lower-object obj [system] [#:target #f] Return as a value in %store-monad the derivation or

store item corresponding to obj for system, cross-compiling for target if target is true. obj must be an object that has an associated gexp compiler, such as a <package>.

Procedure: gexp->approximate-sexp gexp

Sometimes, it may be useful to convert a G-exp into a S-exp. For example, some linters (veja Invocando guix lint) peek into the build phases of a package to detect potential problems. This conversion can be achieved with this procedure. However, some information can be lost in the process. More specifically, lowerable objects will be silently replaced with some arbitrary object – currently the list (*approximate*), but this may change.


8.13 Invocando guix repl

The guix repl command makes it easier to program Guix in Guile by launching a Guile read-eval-print loop (REPL) for interactive programming (veja Using Guile Interactively em GNU Guile Reference Manual), or by running Guile scripts (veja Running Guile Scripts em GNU Guile Reference Manual). Compared to just launching the guile command, guix repl guarantees that all the Guix modules and all its dependencies are available in the search path.

The general syntax is:

guix repl options [file args]

When a file argument is provided, file is executed as a Guile scripts:

guix repl my-script.scm

To pass arguments to the script, use -- to prevent them from being interpreted as arguments to guix repl itself:

guix repl -- my-script.scm --input=foo.txt

To make a script executable directly from the shell, using the guix executable that is on the user’s search path, add the following two lines at the top of the script:

#!/usr/bin/env -S guix repl --
!#

To make a script that launches an interactive REPL directly from the shell, use the --interactive flag:

#!/usr/bin/env -S guix repl --interactive
!#

Without a file name argument, a Guile REPL is started, allowing for interactive use (veja Using Guix Interactively):

$ guix repl
scheme@(guile-user)> ,use (gnu packages base)
scheme@(guile-user)> coreutils
$1 = #<package coreutils@8.29 gnu/packages/base.scm:327 3e28300>

In addition, guix repl implements a simple machine-readable REPL protocol for use by (guix inferior), a facility to interact with inferiors, separate processes running a potentially different revision of Guix.

The available options are as follows:

--list-types

Display the TYPE options for guix repl --type=TYPE and exit.

--type=type
-t tipo

Start a REPL of the given TYPE, which can be one of the following:

guile

This is default, and it spawns a standard full-featured Guile REPL.

machine

Spawn a REPL that uses the machine-readable protocol. This is the protocol that the (guix inferior) module speaks.

--listen=endpoint

By default, guix repl reads from standard input and writes to standard output. When this option is passed, it will instead listen for connections on endpoint. Here are examples of valid options:

--listen=tcp:37146

Accept connections on localhost on port 37146.

--listen=unix:/tmp/socket

Accept connections on the Unix-domain socket /tmp/socket.

--interactive
-i

Launch the interactive REPL after file is executed.

--load-path=directory
-L diretório

Add directory to the front of the package module search path (veja Módulos de pacote).

This allows users to define their own packages and make them visible to the script or REPL.

-q

Inhibit loading of the ~/.guile file. By default, that configuration file is loaded when spawning a guile REPL.


8.14 Using Guix Interactively

The guix repl command gives you access to a warm and friendly read-eval-print loop (REPL) (veja Invocando guix repl). If you’re getting into Guix programming—defining your own packages, writing manifests, defining services for Guix System or Guix Home, etc.—you will surely find it convenient to toy with ideas at the REPL.

If you use Emacs, the most convenient way to do that is with Geiser (veja A configuração perfeita), but you do not have to use Emacs to enjoy the REPL. When using guix repl or guile in the terminal, we recommend using Readline for completion and Colorized to get colorful output. To do that, you can run:

guix install guile guile-readline guile-colorized

... and then create a .guile file in your home directory containing this:

(use-modules (ice-9 readline) (ice-9 colorized))

(activate-readline)
(activate-colorized)

The REPL lets you evaluate Scheme code; you type a Scheme expression at the prompt, and the REPL prints what it evaluates to:

$ guix repl
scheme@(guix-user)> (+ 2 3)
$1 = 5
scheme@(guix-user)> (string-append "a" "b")
$2 = "ab"

It becomes interesting when you start fiddling with Guix at the REPL. The first thing you’ll want to do is to “import” the (guix) module, which gives access to the main part of the programming interface, and perhaps a bunch of useful Guix modules. You could type (use-modules (guix)), which is valid Scheme code to import a module (veja Using Guile Modules em GNU Guile Reference Manual), but the REPL provides the use command as a shorthand notation (veja REPL Commands em GNU Guile Reference Manual):

scheme@(guix-user)> ,use (guix)
scheme@(guix-user)> ,use (gnu packages base)

Notice that REPL commands are introduced by a leading comma. A REPL command like use is not valid Scheme code; it’s interpreted specially by the REPL.

Guix extends the Guile REPL with additional commands for convenience. Among those, the build command comes in handy: it ensures that the given file-like object is built, building it if needed, and returns its output file name(s). In the example below, we build the coreutils and grep packages, as well as a “computed file” (veja computed-file), and we use the scandir procedure to list the files in Grep’s /bin directory:

scheme@(guix-user)> ,build coreutils
$1 = "/gnu/store/…-coreutils-8.32-debug"
$2 = "/gnu/store/…-coreutils-8.32"
scheme@(guix-user)> ,build grep
$3 = "/gnu/store/…-grep-3.6"
scheme@(guix-user)> ,build (computed-file "x" #~(mkdir #$output))
building /gnu/store/…-x.drv...
$4 = "/gnu/store/…-x"
scheme@(guix-user)> ,use(ice-9 ftw)
scheme@(guix-user)> (scandir (string-append $3 "/bin"))
$5 = ("." ".." "egrep" "fgrep" "grep")

As a packager, you may be willing to inspect the build phases or flags of a given package; this is particularly useful when relying a lot on inheritance to define package variants (veja Defining Package Variants) or when package arguments are a result of some computation, both of which can make it harder to foresee what ends up in the package arguments. Additional commands let you inspect those package arguments:

scheme@(guix-user)> ,phases grep
$1 = (modify-phases %standard-phases
       (add-after 'install 'fix-egrep-and-fgrep
         (lambda* (#:key outputs #:allow-other-keys)
           (let* ((out (assoc-ref outputs "out"))
                  (bin (string-append out "/bin")))
             (substitute* (list (string-append bin "/egrep")
                                (string-append bin "/fgrep"))
               (("^exec grep")
                (string-append "exec " bin "/grep")))))))
scheme@(guix-user)> ,configure-flags findutils
$2 = (list "--localstatedir=/var")
scheme@(guix-user)> ,make-flags binutils
$3 = '("MAKEINFO=true")

At a lower-level, a useful command is lower: it takes a file-like object and “lowers” it into a derivation (veja Derivações) or a store file:

scheme@(guix-user)> ,lower grep
$6 = #<derivation /gnu/store/…-grep-3.6.drv => /gnu/store/…-grep-3.6 7f0e639115f0>
scheme@(guix-user)> ,lower (plain-file "x" "Hello!")
$7 = "/gnu/store/…-x"

The full list of REPL commands can be seen by typing ,help guix and is given below for reference.

REPL command: build object

Lower object and build it if it’s not already built, returning its output file name(s).

REPL command: lower object

Lower object into a derivation or store file name and return it.

REPL command: verbosity level

Change build verbosity to level.

This is similar to the --verbosity command-line option (veja Opções de compilação comum): level 0 means total silence, level 1 shows build events only, and higher levels print build logs.

REPL command: phases package
REPL command: configure-flags package
REPL command: make-flags package

These REPL commands return the value of one element of the arguments field of package (veja package Reference): the first one show the staged code associated with #:phases (veja Build Phases), the second shows the code for #:configure-flags, and ,make-flags returns the code for #:make-flags.

REPL command: run-in-store exp

Run exp, a monadic expression, through the store monad. Veja A mônada do armazém, for more information.

REPL command: enter-store-monad

Enter a new REPL to evaluate monadic expressions (veja A mônada do armazém). You can quit this “inner” REPL by typing ,q.


9 Utilitários

This section describes Guix command-line utilities. Some of them are primarily targeted at developers and users who write new package definitions, while others are more generally useful. They complement the Scheme programming interface of Guix in a convenient way.


9.1 Invocando guix build

The guix build command builds packages or derivations and their dependencies, and prints the resulting store paths. Note that it does not modify the user’s profile—this is the job of the guix package command (veja Invocando guix package). Thus, it is mainly useful for distribution developers.

The general syntax is:

guix build options package-or-derivation

As an example, the following command builds the latest versions of Emacs and of Guile, displays their build logs, and finally displays the resulting directories:

guix build emacs guile

Similarly, the following command builds all the available packages:

guix build --quiet --keep-going \
  $(guix package -A | awk '{ print $1 "@" $2 }')

package-or-derivation may be either the name of a package found in the software distribution such as coreutils or coreutils@8.20, or a derivation such as /gnu/store/…-coreutils-8.19.drv. In the former case, a package with the corresponding name (and optionally version) is searched for among the GNU distribution modules (veja Módulos de pacote).

Alternatively, the --expression option may be used to specify a Scheme expression that evaluates to a package; this is useful when disambiguating among several same-named packages or package variants is needed.

There may be zero or more options. The available options are described in the subsections below.


9.1.1 Opções de compilação comum

A number of options that control the build process are common to guix build and other commands that can spawn builds, such as guix package or guix archive. These are the following:

--load-path=directory
-L diretório

Add directory to the front of the package module search path (veja Módulos de pacote).

This allows users to define their own packages and make them visible to the command-line tools.

--keep-failed
-K

Keep the build tree of failed builds. Thus, if a build fails, its build tree is kept under /tmp, in a directory whose name is shown at the end of the build log. This is useful when debugging build issues. Veja Depurando falhas de compilação, for tips and tricks on how to debug build issues.

This option implies --no-offload, and it has no effect when connecting to a remote daemon with a guix:// URI (veja the GUIX_DAEMON_SOCKET variable).

--keep-going
-k

Keep going when some of the derivations fail to build; return only once all the builds have either completed or failed.

The default behavior is to stop as soon as one of the specified derivations has failed.

--dry-run
-n

Do not build the derivations.

--fallback

When substituting a pre-built binary fails, fall back to building packages locally (veja Falha na substituição).

--substitute-urls=urls

Consider urls the whitespace-separated list of substitute source URLs, overriding the default list of URLs of guix-daemon (veja guix-daemon URLs).

This means that substitutes may be downloaded from urls, provided they are signed by a key authorized by the system administrator (veja Substitutos).

When urls is the empty string, substitutes are effectively disabled.

--no-substitutes

Não use substitutos para compilar produtos. Ou seja, sempre crie coisas localmente, em vez de permitir downloads de binários pré-compilados (veja Substitutos).

--no-grafts

Do not “graft” packages. In practice, this means that package updates available as grafts are not applied. Veja Atualizações de segurança, for more information on grafts.

--rounds=n

Build each derivation n times in a row, and raise an error if consecutive build results are not bit-for-bit identical.

This is a useful way to detect non-deterministic builds processes. Non-deterministic build processes are a problem because they make it practically impossible for users to verify whether third-party binaries are genuine. Veja Invocando guix challenge, for more.

Quando usado em conjunto com --keep-failed, uma saída de comparação é mantida no armazém, sob /gnu/store/…-check. Isso facilita procurar por diferenças entre os dois resultados.

--no-offload

Do not use offload builds to other machines (veja Usando o recurso de descarregamento). That is, always build things locally instead of offloading builds to remote machines.

--max-silent-time=segundos

Quando o processo de compilação ou substituição permanecer em silêncio por mais de segundos, encerra-o e relata uma falha de compilação.

By default, the daemon’s setting is honored (veja --max-silent-time).

--timeout=segundos

Da mesma forma, quando o processo de compilação ou substituição durar mais que segundos, encerra-o e relata uma falha de compilação.

By default, the daemon’s setting is honored (veja --timeout).

-v level
--verbosity=level

Use the given verbosity level, an integer. Choosing 0 means that no output is produced, 1 is for quiet output; 2 is similar to 1 but it additionally displays download URLs; 3 shows all the build log output on standard error.

--cores=n
-c n

Allow the use of up to n CPU cores for the build. The special value 0 means to use as many CPU cores as available.

--max-jobs=n
-M n

Allow at most n build jobs in parallel. Veja --max-jobs, for details about this option and the equivalent guix-daemon option.

--debug=level

Produce debugging output coming from the build daemon. level must be an integer between 0 and 5; higher means more verbose output. Setting a level of 4 or more may be helpful when debugging setup issues with the build daemon.

Behind the scenes, guix build is essentially an interface to the package-derivation procedure of the (guix packages) module, and to the build-derivations procedure of the (guix derivations) module.

In addition to options explicitly passed on the command line, guix build and other guix commands that support building honor the GUIX_BUILD_OPTIONS environment variable.

Environment Variable: GUIX_BUILD_OPTIONS

Users can define this variable to a list of command line options that will automatically be used by guix build and other guix commands that can perform builds, as in the example below:

$ export GUIX_BUILD_OPTIONS="--no-substitutes -c 2 -L /foo/bar"

These options are parsed independently, and the result is appended to the parsed command-line options.


9.1.2 Opções de transformação de pacote

Another set of command-line options supported by guix build and also guix package are package transformation options. These are options that make it possible to define package variants—for instance, packages built from different source code. This is a convenient way to create customized packages on the fly without having to type in the definitions of package variants (veja Definindo pacotes).

Package transformation options are preserved across upgrades: guix upgrade attempts to apply transformation options initially used when creating the profile to the upgraded packages.

The available options are listed below. Most commands support them and also support a --help-transform option that lists all the available options and a synopsis (these options are not shown in the --help output for brevity).

--tune[=cpu]

Use versions of the packages marked as “tunable” optimized for cpu. When cpu is native, or when it is omitted, tune for the CPU on which the guix command is running.

Valid cpu names are those recognized by the underlying compiler, by default the GNU Compiler Collection. On x86_64 processors, this includes CPU names such as nehalem, haswell, and skylake (veja -march em Using the GNU Compiler Collection (GCC)).

