name: Create and publish a Docker image

on:
  push:
    branches: ['main']

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

jobs:
  build:
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
        platform:
          - linux/amd64
          - linux/arm/v7
          - linux/arm64
    steps:
      -
        name: Checkout
        uses: actions/checkout@v3
      -
        name: Docker meta
        id: meta
        uses: docker/metadata-action@v4
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}

      -
        name: Set up QEMU
        uses: docker/setup-qemu-action@v2
      -
        name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v2
      -
        name: Login to Docker Hub
        uses: docker/login-action@v2
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}
      -
        name: Cache Docker layers
        uses: actions/cache@v3
        with:
          path: /tmp/.buildx-cache
          key: ${{ runner.os }}-multi-${{ matrix.platform }}-buildx-${{ github.sha }}
          restore-keys: |
            ${{ runner.os }}-multi-${{ matrix.platform }}-buildx
      -
        name: Build and push by digest
        id: build
        uses: docker/build-push-action@v4
        with:
          context: .
          platforms: ${{ matrix.platform }}
            #tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          outputs: type=image,name=${{ env.REGISTRY }}/${{ env.IMAGE_NAME }},push-by-digest=true,name-canonical=true,push=true
          cache-from: type=local,src=/tmp/.buildx-cache
          # Note the mode=max here
          # More: https://github.com/moby/buildkit#--export-cache-options
          # And: https://github.com/docker/buildx#--cache-tonametypetypekeyvalue
          cache-to: type=local,mode=max,dest=/tmp/.buildx-cache-new
      -
        name: Export digest
        run: |
          mkdir -p /tmp/digests
          digest="${{ steps.build.outputs.digest }}"
          touch "/tmp/digests/${digest#sha256:}"
      -
        name: Upload digest
        uses: actions/upload-artifact@v3
        with:
          name: digests
          path: /tmp/digests/*
          if-no-files-found: error
          retention-days: 1
      - name: Move cache
        run: |
          rm -rf /tmp/.buildx-cache
          mv /tmp/.buildx-cache-new /tmp/.buildx-cache
  merge:
    runs-on: ubuntu-latest
    needs:
      - build
    steps:
      -
        name: Download digests
        uses: actions/download-artifact@v3
        with:
          name: digests
          path: /tmp/digests
      -
        name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v2
      -
        name: Docker meta
        id: meta
        uses: docker/metadata-action@v4
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
      -
        name: Login to Docker Hub
        uses: docker/login-action@v2
        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") \
            $(printf '${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}@sha256:%s ' *)
      -
        name: Inspect image
        run: |
          docker buildx imagetools inspect ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ steps.meta.outputs.version }}