main.yml

name: Publish Docker image

on:
  workflow_dispatch:
  release:
    types: [published]

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

jobs:
  build:
    name: Build Docker images
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
        platform:
          - linux/amd64
          - linux/arm64
    steps:
      -
        name: Prepare
        run: |
          platform=${{ matrix.platform }}
          echo "PLATFORM_PAIR=${platform//\//-}" >> $GITHUB_ENV 
      -
        name: Checkout
        uses: actions/checkout@v4
      - 
        name: Extract metadata
        id: meta
        uses: docker/metadata-action@v5
        with:
          context: git
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
          # "Push by digest" needs an untagged ref
          tags: |
            type=raw,value=
      -
        name: Set up QEMU
        uses: docker/setup-qemu-action@v3
      -
        name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3
        with:
          version: v0.12.0
        env:
          BUILDX_NO_DEFAULT_ATTESTATIONS: 1
      -
        name: Login to GitHub Container Registry (${{ env.REGISTRY }})
        uses: docker/login-action@v3
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}
      -
        name: Build and Push by digest
        id: build
        uses: docker/build-push-action@v5
        with:
          context: .
          file: docker/Dockerfile
          platforms: ${{ matrix.platform }}
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          annotations: ${{ steps.meta.outputs.annotations }}
          outputs: type=image,name=${{ env.REGISTRY }}/${{ env.IMAGE_NAME }},push-by-digest=true,name-canonical=true,push=true
      -
        name: Export digest
        run: |
          mkdir -p /tmp/digests
          digest="${{ steps.build.outputs.digest }}"
          touch "/tmp/digests/${digest#sha256:}"          
      -
        name: Upload digest
        uses: actions/upload-artifact@v4
        with:
          name: digests-${{ env.PLATFORM_PAIR }}
          path: /tmp/digests/*
          if-no-files-found: error
          retention-days: 1

  merge:
    name: Create merged manifest and push to Github Packages
    runs-on: ubuntu-latest
    needs:
      - build
    steps:
      -
        # Needed to get the git information for the meta step
        name: Checkout
        uses: actions/checkout@v4
      -
        name: Download digests
        uses: actions/download-artifact@v4
        with:
          path: /tmp/digests
          pattern: digests-*
          merge-multiple: true
      -
        name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3
        with:
          version: v0.12.0
        env:
          BUILDX_NO_DEFAULT_ATTESTATIONS: 1
      -
        # Extract metadata to easily get the version and annotations to put in the manifest
        name: Docker meta
        id: meta
        uses: docker/metadata-action@v5
        with:
          context: git
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
          tags: |
            type=semver,pattern={{version}}
            type=edge,branch=${{ github.ref_name }}
      -
        name: Login to Docker Hub
        uses: docker/login-action@v3
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}
      -
        name: Create manifest list and push
        working-directory: /tmp/digests
        run: |
          docker buildx imagetools create \
            $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
            --annotation index:org.opencontainers.image.created="${{ fromJSON(steps.meta.outputs.json).labels['org.opencontainers.image.created'] }}" \
            --annotation index:org.opencontainers.image.description="${{ fromJSON(steps.meta.outputs.json).labels['org.opencontainers.image.description'] }}" \
            --annotation index:org.opencontainers.image.version="${{ fromJSON(steps.meta.outputs.json).labels['org.opencontainers.image.version'] }}" \
            --annotation index:org.opencontainers.image.licenses="${{ fromJSON(steps.meta.outputs.json).labels['org.opencontainers.image.licenses'] }}" \
            --annotation index:org.opencontainers.image.title="${{ fromJSON(steps.meta.outputs.json).labels['org.opencontainers.image.title'] }}" \
            --annotation index:org.opencontainers.image.source="${{ fromJSON(steps.meta.outputs.json).labels['org.opencontainers.image.source'] }}" \
            --annotation index:org.opencontainers.image.url="${{ fromJSON(steps.meta.outputs.json).labels['org.opencontainers.image.url'] }}" \
            --annotation index:org.opencontainers.image.revision="${{ fromJSON(steps.meta.outputs.json).labels['org.opencontainers.image.revision'] }}" \
            $(printf '${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}@sha256:%s ' *)          
      -
        name: Inspect image
        run: |
          docker buildx imagetools inspect ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ steps.meta.outputs.version }}