ci: build multi-arch images via matrix and digest merge

.github/workflows/cicd.yml

@@ -106,43 +106,124 @@ jobs:
           NODE_ENV: test
 
   build:
-    runs-on: ubuntu-24.04-arm
     permissions:
       contents: read
       packages: write
       id-token: write
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - platform: linux/amd64
+            runner: ubuntu-24.04
+            platform_pair: amd64
+          - platform: linux/arm64
+            runner: ubuntu-24.04-arm
+            platform_pair: arm64
+    runs-on: ${{ matrix.runner }}
 
     steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
+
+      - name: Set lowercase image name
+        id: image
+        run: echo "name=ghcr.io/$(echo '${{ github.repository }}' | tr '[:upper:]' '[:lower:]')" >> "$GITHUB_OUTPUT"
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@e468171a9de216ec08956ac3ada2f0791b6bd435 # v3.11.1
+
+      - name: Login to GHCR
+        if: github.event_name == 'push'
+        uses: docker/login-action@4907a6ddec9925e35a0a9e82d7399ccc52663121 # v4.1.0
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
       - name: Docker meta
         id: meta
         uses: docker/metadata-action@030e881283bb7a6894de51c315a6bfe6a94e05cf # v6.0.0
         with:
-          images: |
-            ghcr.io/${{ github.repository }}
-          tags: |
-            type=raw,value={{sha}}
-            type=raw,value=latest
+          images: ${{ steps.image.outputs.name }}
+
+      - name: Build and push by digest
+        id: build
+        uses: docker/build-push-action@bcafcacb16a39f128d818304e6c9c0c18556b85f # v7.1.0
+        with:
+          context: .
+          platforms: ${{ matrix.platform }}
+          labels: ${{ steps.meta.outputs.labels }}
+          outputs: type=image,name=${{ steps.image.outputs.name }},push-by-digest=true,name-canonical=true,push=${{ github.event_name == 'push' }}
+          cache-from: type=gha,scope=${{ matrix.platform_pair }}
+          cache-to: type=gha,mode=max,scope=${{ matrix.platform_pair }}
+
+      - name: Export digest
+        if: github.event_name == 'push'
+        run: |
+          mkdir -p /tmp/digests
+          digest="${{ steps.build.outputs.digest }}"
+          touch "/tmp/digests/${digest#sha256:}"
+
+      - name: Upload digest
+        if: github.event_name == 'push'
+        uses: actions/upload-artifact@330a01c490aca151604b8cf639adc76d48f6c5d4 # v6.0.1
+        with:
+          name: digest-${{ matrix.platform_pair }}
+          path: /tmp/digests/*
+          if-no-files-found: error
+          retention-days: 1
+
+  build-merge:
+    if: github.event_name == 'push'
+    needs: [build]
+    runs-on: ubuntu-24.04
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Set lowercase image name
+        id: image
+        run: echo "name=ghcr.io/$(echo '${{ github.repository }}' | tr '[:upper:]' '[:lower:]')" >> "$GITHUB_OUTPUT"
+
+      - name: Download digests
+        uses: actions/download-artifact@018cc2cf5baa6db3ef3c5f8a56943fffe632ef53 # v6.0.0
+        with:
+          pattern: digest-*
+          path: /tmp/digests
+          merge-multiple: true
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@e468171a9de216ec08956ac3ada2f0791b6bd435 # v3.11.1
 
       - name: Login to GHCR
-        if: github.ref == 'refs/heads/main'
         uses: docker/login-action@4907a6ddec9925e35a0a9e82d7399ccc52663121 # v4.1.0
         with:
           registry: ghcr.io
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
-      - name: Build and maybe Push Docker image
-        uses: docker/build-push-action@bcafcacb16a39f128d818304e6c9c0c18556b85f # v7.1.0
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@030e881283bb7a6894de51c315a6bfe6a94e05cf # v6.0.0
         with:
-          push: ${{ github.ref == 'refs/heads/main' }}
-          tags: ${{ steps.meta.outputs.tags }}
-          labels: ${{ steps.meta.outputs.labels }}
-          #cache-from: type=gha
-          #cache-to: type=gha,mode=max
+          images: ${{ steps.image.outputs.name }}
+          tags: |
+            type=raw,value={{sha}}
+            type=raw,value=latest,enable=${{ github.ref == 'refs/heads/main' }}
+
+      - name: Create and push manifest
+        working-directory: /tmp/digests
+        run: |
+          docker buildx imagetools create \
+            $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< '${{ steps.meta.outputs.json }}') \
+            $(printf '${{ steps.image.outputs.name }}@sha256:%s ' *)
 
   deploy:
     if: github.ref == 'refs/heads/main'
-    needs: [lint, test, typecheck, build]
+    needs: [lint, test, typecheck, build-merge]
     runs-on: ubuntu-slim
     environment:
       name: prod