As new generations of CPUs come out, they augment the standard instruction set architecture (ISA) with additional instructions, in particular instructions for single-instruction/multiple-data (SIMD) parallel processing. For example, while Core2 and Skylake CPUs both implement the x86_64 ISA, only the latter supports AVX2 SIMD instructions.

The primary gain one can expect from --tune is for programs that can make use of those SIMD capabilities and that do not already have a mechanism to select the right optimized code at run time. Packages that have the tunable? property set are considered tunable packages by the --tune option; a package definition with the property set looks like this:

(package
  (name "hello-simd")
  ;; ...

  ;; This package may benefit from SIMD extensions so
  ;; mark it as "tunable".
  (properties '((tunable? . #t))))

Other packages are not considered tunable. This allows Guix to use generic binaries in the cases where tuning for a specific CPU is unlikely to provide any gain.

Tuned packages are built with -march=CPU; under the hood, the -march option is passed to the actual wrapper by a compiler wrapper. Since the build machine may not be able to run code for the target CPU micro-architecture, the test suite is not run when building a tuned package.

To reduce rebuilds to the minimum, tuned packages are grafted onto packages that depend on them (veja grafts). Thus, using --no-grafts cancels the effect of --tune.

We call this technique package multi-versioning: several variants of tunable packages may be built, one for each CPU variant. It is the coarse-grain counterpart of function multi-versioning as implemented by the GNU tool chain (veja Function Multiversioning em Using the GNU Compiler Collection (GCC)).

--with-source=fonte
--with-source=pacote=fonte
--with-source=package@version=source

Use source as the source of package, and version as its version number. source must be a file name or a URL, as for guix download (veja Invocando guix download).

When package is omitted, it is taken to be the package name specified on the command line that matches the base of source—e.g., if source is /src/guile-2.0.10.tar.gz, the corresponding package is guile.

Likewise, when version is omitted, the version string is inferred from source; in the previous example, it is 2.0.10.

This option allows users to try out versions of packages other than the one provided by the distribution. The example below downloads ed-1.7.tar.gz from a GNU mirror and uses that as the source for the ed package:

guix build ed --with-source=mirror://gnu/ed/ed-1.4.tar.gz

As a developer, --with-source makes it easy to test release candidates, and even to test their impact on packages that depend on them:

guix build elogind --with-source=…/shepherd-0.9.0rc1.tar.gz

… or to build from a checkout in a pristine environment:

$ git clone git://git.sv.gnu.org/guix.git
$ guix build guix --with-source=guix@1.0=./guix
--with-input=pacote=substituto

Replace dependency on package by a dependency on replacement. package must be a package name, and replacement must be a package specification such as guile or guile@1.8.

For instance, the following command builds Guix, but replaces its dependency on the current stable version of Guile with a dependency on the legacy version of Guile, guile@2.2:

guix build --with-input=guile=guile@2.2 guix

This is a recursive, deep replacement. So in this example, both guix and its dependency guile-json (which also depends on guile) get rebuilt against guile@2.2.

This is implemented using the package-input-rewriting/spec Scheme procedure (veja package-input-rewriting/spec).

--with-graft=package=replacement

This is similar to --with-input but with an important difference: instead of rebuilding the whole dependency chain, replacement is built and then grafted onto the binaries that were initially referring to package. Veja Atualizações de segurança, for more information on grafts.

For example, the command below grafts version 3.5.4 of GnuTLS onto Wget and all its dependencies, replacing references to the version of GnuTLS they currently refer to:

guix build --with-graft=gnutls=gnutls@3.5.4 wget

This has the advantage of being much faster than rebuilding everything. But there is a caveat: it works if and only if package and replacement are strictly compatible—for example, if they provide a library, the application binary interface (ABI) of those libraries must be compatible. If replacement is somehow incompatible with package, then the resulting package may be unusable. Use with care!

--with-debug-info=package

Build package in a way that preserves its debugging info and graft it onto packages that depend on it. This is useful if package does not already provide debugging info as a debug output (veja Instalando arquivos de depuração).

For example, suppose you’re experiencing a crash in Inkscape and would like to see what’s up in GLib, a library deep down in Inkscape’s dependency graph. GLib lacks a debug output, so debugging is tough. Fortunately, you rebuild GLib with debugging info and tack it on Inkscape:

guix install inkscape --with-debug-info=glib

Only GLib needs to be recompiled so this takes a reasonable amount of time. Veja Instalando arquivos de depuração, for more info.

Nota: Under the hood, this option works by passing the ‘#:strip-binaries? #f’ to the build system of the package of interest (veja Sistemas de compilação). Most build systems support that option but some do not. In that case, an error is raised.

Likewise, if a C/C++ package is built without -g (which is rarely the case), debugging info will remain unavailable even when #:strip-binaries? is false.

--with-c-toolchain=package=toolchain

This option changes the compilation of package and everything that depends on it so that they get built with toolchain instead of the default GNU tool chain for C/C++.

Consider this example:

guix build octave-cli \
  --with-c-toolchain=fftw=gcc-toolchain@10 \
  --with-c-toolchain=fftwf=gcc-toolchain@10

The command above builds a variant of the fftw and fftwf packages using version 10 of gcc-toolchain instead of the default tool chain, and then builds a variant of the GNU Octave command-line interface using them. GNU Octave itself is also built with gcc-toolchain@10.

This other example builds the Hardware Locality (hwloc) library and its dependents up to intel-mpi-benchmarks with the Clang C compiler:

guix build --with-c-toolchain=hwloc=clang-toolchain \
           intel-mpi-benchmarks

Nota: There can be application binary interface (ABI) incompatibilities among tool chains. This is particularly true of the C++ standard library and run-time support libraries such as that of OpenMP. By rebuilding all dependents with the same tool chain, --with-c-toolchain minimizes the risks of incompatibility but cannot entirely eliminate them. Choose package wisely.

--with-git-url=pacote=url

Build package from the latest commit of the master branch of the Git repository at url. Git sub-modules of the repository are fetched, recursively.

For example, the following command builds the NumPy Python library against the latest commit of the master branch of Python itself:

guix build python-numpy \
  --with-git-url=python=https://github.com/python/cpython

This option can also be combined with --with-branch or --with-commit (see below).

Obviously, since it uses the latest commit of the given branch, the result of such a command varies over time. Nevertheless it is a convenient way to rebuild entire software stacks against the latest commit of one or more packages. This is particularly useful in the context of continuous integration (CI).

Checkouts are kept in a cache under ~/.cache/guix/checkouts to speed up consecutive accesses to the same repository. You may want to clean it up once in a while to save disk space.

--with-branch=pacote=ramo

Build package from the latest commit of branch. If the source field of package is an origin with the git-fetch method (veja origin Reference) or a git-checkout object, the repository URL is taken from that source. Otherwise you have to use --with-git-url to specify the URL of the Git repository.

For instance, the following command builds guile-sqlite3 from the latest commit of its master branch, and then builds guix (which depends on it) and cuirass (which depends on guix) against this specific guile-sqlite3 build:

guix build --with-branch=guile-sqlite3=master cuirass
--with-commit=pacote=commit

This is similar to --with-branch, except that it builds from commit rather than the tip of a branch. commit must be a valid Git commit SHA1 identifier, a tag, or a git describe style identifier such as 1.0-3-gabc123.

--with-patch=package=file

Add file to the list of patches applied to package, where package is a spec such as python@3.8 or glibc. file must contain a patch; it is applied with the flags specified in the origin of package (veja origin Reference), which by default includes -p1 (veja patch Directories em Comparing and Merging Files).

As an example, the command below rebuilds Coreutils with the GNU C Library (glibc) patched with the given patch:

guix build coreutils --with-patch=glibc=./glibc-frob.patch

In this example, glibc itself as well as everything that leads to Coreutils in the dependency graph is rebuilt.

--with-configure-flag=package=flag

Append flag to the configure flags of package, where package is a spec such as guile@3.0 or glibc. The build system of package must support the #:configure-flags argument.

For example, the command below builds GNU Hello with the configure flag --disable-nls:

guix build hello --with-configure-flag=hello=--disable-nls

The following command passes an extra flag to cmake as it builds lapack:

guix build lapack \
  --with-configure-flag=lapack=-DBUILD_SHARED_LIBS=OFF

Nota: Under the hood, this option works by passing the ‘#:configure-flags’ argument to the build system of the package of interest (veja Sistemas de compilação). Most build systems support that option but some do not. In that case, an error is raised.

--with-latest=package
--with-version=package=version

So you like living on the bleeding edge? The --with-latest option is for you! It replaces occurrences of package in the dependency graph with its latest upstream version, as reported by guix refresh (veja Invocando guix refresh).

It does so by determining the latest upstream release of package (if possible), downloading it, and authenticating it if it comes with an OpenPGP signature.

As an example, the command below builds Guix against the latest version of Guile-JSON:

guix build guix --with-latest=guile-json

The --with-version works similarly except that it lets you specify that you want precisely version, assuming that version exists upstream. For example, to spawn a development environment with SciPy built against version 1.22.4 of NumPy (skipping its test suite because hey, we’re not gonna wait this long), you would run:

guix shell python python-scipy --with-version=python-numpy=1.22.4

Aviso: Because they depend on source code published at a given point in time on upstream servers, deployments made with --with-latest and --with-version may be non-reproducible: source might disappear or be modified in place on the servers.

To deploy old software versions without compromising on reproducibility, veja guix time-machine.

There are limitations. First, in cases where the tool cannot or does not know how to authenticate source code, you are at risk of running malicious code; a warning is emitted in this case. Second, this option simply changes the source used in the existing package definitions, which is not always sufficient: there might be additional dependencies that need to be added, patches to apply, and more generally the quality assurance work that Guix developers normally do will be missing.

You’ve been warned! When those limitations are acceptable, it’s a snappy way to stay on top. We encourage you to submit patches updating the actual package definitions once you have successfully tested an upgrade with --with-latest (veja Contribuindo).

--without-tests=package

Build package without running its tests. This can be useful in situations where you want to skip the lengthy test suite of a intermediate package, or if a package’s test suite fails in a non-deterministic fashion. It should be used with care because running the test suite is a good way to ensure a package is working as intended.

Turning off tests leads to a different store item. Consequently, when using this option, anything that depends on package must be rebuilt, as in this example:

guix install --without-tests=python python-notebook

The command above installs python-notebook on top of python built without running its test suite. To do so, it also rebuilds everything that depends on python, including python-notebook itself.

Internally, --without-tests relies on changing the #:tests? option of a package’s check phase (veja Sistemas de compilação). Note that some packages use a customized check phase that does not respect a #:tests? #f setting. Therefore, --without-tests has no effect on these packages.

Wondering how to achieve the same effect using Scheme code, for example in your manifest, or how to write your own package transformation? Veja Defining Package Variants, for an overview of the programming interfaces available.


9.1.3 Opções de compilação adicional

The command-line options presented below are specific to guix build.

--quiet
-q

Build quietly, without displaying the build log; this is equivalent to --verbosity=0. Upon completion, the build log is kept in /var (or similar) and can always be retrieved using the --log-file option.

--file=file
-f arquivo

Build the package, derivation, or other file-like object that the code within file evaluates to (veja file-like objects).

As an example, file might contain a package definition like this (veja Definindo pacotes):

(use-modules (guix)
             (guix build-system gnu)
             (guix licenses))

(package
  (name "hello")
  (version "2.10")
  (source (origin
            (method url-fetch)
            (uri (string-append "mirror://gnu/hello/hello-" version
                                ".tar.gz"))
            (sha256
             (base32
              "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i"))))
  (build-system gnu-build-system)
  (synopsis "Hello, GNU world: An example GNU package")
  (description "Guess what GNU Hello prints!")
  (home-page "http://www.gnu.org/software/hello/")
  (license gpl3+))

The file may also contain a JSON representation of one or more package definitions. Running guix build -f on hello.json with the following contents would result in building the packages myhello and greeter:

[
  {
    "name": "myhello",
    "version": "2.10",
    "source": "mirror://gnu/hello/hello-2.10.tar.gz",
    "build-system": "gnu",
    "arguments": {
      "tests?": false
    },
    "home-page": "https://www.gnu.org/software/hello/",
    "synopsis": "Hello, GNU world: An example GNU package",
    "description": "GNU Hello prints a greeting.",
    "license": "GPL-3.0+",
    "native-inputs": ["gettext"]
  },
  {
    "name": "greeter",
    "version": "1.0",
    "source": "mirror://gnu/hello/hello-2.10.tar.gz",
    "build-system": "gnu",
    "arguments": {
      "test-target": "foo",
      "parallel-build?": false
    },
    "home-page": "https://example.com/",
    "synopsis": "Greeter using GNU Hello",
    "description": "This is a wrapper around GNU Hello.",
    "license": "GPL-3.0+",
    "inputs": ["myhello", "hello"]
  }
]
--manifest=manifest
-m manifest

Build all packages listed in the given manifest (veja --manifest).

--expression=expr
-e expr

Build the package or derivation expr evaluates to.

For example, expr may be (@ (gnu packages guile) guile-1.8), which unambiguously designates this specific variant of version 1.8 of Guile.

Alternatively, expr may be a G-expression, in which case it is used as a build program passed to gexp->derivation (veja Expressões-G).

Lastly, expr may refer to a zero-argument monadic procedure (veja A mônada do armazém). The procedure must return a derivation as a monadic value, which is then passed through run-with-store.

--source
-S

Build the source derivations of the packages, rather than the packages themselves.

For instance, guix build -S gcc returns something like /gnu/store/…-gcc-4.7.2.tar.bz2, which is the GCC source tarball.

The returned source tarball is the result of applying any patches and code snippets specified in the package origin (veja Definindo pacotes).

As with other derivations, the result of building a source derivation can be verified using the --check option (veja build-check). This is useful to validate that a (potentially already built or substituted, thus cached) package source matches against its declared hash.

Note that guix build -S compiles the sources only of the specified packages. They do not include the sources of statically linked dependencies and by themselves are insufficient for reproducing the packages.

--sources

Fetch and return the source of package-or-derivation and all their dependencies, recursively. This is a handy way to obtain a local copy of all the source code needed to build packages, allowing you to eventually build them even without network access. It is an extension of the --source option and can accept one of the following optional argument values:

pacote

This value causes the --sources option to behave in the same way as the --source option.

all

Build the source derivations of all packages, including any source that might be listed as inputs. This is the default value.

