Nixpkgs: cachix: fails to build on master blocking nixpkgs-unstable

[worldofpeace]

Describe the bug
https://hydra.nixos.org/job/nixpkgs/trunk/unstable#tabs-constituents
https://hydra.nixos.org/job/nixpkgs/trunk/cachix.x86_64-linux
https://hydra.nixos.org/build/117813858

It seems servant-client is timing out to build for hours https://hydra.nixos.org/build/117846655.

cc @domenkozar

[nixos-discourse]

This issue has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/derivation-to-install-haskell-stack-from-released-binaries/6923/5

[cdepillabout]

@worldofpeace I tried building cachix (and servant-client) locally with the following command:

$ cd /some/path/to/nixpkgs
$ nix-build -A cachix
...
/nix/store/d1qv22mbccvaiczvmmccr5cqwn30ymxz-cachix-0.3.7

It looks like it succeeded building. This is on commit b7f80f00ef.

I'm not sure why Hydra would be having a problem with this. Looking through the output of the build of servant-client, I don't see anything particularly strange (both my local build and https://hydra.nixos.org/build/117846655/nixlog/1).

Here's what I suggest we do about this:

• Try restarting the build on Hydra. @worldofpeace Could you do this? I don't think I have permission.
• If restarting the build fails, we can probably just disable the tests for servant-client, since it appears that is where it is hanging.
• We could also remove cachix from the list of required jobs, but I'm pretty sure @domenkozar wants it there.

[cdepillabout]

Also ping @peti so he is aware of this.

[domenkozar]

Restarted the builds.

[peti]

The servant error looks like a system-level problem. The build has succeeded, but for the part where the build result is copied back to the Hydra master (or the cache, or whatever). Maybe the LAN was down at that time? I think there's a good chance that the restarted build will succeed.

[vcunat]

Succeeded. I assume it was a rare error that isn't worth attempting to mitigate in some other way?

[domenkozar]

It seems like and error in the infrastructure rather than in the build to me.