bug#33378: offload: Avoid hosts with little or no free disk space

["Ludovic Courtès" <ludo@gnu.org>]

Hi Mark,

Mark H Weaver <mhw@netris.org> skribis:

> Ludovic Courtès <ludo@gnu.org> writes:
>
>> ludo@gnu.org (Ludovic Courtès) skribis:
>>
>>> ‘choose-build-machine’ in (guix scripts offload) could/should exclude
>>> build machines that don’t have at least, say, 100 MiB available in their
>>> store.  That would avoid ENOSPC build failures such as
>>> <https://berlin.guixsd.org/log/0hvhrfdjwnmdm2rdf58knshbbikm4ryv-r-bsgenome-hsapiens-ucsc-hg19-masked-1.3.99>.
>>
>> Done in commit 63b0c3eaccdf1816b419632cd7fe721934d2eb27.
>
> Many builds require more free space than 100 MB, so this is only a
> partial solution.  Also, if multiple builds are happening on the same
> machine, the amount of free space available for each build will be less
> than 100 MB.

You’re right, but this at least avoids the most obvious problems.

> Finally, the other related commit that attempts to detect build failures
> caused by ENOSPC by checking if there's at least 10 MB free after the
> failure won't often work in practice, I suspect.  The problem is, by the
> time you perform that check, the build directory has already been
> deleted.

Correct.  (I wasn’t sure the build directory would already be deleted at
that point but rereading build.cc confirms this.)

I suppose the only way to solve this correctly would be to keep the
build tree and then delete it from (guix scripts offload).  WDYT?

Thanks for your feedback!

Ludo’.