release-debug.yml

name: Release debugging image

# 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" ]
    tags: [ "*" ]
    paths: [ "images/debug/**" ]
  pull_request:
    branches: [ "main" ]
    paths: [ "images/debug/**" ]

env:
  # Use docker.io for Docker Hub if empty
  REGISTRY: ghcr.io
  IMAGE_NAME: ${{ github.repository }}/distroless-debug

# Declare default permissions as read only.
permissions: read-all

jobs:
  build:
    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@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0

      - name: Get image tag
        id: get_image_tag
        run: |
          VERSION=$(grep "^ARG VERSION=" images/debug/Dockerfile \
            | cut -d'=' -f2 \
            | tr -d '"' \
            | tr -d "'" \
            | tr -d [:space:])
          echo $VERSION
          echo "image_tag=${VERSION}" >> $GITHUB_OUTPUT

      # 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@faadad0cce49287aee09b3a48701e75088a2c6ad #v4.0.0
        with:
          cosign-release: 'v2.5.3'

      # Set up BuildKit Docker container builder to be able to build
      # multi-platform images and export cache
      # https://github.com/docker/setup-buildx-action
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@e468171a9de216ec08956ac3ada2f0791b6bd435 # v3.11.1

      # 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@5e57cd118135c172c3672efd75eb46360885c0ef # v3.6.0
        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@c1e51972afc2121e065aed6d45c65596fe445f3f # v5.8.0
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
          # tag image with version specified in ARG VERSION in Dockerfile if event is a push
          # or with given tag if event is tag
          tags: |
            type=semver,pattern={{version}},value=${{ steps.get_image_tag.outputs.image_tag }},enable=${{ github.event_name == 'push' && startsWith(github.ref, 'refs/heads/') }}
            type=raw,value=latest,enable=${{ github.ref == format('refs/heads/{0}', 'main') }}
            type=ref,event=tag,enable=${{ startsWith(github.ref, 'refs/tags/') }}
          flavor: |
            latest=false

      # Build and push Docker image with Buildx (don't push on PR)
      # https://github.com/docker/build-push-action
      - name: Build and push Docker image
        id: build-and-push
        uses: docker/build-push-action@263435318d21b8e681c14492fe198d362a7d2c83 # v6.18.0
        with:
          context: images/debug
          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

      # Sign the resulting Docker image digest except on PRs.
      # This will only write to the public Rekor transparency log when the Docker
      # repository is public to avoid leaking data.  If you would like to publish
      # transparency data even for private images, pass --force to cosign below.
      # https://github.com/sigstore/cosign
      - name: Sign the published Docker image
        if: ${{ github.event_name != 'pull_request' }}
        env:
          # https://docs.github.com/en/actions/security-guides/security-hardening-for-github-actions#using-an-intermediate-environment-variable
          TAGS: ${{ steps.meta.outputs.tags }}
          DIGEST: ${{ steps.build-and-push.outputs.digest }}
        # This step uses the identity token to provision an ephemeral certificate
        # against the sigstore community Fulcio instance.
        run: echo "${TAGS}" | xargs -I {} cosign sign --yes {}@${DIGEST}

      - name: Verify ghcr image signatures
        if: ${{ github.event_name != 'pull_request' }}
        shell: bash
        env:
          COSIGN_EXPERIMENTAL: 1
          TAGS: ${{ steps.meta.outputs.tags }}
          DIGEST: ${{ steps.build-and-push.outputs.digest }}
        run: |
          echo "${TAGS}" | xargs -I {} cosign verify \
          --certificate-identity=https://github.com/${{ github.repository }}/.github/workflows/release-debug.yml@${{ github.ref }} \
          --certificate-oidc-issuer=https://token.actions.githubusercontent.com \
          "{}@${DIGEST}"