docker.yml

name: Create and publish a Docker image

on:
  push:
    branches: ['main', 'travis/qemu-speedup']
  release:
    types: ['published']

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

concurrency:
  cancel-in-progress: true
  group: ${{ github.workflow }}-${{ github.ref }}

jobs:
  build:
    runs-on: ${{ matrix.os }}
    permissions:
      contents: read
      packages: write
    strategy:
      fail-fast: false
      matrix:
        os: [ubuntu-latest, macos-latest-xlarge]
        platform:
          - linux/amd64
          - linux/arm/v6
          - linux/arm/v7
          - linux/arm64
        exclude:
          - os: ubuntu-latest
            platform: linux/arm/v6
          - os: ubuntu-latest
            platform: linux/arm/v7
          - os: ubuntu-latest
            platform: linux/arm64
          - os: macos-latest-xlarge
            platform: linux/amd64

    steps:
      - name: Prepare
        run: |
          platform=${{ matrix.platform }}
          echo "PLATFORM_PAIR=${platform//\//-}" >> $GITHUB_ENV

      - name: Setup docker (missing on MacOS)
        if: runner.os == 'macos'
        run: |
          brew install docker

      - name: Checkout
        uses: actions/checkout@v4

      - name: Docker meta
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}

      - name: Set up QEMU
        uses: docker/setup-qemu-action@v3

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      - name: Login
        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: .
          platforms: ${{ matrix.platform }}
          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-${{ env.PLATFORM_PAIR }}
          path: /tmp/digests/*
          if-no-files-found: error
          retention-days: 1

  merge:
    runs-on: ubuntu-latest
    needs: [build]
    steps:
      - 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

      - name: Docker meta
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.REGISTRY  }}/${{ env.IMAGE_NAME }}

      - name: Login
        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") \
          $(printf '${{ env.REGISTRY  }}/${{ env.IMAGE_NAME }}@sha256:%s ' *)

      - name: Inspect image
        run: |
          docker buildx imagetools inspect ${{ env.REGISTRY  }}/${{ env.IMAGE_NAME }}:${{ steps.meta.outputs.version }}