Continuous Integration with GitHub Actions

In this tutorial, we’ll show you a few short steps to get started using GitHub Actions as your continuous integration (CI) workflow for commits and pull requests.

Caching builds using Cachix

One benefit of Nix is that CI can build and cache developer environments for every project on every branch using binary caches.

An important aspect of CI is the feedback loop of, how many minutes does the build take to finish?

Using Cachix you’ll never have to waste time building a derivation twice, and you’ll share built derivations with all your developers.

After each job, just-built derivations are pushed to your binary cache.

Before each job, derivations to be built are first substituted (if they exist) from your binary cache.

1. Creating your first binary cache

It’s recommended to have different binary caches per team, depending who will have write/read access to it.

Fill out the form on the create binary cache page.

On your freshly created binary cache, follow the Push binaries tab instructions.

2. Setting up secrets

On your GitHub repository or organization (for use across all repositories):

  1. Click on Settings.

  2. Click on Secrets.

  3. Add your previously generated secrets (CACHIX_SIGNING_KEY and/or CACHIX_AUTH_TOKEN).

Setting up GitHub Actions

Create .github/workflows/test.yml with:

name: "Test"
    runs-on: ubuntu-latest
    - uses: actions/[email protected]
    - uses: cachix/[email protected]
        nix_path: nixpkgs=channel:nixos-unstable
    - uses: cachix/[email protected]
        name: mycache
        # If you chose signing key for write access
        signingKey: '${{ secrets.CACHIX_SIGNING_KEY }}'
        # If you chose API tokens for write access OR if you have a private cache
        authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
    - run: nix-build
    - run: nix-shell --run "echo OK"

Once you commit and push to your GitHub repository, you should see status checks appearing on commits and PRs.

Next steps