Re: Checking for substitutes

[Timothy Sample]

Hi Konrad,

Konrad Hinsen <address@hidden> writes:

> Hi Guix,
>
> I wonder if there is any way to check if substitutes are available for a
> given set of packages (e.g. a single package with its dependencies, or a
> complete manifest).
>
> The context is optimizing package updates: if I know everything I need
> is available as a substitute, I can do an update immediately, but if big
> packages need to be built locally, I prefer to wait until my computer is
> idle.
>
> Ideally, I'd like "guix package" to have an option –only-substitutes
> that will stop if local builds are required, providing a list of the
> packages that must be built.

There’s an old feature request for this:

  https://debbugs.gnu.org/cgi/bugreport.cgi?bug=26608

I looked into it some time ago, and there were a lot of blockers.  See
https://lists.gnu.org/archive/html/guix-devel/2017-06/msg00190.html for
details.

At the end of that thread, I posted a small shell script that scrapes
the most recent fully evaluated commit from the build farm.  That way,
you can update to that commit, and have a much better chance of getting
all substitutes.  To be honest, I only use the script if I see something
like Icecat building.  In that case, I rollback to the latest complete
evaluation.

There’s also the ‘guix weather’ command.  It is supposed to provide info
about available substitutes.  I have not made much of use of it, though.

Hope that helps.


-- Tim