ci: refactor docker workflow for parallel platform builds

.github/workflows/docker-publish.yml

@@ -18,31 +18,28 @@ env:
   BUILDX_VERSION: v0.20.1
 
 jobs:
-  docker-publish:
+  env:
     # release-please によるコミットの時は workflow_call でのみ実行する
     if: ${{ !( github.workflow == 'docker publish' && startsWith(github.event.head_commit.message, 'release:') && github.event.head_commit.author.name == 'github-actions[bot]' ) }}
     runs-on: ubuntu-latest
     outputs:
-      image_tags: ${{ steps.metadata.outputs.tags }}
-    permissions:
-      packages: write
-
+      REGISTRY_IMAGE: ${{ steps.lowercase.outputs.REGISTRY_IMAGE }}
+      PUSH: ${{ github.event_name != 'pull_request' && github.ref_name == github.event.repository.default_branch }}
     steps:
-      - name: Checkout repository
-        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-
-      - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@6524bf65af31da8d45b59e8c27de4bd072b392f5 # v3.8.0
-        with:
-          version: ${{ env.BUILDX_VERSION }}
-
-      - name: Log in to the Container registry
-        uses: docker/login-action@9780b0c442fbb1117ed29e0efdff1e18412f7567 # v3.3.0
-        with:
-          registry: ghcr.io
-          username: ${{ github.actor }}
-          password: ${{ secrets.GITHUB_TOKEN }}
+      - id: lowercase
+        run: |
+          registory_image='ghcr.io/${{ env.IMAGE_NAME }}'
+          echo "REGISTRY_IMAGE=${registory_image@L}" >> $GITHUB_OUTPUT
 
+  meta:
+    needs: [env]
+    runs-on: ubuntu-latest
+    outputs:
+      version: ${{ steps.metadata.outputs.version}}
+      tags: ${{ steps.metadata.outputs.tags }}
+      labels: ${{ steps.labels.outputs.labels }}
+      json: ${{ steps.metadata.outputs.json }}
+    steps:
       - name: Docker Metadata
         uses: docker/metadata-action@369eb591f429131d6889c46b94e711f089e6ca96 # v5.6.1
         id: metadata
@@ -63,17 +60,52 @@ jobs:
           EOF
           EOS
 
+  docker-publish:
+    permissions:
+      packages: write
+    needs: [env, meta]
+    outputs:
+      digest: ${{ steps.build-push.outputs.digest }}
+
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - platform: linux/amd64
+            on: ubuntu-24.04
+          - platform: linux/arm64
+            on: ubuntu-24.04-arm
+
+    runs-on: ${{ matrix.on }}
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@6524bf65af31da8d45b59e8c27de4bd072b392f5 # v3.8.0
+        with:
+          version: ${{ env.BUILDX_VERSION }}
+
+      - name: Log in to the Container registry
+        uses: docker/login-action@9780b0c442fbb1117ed29e0efdff1e18412f7567 # v3.3.0
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
       - id: build-push
-        name: Build and push Docker image
+        name: Build and push by digest
         uses: docker/build-push-action@ca877d9245402d1537745e0e356eab47c3520991 # v6.13.0
         with:
           context: .
           push: ${{ github.event_name != 'pull_request' }}
-          platforms: linux/amd64,linux/arm64
-          tags: ${{ steps.metadata.outputs.tags }}
-          labels: ${{ steps.labels.outputs.labels }}
-          cache-from: type=gha
-          cache-to: type=gha,mode=max
+          platforms: ${{ matrix.platform }}
+          tags: ${{ needs.meta.outputs.tags }}
+          labels: ${{ needs.meta.outputs.labels }}
+          outputs: type=image,name=${{ needs.env.outputs.REGISTRY_IMAGE }},push-by-digest=true,name-canonical=true,push=${{ fromJson(needs.env.outputs.PUSH) }}
+          cache-from: type=gha,scope=buildkit-${{ matrix.platform }}
+          cache-to: type=gha,scope=buildkit-${{ matrix.platform }},mode=max
 
       - if: ${{ github.event_name != 'pull_request' }}
         name: Display image digest
@@ -86,3 +118,60 @@ jobs:
           echo '```' >> $GITHUB_STEP_SUMMARY
           echo "$name@$DIGEST" >> $GITHUB_STEP_SUMMARY
           echo '```' >> $GITHUB_STEP_SUMMARY
+
+      - id: export-digest
+        if: ${{ fromJson(needs.env.outputs.PUSH) }}
+        name: Export digest
+        run: |
+          mkdir -p /tmp/digests
+          digest="${{ steps.build-push.outputs.digest }}"
+          touch "/tmp/digests/${digest#sha256:}"
+      - id: prepare
+        if: ${{ steps.export-digest.conclusion == 'success' }}
+        name: Prepare
+        run: |
+          platform=${{ matrix.platform }}
+          echo "PLATFORM_PAIR=${platform//\//-}" >> $GITHUB_OUTPUT
+      - if: ${{ steps.export-digest.conclusion == 'success' }}
+        name: Upload digest
+        uses: actions/upload-artifact@65c4c4a1ddee5b72f698fdd19549f0f0fb45cf08 # v4.6.0
+        with:
+          name: digests-${{ steps.prepare.outputs.PLATFORM_PAIR }}
+          path: /tmp/digests/*
+          if-no-files-found: error
+          retention-days: 1
+
+
+  merge:
+    permissions:
+      packages: write
+    needs: [env, meta, docker-publish]
+    if: ${{ fromJson(needs.env.outputs.PUSH) }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Download digests
+        uses: actions/download-artifact@fa0a91b85d4f404e444e00e005971372dc801d16 # v4.1.8
+        with:
+          path: /tmp/digests
+          pattern: digests-*
+          merge-multiple: true
+
+      - name: Log in to the Container registry
+        uses: docker/login-action@9780b0c442fbb1117ed29e0efdff1e18412f7567 # v3.3.0
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Create manifest list and push
+        working-directory: /tmp/digests
+        shell: bash -xe {0}
+        env:
+          DOCKER_METADATA_OUTPUT_JSON: ${{ needs.meta.outputs.json }}
+        run: |
+          docker buildx imagetools create $(jq -cr '.tags | map("--tag=" + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
+          $(printf '${{ needs.env.outputs.REGISTRY_IMAGE }}@sha256:%s ' *)
+
+      - name: Inspect image
+        run: |
+          docker buildx imagetools inspect ${{ needs.env.outputs.REGISTRY_IMAGE }}:${{ needs.meta.outputs.version }}