Re: updating list of substitutes

[ludo@gnu.org (Ludovic Courtès)]

Pjotr Prins <pjotr.public12@thebird.nl> skribis:

> Pretty much every time I want to install a package I get a search for
>
>   updating list of substitutes 
>
> being on a slow internet line this sucks (not everyone has fast
> internet! Think outside the US/Europe where internet is often still
> metered on mobile lines), besides installing the same software often
> install a host of new versions of dependencies. I don't like the
> system changing under me - that is not a reproducible setup.
>
> Q1: Do we retain older builds of binaries for some time for download?

Yes, but the amount of time is unspecified.

On hydra.gnu.org it can be quite long in practice, so that would call in
favor of increasing the default TTL in ‘guix substitute’.

In the longer run, we need servers to advertise their TTL (someone
running ‘guix publish’ may have a different TTL.)

> Q2: Can we switch off updating list of substitutes? A command line
>     switch would do. '--no-update-supstitutes'

No.

> Q3: Would it be possible to version the list of substitutes and use
>     that for (re)deployment? That way I can truely regenerate an existing
>     system.

You can always regenerate an existing system.  The list of substitutes
reflects what’s currently available on hydra.gnu.org.  If some
substitutes vanish, Guix automatically falls back to building from
source.

HTH,
Ludo’.