publish-cloudrunner-images.yml

---
name: Build CloudRunner Docker Images

# This workflow uses actions that are not certified by GitHub.
# They are provided by a third-party and are governed by
# separate terms of service, privacy policy, and support
# documentation.

on:
  push:
    branches: [main]
    paths:
      - 'ci/cloudrunners/Dockerfile*'
      - 'ci/cloudrunners/oci/**'
  pull_request:
    branches: [main]
    paths:
      - 'ci/cloudrunners/Dockerfile*'
      - 'ci/cloudrunners/oci/**'
  workflow_dispatch:

env:
  # Use docker.io for Docker Hub if empty
  REGISTRY: ghcr.io
  # IMAGE_NAME maps to the Docker image name
  IMAGE_NAME: cncf/gha-cloudrunner

jobs:
  build-cloudrunner-images:
    outputs:
      image: ${{ steps.image.outputs.image }}
      digest: ${{ steps.build-and-push.outputs.digest }}
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write
      # This is used to complete the identity challenge
      # with sigstore/fulcio when running outside of PRs.
      id-token: write

    steps:
      - name: Checkout repository
        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd

      # Install the cosign tool except on PR
      # https://github.com/sigstore/cosign-installer
      - name: Install cosign
        if: github.event_name != 'pull_request'
        uses: sigstore/cosign-installer@main
      - name: Set up QEMU
        uses: docker/setup-qemu-action@v3
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      # Login against a Docker registry except on PR
      # https://github.com/docker/login-action
      - name: Log into registry ${{ env.REGISTRY }}
        if: github.event_name != 'pull_request'
        uses: docker/login-action@28218f9b04b4f3f62068d7b6ce6ca5b26e35336c
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      # Extract metadata (tags, labels) for Docker
      # https://github.com/docker/metadata-action
      - name: Extract Docker metadata
        id: meta
        uses: docker/metadata-action@98669ae865ea3cffbcbaa878cf57c20bbf1c6c38
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}

      # Build and push Docker image with Buildx (don't push on PR)
      # https://github.com/docker/build-push-action
      - name: Build and push Cloudrunner Docker image
        id: build-and-push
        uses: docker/build-push-action@v6
        with:
          context: ./ci/cloudrunners/
          platforms: |
            linux/amd64
            linux/arm64
          push: ${{ github.event_name != 'pull_request' }}
          labels: ${{ steps.meta.outputs.labels }}
          file: ./ci/cloudrunners/Dockerfile
          tags: |
            ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ github.run_id }}

      - name: Sign the published Cloudrunner Docker image
        if: ${{ github.event_name != 'pull_request' }}
        env:
          COSIGN_EXPERIMENTAL: "true"
        # Uses the identity token to provision an ephemeral certificate
        # against the sigstore community Fulcio instance.
        run: cosign sign -y ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}@${{ steps.build-and-push.outputs.digest }}

      - name: Output image
        id: image
        run: echo "image=${REGISTRY}/${IMAGE_NAME}:${{ github.ref_name }}" >> "$GITHUB_OUTPUT"
  
  # Generate SLSA provenance for the image
  # Upload the provenance to ghcr.io
  provenance:
    if: ${{ github.event_name != 'pull_request' }}
    needs: [build-cloudrunner-images]
    permissions:
      id-token: write  # For signing.
      actions: read    # For reading workflow info.
      packages: write  # For uploading attestations.
    uses: slsa-framework/slsa-github-generator/.github/workflows/generator_container_slsa3.yml@main
    with:
      image: ${{ needs.build-cloudrunner-images.outputs.image }}
      digest: ${{ needs.build-cloudrunner-images.outputs.digest }}
      registry-username: ${{ github.actor }}
      compile-generator: true
    secrets:
      registry-password: ${{ secrets.GITHUB_TOKEN }}

  # Verify the created provenance attestation.
  verify:
    # NOTE: this name is used as the status check name and by protected
    # branches for required status checks. It should have a unique name among
    # other pre-submits.
    name: verify container provenance
    needs: [build-cloudrunner-images, provenance]
    permissions:
      packages: read  # For reading attestations.
    runs-on: ubuntu-latest
    if: ${{ github.event_name != 'pull_request' }}
    steps:
      - uses: sigstore/cosign-installer@main
        with:
          cosign-release: 'v2.4.2'
      - env:
          REGISTRY_USERNAME: ${{ github.actor }}
          REGISTRY_PASSWORD: ${{ secrets.GITHUB_TOKEN }}
          IMAGE_NAME: ${{ needs.build-cloudrunner-images.outputs.image }}
          IMAGE_DIGEST: ${{ needs.build-cloudrunner-images.outputs.digest }}
        run: |
          cosign version
          COSIGN_EXPERIMENTAL=1 cosign verify-attestation \
            --certificate-identity-regexp=".*" \
            --certificate-oidc-issuer-regexp=".*" \
            --type slsaprovenance "${{ env.IMAGE_NAME }}@${{env.IMAGE_DIGEST}}"
      # TODO (github.com/slsa-framework/slsa-verifier/issues/92):
      #       Add step to verify using slsa-verifier