name: Docker

# 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" ]
    # Publish semver tags as releases.
    tags: [ 'v*.*.*' ]
  pull_request:
    branches: [ "main" ]

env:
  # Use docker.io for Docker Hub if empty
  REGISTRY: ghcr.io
  # github.repository as <account>/<repo>
  IMAGE_NAME: ${{ github.repository }}


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@v4

      # Workaround: https://github.com/docker/build-push-action/issues/461
      - name: Setup 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@v3
        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@v5
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
          tags: |
            type=ref,event=branch
            type=ref,event=branch,prefix=,suffix=-{{sha}}-{{date 'x'}}
            type=ref,event=pr
            type=semver,pattern={{version}}
            type=semver,pattern={{major}}.{{minor}},enable=${{ !startsWith(github.ref, 'refs/tags/v0.0.') && !contains(github.ref, '-') }}
            type=semver,pattern={{major}},enable=${{ !startsWith(github.ref, 'refs/tags/v0.') && !contains(github.ref, '-') }}
          flavor: |
            latest=${{ startsWith(github.ref, 'refs/tags/v') && !contains(github.ref, '-') }}

      # Cache dependencies
      # https://github.com/actions/cache
      - name: Cache Docker layers
        uses: actions/cache@v4
        with:
          path: /tmp/.buildx-cache
          key: ${{ runner.os }}-multi-buildx-${{ github.sha }}
          restore-keys: |
            ${{ runner.os }}-multi-buildx

      # 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@v6
        with:
          context: .
          push: ${{ github.event_name != 'pull_request' }}
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          cache-from: type=local,src=/tmp/.buildx-cache
          # Note the mode=max here
          # More: https://github.com/moby/buildkit#--export-cache-options
          # And: https://github.com/docker/buildx#--cache-tonametypetypekeyvalue
          cache-to: type=local,mode=max,dest=/tmp/.buildx-cache-new

      # Temp fix / Disabled on self-hosted runner
      # https://github.com/docker/build-push-action/issues/252
      # https://github.com/moby/buildkit/issues/1896
      - name: Move cache
        run: |
          rm -rf /tmp/.buildx-cache
          mv /tmp/.buildx-cache-new /tmp/.buildx-cache


      # 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@v3
        # with:
        #   cosign-release: 'v2.2.2'

      # 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: ${{ github.event_name != 'pull_request' }}
        env:
          COSIGN_EXPERIMENTAL: "true"
        # This step uses the identity token to provision an ephemeral certificate
        # against the sigstore community Fulcio instance.
        run: echo "${{ steps.meta.outputs.tags }}" | grep -E '^(.+):(.+)-(.+)-(.+)$|^(.+):([0-9]+).([0-9]+).([0-9]+)(.+)$' | xargs -I {} cosign sign --yes {}@${{ steps.build-and-push.outputs.digest }}