ci: Fixed multi-platform images push overrides by merging the results (based on docker/docs#21854)

Author: frol

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

@@ -8,6 +8,9 @@ on:
     # Daily
     - cron: '0 0 * * *'
 
+env:
+  DOCKERHUB_REPO: frolvlad/alpine-glibc
+
 jobs:
   build:
     strategy:
@@ -20,6 +23,18 @@ jobs:
           os: ubuntu-24.04-arm
     runs-on: ${{ matrix.os }}
     steps:
+      - name: Prepare
+        run: |
+          platform=${{ matrix.platform }}
+          echo "PLATFORM_PAIR=${platform//\//-}" >> $GITHUB_ENV
+
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: |
+            ${{ env.DOCKERHUB_REPO }}
+
       - name: Login to Docker Hub
         uses: docker/login-action@v3
         with:
@@ -34,8 +49,62 @@ jobs:
         uses: docker/build-push-action@v6
         with:
           platforms: ${{ matrix.platform }}
-          pull: true
-          push: true
-          tags: frolvlad/alpine-glibc:latest,frolvlad/alpine-glibc:alpine-3.21_glibc-2.41,frolvlad/alpine-glibc:alpine-3_glibc-2.41,frolvlad/alpine-glibc:alpine-3.21,frolvlad/alpine-glibc:alpine-3,frolvlad/alpine-glibc:glibc-2.41
-          cache-from: type=registry,ref=frolvlad/alpine-glibc:latest
-          cache-to: type=inline
+          labels: ${{ steps.meta.outputs.labels }}
+          outputs: type=image,"name=${{ env.DOCKERHUB_REPO }}",push-by-digest=true,name-canonical=true,push=true
+
+      - 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: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: |
+            ${{ env.DOCKERHUB_REPO }}
+          tags: |
+            type=ref,event=branch
+            type=ref,event=pr
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+
+      - name: Create manifest list and push
+        working-directory: ${{ runner.temp }}/digests
+        run: |
+          docker buildx imagetools create $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
+            $(printf '${{ env.DOCKERHUB_REPO }}@sha256:%s ' *)
+
+      - name: Inspect image
+        run: |
+          docker buildx imagetools inspect ${{ env.DOCKERHUB_REPO }}:${{ steps.meta.outputs.version }}