$ guix build --sources tzdata
The following derivations will be built:
   /gnu/store/…-tzdata2015b.tar.gz.drv
   /gnu/store/…-tzcode2015b.tar.gz.drv
transitive

Build the source derivations of all packages, as well of all transitive inputs to the packages. This can be used e.g. to prefetch package source for later offline building.

$ guix build --sources=transitive tzdata
The following derivations will be built:
   /gnu/store/…-tzcode2015b.tar.gz.drv
   /gnu/store/…-findutils-4.4.2.tar.xz.drv
   /gnu/store/…-grep-2.21.tar.xz.drv
   /gnu/store/…-coreutils-8.23.tar.xz.drv
   /gnu/store/…-make-4.1.tar.xz.drv
   /gnu/store/…-bash-4.3.tar.xz.drv
…
--system=system
-s sistema

Attempt to build for system—e.g., i686-linux—instead of the system type of the build host. The guix build command allows you to repeat this option several times, in which case it builds for all the specified systems; other commands ignore extraneous -s options.

Nota: The --system flag is for native compilation and must not be confused with cross-compilation. See --target below for information on cross-compilation.

An example use of this is on Linux-based systems, which can emulate different personalities. For instance, passing --system=i686-linux on an x86_64-linux system or --system=armhf-linux on an aarch64-linux system allows you to build packages in a complete 32-bit environment.

Nota: Building for an armhf-linux system is unconditionally enabled on aarch64-linux machines, although certain aarch64 chipsets do not allow for this functionality, notably the ThunderX.

Similarly, when transparent emulation with QEMU and binfmt_misc is enabled (veja qemu-binfmt-service-type), you can build for any system for which a QEMU binfmt_misc handler is installed.

Builds for a system other than that of the machine you are using can also be offloaded to a remote machine of the right architecture. Veja Usando o recurso de descarregamento, for more information on offloading.

--target=triplet

Cross-build for triplet, which must be a valid GNU triplet, such as "aarch64-linux-gnu" (veja GNU configuration triplets em Autoconf).

--list-systems

List all the supported systems, that can be passed as an argument to --system.

--list-targets

List all the supported targets, that can be passed as an argument to --target.

--check

Rebuild package-or-derivation, which are already available in the store, and raise an error if the build results are not bit-for-bit identical.

This mechanism allows you to check whether previously installed substitutes are genuine (veja Substitutos), or whether the build result of a package is deterministic. Veja Invocando guix challenge, for more background information and tools.

Quando usado em conjunto com --keep-failed, uma saída de comparação é mantida no armazém, sob /gnu/store/…-check. Isso facilita procurar por diferenças entre os dois resultados.

--repair

Attempt to repair the specified store items, if they are corrupt, by re-downloading or rebuilding them.

This operation is not atomic and thus restricted to root.

--derivations
-d

Return the derivation paths, not the output paths, of the given packages.

--root=arquivo
-r arquivo

Make file a symlink to the result, and register it as a garbage collector root.

Consequently, the results of this guix build invocation are protected from garbage collection until file is removed. When that option is omitted, build results are eligible for garbage collection as soon as the build completes. Veja Invocando guix gc, for more on GC roots.

--log-file

Return the build log file names or URLs for the given package-or-derivation, or raise an error if build logs are missing.

This works regardless of how packages or derivations are specified. For instance, the following invocations are equivalent:

guix build --log-file $(guix build -d guile)
guix build --log-file $(guix build guile)
guix build --log-file guile
guix build --log-file -e '(@ (gnu packages guile) guile-2.0)'

If a log is unavailable locally, and unless --no-substitutes is passed, the command looks for a corresponding log on one of the substitute servers.

So for instance, imagine you want to see the build log of GDB on aarch64, but you are actually on an x86_64 machine:

$ guix build --log-file gdb -s aarch64-linux
https://bordeaux.guix.gnu.org/log/…-gdb-7.10

You can freely access a huge library of build logs!


9.1.4 Depurando falhas de compilação

When defining a new package (veja Definindo pacotes), you will probably find yourself spending some time debugging and tweaking the build until it succeeds. To do that, you need to operate the build commands yourself in an environment as close as possible to the one the build daemon uses.

To that end, the first thing to do is to use the --keep-failed or -K option of guix build, which will keep the failed build tree in /tmp or whatever directory you specified as TMPDIR (veja --keep-failed).

From there on, you can cd to the failed build tree and source the environment-variables file, which contains all the environment variable definitions that were in place when the build failed. So let’s say you’re debugging a build failure in package foo; a typical session would look like this:

$ guix build foo -K
… build fails
$ cd /tmp/guix-build-foo.drv-0
$ source ./environment-variables
$ cd foo-1.2

Now, you can invoke commands as if you were the daemon (almost) and troubleshoot your build process.

Sometimes it happens that, for example, a package’s tests pass when you run them manually but they fail when the daemon runs them. This can happen because the daemon runs builds in containers where, unlike in our environment above, network access is missing, /bin/sh does not exist, etc. (veja Configuração do ambiente de compilação).

In such cases, you may need to inspect the build process from within a container similar to the one the build daemon creates:

$ guix build -K foo
…
$ cd /tmp/guix-build-foo.drv-0
$ guix shell --no-grafts -C -D foo strace gdb
[env]# source ./environment-variables
[env]# cd foo-1.2

Here, guix shell -C creates a container and spawns a new shell in it (veja Invoking guix shell). The strace gdb part adds the strace and gdb commands to the container, which you may find handy while debugging. The --no-grafts option makes sure we get the exact same environment, with ungrafted packages (veja Atualizações de segurança, for more info on grafts).

To get closer to a container like that used by the build daemon, we can remove /bin/sh:

[env]# rm /bin/sh

(Don’t worry, this is harmless: this is all happening in the throw-away container created by guix shell.)

The strace command is probably not in the search path, but we can run:

[env]# $GUIX_ENVIRONMENT/bin/strace -f -o log make check

In this way, not only you will have reproduced the environment variables the daemon uses, you will also be running the build process in a container similar to the one the daemon uses.


9.2 Invocando guix edit

So many packages, so many source files! The guix edit command facilitates the life of users and packagers by pointing their editor at the source file containing the definition of the specified packages. For instance:

guix edit gcc@4.9 vim

launches the program specified in the VISUAL or in the EDITOR environment variable to view the recipe of GCC 4.9.3 and that of Vim.

If you are using a Guix Git checkout (veja Compilando do git), or have created your own packages on GUIX_PACKAGE_PATH (veja Módulos de pacote), you will be able to edit the package recipes. In other cases, you will be able to examine the read-only recipes for packages currently in the store.

Instead of GUIX_PACKAGE_PATH, the command-line option --load-path=directory (or in short -L directory) allows you to add directory to the front of the package module search path and so make your own packages visible.


9.3 Invocando guix download

When writing a package definition, developers typically need to download a source tarball, compute its SHA256 hash, and write that hash in the package definition (veja Definindo pacotes). The guix download tool helps with this task: it downloads a file from the given URI, adds it to the store, and prints both its file name in the store and its SHA256 hash.

The fact that the downloaded file is added to the store saves bandwidth: when the developer eventually tries to build the newly defined package with guix build, the source tarball will not have to be downloaded again because it is already in the store. It is also a convenient way to temporarily stash files, which may be deleted eventually (veja Invocando guix gc).

The guix download command supports the same URIs as used in package definitions. In particular, it supports mirror:// URIs. https URIs (HTTP over TLS) are supported provided the Guile bindings for GnuTLS are available in the user’s environment; when they are not available, an error is raised. Veja how to install the GnuTLS bindings for Guile em GnuTLS-Guile, for more information.

guix download verifies HTTPS server certificates by loading the certificates of X.509 authorities from the directory pointed to by the SSL_CERT_DIR environment variable (veja Certificados X.509), unless --no-check-certificate is used.

Alternatively, guix download can also retrieve a Git repository, possibly a specific commit, tag, or branch.

The following options are available:

--hash=algorithm
-H algorithm

Compute a hash using the specified algorithm. Veja Invocando guix hash, for more information.

--format=fmt
-f fmt

Write the hash in the format specified by fmt. For more information on the valid values for fmt, veja Invocando guix hash.

--no-check-certificate

Do not validate the X.509 certificates of HTTPS servers.

When using this option, you have absolutely no guarantee that you are communicating with the authentic server responsible for the given URL, which makes you vulnerable to “man-in-the-middle” attacks.

--output=arquivo
-o arquivo

Save the downloaded file to file instead of adding it to the store.

--git
-g

Checkout the Git repository at the latest commit on the default branch.

--commit=commit-or-tag

Checkout the Git repository at commit-or-tag.

commit-or-tag can be either a tag or a commit defined in the Git repository.

--branch=ramo

Checkout the Git repository at branch.

The repository will be checked out at the latest commit of branch, which must be a valid branch of the Git repository.

--recursive
-r

Recursively clone the Git repository.


9.4 Invocando guix hash

The guix hash command computes the hash of a file. It is primarily a convenience tool for anyone contributing to the distribution: it computes the cryptographic hash of one or more files, which can be used in the definition of a package (veja Definindo pacotes).

The general syntax is:

guix hash option file ...

When file is - (a hyphen), guix hash computes the hash of data read from standard input. guix hash has the following options:

--hash=algorithm
-H algorithm

Compute a hash using the specified algorithm, sha256 by default.

algorithm must be the name of a cryptographic hash algorithm supported by Libgcrypt via Guile-Gcrypt—e.g., sha512 or sha3-256 (veja Hash Functions em Guile-Gcrypt Reference Manual).

--format=fmt
-f fmt

Write the hash in the format specified by fmt.

Supported formats: base64, nix-base32, base32, base16 (hex and hexadecimal can be used as well).

If the --format option is not specified, guix hash will output the hash in nix-base32. This representation is used in the definitions of packages.

--recursive
-r

The --recursive option is deprecated in favor of --serializer=nar (see below); -r remains accepted as a convenient shorthand.

--serializer=type
-S type

Compute the hash on file using type serialization.

type may be one of the following:

nenhuma

This is the default: it computes the hash of a file’s contents.

nar

Compute the hash of a “normalized archive” (or “nar”) containing file, including its children if it is a directory. Some of the metadata of file is part of the archive; for instance, when file is a regular file, the hash is different depending on whether file is executable or not. Metadata such as time stamps have no impact on the hash (veja Invocando guix archive, for more info on the nar format).

git

Compute the hash of the file or directory as a Git “tree”, following the same method as the Git version control system.

--exclude-vcs
-x

When combined with --recursive, exclude version control system directories (.bzr, .git, .hg, etc.).

As an example, here is how you would compute the hash of a Git checkout, which is useful when using the git-fetch method (veja origin Reference):

$ git clone http://example.org/foo.git
$ cd foo
$ guix hash -x --serializer=nar .

9.5 Invoking guix import

The guix import command is useful for people who would like to add a package to the distribution with as little work as possible—a legitimate demand. The command knows of a few repositories from which it can “import” package metadata. The result is a package definition, or a template thereof, in the format we know (veja Definindo pacotes).

The general syntax is:

guix import [global-options…] importer package [options…]

importer specifies the source from which to import package metadata, and options specifies a package identifier and other options specific to importer. guix import itself has the following global-options:

--insert=file
-i file

Insert the package definition(s) that the importer generated into the specified file, either in alphabetical order among existing package definitions, or at the end of the file otherwise.

Some of the importers rely on the ability to run the gpgv command. For these, GnuPG must be installed and in $PATH; run guix install gnupg if needed.

Currently, the available “importers” are:

gnu

Import metadata for the given GNU package. This provides a template for the latest version of that GNU package, including the hash of its source tarball, and its canonical synopsis and description.

Additional information such as the package dependencies and its license needs to be figured out manually.

For example, the following command returns a package definition for GNU Hello:

guix import gnu hello

Specific command-line options are:

--key-download=policy

As for guix refresh, specify the policy to handle missing OpenPGP keys when verifying the package signature. Veja --key-download.

pypi

Import metadata from the Python Package Index. Information is taken from the JSON-formatted description available at pypi.python.org and usually includes all the relevant information, including package dependencies. For maximum efficiency, it is recommended to install the unzip utility, so that the importer can unzip Python wheels and gather data from them.

The command below imports metadata for the latest version of the itsdangerous Python package:

guix import pypi itsdangerous

You can also ask for a specific version:

guix import pypi itsdangerous@1.1.0
--recursive
-r

Traverse the dependency graph of the given upstream package recursively and generate package expressions for all those packages that are not yet in Guix.

gem

Import metadata from RubyGems. Information is taken from the JSON-formatted description available at rubygems.org and includes most relevant information, including runtime dependencies. There are some caveats, however. The metadata doesn’t distinguish between synopses and descriptions, so the same string is used for both fields. Additionally, the details of non-Ruby dependencies required to build native extensions is unavailable and left as an exercise to the packager.

The command below imports metadata for the rails Ruby package:

guix import gem rails

You can also ask for a specific version:

guix import gem rails@7.0.4
--recursive
-r

Traverse the dependency graph of the given upstream package recursively and generate package expressions for all those packages that are not yet in Guix.

minetest

Import metadata from ContentDB. Information is taken from the JSON-formatted metadata provided through ContentDB’s API and includes most relevant information, including dependencies. There are some caveats, however. The license information is often incomplete. The commit hash is sometimes missing. The descriptions are in the Markdown format, but Guix uses Texinfo instead. Texture packs and subgames are unsupported.

The command below imports metadata for the Mesecons mod by Jeija:

guix import minetest Jeija/mesecons

The author name can also be left out:

guix import minetest mesecons
--recursive
-r

Traverse the dependency graph of the given upstream package recursively and generate package expressions for all those packages that are not yet in Guix.

cpan

Import metadata from MetaCPAN. Information is taken from the JSON-formatted metadata provided through MetaCPAN’s API and includes most relevant information, such as module dependencies. License information should be checked closely. If Perl is available in the store, then the corelist utility will be used to filter core modules out of the list of dependencies.

