e2e_runtime-reproducibility.yml

name: e2e test runtime reproducibility

on:
  workflow_dispatch:
  schedule:
    - cron: '0 19 * * 0' # 7pm UTC on Sundays

jobs:
  os-matrix:
    strategy:
      matrix:
        os: [ubuntu-22.04, ubuntu-20.04]
        # As we do not use the Cachix cache containing the artifacts built by developers in this workflow,
        # building the node-installer-image ensures that the whole transitive closure of the packages we build (i.e. everything
        # except what's in cache.nixos.org). Therefore, building this ensures that the kernel, image, IGVM, runtime and the image itself
        # is reproducible across individual builds (as the --rebuild flag is used, causing Nix to rebuild the node-installer-image derivation)
        # and across independent builds on Ubuntu 20.04 and 22.04 (which also test the reproducibility of the transitive closure of our packages, as no shared
        # cache is present between the two machines)
        build-target: ["microsoft.contrast-node-installer-image"]
      fail-fast: false
    # Usually we would define the matrix outputs here, but as GitHub Actions don't seem to allow per-combination outputs,
    # we'll write the outputs without defining them here. See https://github.com/orgs/community/discussions/17245#discussioncomment-3814009.
    runs-on: ${{ matrix.os }}
    permissions:
      contents: write
    steps:
      - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
      - uses: ./.github/actions/setup_nix
        with:
          githubToken: ${{ secrets.GITHUB_TOKEN }}
          cachixToken: "" # Don't use the cachix cache
      - uses: nicknovitski/nix-develop@a2060d116a50b36dfab02280af558e73ab52427d # v1.1.0
      - name: Build
        id: build
        run: |
          nix build .#${{ matrix.build-target }} --option substituters https://cache.nixos.org --builders ""
          reference_checksum="$(jq  -r '.manifests[0].digest' result/index.json)"
          echo "reference-checksum-${{ matrix.os }}-${{ matrix.build-target}}=$reference_checksum" >> "$GITHUB_OUTPUT"

          nix build .#${{ matrix.build-target }} --rebuild --option substituters https://cache.nixos.org --builders "" -o rebuild
          rebuild_checksum="$(jq  -r '.manifests[0].digest' rebuild/index.json)"
          echo "rebuild-checksum-${{ matrix.os }}-${{ matrix.build-target}}=$rebuild_checksum" >> "$GITHUB_OUTPUT"
      - name: Upload Build Artifacts
        uses: actions/upload-artifact@0b2256b8c012f0828dc542b3febcab082c67f72b # v4.3.4
        with:
          name: ${{ matrix.build-target }}-${{ matrix.os }}
          path: result
      - name: Upload Build Artifacts (Rebuild)
        uses: actions/upload-artifact@0b2256b8c012f0828dc542b3febcab082c67f72b # v4.3.4
        with:
          name: ${{ matrix.build-target }}-${{ matrix.os }}-rebuild
          path: rebuild

  collect-checksums:
    runs-on: ubuntu-22.04
    permissions:
      contents: read
    needs: os-matrix
    steps:
      - name: Collect checksums
        id: collect
        shell: python
        run: |
          import json, os
          seen = {}
          with open(os.getenv("GITHUB_OUTPUT")) as f:
              for line in f:
                  matrix, checksum = line.strip().split("=")
                  if not checksum in seen:
                      seen[checksum] = []
                  seen[checksum].append(matrix)

          if len(seen) > 1:
            print("At least one checksum mismatched:")
            print(json.dumps(seen, indent=2))
            exit(1)

          print("All checksums were equal")