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 (see substitutes) 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.