The command below imports metadata for the Acme::Boolean Perl module:

guix import cpan Acme::Boolean
cran

Import metadata from CRAN, the central repository for the GNU R statistical and graphical environment.

Information is extracted from the DESCRIPTION file of the package.

The command below imports metadata for the Cairo R package:

guix import cran Cairo

You can also ask for a specific version:

guix import cran rasterVis@0.50.3

When --recursive is added, the importer will traverse the dependency graph of the given upstream package recursively and generate package expressions for all those packages that are not yet in Guix.

When --style=specification is added, the importer will generate package definitions whose inputs are package specifications instead of references to package variables. This is useful when generated package definitions are to be appended to existing user modules, as the list of used package modules need not be changed. The default is --style=variable.

When --prefix=license: is added, the importer will prefix license atoms with license:, allowing a prefixed import of (guix licenses).

When --archive=bioconductor is added, metadata is imported from Bioconductor, a repository of R packages for the analysis and comprehension of high-throughput genomic data in bioinformatics.

Information is extracted from the DESCRIPTION file contained in the package archive.

The command below imports metadata for the GenomicRanges R package:

guix import cran --archive=bioconductor GenomicRanges

Finally, you can also import R packages that have not yet been published on CRAN or Bioconductor as long as they are in a git repository. Use --archive=git followed by the URL of the git repository:

guix import cran --archive=git https://github.com/immunogenomics/harmony
texlive

Import TeX package information from the TeX Live package database for TeX packages that are part of the TeX Live distribution.

Information about the package is obtained from the TeX Live package database, a plain text file that is included in the texlive-scripts package. The source code is downloaded from possibly multiple locations in the SVN repository of the Tex Live project. Note that therefore SVN must be installed and in $PATH; run guix install subversion if needed.

The command below imports metadata for the fontspec TeX package:

guix import texlive fontspec

Additional options include:

--recursive
-r

Traverse the dependency graph of the given upstream package recursively and generate package expressions for all those packages that are not yet in Guix.

json

Import package metadata from a local JSON file. Consider the following example package definition in JSON format:

{
  "name": "hello",
  "version": "2.10",
  "source": "mirror://gnu/hello/hello-2.10.tar.gz",
  "build-system": "gnu",
  "home-page": "https://www.gnu.org/software/hello/",
  "synopsis": "Hello, GNU world: An example GNU package",
  "description": "GNU Hello prints a greeting.",
  "license": "GPL-3.0+",
  "native-inputs": ["gettext"]
}

The field names are the same as for the <package> record (Veja Definindo pacotes). References to other packages are provided as JSON lists of quoted package specification strings such as guile or guile@2.0.

The importer also supports a more explicit source definition using the common fields for <origin> records:

{
  …
  "source": {
    "method": "url-fetch",
    "uri": "mirror://gnu/hello/hello-2.10.tar.gz",
    "sha256": {
      "base32": "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i"
    }
  }
  …
}

The command below reads metadata from the JSON file hello.json and outputs a package expression:

guix import json hello.json
hackage

Import metadata from the Haskell community’s central package archive Hackage. Information is taken from Cabal files and includes all the relevant information, including package dependencies.

Specific command-line options are:

--stdin
-s

Read a Cabal file from standard input.

--no-test-dependencies
-t

Do not include dependencies required only by the test suites.

--cabal-environment=alist
-e alist

alist is a Scheme alist defining the environment in which the Cabal conditionals are evaluated. The accepted keys are: os, arch, impl and a string representing the name of a flag. The value associated with a flag has to be either the symbol true or false. The value associated with other keys has to conform to the Cabal file format definition. The default value associated with the keys os, arch and impl is ‘linux’, ‘x86_64’ and ‘ghc’, respectively.

--recursive
-r

Traverse the dependency graph of the given upstream package recursively and generate package expressions for all those packages that are not yet in Guix.

The command below imports metadata for the latest version of the HTTP Haskell package without including test dependencies and specifying the value of the flag ‘network-uri’ as false:

guix import hackage -t -e "'((\"network-uri\" . false))" HTTP

A specific package version may optionally be specified by following the package name by an at-sign and a version number as in the following example:

guix import hackage mtl@2.1.3.1
stackage

The stackage importer is a wrapper around the hackage one. It takes a package name, looks up the package version included in a long-term support (LTS) Stackage release and uses the hackage importer to retrieve its metadata. Note that it is up to you to select an LTS release compatible with the GHC compiler used by Guix.

Specific command-line options are:

--no-test-dependencies
-t

Do not include dependencies required only by the test suites.

--lts-version=versão
-l versão

version is the desired LTS release version. If omitted the latest release is used.

--recursive
-r

Traverse the dependency graph of the given upstream package recursively and generate package expressions for all those packages that are not yet in Guix.

The command below imports metadata for the HTTP Haskell package included in the LTS Stackage release version 7.18:

guix import stackage --lts-version=7.18 HTTP
elpa

Import metadata from an Emacs Lisp Package Archive (ELPA) package repository (veja Packages em The GNU Emacs Manual).

Specific command-line options are:

--archive=repo
-a repo

repo identifies the archive repository from which to retrieve the information. Currently the supported repositories and their identifiers are:

  • - GNU, selected by the gnu identifier. This is the default.

    Packages from elpa.gnu.org are signed with one of the keys contained in the GnuPG keyring at share/emacs/25.1/etc/package-keyring.gpg (or similar) in the emacs package (veja ELPA package signatures em The GNU Emacs Manual).

  • - NonGNU, selected by the nongnu identifier.
  • - MELPA-Stable, selected by the melpa-stable identifier.
  • - MELPA, selected by the melpa identifier.
--recursive
-r

Traverse the dependency graph of the given upstream package recursively and generate package expressions for all those packages that are not yet in Guix.

crate

Import metadata from the crates.io Rust package repository crates.io, as in this example:

guix import crate blake2-rfc

The crate importer also allows you to specify a version string:

guix import crate constant-time-eq@0.1.0

Additional options include:

--recursive
-r

Traverse the dependency graph of the given upstream package recursively and generate package expressions for all those packages that are not yet in Guix.

--recursive-dev-dependencies

If --recursive-dev-dependencies is specified, also the recursively imported packages contain their development dependencies, which are recursively imported as well.

--allow-yanked

If no non-yanked version of a crate is available, use the latest yanked version instead instead of aborting.

elm

Import metadata from the Elm package repository package.elm-lang.org, as in this example:

guix import elm elm-explorations/webgl

The Elm importer also allows you to specify a version string:

guix import elm elm-explorations/webgl@1.1.3

Additional options include:

--recursive
-r

Traverse the dependency graph of the given upstream package recursively and generate package expressions for all those packages that are not yet in Guix.

npm-binary

Import metadata from the npm Registry, as in this example:

guix import npm-binary buffer-crc32

The npm-binary importer also allows you to specify a version string:

guix import npm-binary buffer-crc32@1.0.0

Nota: Generated package expressions skip the build step of the node-build-system. As such, generated package expressions often refer to transpiled or generated files, instead of being built from source.

Additional options include:

--recursive
-r

Traverse the dependency graph of the given upstream package recursively and generate package expressions for all those packages that are not yet in Guix.

opam

Import metadata from the OPAM package repository used by the OCaml community.

Additional options include:

--recursive
-r

Traverse the dependency graph of the given upstream package recursively and generate package expressions for all those packages that are not yet in Guix.

composer

Import metadata from the Composer package archive used by the PHP community, as in this example:

guix import composer phpunit/phpunit

Additional options include:

--recursive
-r

Traverse the dependency graph of the given upstream package recursively and generate package expressions for all those packages that are not yet in Guix.

--repo

By default, packages are searched in the official OPAM repository. This option, which can be used more than once, lets you add other repositories which will be searched for packages. It accepts as valid arguments:

  • the name of a known repository - can be one of opam, coq (equivalent to coq-released), coq-core-dev, coq-extra-dev or grew.
  • the URL of a repository as expected by the opam repository add command (for instance, the URL equivalent of the above opam name would be https://opam.ocaml.org).
  • the path to a local copy of a repository (a directory containing a packages/ sub-directory).

Repositories are assumed to be passed to this option by order of preference. The additional repositories will not replace the default opam repository, which is always kept as a fallback.

Also, please note that versions are not compared across repositories. The first repository (from left to right) that has at least one version of a given package will prevail over any others, and the version imported will be the latest one found in this repository only.

go

Import metadata for a Go module using proxy.golang.org.

guix import go gopkg.in/yaml.v2

It is possible to use a package specification with a @VERSION suffix to import a specific version.

Additional options include:

--recursive
-r

Traverse the dependency graph of the given upstream package recursively and generate package expressions for all those packages that are not yet in Guix.

--pin-versions

When using this option, the importer preserves the exact versions of the Go modules dependencies instead of using their latest available versions. This can be useful when attempting to import packages that recursively depend on former versions of themselves to build. When using this mode, the symbol of the package is made by appending the version to its name, so that multiple versions of the same package can coexist.

egg

Import metadata for CHICKEN eggs. The information is taken from PACKAGE.egg files found in the eggs-5-all Git repository. However, it does not provide all the information that we need, there is no “description” field, and the licenses used are not always precise (BSD is often used instead of BSD-N).

guix import egg sourcehut

You can also ask for a specific version:

guix import egg arrays@1.0

Additional options include:

--recursive
-r

Traverse the dependency graph of the given upstream package recursively and generate package expressions for all those packages that are not yet in Guix.

hexpm

Import metadata from the hex.pm Erlang and Elixir package repository hex.pm, as in this example:

guix import hexpm stun

The importer tries to determine the build system used by the package.

The hexpm importer also allows you to specify a version string:

guix import hexpm cf@0.3.0

Additional options include:

--recursive
-r

Traverse the dependency graph of the given upstream package recursively and generate package expressions for all those packages that are not yet in Guix.

The structure of the guix import code is modular. It would be useful to have more importers for other package formats, and your help is welcome here (veja Contribuindo).


9.6 Invocando guix refresh

The primary audience of the guix refresh command is packagers. As a user, you may be interested in the --with-latest option, which can bring you package update superpowers built upon guix refresh (veja --with-latest). By default, guix refresh reports any packages provided by the distribution that are outdated compared to the latest upstream version, like this:

$ guix refresh
gnu/packages/gettext.scm:29:13: gettext would be upgraded from 0.18.1.1 to 0.18.2.1
gnu/packages/glib.scm:77:12: glib would be upgraded from 2.34.3 to 2.37.0

Alternatively, one can specify packages to consider, in which case a warning is emitted for packages that lack an updater:

$ guix refresh coreutils guile guile-ssh
gnu/packages/ssh.scm:205:2: warning: no updater for guile-ssh
gnu/packages/guile.scm:136:12: guile would be upgraded from 2.0.12 to 2.0.13

guix refresh browses the upstream repository of each package and determines the highest version number of the releases therein. The command knows how to update specific types of packages: GNU packages, ELPA packages, etc.—see the documentation for --type below. There are many packages, though, for which it lacks a method to determine whether a new upstream release is available. However, the mechanism is extensible, so feel free to get in touch with us to add a new method!

--recursive

Consider the packages specified, and all the packages upon which they depend.

$ guix refresh --recursive coreutils
gnu/packages/acl.scm:40:13: acl would be upgraded from 2.2.53 to 2.3.1
gnu/packages/m4.scm:30:12: 1.4.18 is already the latest version of m4
gnu/packages/xml.scm:68:2: warning: no updater for expat
gnu/packages/multiprecision.scm:40:12: 6.1.2 is already the latest version of gmp
…

If for some reason you don’t want to update to the latest version, you can update to a specific version by appending an equal sign and the desired version number to the package specification. Note that not all updaters support this; an error is reported when an updater cannot refresh to the specified version.

$ guix refresh trytond-party
gnu/packages/guile.scm:392:2: guile would be upgraded from 3.0.3 to 3.0.5
$ guix refresh -u guile=3.0.4
…
gnu/packages/guile.scm:392:2: guile: updating from version 3.0.3 to version 3.0.4...
…
$ guix refresh -u guile@2.0=2.0.12
…
gnu/packages/guile.scm:147:2: guile: updating from version 2.0.10 to version 2.0.12...
…

In some specific cases, you may have many packages specified via a manifest or a module selection which should all be updated together; for these cases, the --target-version option can be provided to have them all refreshed to the same version, as shown in the examples below:

$ guix refresh qtbase qtdeclarative --target-version=6.5.2
gnu/packages/qt.scm:1248:13: qtdeclarative would be upgraded from 6.3.2 to 6.5.2
gnu/packages/qt.scm:584:2: qtbase would be upgraded from 6.3.2 to 6.5.2
$ guix refresh --manifest=qt5-manifest.scm --target-version=5.15.10
gnu/packages/qt.scm:1173:13: qtxmlpatterns would be upgraded from 5.15.8 to 5.15.10
gnu/packages/qt.scm:1202:13: qtdeclarative would be upgraded from 5.15.8 to 5.15.10
gnu/packages/qt.scm:1762:13: qtserialbus would be upgraded from 5.15.8 to 5.15.10
gnu/packages/qt.scm:2070:13: qtquickcontrols2 would be upgraded from 5.15.8 to 5.15.10
…

Sometimes the upstream name differs from the package name used in Guix, and guix refresh needs a little help. Most updaters honor the upstream-name property in package definitions, which can be used to that effect:

(define-public network-manager
  (package
    (name "network-manager")
    ;; …
    (properties '((upstream-name . "NetworkManager")))))

When passed --update, it modifies distribution source files to update the version numbers and source code hashes of those package definitions, as well as possibly their inputs (veja Definindo pacotes). This is achieved by downloading each package’s latest source tarball and its associated OpenPGP signature, authenticating the downloaded tarball against its signature using gpgv, and finally computing its hash—note that GnuPG must be installed and in $PATH; run guix install gnupg if needed.

When the public key used to sign the tarball is missing from the user’s keyring, an attempt is made to automatically retrieve it from a public key server; when this is successful, the key is added to the user’s keyring; otherwise, guix refresh reports an error.

The following options are supported:

--expression=expr
-e expr

Consider the package expr evaluates to.

