10.10 Invoking 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:

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:

package

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 (see --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:

At the bottom of the graph, we see all the implicit inputs of gnu-build-system (see gnu-build-system).

Now, note that the dependencies of these implicit inputs—that is, the bootstrap dependencies (see 引导)—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 (see Derivations) 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)

模块

This is the graph of package modules (see 软件包模块). 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 (see Invoking 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 (see Invoking 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 type

Produce a graph output of type, where type must be one of the values listed above.

--list-types

List the supported graph types.

--backend=backend

-b backend

Produce a graph using the selected backend.

--list-backends

List the supported graph backends.

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 system

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 directory

Add directory to the front of the package module search path (see 软件包模块).

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 (see 软件包转换选项). 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!