Continuous builds on Hydra

[Ludovic Courtès]

Hi!

Guix has been under continuous integration at:

  http://hydra.nixos.org/jobset/gnu/guix-master

And now the distro itself is being built at:

  http://hydra.nixos.org/jobset/gnu/guix-distro-master

Binaries can be downloaded from there.  You first need to fetch the
manifest using:

  nix-pull 
http://hydra.nixos.org/jobset/gnu/guix-distro-master/channel/latest/MANIFEST

Then nix-worker is able to use those binary substitutes, instead of
building things locally.  So, for instance, this is what happens when I
attempt to build Autoconf:

--8<---------------cut here---------------start------------->8---
$ ./pre-inst-env guix-build autoconf 
WARNING: (distro packages wget): imported module (distro packages gettext) 
overrides core binding `gettext'
WARNING: (distro packages nano): imported module (distro packages gettext) 
overrides core binding `gettext'
warning: you did not specify `--add-root'; the result might be removed by the 
garbage collector
the following derivations will be built:
    /nix/store/bh1h8xmik41caqn27w7wxnqcbanf6ngy-autoconf-2.69.drv
    /nix/store/4h72sc453rbwsqn0gbgdd2y2nl5vvvzp-module-import-compiled.drv
    /nix/store/fpwjxm8wamgmi0z05d13fv8cs2ki6nv3-patch-2.6.1.drv
    /nix/store/lpqk72h4mjx7blyfsmgxmkzg44946130-autoconf-2.69.tar.xz.drv
    /nix/store/r8lbjvaw4p7lkpgjx01l14c7036va443-module-import.drv
@ substituter-started /nix/store/sj4isnlaysjdcq1nbrafl8m4pj8zl9wv-autoconf-2.69 
/nix/store/96rgql0340rc6vyrwrb0p5jd7j9q017h-nix-1.2pre2910_b674665/libexec/nix/substituters/download-using-manifests.pl

*** Trying to download/patch 
`/nix/store/sj4isnlaysjdcq1nbrafl8m4pj8zl9wv-autoconf-2.69'

*** Step 1/1: downloading 
`http://hydra.nixos.org/nar/sj4isnlaysjdcq1nbrafl8m4pj8zl9wv-autoconf-2.69' 
into `/nix/store/sj4isnlaysjdcq1nbrafl8m4pj8zl9wv-autoconf-2.69'
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  631k    0  631k    0     0   236k      0 --:--:--  0:00:02 --:--:--  241k

@ substituter-succeeded 
/nix/store/sj4isnlaysjdcq1nbrafl8m4pj8zl9wv-autoconf-2.69
/nix/store/sj4isnlaysjdcq1nbrafl8m4pj8zl9wv-autoconf-2.69
--8<---------------cut here---------------end--------------->8---

What happened is that the daemon directly downloaded the Autoconf binary
from hydra.nixos.org, and nothing got built locally.

The recipe that tells what the jobs is in the ‘hydra.scm’ file.

This is currently x86_64-linux-only, because of the Hydra bug reported
at <https://github.com/NixOS/hydra/issues/50>.

Note that hydra.nixos.org uses hardware generously made available by the
NixOS project and TU Delft, the Netherlands (thanks!).  As noted in the
‘TODO’ file, we should arrange with the FSF sysadmins to setup our own
Hydra instance, and help is welcome on this front!  I have experience
setting up Hydra, so I could help on this.

Happy hacking,
Ludo’.