This is useful to precisely refer to a package, as in this example:

guix refresh -l -e '(@@ (gnu packages commencement) glibc-final)'

This command lists the dependents of the “final” libc (essentially all the packages).

--update
-u

Update distribution source files (package definitions) in place. This is usually run from a checkout of the Guix source tree (veja Executando guix antes dele ser instalado):

./pre-inst-env guix refresh -s non-core -u

Veja Definindo pacotes, for more information on package definitions. You can also run it on packages from a third-party channel:

guix refresh -L /path/to/channel -u package

Veja Creating a Channel, on how to create a channel.

This command updates the version and source code hash of the package. Depending on the updater being used, it can also update the various ‘inputs’ fields of the package. In some cases, the updater might get inputs wrong—it might not know about an extra input that’s necessary, or it might add an input that should be avoided.

To address that, packagers can add properties stating inputs that should be added to those found by the updater or inputs that should be ignored: the updater-extra-inputs and updater-ignored-inputs properties pertain to “regular” inputs, and there are equivalent properties for ‘native’ and ‘propagated’ inputs. In the example below, we tell the updater that we need ‘openmpi’ as an additional input:

(define-public python-mpi4py
  (package
    (name "python-mpi4py")
    ;; …
    (inputs (list openmpi))
    (properties
     '((updater-extra-inputs . ("openmpi"))))))

That way, guix refresh -u python-mpi4py will leave the ‘openmpi’ input, even if it is not among the inputs it would normally add.

--select=[subset]
-s subset

Select all the packages in subset, one of core, non-core or module:name.

The core subset refers to all the packages at the core of the distribution—i.e., packages that are used to build “everything else”. This includes GCC, libc, Binutils, Bash, etc. Usually, changing one of these packages in the distribution entails a rebuild of all the others. Thus, such updates are an inconvenience to users in terms of build time or bandwidth used to achieve the upgrade.

The non-core subset refers to the remaining packages. It is typically useful in cases where an update of the core packages would be inconvenient.

The module:name subset refers to all the packages in a specified guile module. The module can be specified as module:guile or module:(gnu packages guile), the former is a shorthand for the later.

--manifest=arquivo
-m arquivo

Select all the packages from the manifest in file. This is useful to check if any packages of the user manifest can be updated.

--type=updater
-t updater

Select only packages handled by updater (may be a comma-separated list of updaters). Currently, updater may be one of:

gnu

the updater for GNU packages;

savannah

the updater for packages hosted at Savannah;

sourceforge

the updater for packages hosted at SourceForge;

gnome

the updater for GNOME packages;

kde

the updater for KDE packages;

xorg

the updater for X.org packages;

kernel.org

the updater for packages hosted on kernel.org;

egg

the updater for Egg packages;

elpa

the updater for ELPA packages;

cran

the updater for CRAN packages;

bioconductor

the updater for Bioconductor R packages;

cpan

the updater for CPAN packages;

pypi

the updater for PyPI packages.

gem

the updater for RubyGems packages.

github

the updater for GitHub packages.

hackage

the updater for Hackage packages.

stackage

the updater for Stackage packages.

crate

the updater for Crates packages.

launchpad

the updater for Launchpad packages.

generic-html

a generic updater that crawls the HTML page where the source tarball of the package is hosted, when applicable, or the HTML page specified by the release-monitoring-url property of the package.

generic-git

a generic updater for packages hosted on Git repositories. It tries to be smart about parsing Git tag names, but if it is not able to parse the tag name and compare tags correctly, users can define the following properties for a package.

  • release-tag-prefix: a regular expression for matching a prefix of the tag name.
  • release-tag-suffix: a regular expression for matching a suffix of the tag name.
  • release-tag-version-delimiter: a string used as the delimiter in the tag name for separating the numbers of the version.
  • accept-pre-releases: by default, the updater will ignore pre-releases; to make it also look for pre-releases, set the this property to #t.
(package
  (name "foo")
  ;; ...
  (properties
    '((release-tag-prefix . "^release0-")
      (release-tag-suffix . "[a-z]?$")
      (release-tag-version-delimiter . ":"))))

For instance, the following command only checks for updates of Emacs packages hosted at elpa.gnu.org and for updates of CRAN packages:

$ guix refresh --type=elpa,cran
gnu/packages/statistics.scm:819:13: r-testthat would be upgraded from 0.10.0 to 0.11.0
gnu/packages/emacs.scm:856:13: emacs-auctex would be upgraded from 11.88.6 to 11.88.9
--list-updaters

List available updaters and exit (see --type above).

For each updater, display the fraction of packages it covers; at the end, display the fraction of packages covered by all these updaters.

In addition, guix refresh can be passed one or more package names, as in this example:

$ ./pre-inst-env guix refresh -u emacs idutils gcc@4.8

The command above specifically updates the emacs and idutils packages. The --select option would have no effect in this case. You might also want to update definitions that correspond to the packages installed in your profile:

$ ./pre-inst-env guix refresh -u \
       $(guix package --list-installed | cut -f1)

When considering whether to upgrade a package, it is sometimes convenient to know which packages would be affected by the upgrade and should be checked for compatibility. For this the following option may be used when passing guix refresh one or more package names:

--list-dependent
-l

List top-level dependent packages that would need to be rebuilt as a result of upgrading one or more packages.

Veja the reverse-package type of guix graph, for information on how to visualize the list of dependents of a package.

Be aware that the --list-dependent option only approximates the rebuilds that would be required as a result of an upgrade. More rebuilds might be required under some circumstances.

$ guix refresh --list-dependent flex
Building the following 120 packages would ensure 213 dependent packages are rebuilt:
hop@2.4.0 emacs-geiser@0.13 notmuch@0.18 mu@0.9.9.5 cflow@1.4 idutils@4.6 …

The command above lists a set of packages that could be built to check for compatibility with an upgraded flex package.

--list-transitive
-T

List all the packages which one or more packages depend upon.

$ guix refresh --list-transitive flex
flex@2.6.4 depends on the following 25 packages: perl@5.28.0 help2man@1.47.6
bison@3.0.5 indent@2.2.10 tar@1.30 gzip@1.9 bzip2@1.0.6 xz@5.2.4 file@5.33 …

The command above lists a set of packages which, when changed, would cause flex to be rebuilt.

The following options can be used to customize GnuPG operation:

--gpg=command

Use command as the GnuPG 2.x command. command is searched for in $PATH.

--keyring=file

Use file as the keyring for upstream keys. file must be in the keybox format. Keybox files usually have a name ending in .kbx and the GNU Privacy Guard (GPG) can manipulate these files (veja kbxutil em Using the GNU Privacy Guard, for information on a tool to manipulate keybox files).

When this option is omitted, guix refresh uses ~/.config/guix/upstream/trustedkeys.kbx as the keyring for upstream signing keys. OpenPGP signatures are checked against keys from this keyring; missing keys are downloaded to this keyring as well (see --key-download below).

You can export keys from your default GPG keyring into a keybox file using commands like this one:

gpg --export rms@gnu.org | kbxutil --import-openpgp >> mykeyring.kbx

Likewise, you can fetch keys to a specific keybox file like this:

gpg --no-default-keyring --keyring mykeyring.kbx \
  --recv-keys 3CE464558A84FDC69DB40CFB090B11993D9AEBB5

Veja --keyring em Using the GNU Privacy Guard, for more information on GPG’s --keyring option.

--key-download=policy

Handle missing OpenPGP keys according to policy, which may be one of:

always

Always download missing OpenPGP keys from the key server, and add them to the user’s GnuPG keyring.

never

Never try to download missing OpenPGP keys. Instead just bail out.

interactive

When a package signed with an unknown OpenPGP key is encountered, ask the user whether to download it or not. This is the default behavior.

--key-server=host

Use host as the OpenPGP key server when importing a public key.

--load-path=directory
-L diretório

Add directory to the front of the package module search path (veja Módulos de pacote).

This allows users to define their own packages and make them visible to the command-line tools.

The github updater uses the GitHub API to query for new releases. When used repeatedly e.g. when refreshing all packages, GitHub will eventually refuse to answer any further API requests. By default 60 API requests per hour are allowed, and a full refresh on all GitHub packages in Guix requires more than this. Authentication with GitHub through the use of an API token alleviates these limits. To use an API token, set the environment variable GUIX_GITHUB_TOKEN to a token procured from https://github.com/settings/tokens or otherwise.


9.7 Invoking guix style

The guix style command helps users and packagers alike style their package definitions and configuration files according to the latest fashionable trends. It can either reformat whole files, with the --whole-file option, or apply specific styling rules to individual package definitions. The command currently provides the following styling rules:

  • formatting package definitions according to the project’s conventions (veja Formatação de código);
  • rewriting package inputs to the “new style”, as explained below.

The way package inputs are written is going through a transition (veja package Reference, for more on package inputs). Until version 1.3.0, package inputs were written using the “old style”, where each input was given an explicit label, most of the time the package name:

(package
  ;; …
  ;; The "old style" (deprecated).
  (inputs `(("libunistring" ,libunistring)
            ("libffi" ,libffi))))

Today, the old style is deprecated and the preferred style looks like this:

(package
  ;; …
  ;; The "new style".
  (inputs (list libunistring libffi)))

Likewise, uses of alist-delete and friends to manipulate inputs is now deprecated in favor of modify-inputs (veja Defining Package Variants, for more info on modify-inputs).

In the vast majority of cases, this is a purely mechanical change on the surface syntax that does not even incur a package rebuild. Running guix style -S inputs can do that for you, whether you’re working on packages in Guix proper or in an external channel.

The general syntax is:

guix style [options] package

This causes guix style to analyze and rewrite the definition of package… or, when package is omitted, of all the packages. The --styling or -S option allows you to select the style rule, the default rule being format—see below.

To reformat entire source files, the syntax is:

guix style --whole-file file

The available options are listed below.

--dry-run
-n

Show source file locations that would be edited but do not modify them.

--whole-file
-f

Reformat the given files in their entirety. In that case, subsequent arguments are interpreted as file names (rather than package names), and the --styling option has no effect.

As an example, here is how you might reformat your operating system configuration (you need write permissions for the file):

guix style -f /etc/config.scm
--alphabetical-sort
-A

Place the top-level package definitions in the given files in alphabetical order. Package definitions with matching names are placed with versions in descending order. This option only has an effect in combination with --whole-file.

--styling=rule
-S rule

Apply rule, one of the following styling rules:

format

Format the given package definition(s)—this is the default styling rule. For example, a packager running Guix on a checkout (veja Executando guix antes dele ser instalado) might want to reformat the definition of the Coreutils package like so:

./pre-inst-env guix style coreutils
entradas

Rewrite package inputs to the “new style”, as described above. This is how you would rewrite inputs of package whatnot in your own channel:

guix style -L ~/my/channel -S inputs whatnot

Rewriting is done in a conservative way: preserving comments and bailing out if it cannot make sense of the code that appears in an inputs field. The --input-simplification option described below provides fine-grain control over when inputs should be simplified.

arguments

Rewrite package arguments to use G-expressions (veja Expressões-G). For example, consider this package definition:

(define-public my-package
  (package
    ;; …
    (arguments      ;old-style quoted arguments
     '(#:make-flags '("V=1")
       #:phases (modify-phases %standard-phases
                  (delete 'build))))))

Running guix style -S arguments on this package would rewrite its arguments field like to:

(define-public my-package
  (package
    ;; …
    (arguments
      (list #:make-flags #~'("V=1")
            #:phases #~(modify-phases %standard-phases
                         (delete 'build))))))

Note that changes made by the arguments rule do not entail a rebuild of the affected packages. Furthermore, if a package definition happens to be using G-expressions already, guix style leaves it unchanged.

--list-stylings
-l

List and describe the available styling rules and exit.

--load-path=directory
-L diretório

Add directory to the front of the package module search path (veja Módulos de pacote).

--expression=expr
-e expr

Style the package expr evaluates to.

For example, running:

guix style -e '(@ (gnu packages gcc) gcc-5)'

styles the gcc-5 package definition.

--input-simplification=policy

When using the inputs styling rule, with ‘-S inputs’, this option specifies the package input simplification policy for cases where an input label does not match the corresponding package name. policy may be one of the following:

silent

Simplify inputs only when the change is “silent”, meaning that the package does not need to be rebuilt (its derivation is unchanged).

safe

Simplify inputs only when that is “safe” to do: the package might need to be rebuilt, but the change is known to have no observable effect.

always

Simplify inputs even when input labels do not match package names, and even if that might have an observable effect.

The default is silent, meaning that input simplifications do not trigger any package rebuild.


9.8 Invocando guix lint

The guix lint command is meant to help package developers avoid common errors and use a consistent style. It runs a number of checks on a given set of packages in order to find common mistakes in their definitions. Available checkers include (see --list-checkers for a complete list):

synopsis
description

Validate certain typographical and stylistic rules about package descriptions and synopses.

inputs-should-be-native

Identify inputs that should most likely be native inputs.

source
página inicial
mirror-url
github-url
source-file-name

Probe home-page and source URLs and report those that are invalid. Suggest a mirror:// URL when applicable. If the source URL redirects to a GitHub URL, recommend usage of the GitHub URL. Check that the source file name is meaningful, e.g. is not just a version number or “git-checkout”, without a declared file-name (veja origin Reference).

source-unstable-tarball

Parse the source URL to determine if a tarball from GitHub is autogenerated or if it is a release tarball. Unfortunately GitHub’s autogenerated tarballs are sometimes regenerated.

derivation

Check that the derivation of the given packages can be successfully computed for all the supported systems (veja Derivações).

profile-collisions

Check whether installing the given packages in a profile would lead to collisions. Collisions occur when several packages with the same name but a different version or a different store file name are propagated. Veja propagated-inputs, for more information on propagated inputs.

archival

Checks whether the package’s source code is archived at Software Heritage.

When the source code that is not archived comes from a version-control system (VCS)—e.g., it’s obtained with git-fetch, send Software Heritage a “save” request so that it eventually archives it. This ensures that the source will remain available in the long term, and that Guix can fall back to Software Heritage should the source code disappear from its original host. The status of recent “save” requests can be viewed on-line.

