bug#31825: guix offload fails with guix-authenticate error

[Maxim Cournoyer <maxim.cournoyer@gmail.com>]

Hi!

ludo@gnu.org (Ludovic Courtès) writes:

> Maxim Cournoyer <maxim.cournoyer@gmail.com> skribis:
>
>> Attached is the log for the offloading machine.
>>
>> From what I can see, the guix-daemon is trying to find the authorized
>> key in /etc/guix/acl, but the key is added by Guix to
>> /usr/local/etc/guix/acl...
>
> Hmm you may be using two different ‘guix’ commands no?
>
>> 2. The error message should capture the complete error output to ease
>> debugging: we can see the useful message "25056 write(2, "guix
>> authenticate: error: error: unauthorized public key: (public-key \n (ecc
>> \n  (curve Ed25519)\n  (q
>> #EEA139318243D36EB4C728DB96856AB15C47AB64C765FA134CCFB12444B82A7C#)\n
>> )\n )\n", 176) = 176" in strace. Had I seen this from the start, we
>> would have saved some debugging time :).
>
> I agree.
>
>> I could work around the issue by copying manually the authorized key
>> sexp to /etc/guix/acl; I now see:
>>
>> guix offload: testing 1 build machines defined in '/etc/guix/machines.scm'...
>> guix offload: '192.168.1.105' is running guile (GNU Guile) 2.2.3
>> guix offload: Guix is usable on '192.168.1.105' (test returned "/gnu/store/883yjkl46dxw9mzykykmbs0yzwyxm17z-test")
>> sending 1 store item to '192.168.1.105'...
>> exporting path `/gnu/store/np9jwqvxjvasz41nrrh6g3gyn4rpkscw-export-test'
>> guix offload: '192.168.1.105' successfully imported '/gnu/store/np9jwqvxjvasz41nrrh6g3gyn4rpkscw-export-test'
>> retrieving 1 store item from '192.168.1.105'...
>> guix offload: error: build failed: implementation cannot deal with > 32-bit integers
>
> The log has this:
>
> 10529 write(4, "atad\0\0\0\0\0\200\0\0\0\0\0\0", 16) = 16
> 10529 read(4, "W\1\0\0\0\0\0\0\1\0\0\0\0\0\0\0\r\0\0\0\0\0\0\0nix-archive-1\0\0\0\1\0\0\0\0\0\0\0(\0\0\0\0\0\0\0\4\0\0\0\0\0\0\0type\0\0\0\0\7\0\0\0\0\0\0\0regular\0\10\0\0\0\0\0\0\0contents\23\0\0\0\0\0\0\000192.168.1.105-83353\0\0\0\0\0\1\0\0\0\0\0\0\0)\0\0\0\0\0\0\0NIXE\0\0\0\0007\0\0\0\0\0\0\0/gnu/store/wf774mzvfjpw306y5x06wid80d9k90qq-import-test\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\1\0\0\0\0\0\0\0(protocol-error 1 \"getting status of `/etc/guix/signing-key.sec': Aucun fichier ou dossier de ce "..., 32768) = 352
>
> Again the error should be reported…

Yes, this error was totally wrong, thanks for pointing it out. The
actual error was the 192.168.1.105 offload machine not finding the key
at /etc/guix/singning-key.sec (since it using the prefix
/usr/local/etc/guix for some reason).

I just did:

--8<---------------cut here---------------start------------->8---
sudo cp /usr/local/etc/guix/signing* /etc/guix/
--8<---------------cut here---------------end--------------->8---

And it is now working. Ouf!

Summarizing this adventure:

0) Make sure your .bashrc doesn't exit early when it is executed in
non-interactive mode (as is the case in Ubuntu).

1) Make sure the guix-authenticate program is available on the host as
well as the offload machines, by installing guix (guix package -i guix)
in the corresponding user profiles and sourcing
$HOME/guix.profile/etc/profile in the ~/.bashrc.

2) Make sure all your guix-daemons are configured to use /etc/guix as
their sysconfdir, as Guix offload currently seems hardcoded to only look
things under /etc/guix.

3) Don't trust any errors output by guix offload ;)

It'd be nice if this was as simple as setting up a Jenkins node... You
tell Guix which machine you want to use and give it SSH access, and it
does the required setup without having the user messing around with keys
and what not.

But I'm seeing far ahead. For now, we could start by adding some points
to the `guix offload` info manual. Then we can try to modify the code to
better capture the error messages. 

I'll start with the documentation.

Thank you,

Maxim