git.stella-ops.org/.github/workflows/examples/example-container-sign.yml

# .github/workflows/examples/example-container-sign.yml
# Example: Sign container image with keyless signing
#
# This example shows how to:
# 1. Build a container image
# 2. Push to registry
# 3. Sign using StellaOps keyless signing
# 4. Attach attestation to image
#
# Adapt to your repository by:
# - Updating the registry URL
# - Adjusting Dockerfile path
# - Adding your specific build args

name: Build and Sign Container

on:
  push:
    branches: [main]
    tags: ['v*']
  pull_request:
    branches: [main]

env:
  REGISTRY: ghcr.io
  IMAGE_NAME: ${{ github.repository }}

jobs:
  build:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write

    outputs:
      digest: ${{ steps.build.outputs.digest }}
      image: ${{ steps.build.outputs.image }}

    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      - name: Log in to Container Registry
        if: github.event_name != 'pull_request'
        uses: docker/login-action@v3
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Extract Metadata
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
          tags: |
            type=ref,event=branch
            type=ref,event=pr
            type=semver,pattern={{version}}
            type=semver,pattern={{major}}.{{minor}}
            type=sha

      - name: Build and Push
        id: build
        uses: docker/build-push-action@v5
        with:
          context: .
          push: ${{ github.event_name != 'pull_request' }}
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          cache-from: type=gha
          cache-to: type=gha,mode=max
          provenance: true
          sbom: true

      - name: Output Image Digest
        if: github.event_name != 'pull_request'
        run: |
          echo "digest=${{ steps.build.outputs.digest }}" >> $GITHUB_OUTPUT
          echo "image=${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}@${{ steps.build.outputs.digest }}" >> $GITHUB_OUTPUT

  sign:
    needs: build
    if: github.event_name != 'pull_request'
    uses: ./.github/workflows/examples/stellaops-sign.yml
    with:
      artifact-digest: ${{ needs.build.outputs.digest }}
      artifact-type: image
      push-attestation: true
    permissions:
      id-token: write
      contents: read
      packages: write

  verify:
    needs: [build, sign]
    if: github.event_name != 'pull_request'
    uses: ./.github/workflows/examples/stellaops-verify.yml
    with:
      artifact-digest: ${{ needs.build.outputs.digest }}
      certificate-identity: 'repo:${{ github.repository }}:ref:${{ github.ref }}'
      certificate-oidc-issuer: 'https://token.actions.githubusercontent.com'
      require-rekor: true
      strict: true
    permissions:
      contents: read
      packages: read

  summary:
    needs: [build, sign, verify]
    if: github.event_name != 'pull_request'
    runs-on: ubuntu-latest
    steps:
      - name: Generate Release Summary
        run: |
          cat >> $GITHUB_STEP_SUMMARY << EOF
          ## Container Image Published

          **Image:** \`${{ needs.build.outputs.image }}\`

          ### Pull Command

          \`\`\`bash
          docker pull ${{ needs.build.outputs.image }}
          \`\`\`

          ### Verify Signature

          \`\`\`bash
          stella attest verify \\
            --artifact "${{ needs.build.outputs.digest }}" \\
            --certificate-identity "repo:${{ github.repository }}:ref:${{ github.ref }}" \\
            --certificate-oidc-issuer "https://token.actions.githubusercontent.com"
          \`\`\`

          ### Attestations

          | Type | Digest |
          |------|--------|
          | Signature | \`${{ needs.sign.outputs.attestation-digest }}\` |
          | Rekor | \`${{ needs.sign.outputs.rekor-uuid }}\` |
          EOF