When source code is a tarball obtained with url-fetch, simply print a message when it is not archived. As of this writing, Software Heritage does not allow requests to save arbitrary tarballs; we are working on ways to ensure that non-VCS source code is also archived.

Software Heritage limits the request rate per IP address. When the limit is reached, guix lint prints a message and the archival checker stops doing anything until that limit has been reset.

cve

Report known vulnerabilities found in the Common Vulnerabilities and Exposures (CVE) databases of the current and past year published by the US NIST.

To view information about a particular vulnerability, visit pages such as:

  • https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-YYYY-ABCD
  • https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-YYYY-ABCD

where CVE-YYYY-ABCD is the CVE identifier—e.g., CVE-2015-7554.

Package developers can specify in package recipes the Common Platform Enumeration (CPE) name and version of the package when they differ from the name or version that Guix uses, as in this example:

(package
  (name "grub")
  ;; …
  ;; CPE calls this package "grub2".
  (properties '((cpe-name . "grub2")
                (cpe-version . "2.3"))))

Some entries in the CVE database do not specify which version of a package they apply to, and would thus “stick around” forever. Package developers who found CVE alerts and verified they can be ignored can declare them as in this example:

(package
  (name "t1lib")
  ;; …
  ;; These CVEs no longer apply and can be safely ignored.
  (properties `((lint-hidden-cve . ("CVE-2011-0433"
                                    "CVE-2011-1553"
                                    "CVE-2011-1554"
                                    "CVE-2011-5244")))))
formatting

Warn about obvious source code formatting issues: trailing white space, use of tabulations, etc.

input-labels

Report old-style input labels that do not match the name of the corresponding package. This aims to help migrate from the “old input style”. Veja package Reference, for more information on package inputs and input styles. Veja Invoking guix style, on how to migrate to the new style.

The general syntax is:

guix lint options package

If no package is given on the command line, then all packages are checked. The options may be zero or more of the following:

--list-checkers
-l

List and describe all the available checkers that will be run on packages and exit.

--checkers
-c

Only enable the checkers specified in a comma-separated list using the names returned by --list-checkers.

--exclude
-x

Only disable the checkers specified in a comma-separated list using the names returned by --list-checkers.

--expression=expr
-e expr

Consider the package expr evaluates to.

This is useful to unambiguously designate packages, as in this example:

guix lint -c archival -e '(@ (gnu packages guile) guile-3.0)'
--no-network
-n

Only enable the checkers that do not depend on Internet access.

--load-path=directory
-L diretório

Add directory to the front of the package module search path (veja Módulos de pacote).

This allows users to define their own packages and make them visible to the command-line tools.


9.9 Invocando guix size

The guix size command helps package developers profile the disk usage of packages. It is easy to overlook the impact of an additional dependency added to a package, or the impact of using a single output for a package that could easily be split (veja Pacotes com múltiplas saídas). Such are the typical issues that guix size can highlight.

The command can be passed one or more package specifications such as gcc@4.8 or guile:debug, or a file name in the store. Consider this example:

$ guix size coreutils
store item                               total    self
/gnu/store/…-gcc-5.5.0-lib           60.4    30.1  38.1%
/gnu/store/…-glibc-2.27              30.3    28.8  36.6%
/gnu/store/…-coreutils-8.28          78.9    15.0  19.0%
/gnu/store/…-gmp-6.1.2               63.1     2.7   3.4%
/gnu/store/…-bash-static-4.4.12       1.5     1.5   1.9%
/gnu/store/…-acl-2.2.52              61.1     0.4   0.5%
/gnu/store/…-attr-2.4.47             60.6     0.2   0.3%
/gnu/store/…-libcap-2.25             60.5     0.2   0.2%
total: 78.9 MiB

The store items listed here constitute the transitive closure of Coreutils—i.e., Coreutils and all its dependencies, recursively—as would be returned by:

$ guix gc -R /gnu/store/…-coreutils-8.23

Here the output shows three columns next to store items. The first column, labeled “total”, shows the size in mebibytes (MiB) of the closure of the store item—that is, its own size plus the size of all its dependencies. The next column, labeled “self”, shows the size of the item itself. The last column shows the ratio of the size of the item itself to the space occupied by all the items listed here.

In this example, we see that the closure of Coreutils weighs in at 79 MiB, most of which is taken by libc and GCC’s run-time support libraries. (That libc and GCC’s libraries represent a large fraction of the closure is not a problem per se because they are always available on the system anyway.)

Since the command also accepts store file names, assessing the size of a build result is straightforward:

guix size $(guix system build config.scm)

When the package(s) passed to guix size are available in the store25, guix size queries the daemon to determine its dependencies, and measures its size in the store, similar to du -ms --apparent-size (veja du invocation em GNU Coreutils).

When the given packages are not in the store, guix size reports information based on the available substitutes (veja Substitutos). This makes it possible to profile the disk usage of store items that are not even on disk, only available remotely.

You can also specify several package names:

$ guix size coreutils grep sed bash
store item                               total    self
/gnu/store/…-coreutils-8.24          77.8    13.8  13.4%
/gnu/store/…-grep-2.22               73.1     0.8   0.8%
/gnu/store/…-bash-4.3.42             72.3     4.7   4.6%
/gnu/store/…-readline-6.3            67.6     1.2   1.2%
…
total: 102.3 MiB

In this example we see that the combination of the four packages takes 102.3 MiB in total, which is much less than the sum of each closure since they have a lot of dependencies in common.

When looking at the profile returned by guix size, you may find yourself wondering why a given package shows up in the profile at all. To understand it, you can use guix graph --path -t references to display the shortest path between the two packages (veja Invocando guix graph).

The available options are:

--substitute-urls=urls

Use substitute information from urls. Veja the same option for guix build.

--sort=key

Sort lines according to key, one of the following options:

próprio

the size of each item (the default);

closure

the total size of the item’s closure.

--map-file=arquivo

Write a graphical map of disk usage in PNG format to file.

For the example above, the map looks like this:

map of Coreutils disk usage produced
by guix size

This option requires that Guile-Charting be installed and visible in Guile’s module search path. When that is not the case, guix size fails as it tries to load it.

--system=system
-s sistema

Consider packages for system—e.g., x86_64-linux.

--load-path=directory
-L diretório

Add directory to the front of the package module search path (veja Módulos de pacote).

This allows users to define their own packages and make them visible to the command-line tools.


9.10 Invocando guix graph

Packages and their dependencies form a graph, specifically a directed acyclic graph (DAG). It can quickly become difficult to have a mental model of the package DAG, so the guix graph command provides a visual representation of the DAG. By default, guix graph emits a DAG representation in the input format of Graphviz, so its output can be passed directly to the dot command of Graphviz. It can also emit an HTML page with embedded JavaScript code to display a “chord diagram” in a Web browser, using the d3.js library, or emit Cypher queries to construct a graph in a graph database supporting the openCypher query language. With --path, it simply displays the shortest path between two packages. The general syntax is:

guix graph options package

For example, the following command generates a PDF file representing the package DAG for the GNU Core Utilities, showing its build-time dependencies:

guix graph coreutils | dot -Tpdf > dag.pdf

The output looks like this:

Dependency graph of the GNU Coreutils

Nice little graph, no?

You may find it more pleasant to navigate the graph interactively with xdot (from the xdot package):

guix graph coreutils | xdot -

But there is more than one graph! The one above is concise: it is the graph of package objects, omitting implicit inputs such as GCC, libc, grep, etc. It is often useful to have such a concise graph, but sometimes one may want to see more details. guix graph supports several types of graphs, allowing you to choose the level of detail:

pacote

This is the default type used in the example above. It shows the DAG of package objects, excluding implicit dependencies. It is concise, but filters out many details.

reverse-package

This shows the reverse DAG of packages. For example:

guix graph --type=reverse-package ocaml

... yields the graph of packages that explicitly depend on OCaml (if you are also interested in cases where OCaml is an implicit dependency, see reverse-bag below).

Note that for core packages this can yield huge graphs. If all you want is to know the number of packages that depend on a given package, use guix refresh --list-dependent (veja --list-dependent).

bag-emerged

This is the package DAG, including implicit inputs.

For instance, the following command:

guix graph --type=bag-emerged coreutils

... yields this bigger graph:

Detailed dependency graph of the GNU
Coreutils

At the bottom of the graph, we see all the implicit inputs of gnu-build-system (veja gnu-build-system).

Now, note that the dependencies of these implicit inputs—that is, the bootstrap dependencies (veja Inicializando)—are not shown here, for conciseness.

bag

Similar to bag-emerged, but this time including all the bootstrap dependencies.

bag-with-origins

Similar to bag, but also showing origins and their dependencies.

reverse-bag

This shows the reverse DAG of packages. Unlike reverse-package, it also takes implicit dependencies into account. For example:

guix graph -t reverse-bag dune

... yields the graph of all packages that depend on Dune, directly or indirectly. Since Dune is an implicit dependency of many packages via dune-build-system, this shows a large number of packages, whereas reverse-package would show very few if any.

derivation

This is the most detailed representation: It shows the DAG of derivations (veja Derivações) and plain store items. Compared to the above representation, many additional nodes are visible, including build scripts, patches, Guile modules, etc.

For this type of graph, it is also possible to pass a .drv file name instead of a package name, as in:

guix graph -t derivation $(guix system build -d my-config.scm)
modulo

This is the graph of package modules (veja Módulos de pacote). For example, the following command shows the graph for the package module that defines the guile package:

guix graph -t module guile | xdot -

All the types above correspond to build-time dependencies. The following graph type represents the run-time dependencies:

references

This is the graph of references of a package output, as returned by guix gc --references (veja Invocando guix gc).

If the given package output is not available in the store, guix graph attempts to obtain dependency information from substitutes.

Here you can also pass a store file name instead of a package name. For example, the command below produces the reference graph of your profile (which can be big!):

guix graph -t references $(readlink -f ~/.guix-profile)
referrers

This is the graph of the referrers of a store item, as returned by guix gc --referrers (veja Invocando guix gc).

This relies exclusively on local information from your store. For instance, let us suppose that the current Inkscape is available in 10 profiles on your machine; guix graph -t referrers inkscape will show a graph rooted at Inkscape and with those 10 profiles linked to it.

It can help determine what is preventing a store item from being garbage collected.

Often, the graph of the package you are interested in does not fit on your screen, and anyway all you want to know is why that package actually depends on some seemingly unrelated package. The --path option instructs guix graph to display the shortest path between two packages (or derivations, or store items, etc.):

$ guix graph --path emacs libunistring
emacs@26.3
mailutils@3.9
libunistring@0.9.10
$ guix graph --path -t derivation emacs libunistring
/gnu/store/…-emacs-26.3.drv
/gnu/store/…-mailutils-3.9.drv
/gnu/store/…-libunistring-0.9.10.drv
$ guix graph --path -t references emacs libunistring
/gnu/store/…-emacs-26.3
/gnu/store/…-libidn2-2.2.0
/gnu/store/…-libunistring-0.9.10

Sometimes you still want to visualize the graph but would like to trim it so it can actually be displayed. One way to do it is via the --max-depth (or -M) option, which lets you specify the maximum depth of the graph. In the example below, we visualize only libreoffice and the nodes whose distance to libreoffice is at most 2:

guix graph -M 2 libreoffice | xdot -f fdp -

Mind you, that’s still a big ball of spaghetti, but at least dot can render it quickly and it can be browsed somewhat.

The available options are the following:

--type=type
-t tipo

Produce a graph output of type, where type must be one of the values listed above.

--list-types

Lista os tipos de gráficos disponíveis.

--backend=backend
-b backend

Produce a graph using the selected backend.

--list-backends

Lista os backends de gráficos disponíveis.

Currently, the available backends are Graphviz and d3.js.

--path

Display the shortest path between two nodes of the type specified by --type. The example below shows the shortest path between libreoffice and llvm according to the references of libreoffice:

$ guix graph --path -t references libreoffice llvm
/gnu/store/…-libreoffice-6.4.2.2
/gnu/store/…-libepoxy-1.5.4
/gnu/store/…-mesa-19.3.4
/gnu/store/…-llvm-9.0.1
--expression=expr
-e expr

Consider the package expr evaluates to.

This is useful to precisely refer to a package, as in this example:

guix graph -e '(@@ (gnu packages commencement) gnu-make-final)'
--system=system
-s sistema

Display the graph for system—e.g., i686-linux.

The package dependency graph is largely architecture-independent, but there are some architecture-dependent bits that this option allows you to visualize.

--load-path=directory
-L diretório

Add directory to the front of the package module search path (veja Módulos de pacote).

This allows users to define their own packages and make them visible to the command-line tools.

On top of that, guix graph supports all the usual package transformation options (veja Opções de transformação de pacote). This makes it easy to view the effect of a graph-rewriting transformation such as --with-input. For example, the command below outputs the graph of git once openssl has been replaced by libressl everywhere in the graph:

guix graph git --with-input=openssl=libressl

So many possibilities, so much fun!


9.11 Invocando guix publish

The purpose of guix publish is to enable users to easily share their store with others, who can then use it as a substitute server (veja Substitutos).

When guix publish runs, it spawns an HTTP server which allows anyone with network access to obtain substitutes from it. This means that any machine running Guix can also act as if it were a build farm, since the HTTP interface is compatible with Cuirass, the software behind the bordeaux.guix.gnu.org build farm.

For security, each substitute is signed, allowing recipients to check their authenticity and integrity (veja Substitutos). Because guix publish uses the signing key of the system, which is only readable by the system administrator, it must be started as root; the --user option makes it drop root privileges early on.

The signing key pair must be generated before guix publish is launched, using guix archive --generate-key (veja Invocando guix archive).

When the --advertise option is passed, the server advertises its availability on the local network using multicast DNS (mDNS) and DNS service discovery (DNS-SD), currently via Guile-Avahi (veja Using Avahi in Guile Scheme Programs).

The general syntax is:

guix publish options

Running guix publish without any additional arguments will spawn an HTTP server on port 8080:

guix publish

guix publish can also be started following the systemd “socket activation” protocol (veja make-systemd-constructor em The GNU Shepherd Manual).

Once a publishing server has been authorized, the daemon may download substitutes from it. Veja Getting Substitutes from Other Servers.

