ci: Automate building ARM64 images in addition to AMD64

Author: frol

.github/workflows/build-and-push.yaml

@@ -6,30 +6,100 @@ on:
       - 'master'
   schedule:
     # Daily
-    - cron: '0 0 * * *'
+    - cron: '0 4 * * *'
+  workflow_dispatch:
+
+env:
+  DOCKERHUB_REPO: frolvlad/alpine-openjdk
 
 jobs:
-  docker:
-    runs-on: ubuntu-latest
+  build:
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+        - platform: linux/amd64
+          os: ubuntu-24.04
+        - platform: linux/arm64
+          os: ubuntu-24.04-arm
+    runs-on: ${{ matrix.os }}
     steps:
-      -
-        name: Set up QEMU
-        uses: docker/setup-qemu-action@v2
-      -
-        name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v2
-      -
-        name: Login to Docker Hub
-        uses: docker/login-action@v2
+      - name: Prepare
+        run: |
+          platform=${{ matrix.platform }}
+          echo "PLATFORM_PAIR=${platform//\//-}" >> $GITHUB_ENV
+
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: |
+            ${{ env.DOCKERHUB_REPO }}
+          labels: |
+            org.opencontainers.image.created={{commit_date 'YYYY-MM-DDTHH:mm:ss.SSS[Z]'}}
+
+      - name: Login to Docker Hub
+        uses: docker/login-action@v3
         with:
-          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          username: ${{ vars.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
-      -
-        name: Build and push
-        uses: docker/build-push-action@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Build and push by digest
+        id: build
+        uses: docker/build-push-action@v6
         with:
-          pull: true
+          platforms: ${{ matrix.platform }}
+          labels: ${{ steps.meta.outputs.labels }}
+          outputs: type=image,"name=${{ env.DOCKERHUB_REPO }}",push-by-digest=true,name-canonical=true,push=true
           push: true
-          tags: frolvlad/alpine-openjdk:latest
-          cache-from: type=registry,ref=frolvlad/alpine-openjdk:latest
-          cache-to: type=inline
+          cache-from: type=registry,ref=${{ env.DOCKERHUB_REPO }}:buildcache-${{ env.PLATFORM_PAIR }}
+          cache-to: type=registry,ref=${{ env.DOCKERHUB_REPO }}:buildcache-${{ env.PLATFORM_PAIR }},mode=max
+
+      - name: Export digest
+        run: |
+          mkdir -p ${{ runner.temp }}/digests
+          digest="${{ steps.build.outputs.digest }}"
+          touch "${{ runner.temp }}/digests/${digest#sha256:}"
+
+      - name: Upload digest
+        uses: actions/upload-artifact@v4
+        with:
+          name: digests-${{ env.PLATFORM_PAIR }}
+          path: ${{ runner.temp }}/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: ${{ runner.temp }}/digests
+          pattern: digests-*
+          merge-multiple: true
+
+      - name: Login to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ vars.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Create manifest list and push
+        working-directory: ${{ runner.temp }}/digests
+        run: |
+          docker buildx imagetools create \
+            -t ${{ env.DOCKERHUB_REPO }}:latest \
+            $(printf '${{ env.DOCKERHUB_REPO }}@sha256:%s ' *)
+
+      - name: Inspect image
+        run: |
+          docker buildx imagetools inspect ${{ env.DOCKERHUB_REPO }}:latest