docker-publish.yml

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:
    strategy:
      fail-fast: false
      matrix:
        platform:
          - docker: linux/amd64
            go: amd64
          - docker: linux/arm/v6
            go: arm
            qemu: arm
            dockerfile: alpine.Dockerfile
          - docker: linux/arm/v7
            go: arm
            qemu: arm
          - docker: linux/arm64
            go: arm64
            qemu: arm64
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write

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

      - name: Set up QEMU
        uses: docker/setup-qemu-action@v3.0.0
        if: matrix.platform.qemu
        with:
          platforms: ${{ matrix.platform.qemu }}

      # Set up BuildKit Docker container builder to be able to build
      # multi-platform images and export cache
      # https://github.com/docker/setup-buildx-action
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3
        with:
          version: v0.16.2

      - name: Go package cache
        uses: actions/cache@v4
        with:
          path: go-package-cache
          key: ${{ matrix.platform.go }}-docker-go-package-${{ hashFiles('go.sum') }}
          restore-keys: |
            ${{ matrix.platform.go }}-docker-go-package-

      - name: Go build cache
        uses: actions/cache@v4
        with:
          path: go-build-cache
          key: ${{ matrix.platform.go }}-docker-go-build-${{ hashFiles('go.sum') }}
          restore-keys: |
            ${{ matrix.platform.go }}-docker-go-build-

      - name: Inject go package cache into docker
        uses: reproducible-containers/buildkit-cache-dance@v3
        with:
          cache-map: |
            {
              "go-package-cache": "/root/go/pkg/mod",
              "go-build-cache": "/root/.cache/go-build"
            }

      # 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 }}

      # 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 in PR
        id: build-and-push-pr
        uses: docker/build-push-action@v6
        if: github.event_name == 'pull_request'
        with:
          context: .
          file: ${{ matrix.platform.dockerfile && matrix.platform.dockerfile || 'Dockerfile' }}
          build-args: GOARCH=${{ matrix.platform.go }}
          platforms: ${{ matrix.platform.docker }}
          push: false
          labels: ${{ steps.meta.outputs.labels }}
          annotations: ${{ steps.meta.outputs.labels }}
          cache-from: type=gha
          cache-to: type=gha,mode=max

      # Build and push Docker image with Buildx (push if not on PR)
      # https://github.com/docker/build-push-action
      - name: Build and push Docker image outside Branch
        id: build-and-push
        uses: docker/build-push-action@v6
        if: github.event_name != 'pull_request'
        with:
          context: .
          file: ${{ matrix.platform.dockerfile && matrix.platform.dockerfile || 'Dockerfile' }}
          build-args: GOARCH=${{ matrix.platform.go }}
          platforms: ${{ matrix.platform.docker }}
          push: true
          labels: ${{ steps.meta.outputs.labels }}
          annotations: ${{ steps.meta.outputs.labels }}
          cache-from: type=gha
          cache-to: type=gha,mode=max
          outputs: type=registry,name=${{ env.REGISTRY }}/${{ env.IMAGE_NAME }},push-by-digest=true,name-canonical=true

      - name: Export digest
        if: github.event_name != 'pull_request'
        run: |
          mkdir -p /tmp/digests
          digest="${{ steps.build-and-push.outputs.digest }}"
          touch "/tmp/digests/${digest#sha256:}"

      - name: Upload digest
        if: github.event_name != 'pull_request'
        uses: actions/upload-artifact@v4
        with:
          name: digests-${{ strategy.job-index }}
          path: /tmp/digests/*
          if-no-files-found: error
          retention-days: 1
  create-manifests:
    runs-on: ubuntu-latest
    needs: [ build ]
    if: github.event_name != 'pull_request'
    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: Download digests
        uses: actions/download-artifact@v4
        with:
          pattern: digests-*
          merge-multiple: true
          path: /tmp/digests

      # Set up BuildKit Docker container builder to be able to build
      # multi-platform images and export cache
      # https://github.com/docker/setup-buildx-action
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3
        with:
          version: v0.16.2

      # Login against a Docker registry except on PR
      # https://github.com/docker/login-action
      - name: Log into registry ${{ env.REGISTRY }}
        uses: docker/login-action@v3
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      # Install the cosign tool except on PR
      # https://github.com/sigstore/cosign-installer
      - name: Install cosign
        uses: sigstore/cosign-installer@v3
        with:
          cosign-release: 'v2.3.0'


      # 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=edge,branch=main
            type=ref,event=branch
            type=ref,event=pr
            type=semver,pattern={{version}}
            type=semver,pattern={{major}}.{{minor}}
            type=semver,pattern={{major}}
            type=sha,enable=false

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

      # 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
        working-directory: /tmp/digests
        # This step uses the identity token to provision an ephemeral certificate
        # against the sigstore community Fulcio instance.
        run: |
          RAW_TAGS="$(jq -crj '.tags | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON")"
          TAGS=""
          for RAW_TAG in ${RAW_TAGS}; do
            TAGS="${TAGS}$(printf "${RAW_TAG}@sha256:%s " *)"
          done
          for TAG in ${TAGS}; do
            echo "Signing ${TAG}"
            cosign sign --yes "${TAG}"
          done

      - name: Inspect image
        run: |
          RAW_TAGS="$(jq -crj '.tags | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON")"
          for RAW_TAG in ${RAW_TAGS}; do
            echo "Inspecting ${RAW_TAG}"
            docker buildx imagetools inspect "${RAW_TAG}"
          done