By default, guix publish compresses archives on the fly as it serves them. This “on-the-fly” mode is convenient in that it requires no setup and is immediately available. However, when serving lots of clients, we recommend using the --cache option, which enables caching of the archives before they are sent to clients—see below for details. The guix weather command provides a handy way to check what a server provides (veja Invocando guix weather).

As a bonus, guix publish also serves as a content-addressed mirror for source files referenced in origin records (veja origin Reference). For instance, assuming guix publish is running on example.org, the following URL returns the raw hello-2.10.tar.gz file with the given SHA256 hash (represented in nix-base32 format, veja Invocando guix hash):

http://example.org/file/hello-2.10.tar.gz/sha256/0ssi1…ndq1i

Obviously, these URLs only work for files that are in the store; in other cases, they return 404 (“Not Found”).

Build logs are available from /log URLs like:

http://example.org/log/gwspk…-guile-2.2.3

When guix-daemon is configured to save compressed build logs, as is the case by default (veja Invocando guix-daemon), /log URLs return the compressed log as-is, with an appropriate Content-Type and/or Content-Encoding header. We recommend running guix-daemon with --log-compression=gzip since Web browsers can automatically decompress it, which is not the case with Bzip2 compression.

The following options are available:

--port=porta
-p porta

Ouve requisições HTTP na porta.

--listen=host

Listen on the network interface for host. The default is to accept connections from any interface.

--user=user
-u usuário

Change privileges to user as soon as possible—i.e., once the server socket is open and the signing key has been read.

--compression[=method[:level]]
-C [method[:level]]

Compress data using the given method and level. method is one of lzip, zstd, and gzip; when method is omitted, gzip is used.

When level is zero, disable compression. The range 1 to 9 corresponds to different compression levels: 1 is the fastest, and 9 is the best (CPU-intensive). The default is 3.

Usually, lzip compresses noticeably better than gzip for a small increase in CPU usage; see benchmarks on the lzip Web page. However, lzip achieves low decompression throughput (on the order of 50 MiB/s on modern hardware), which can be a bottleneck for someone who downloads over a fast network connection.

The compression ratio of zstd is between that of lzip and that of gzip; its main advantage is a high decompression speed.

Unless --cache is used, compression occurs on the fly and the compressed streams are not cached. Thus, to reduce load on the machine that runs guix publish, it may be a good idea to choose a low compression level, to run guix publish behind a caching proxy, or to use --cache. Using --cache has the advantage that it allows guix publish to add Content-Length HTTP header to its responses.

This option can be repeated, in which case every substitute gets compressed using all the selected methods, and all of them are advertised. This is useful when users may not support all the compression methods: they can select the one they support.

--cache=directory
-c directory

Cache archives and meta-data (.narinfo URLs) to directory and only serve archives that are in cache.

When this option is omitted, archives and meta-data are created on-the-fly. This can reduce the available bandwidth, especially when compression is enabled, since this may become CPU-bound. Another drawback of the default mode is that the length of archives is not known in advance, so guix publish does not add a Content-Length HTTP header to its responses, which in turn prevents clients from knowing the amount of data being downloaded.

Conversely, when --cache is used, the first request for a store item (via a .narinfo URL) triggers a background process to bake the archive—computing its .narinfo and compressing the archive, if needed. Once the archive is cached in directory, subsequent requests succeed and are served directly from the cache, which guarantees that clients get the best possible bandwidth.

That first .narinfo request nonetheless returns 200, provided the requested store item is “small enough”, below the cache bypass threshold—see --cache-bypass-threshold below. That way, clients do not have to wait until the archive is baked. For larger store items, the first .narinfo request returns 404, meaning that clients have to wait until the archive is baked.

The “baking” process is performed by worker threads. By default, one thread per CPU core is created, but this can be customized. See --workers below.

When --ttl is used, cached entries are automatically deleted when they have expired.

--workers=N

When --cache is used, request the allocation of N worker threads to “bake” archives.

--ttl=ttl

Produce Cache-Control HTTP headers that advertise a time-to-live (TTL) of ttl. ttl must denote a duration: 5d means 5 days, 1m means 1 month, and so on.

This allows the user’s Guix to keep substitute information in cache for ttl. However, note that guix publish does not itself guarantee that the store items it provides will indeed remain available for as long as ttl.

Additionally, when --cache is used, cached entries that have not been accessed for ttl and that no longer have a corresponding item in the store, may be deleted.

--negative-ttl=ttl

Similarly produce Cache-Control HTTP headers to advertise the time-to-live (TTL) of negative lookups—missing store items, for which the HTTP 404 code is returned. By default, no negative TTL is advertised.

This parameter can help adjust server load and substitute latency by instructing cooperating clients to be more or less patient when a store item is missing.

--cache-bypass-threshold=size

When used in conjunction with --cache, store items smaller than size are immediately available, even when they are not yet in cache. size is a size in bytes, or it can be suffixed by M for megabytes and so on. The default is 10M.

“Cache bypass” allows you to reduce the publication delay for clients at the expense of possibly additional I/O and CPU use on the server side: depending on the client access patterns, those store items can end up being baked several times until a copy is available in cache.

Increasing the threshold may be useful for sites that have few users, or to guarantee that users get substitutes even for store items that are not popular.

--nar-path=path

Use path as the prefix for the URLs of “nar” files (veja normalized archives).

By default, nars are served at a URL such as /nar/gzip/…-coreutils-8.25. This option allows you to change the /nar part to path.

--public-key=file
--private-key=file

Use the specific files as the public/private key pair used to sign the store items being published.

The files must correspond to the same key pair (the private key is used for signing and the public key is merely advertised in the signature metadata). They must contain keys in the canonical s-expression format as produced by guix archive --generate-key (veja Invocando guix archive). By default, /etc/guix/signing-key.pub and /etc/guix/signing-key.sec are used.

--repl[=port]
-r [porta]

Spawn a Guile REPL server (veja REPL Servers em GNU Guile Reference Manual) on port (37146 by default). This is used primarily for debugging a running guix publish server.

Enabling guix publish on Guix System is a one-liner: just instantiate a guix-publish-service-type service in the services field of the operating-system declaration (veja guix-publish-service-type).

If you are instead running Guix on a “foreign distro”, follow these instructions:

  • If your host distro uses the systemd init system:
    # ln -s ~root/.guix-profile/lib/systemd/system/guix-publish.service \
            /etc/systemd/system/
    # systemctl start guix-publish && systemctl enable guix-publish
    
  • Se sua distro hospedeira usa o sistema init Upstart:
    # ln -s ~root/.guix-profile/lib/upstart/system/guix-publish.conf /etc/init/
    # start guix-publish
    
  • Otherwise, proceed similarly with your distro’s init system.

9.12 Invocando guix challenge

Do the binaries provided by this server really correspond to the source code it claims to build? Is a package build process deterministic? These are the questions the guix challenge command attempts to answer.

The former is obviously an important question: Before using a substitute server (veja Substitutos), one had better verify that it provides the right binaries, and thus challenge it. The latter is what enables the former: If package builds are deterministic, then independent builds of the package should yield the exact same result, bit for bit; if a server provides a binary different from the one obtained locally, it may be either corrupt or malicious.

We know that the hash that shows up in /gnu/store file names is the hash of all the inputs of the process that built the file or directory—compilers, libraries, build scripts, etc. (veja Introdução). Assuming deterministic build processes, one store file name should map to exactly one build output. guix challenge checks whether there is, indeed, a single mapping by comparing the build outputs of several independent builds of any given store item.

The command output looks like this:

$ guix challenge \
  --substitute-urls="https://bordeaux.guix.gnu.org https://guix.example.org" \
  openssl git pius coreutils grep
updating substitutes from 'https://bordeaux.guix.gnu.org'... 100.0%
updating substitutes from 'https://guix.example.org'... 100.0%
/gnu/store/…-openssl-1.0.2d contents differ:
  local hash: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
  https://bordeaux.guix.gnu.org/nar/…-openssl-1.0.2d: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
  https://guix.example.org/nar/…-openssl-1.0.2d: 1zy4fmaaqcnjrzzajkdn3f5gmjk754b43qkq47llbyak9z0qjyim
  differing files:
    /lib/libcrypto.so.1.1
    /lib/libssl.so.1.1

/gnu/store/…-git-2.5.0 contents differ:
  local hash: 00p3bmryhjxrhpn2gxs2fy0a15lnip05l97205pgbk5ra395hyha
  https://bordeaux.guix.gnu.org/nar/…-git-2.5.0: 069nb85bv4d4a6slrwjdy8v1cn4cwspm3kdbmyb81d6zckj3nq9f
  https://guix.example.org/nar/…-git-2.5.0: 0mdqa9w1p6cmli6976v4wi0sw9r4p5prkj7lzfd1877wk11c9c73
  differing file:
    /libexec/git-core/git-fsck

/gnu/store/…-pius-2.1.1 contents differ:
  local hash: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
  https://bordeaux.guix.gnu.org/nar/…-pius-2.1.1: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
  https://guix.example.org/nar/…-pius-2.1.1: 1cy25x1a4fzq5rk0pmvc8xhwyffnqz95h2bpvqsz2mpvlbccy0gs
  differing file:
    /share/man/man1/pius.1.gz

…

5 store items were analyzed:
  - 2 (40.0%) were identical
  - 3 (60.0%) differed
  - 0 (0.0%) were inconclusive

In this example, guix challenge queries all the substitute servers for each of the fives packages specified on the command line. It then reports those store items for which the servers obtained a result different from the local build (if it exists) and/or different from one another; here, the ‘local hash’ lines indicate that a local build result was available for each of these packages and shows its hash.

As an example, guix.example.org always gets a different answer. Conversely, bordeaux.guix.gnu.org agrees with local builds, except in the case of Git. This might indicate that the build process of Git is non-deterministic, meaning that its output varies as a function of various things that Guix does not fully control, in spite of building packages in isolated environments (veja Recursos). Most common sources of non-determinism include the addition of timestamps in build results, the inclusion of random numbers, and directory listings sorted by inode number. See https://reproducible-builds.org/docs/, for more information.

To find out what is wrong with this Git binary, the easiest approach is to run:

guix challenge git \
  --diff=diffoscope \
  --substitute-urls="https://bordeaux.guix.gnu.org https://guix.example.org"

This automatically invokes diffoscope, which displays detailed information about files that differ.

Alternatively, we can do something along these lines (veja Invocando guix archive):

$ wget -q -O - https://bordeaux.guix.gnu.org/nar/lzip/…-git-2.5.0 \
   | lzip -d | guix archive -x /tmp/git
$ diff -ur --no-dereference /gnu/store/…-git.2.5.0 /tmp/git

This command shows the difference between the files resulting from the local build, and the files resulting from the build on bordeaux.guix.gnu.org (veja Comparing and Merging Files em Comparing and Merging Files). The diff command works great for text files. When binary files differ, a better option is Diffoscope, a tool that helps visualize differences for all kinds of files.

Once you have done that work, you can tell whether the differences are due to a non-deterministic build process or to a malicious server. We try hard to remove sources of non-determinism in packages to make it easier to verify substitutes, but of course, this is a process that involves not just Guix, but a large part of the free software community. In the meantime, guix challenge is one tool to help address the problem.

If you are writing packages for Guix, you are encouraged to check whether bordeaux.guix.gnu.org and other substitute servers obtain the same build result as you did with:

guix challenge package

The general syntax is:

guix challenge options argument

where argument is a package specification such as guile@2.0 or glibc:debug or, alternatively, a store file name as returned, for example, by guix build or guix gc --list-live.

When a difference is found between the hash of a locally-built item and that of a server-provided substitute, or among substitutes provided by different servers, the command displays it as in the example above and its exit code is 2 (other non-zero exit codes denote other kinds of errors).

The one option that matters is:

--substitute-urls=urls

Consider urls the whitespace-separated list of substitute source URLs to compare to.

--diff=mode

Upon mismatches, show differences according to mode, one of:

simple (the default)

Show the list of files that differ.

diffoscope
command

Invoke Diffoscope, passing it two directories whose contents do not match.

When command is an absolute file name, run command instead of Diffoscope.

nenhuma

Do not show further details about the differences.

Thus, unless --diff=none is passed, guix challenge downloads the store items from the given substitute servers so that it can compare them.

--verbose
-v

Show details about matches (identical contents) in addition to information about mismatches.


9.13 Invocando guix copy

The guix copy command copies items from the store of one machine to that of another machine over a secure shell (SSH) connection26. For example, the following command copies the coreutils package, the user’s profile, and all their dependencies over to host, logged in as user:

guix copy --to=user@host \
          coreutils $(readlink -f ~/.guix-profile)

If some of the items to be copied are already present on host, they are not actually sent.

The command below retrieves libreoffice and gimp from host, assuming they are available there:

guix copy --from=host libreoffice gimp

The SSH connection is established using the Guile-SSH client, which is compatible with OpenSSH: it honors ~/.ssh/known_hosts and ~/.ssh/config, and uses the SSH agent for authentication.

The key used to sign items that are sent must be accepted by the remote machine. Likewise, the key used by the remote machine to sign items you are retrieving must be in /etc/guix/acl so it is accepted by your own daemon. Veja Invocando guix archive, for more information about store item authentication.

The general syntax is:

guix copy [--to=spec|--from=spec] items

You must always specify one of the following options:

--to=spec
--from=spec

Specify the host to send to or receive from. spec must be an SSH spec such as example.org, charlie@example.org, or charlie@example.org:2222.

The items can be either package names, such as gimp, or store items, such as /gnu/store/…-idutils-4.6.

When specifying the name of a package to send, it is first built if needed, unless --dry-run was specified. Common build options are supported (veja Opções de compilação comum).


9.14 Invocando guix container

Nota: As of version 9356a8c, this tool is experimental. The interface is subject to radical change in the future.

The purpose of guix container is to manipulate processes running within an isolated environment, commonly known as a “container”, typically created by the guix shell (veja Invoking guix shell) and guix system container (veja Invoking guix system) commands.

The general syntax is:

guix container action options

action specifies the operation to perform with a container, and options specifies the context-specific arguments for the action.

The following actions are available:

exec

Execute a command within the context of a running container.

