docker-image.yml

name: Create and publish a Docker image

# Configures this workflow to run every time a change is pushed to the branch called `main` or a tag named 'v*' is pushed.

on:
  workflow_dispatch:
  push:
    branches: ['main']
    tags:
      - 'v*'

# Defines two custom environment variables for the workflow. These are used for the Container registry domain, and a name for the Docker image that this workflow builds.
env:
  REGISTRY: ghcr.io
  IMAGE_NAME: ${{ github.repository }}

# There is a single job in this workflow. It's configured to run on the latest available version of Ubuntu.
jobs:
  build-image:
    strategy:
      fail-fast: false
      matrix:
        base-image: [debian, alpine]
        platform: [linux/amd64, linux/arm64]

    runs-on: ${{ matrix.platform == 'linux/arm64' && 'linux-arm64' || 'ubuntu-latest'  }}

    # Sets the permissions granted to the `GITHUB_TOKEN` for the actions in this job.
    permissions:
      contents: read
      packages: write

    steps:
      - name: Prepare
        run: |
          if [ "${{ matrix.base-image }}" = "debian" ]; then
            echo "DOCKERFILE=openwec.Dockerfile" >> $GITHUB_ENV
            echo "FLAVOR_OPTS=" >> $GITHUB_ENV
          elif [ "${{ matrix.base-image }}" = "alpine" ]; then
            echo "DOCKERFILE=openwec-alpine.Dockerfile" >> $GITHUB_ENV
            echo "FLAVOR_OPTS=suffix=-alpine,onlatest=true" >> $GITHUB_ENV
          fi

          platform=${{ matrix.platform }}
          echo "PLATFORM_PAIR=${platform//\//-}" >> $GITHUB_ENV

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

      - name: Prepare Docker image build
        uses: ./.github/workflows/_prepare-image-build.yml
        with:
          registry: ${{ env.REGISTRY }}

      # This step uses [docker/metadata-action](https://github.com/docker/metadata-action#about) to extract tags and labels that will be applied to the specified image. The `id` "meta" allows the output of this step to be referenced in a subsequent step. The `images` value provides the base name for the tags and labels.
      - name: Extract metadata (tags, labels) for Docker
        id: meta
        uses: docker/metadata-action@8e5442c4ef9f78752691e2d8f8d19755c6f78e81
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}

      # This step uses the `docker/build-push-action` action to build the image, based on your repository's `Dockerfile`. If the build succeeds, it pushes the image to GitHub Packages.
      # It uses the `context` parameter to define the build's context as the set of files located in the specified path. For more information, see "[Usage](https://github.com/docker/build-push-action#usage)" in the README of the `docker/build-push-action` repository.
      # It uses the `tags` and `labels` parameters to tag and label the image with the output from the "meta" step.
      - name: Build and push Docker image
        id: build
        uses: docker/build-push-action@f2a1d5e99d037542a71f64918e516c093c6f3fc4
        with:
          platforms: ${{ matrix.platform }}
          context: .
          file: docker/${{ env.DOCKERFILE }}
          labels: ${{ steps.meta.outputs.labels }}
          outputs: type=image,name=${{ 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-${{ matrix.base-image }}-${{ env.PLATFORM_PAIR }}
          path: /tmp/digests/*
          if-no-files-found: error
          retention-days: 1

  create-multi-arch-manifest:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write

    strategy:
      fail-fast: false
      matrix:
        base-image: [debian, alpine]

    needs:
      - build-image
    steps:
      - name: Download digests
        uses: actions/download-artifact@v4
        with:
          path: /tmp/digests
          pattern: digests-${{ matrix.base-image }}-*
          merge-multiple: true

      - name: Prepare Docker image build
        uses: ./.github/workflows/_prepare-image-build.yml
        with:
          registry: ${{ env.REGISTRY }}

      - name: Extract metadata (tags, labels) for Docker
        id: meta
        uses: docker/metadata-action@9ec57ed1fcdbf14dcef7dfbe97b2010124a938b7
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
          tags: |
            type=ref,event=branch
            type=semver,pattern={{version}}
          flavor: |
            ${{ env.FLAVOR_OPTS }}

      - name: Create multi-arch manifest list and push
        working-directory: /tmp/digests
        run: |
          docker buildx imagetools create $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
            $(printf '${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}@sha256:%s ' *)