docker.yaml

name: Build and Push Docker Image

on:
  push:
    branches:
      - master
    tags:
      - "v*.*.*"           # v1.2.3
      - "v*.*.*-*"         # v1.2.3-rc1, v1.2.3-alpha.1, v1.2.3-beta
      - "v*.*.*-*.*"       # v1.2.3-alpha.1, v1.2.3-rc.2
  pull_request:
    branches:
      - master
    # Skip PRs that cannot change the image. Later patterns override earlier
    # ones, so edits to this workflow itself still trigger a build.
    paths:
      - "**"
      - "!**/*.md"
      - "!.github/**"
      - ".github/workflows/docker.yaml"
  workflow_dispatch:
    inputs:
      ref:
        description: 'Git ref (branch, tag, or commit SHA) to build'
        required: false
        default: 'master'
        type: string
      push_image:
        description: 'Push image to registry'
        required: false
        default: true
        type: boolean

# A new push to the same PR supersedes the previous build. Other events get a
# unique group so every master commit and tag still builds its own image.
concurrency:
  group: docker-${{ github.event_name == 'pull_request' && github.ref || github.run_id }}
  cancel-in-progress: ${{ github.event_name == 'pull_request' }}

env:
  REGISTRY: ghcr.io
  IMAGE_NAME: ${{ github.repository }}
  PUSH_IMAGE: ${{ github.event_name != 'pull_request' && (github.event_name != 'workflow_dispatch' || github.event.inputs.push_image == 'true') }}

jobs:
  # Each platform builds natively on its own runner (no QEMU) and pushes an
  # untagged image by digest; the merge job then publishes the tagged
  # multi-platform manifest list. PRs only compile-check linux/amd64.
  build:
    runs-on: ${{ matrix.platform == 'linux/arm64' && 'ubuntu-24.04-arm' || 'ubuntu-latest' }}
    strategy:
      fail-fast: false
      matrix:
        platform: ${{ github.event_name == 'pull_request' && fromJSON('["linux/amd64"]') || fromJSON('["linux/amd64","linux/arm64"]') }}
    permissions:
      contents: read
      packages: write
    outputs:
      commit_short: ${{ steps.package_info.outputs.COMMIT_SHORT }}

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

      - name: Checkout repository
        uses: actions/checkout@v7
        with:
          ref: ${{ github.event.inputs.ref || github.ref }}
          fetch-depth: 0

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@f87e5991a6d7451dcb8d9637bfbc97413f497069 # v4.4.1

      - name: Log in to Container Registry
        if: env.PUSH_IMAGE == 'true'
        uses: docker/login-action@dbcb813823bdd20940b903addbd779551569679f # v4.6.0
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Extract metadata
        id: meta
        uses: docker/metadata-action@dc802804100637a589fabce1cb79ff13a1411302 # v6.2.0
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}

      - name: Get package info
        id: package_info
        run: |
          echo "PACKAGE_VERSION=$(git describe --tags --always)" >> $GITHUB_OUTPUT
          echo "PACKAGE_COMMIT_ID=$(git rev-parse HEAD)" >> $GITHUB_OUTPUT
          echo "COMMIT_SHORT=$(git rev-parse --short=7 HEAD)" >> $GITHUB_OUTPUT
          GIT_STATUS=$(git status --porcelain)
          if [ -n "$GIT_STATUS" ]; then
            echo "GIT_STATUS=dirty" >> $GITHUB_OUTPUT
          else
            echo "GIT_STATUS=clean" >> $GITHUB_OUTPUT
          fi

      - name: Build and push by digest
        id: build
        uses: docker/build-push-action@c3c9e263c25d99ce0380d002d59b67737d91b0dc # v7.4.0
        with:
          context: .
          platforms: ${{ matrix.platform }}
          labels: ${{ steps.meta.outputs.labels }}
          outputs: type=image,name=${{ env.REGISTRY }}/${{ env.IMAGE_NAME }},push-by-digest=true,name-canonical=true,push=${{ env.PUSH_IMAGE }}
          build-args: |
            PACKAGE_VERSION=${{ steps.package_info.outputs.PACKAGE_VERSION }}
            PACKAGE_COMMIT_ID=${{ steps.package_info.outputs.PACKAGE_COMMIT_ID }}
            GIT_STATUS=${{ steps.package_info.outputs.GIT_STATUS }}
          cache-from: type=gha,scope=${{ env.PLATFORM_PAIR }}
          cache-to: type=gha,mode=max,scope=${{ env.PLATFORM_PAIR }}

      - name: Export digest
        if: env.PUSH_IMAGE == 'true'
        run: |
          mkdir -p ${{ runner.temp }}/digests
          digest="${{ steps.build.outputs.digest }}"
          touch "${{ runner.temp }}/digests/${digest#sha256:}"

      - name: Upload digest
        if: env.PUSH_IMAGE == 'true'
        uses: actions/upload-artifact@v7
        with:
          name: digests-${{ env.PLATFORM_PAIR }}
          path: ${{ runner.temp }}/digests/*
          if-no-files-found: error
          retention-days: 1

  merge:
    needs: build
    if: github.event_name != 'pull_request' && (github.event_name != 'workflow_dispatch' || github.event.inputs.push_image == 'true')
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write
      id-token: write
      attestations: write

    steps:
      - name: Download digests
        uses: actions/download-artifact@v8
        with:
          path: ${{ runner.temp }}/digests
          pattern: digests-*
          merge-multiple: true

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@f87e5991a6d7451dcb8d9637bfbc97413f497069 # v4.4.1

      - name: Log in to Container Registry
        uses: docker/login-action@dbcb813823bdd20940b903addbd779551569679f # v4.6.0
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Extract metadata
        id: meta
        uses: docker/metadata-action@dc802804100637a589fabce1cb79ff13a1411302 # v6.2.0
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
          # github.ref/github.sha describe the dispatching branch, not inputs.ref,
          # so ref-derived tags are only set for push events. A manual dispatch
          # is tagged with the commit that was actually built and never moves
          # latest, a branch tag, or a version tag.
          tags: |
            # set latest tag for master branch pushes
            type=raw,value=latest,enable=${{ github.event_name == 'push' && github.ref == format('refs/heads/{0}', github.event.repository.default_branch) }}
            # set version tag for tags
            type=ref,event=tag,enable=${{ github.event_name == 'push' }}
            # set branch name for branch pushes
            type=ref,event=branch,enable=${{ github.event_name == 'push' }}
            # set sha-<short_sha> for any push
            type=sha,prefix=sha-,enable=${{ github.event_name == 'push' }}
            # set manual-<short_sha> of the built commit for manual workflow dispatch
            type=raw,value=manual-${{ needs.build.outputs.commit_short }},enable=${{ github.event_name == 'workflow_dispatch' }}

      - name: Create manifest list and push
        id: manifest
        working-directory: ${{ runner.temp }}/digests
        run: |
          docker buildx imagetools create \
            $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
            $(printf '${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}@sha256:%s ' *)
          ref=$(jq -r '.tags[0]' <<< "$DOCKER_METADATA_OUTPUT_JSON")
          docker buildx imagetools inspect "$ref"
          digest=$(docker buildx imagetools inspect "$ref" --format '{{json .Manifest}}' | jq -r .digest)
          echo "digest=$digest" >> $GITHUB_OUTPUT

      - name: Generate artifact attestation
        uses: actions/attest-build-provenance@v4
        with:
          subject-name: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME}}
          subject-digest: ${{ steps.manifest.outputs.digest }}
          push-to-registry: true