The syntax is:

guix container exec pid program arguments

pid specifies the process ID of the running container. program specifies an executable file name within the root file system of the container. arguments are the additional options that will be passed to program.

The following command launches an interactive login shell inside a Guix system container, started by guix system container, and whose process ID is 9001:

guix container exec 9001 /run/current-system/profile/bin/bash --login

Note that the pid cannot be the parent process of a container. It must be PID 1 of the container or one of its child processes.


9.15 Invocando guix weather

Occasionally you’re grumpy because substitutes are lacking and you end up building packages by yourself (veja Substitutos). The guix weather command reports on substitute availability on the specified servers so you can have an idea of whether you’ll be grumpy today. It can sometimes be useful info as a user, but it is primarily useful to people running guix publish (veja Invocando guix publish). Sometimes substitutes are available but they are not authorized on your system; guix weather reports it so you can authorize them if you want (veja Getting Substitutes from Other Servers).

Here’s a sample run:

$ guix weather --substitute-urls=https://guix.example.org
computing 5,872 package derivations for x86_64-linux...
looking for 6,128 store items on https://guix.example.org..
updating substitutes from 'https://guix.example.org'... 100.0%
https://guix.example.org
  43.4% substitutes available (2,658 out of 6,128)
  7,032.5 MiB of nars (compressed)
  19,824.2 MiB on disk (uncompressed)
  0.030 seconds per request (182.9 seconds in total)
  33.5 requests per second

  9.8% (342 out of 3,470) of the missing items are queued
  867 queued builds
      x86_64-linux: 518 (59.7%)
      i686-linux: 221 (25.5%)
      aarch64-linux: 128 (14.8%)
  build rate: 23.41 builds per hour
      x86_64-linux: 11.16 builds per hour
      i686-linux: 6.03 builds per hour
      aarch64-linux: 6.41 builds per hour

As you can see, it reports the fraction of all the packages for which substitutes are available on the server—regardless of whether substitutes are enabled, and regardless of whether this server’s signing key is authorized. It also reports the size of the compressed archives (“nars”) provided by the server, the size the corresponding store items occupy in the store (assuming deduplication is turned off), and the server’s throughput. The second part gives continuous integration (CI) statistics, if the server supports it. In addition, using the --coverage option, guix weather can list “important” package substitutes missing on the server (see below).

To achieve that, guix weather queries over HTTP(S) meta-data (narinfos) for all the relevant store items. Like guix challenge, it ignores signatures on those substitutes, which is innocuous since the command only gathers statistics and cannot install those substitutes.

The general syntax is:

guix weather options… [packages…]

When packages is omitted, guix weather checks the availability of substitutes for all the packages, or for those specified with --manifest; otherwise it only considers the specified packages. It is also possible to query specific system types with --system. guix weather exits with a non-zero code when the fraction of available substitutes is below 100%.

The available options are listed below.

--substitute-urls=urls

urls is the space-separated list of substitute server URLs to query. When this option is omitted, the URLs specified with the --substitute-urls option of guix-daemon are used or, as a last resort, the default set of substitute URLs.

--system=system
-s sistema

Query substitutes for system—e.g., aarch64-linux. This option can be repeated, in which case guix weather will query substitutes for several system types.

--manifest=arquivo

Instead of querying substitutes for all the packages, only ask for those specified in file. file must contain a manifest, as with the -m option of guix package (veja Invocando guix package).

This option can be repeated several times, in which case the manifests are concatenated.

--expression=expr
-e expr

Consider the package expr evaluates to.

A typical use case for this option is specifying a package that is hidden and thus cannot be referred to in the usual way, as in this example:

guix weather -e '(@@ (gnu packages rust) rust-bootstrap)'

This option can be repeated.

--coverage[=contagem]
-c [contagem]

Report on substitute coverage for packages: list packages with at least count dependents (zero by default) for which substitutes are unavailable. Dependent packages themselves are not listed: if b depends on a and a has no substitutes, only a is listed, even though b usually lacks substitutes as well. The result looks like this:

$ guix weather --substitute-urls=https://bordeaux.guix.gnu.org https://ci.guix.gnu.org -c 10
computing 8,983 package derivations for x86_64-linux...
looking for 9,343 store items on https://bordeaux.guix.gnu.org https://ci.guix.gnu.org...
updating substitutes from 'https://bordeaux.guix.gnu.org https://ci.guix.gnu.org'... 100.0%
https://bordeaux.guix.gnu.org https://ci.guix.gnu.org
  64.7% substitutes available (6,047 out of 9,343)
…
2502 packages are missing from 'https://bordeaux.guix.gnu.org https://ci.guix.gnu.org' for 'x86_64-linux', among which:
    58  kcoreaddons@5.49.0      /gnu/store/…-kcoreaddons-5.49.0
    46  qgpgme@1.11.1           /gnu/store/…-qgpgme-1.11.1
    37  perl-http-cookiejar@0.008  /gnu/store/…-perl-http-cookiejar-0.008
    …

What this example shows is that kcoreaddons and presumably the 58 packages that depend on it have no substitutes at bordeaux.guix.gnu.org; likewise for qgpgme and the 46 packages that depend on it.

If you are a Guix developer, or if you are taking care of this build farm, you’ll probably want to have a closer look at these packages: they may simply fail to build.

--display-missing

Display the list of store items for which substitutes are missing.


9.16 Invocando guix processes

The guix processes command can be useful to developers and system administrators, especially on multi-user machines and on build farms: it lists the current sessions (connections to the daemon), as well as information about the processes involved27. Here’s an example of the information it returns:

$ sudo guix processes
SessionPID: 19002
ClientPID: 19090
ClientCommand: guix shell python

SessionPID: 19402
ClientPID: 19367
ClientCommand: guix publish -u guix-publish -p 3000 -C 9 …

SessionPID: 19444
ClientPID: 19419
ClientCommand: cuirass --cache-directory /var/cache/cuirass …
LockHeld: /gnu/store/…-perl-ipc-cmd-0.96.lock
LockHeld: /gnu/store/…-python-six-bootstrap-1.11.0.lock
LockHeld: /gnu/store/…-libjpeg-turbo-2.0.0.lock
ChildPID: 20495
ChildCommand: guix offload x86_64-linux 7200 1 28800
ChildPID: 27733
ChildCommand: guix offload x86_64-linux 7200 1 28800
ChildPID: 27793
ChildCommand: guix offload x86_64-linux 7200 1 28800

In this example we see that guix-daemon has three clients: guix shell, guix publish, and the Cuirass continuous integration tool; their process identifier (PID) is given by the ClientPID field. The SessionPID field gives the PID of the guix-daemon sub-process of this particular session.

The LockHeld fields show which store items are currently locked by this session, which corresponds to store items being built or substituted (the LockHeld field is not displayed when guix processes is not running as root). Last, by looking at the ChildPID and ChildCommand fields, we understand that these three builds are being offloaded (veja Usando o recurso de descarregamento).

The output is in Recutils format so we can use the handy recsel command to select sessions of interest (veja Selection Expressions em GNU recutils manual). As an example, the command shows the command line and PID of the client that triggered the build of a Perl package:

$ sudo guix processes | \
    recsel -p ClientPID,ClientCommand -e 'LockHeld ~ "perl"'
ClientPID: 19419
ClientCommand: cuirass --cache-directory /var/cache/cuirass …

Additional options are listed below.

--format=format
-f format

Produce output in the specified format, one of:

recutils

The default option. It outputs a set of Session recutils records that include each ChildProcess as a field.

normalized

Normalize the output records into record sets (veja Record Sets em GNU recutils manual). Normalizing into record sets allows joins across record types. The example below lists the PID of each ChildProcess and the associated PID for Session that spawned the ChildProcess where the Session was started using guix build.

$ guix processes --format=normalized | \
    recsel \
    -j Session \
    -t ChildProcess \
    -p Session.PID,PID \
    -e 'Session.ClientCommand ~ "guix build"'
PID: 4435
Session_PID: 4278

PID: 4554
Session_PID: 4278

PID: 4646
Session_PID: 4278

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10 Foreign Architectures

You can target computers of different CPU architectures when producing packages (veja Invocando guix package), packs (veja Invocando guix pack) or full systems (veja Invoking guix system).

GNU Guix supports two distinct mechanisms to target foreign architectures:

  1. The traditional cross-compilation mechanism.
  2. The native building mechanism which consists in building using the CPU instruction set of the foreign system you are targeting. It often requires emulation, using the QEMU program for instance.

10.1 Cross-Compilation

The commands supporting cross-compilation are proposing the --list-targets and --target options.

The --list-targets option lists all the supported targets that can be passed as an argument to --target.

$ guix build --list-targets
The available targets are:

   - aarch64-linux-gnu
   - arm-linux-gnueabihf
   - avr
   - i586-pc-gnu
   - i686-linux-gnu
   - i686-w64-mingw32
   - mips64el-linux-gnu
   - or1k-elf
   - powerpc-linux-gnu
   - powerpc64le-linux-gnu
   - riscv64-linux-gnu
   - x86_64-linux-gnu
   - x86_64-linux-gnux32
   - x86_64-w64-mingw32
   - xtensa-ath9k-elf

Targets are specified as GNU triplets (veja GNU configuration triplets em Autoconf).

Those triplets are passed to GCC and the other underlying compilers possibly involved when building a package, a system image or any other GNU Guix output.

$ guix build --target=aarch64-linux-gnu hello
/gnu/store/9926by9qrxa91ijkhw9ndgwp4bn24g9h-hello-2.12

$ file /gnu/store/9926by9qrxa91ijkhw9ndgwp4bn24g9h-hello-2.12/bin/hello
/gnu/store/9926by9qrxa91ijkhw9ndgwp4bn24g9h-hello-2.12/bin/hello: ELF
64-bit LSB executable, ARM aarch64 …

The major benefit of cross-compilation is that there are no performance penalty compared to emulation using QEMU. There are however higher risks that some packages fail to cross-compile because fewer users are using this mechanism extensively.


10.2 Native Builds

The commands that support impersonating a specific system have the --list-systems and --system options.

The --list-systems option lists all the supported systems that can be passed as an argument to --system.

$ guix build --list-systems
The available systems are:

   - x86_64-linux [current]
   - aarch64-linux
   - armhf-linux
   - i586-gnu
   - i686-linux
   - mips64el-linux
   - powerpc-linux
   - powerpc64le-linux
   - riscv64-linux

$ guix build --system=i686-linux hello
/gnu/store/cc0km35s8x2z4pmwkrqqjx46i8b1i3gm-hello-2.12

$ file /gnu/store/cc0km35s8x2z4pmwkrqqjx46i8b1i3gm-hello-2.12/bin/hello
/gnu/store/cc0km35s8x2z4pmwkrqqjx46i8b1i3gm-hello-2.12/bin/hello: ELF
32-bit LSB executable, Intel 80386 …

In the above example, the current system is x86_64-linux. The hello package is however built for the i686-linux system.

This is possible because the i686 CPU instruction set is a subset of the x86_64, hence i686 targeting binaries can be run on x86_64.

Still in the context of the previous example, if picking the aarch64-linux system and the guix build --system=aarch64-linux hello has to build some derivations, an extra step might be needed.

The aarch64-linux targeting binaries cannot directly be run on a x86_64-linux system. An emulation layer is requested. The GNU Guix daemon can take advantage of the Linux kernel binfmt_misc mechanism for that. In short, the Linux kernel can defer the execution of a binary targeting a foreign platform, here aarch64-linux, to a userspace program, usually an emulator.

There is a service that registers QEMU as a backend for the binfmt_misc mechanism (veja qemu-binfmt-service-type). On Debian based foreign distributions, the alternative would be the qemu-user-static package.

If the binfmt_misc mechanism is not setup correctly, the building will fail this way:

$ guix build --system=armhf-linux hello --check
…
 unsupported-platform /gnu/store/jjn969pijv7hff62025yxpfmc8zy0aq0-hello-2.12.drv aarch64-linux
while setting up the build environment: a `aarch64-linux' is required to
build `/gnu/store/jjn969pijv7hff62025yxpfmc8zy0aq0-hello-2.12.drv', but
I am a `x86_64-linux'…

whereas, with the binfmt_misc mechanism correctly linked with QEMU, one can expect to see:

$ guix build --system=armhf-linux hello --check
/gnu/store/13xz4nghg39wpymivlwghy08yzj97hlj-hello-2.12

The main advantage of native building compared to cross-compiling, is that more packages are likely to build correctly. However it comes at a price: compilation backed by QEMU is way slower than cross-compilation, because every instruction needs to be emulated.

The availability of substitutes for the architecture targeted by the --system option can mitigate this problem. An other way to work around it is to install GNU Guix on a machine whose CPU supports the targeted instruction set, and set it up as an offload machine (veja Usando o recurso de descarregamento).


11 Configuração do sistema

Guix System supports a consistent whole-system configuration mechanism. By that we mean that all aspects of the global system configuration—such as the available system services, timezone and locale settings, user accounts—are declared in a single place. Such a system configuration can be instantiated—i.e., effected.

One of the advantages of putting all the system configuration under the control of Guix is that it supports transactional system upgrades, and makes it possible to roll back to a previous system instantiation, should something go wrong with the new one (veja Recursos). Another advantage is that it makes it easy to replicate the exact same configuration across different machines, or at different points in time, without having to resort to additional administration tools layered on top of the own tools of the system.

This section describes this mechanism. First we focus on the system administrator’s viewpoint—explaining how the system is configured and instantiated. Then we show how this mechanism can be extended, for instance to support new system services.


11.1 Começando

You’re reading this section probably because you have just installed Guix System (veja Instalação do sistema) and would like to know where to go from here. If you’re already familiar with GNU/Linux system administration, the way Guix System is configured is very different from what you’re used to: you won’t install a system service by running guix install, you won’t configure services by modifying files under /etc, and you won’t create user accounts by invoking useradd; instead, all these aspects are spelled out in a system configuration file.

The first step with Guix System is thus to write the system configuration file; luckily, system installation already generated one for you and stored it under /etc/config.scm.

Nota: You can store your system configuration file anywhere you like—it doesn’t have to be at /etc/config.scm. It’s a good idea to keep it under version control, for instance in a