Observing a "does not appear to be a binary cache" problem with Nix 2.10

[Technius]

I work on a project that uses cachix-action and a private binary cache for CI, and it has been working really well. Today, I observed some problems where the cache was not being picked up, specifically the "warning: XXX does not appear to be a binary cache" message. After some debugging, I noticed that install-nix-action was installing Nix 2.10 -- which was really unexpected because I didn't know it came out today just a few hours ago! The problem went away after the nix version was pinned to 2.9.2.

I'm not sure whether this is a problem with Nix, cachix, or cachix-action, so I'd be happy to post this issue in a more appropriate place.

For reference, here is a version of the workflow file modified to remove any sensitive information:

name: My workflow
on:
  push:
    branches: [ main ]

jobs:
  build-expensive-dependency:
    runs-on: ubuntu-latest
    timeout-minutes: 300
    steps:
      - uses: actions/checkout@v2.4.0
      - uses: cachix/install-nix-action@v17
        # the following two lines are used to workaround the problem
        with:
          install_url: https://releases.nixos.org/nix/nix-2.9.2/install
      - uses: cachix/cachix-action@v10
        with:
          name: my-private-cache-name
          authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
      - name: "Build and cache a dependency that is expensive to build"
        run: |
          nix build --print-build-logs .#my-expensive-dependency

[lorenzo]

We experienced the same issue after upgrading to nix 2.10.0

[jerbaroo]

Builds suddenly started taking hours for us, starting yesterday, I also see this message in GitHub Action logs:

warning: 'https://****.cachix.org/' does not appear to be a binary cache

Here's a snippet of our workflow file:

    steps:
    - uses: actions/checkout@v2.3.4
    - name: Install Cachix
      uses: cachix/install-nix-action@v13
      with:
        nix_path: nixpkgs=channel:nixos-unstable
    - name: Authenticate Cachix
      uses: cachix/cachix-action@v10
      with:
        name: ****
        authToken: '${{ secrets.CACHIX_READ_WRITE_TOKEN }}'
    - name: check-format.sh
      run: |
        cachix watch-store **** &
        nix-shell brittany.nix --run "./scripts/check-format.sh"

[chessai]

I just started experiencing this as well.

[centromere]

I ran in to this myself. Check your netrc file. It probably says:

machine foo.cachix.org password <token>

If you change it to:

machine foo.cachix.org login "" password <token>

it may start working. I think this is related to curl/curl#8908, but I am uncertain.

[centromere]

Related: curl/curl#9148

[domenkozar]

I've pushed a fix to https://hydra.nixos.org/eval/1771392#tabs-unfinished, hopefully @edolstra will make a new Nix release tomorrow.

Workaround is to pin Nix: domenkozar/homelab@c7ab335

PS: it's better to report such issues to support@cachix.org for quicker turnaround.

[domenkozar]

That fix was not enough, I created NixOS/nix#6807

[domenkozar]

It should be fixed, can you confirm?

[centromere]

It is now working for me.

[zmrocze]

I'm experiencing this with nix (Nix) 2.18.1 on nixos-23.11.

Eventhough:

❯ nix store ping --store https://sth.cachix.org
Store URL: https://sth.cachix.org

[zmrocze]

@domenkozar Hey, I still see this message always. Is it to be expected? Does it mean that the cache is not used?

[domenkozar]

Is the cache public? Can you contact support, there's quite a few variables in play here.