hello/.github/workflows/main.yml

name: "Hello"
on:
  push:
    branches: [ main, master ]
  pull_request:
    types: [opened, reopened, synchronize]

permissions:
  contents: read
  issues: write

concurrency:
  group: ${{ github.ref }}
  cancel-in-progress: true

env:
  GIT_BRANCH_NAME: ${{ github.head_ref || github.ref_name }}
  GITHUB_REPOSITORY: ${{ github.repository }}
  GITHUB_SHA: ${{ github.sha }}
  CACHIX_SIGNING_KEY: ${{ secrets.CACHIX_SIGNING_KEY }}

jobs:
  nix-matrix:
    runs-on: ubuntu-latest
    outputs:
      matrix: ${{ steps.set-matrix.outputs.matrix }}
    steps:
      - uses: actions/checkout@v3
      - uses: cachix/install-nix-action@v22
        with:
          nix_path: nixpkgs=channel:nixos-unstable
          github_access_token: ${{ secrets.GITHUB_TOKEN }}
      - id: set-matrix
        name: Generate Nix Matrix
        run: |
          set -Eeu
          echo "matrix=$(nix eval --json '.#githubActions.matrix')" >> "$GITHUB_OUTPUT"
          #echo 'matrix={"include":[{"attr":"githubActions.checks.x86_64-linux.hello","os":["ubuntu-22.04"]},{"attr":"githubActions.checks.x86_64-linux.lxc","os":["ubuntu-22.04"]}]}' >> "$GITHUB_OUTPUT"
          #echo 'matrix={"include":[{"attr":"githubActions.checks.x86_64-linux.lxc","os":["ubuntu-22.04"]}]}' >> "$GITHUB_OUTPUT"

  nix-build:
    needs: nix-matrix
    name: Build on ${{ matrix.attr }}
    runs-on: ubuntu-latest
    strategy:
      matrix: ${{fromJSON(needs.nix-matrix.outputs.matrix)}}
    steps:
      - uses: actions/checkout@v3
      - uses: cachix/install-nix-action@v22
        with:
          nix_path: nixpkgs=channel:nixos-unstable
          CACHIX_SIGNING_KEY: ${{ secrets.CACHIX_SIGNING_KEY }}
          github_access_token: ${{ secrets.GITHUB_TOKEN }}
      - run: nix build -L ".#${{ matrix.attr }}"