7.3 Копирование Guix

The guix describe command shows precisely which commits were used to build the instance of Guix we’re using (see Вызов 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 "d894ab8e9bfabcefa6c49d9ba2e834dd5a73a300"))
      (channel
       (name 'my-personal-packages)
       (url "https://example.org/personal-packages.git")
       (branch "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 (see Вызов guix pull) or guix time-machine (see Запуск 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 (see Вызов 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.

Это даёт вам супервозможности, позволяя вам отслеживать и управлять происхождением артефактов бинарников с точной детализацией, также повторять программные окружения — это воспроизводимость высокого уровня. Смотрите See Младшие версии, чтобы узнать другие преимущества таких супервозможностей.