CI: use multiple runners ...

... to build the image

.github/workflows/ci.yml

@@ -1,21 +1,35 @@
-name: 'Citra Rooms Docker Image CI'
+name: "Citra Rooms Docker Image CI"
 
 on:
   push:
-    branches: [ "*" ]
-    tags: [ "*" ]
+    branches: ["*"]
+    tags: ["*"]
   pull_request:
-    branches: [ master ]
+    branches: [master]
   workflow_dispatch:
     inputs: {}
   schedule:
-    - cron: '0 7 * * 0'
+    - cron: "0 7 * * 0"
+
+env:
+  REGISTRY_IMAGE: citraemu/citra-multiplayer-dedicated
 
 jobs:
   build:
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        platform:
+          - linux/amd64
+          - linux/arm64
     steps:
       - uses: actions/checkout@v3
+      - name: Create Docker Image Label
+        id: meta
+        uses: docker/metadata-action@v4
+        with:
+          images: ${{ env.REGISTRY_IMAGE }}
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v2
       - name: Set up Docker BuildX
@@ -27,8 +41,52 @@ jobs:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
       - name: Build Image
+        id: build
         uses: docker/build-push-action@v4
         with:
-          platforms: linux/amd64,linux/arm64
+          platforms: ${{ matrix.platform }}
           push: ${{ (github.ref == 'refs/heads/master') && (github.repository == 'citra-emu/citra-multiplayer-dedicated') }}
-          tags: citraemu/citra-multiplayer-dedicated:latest
+          outputs: type=image,name=${{ env.REGISTRY_IMAGE }},push-by-digest=true,name-canonical=true
+      - name: Export digest
+        run: |
+          mkdir -p /tmp/digests
+          digest="${{ steps.build.outputs.digest }}"
+          touch "/tmp/digests/${digest#sha256:}"
+      - name: Upload digest
+        uses: actions/upload-artifact@v3
+        with:
+          name: digests
+          path: /tmp/digests/*
+          if-no-files-found: error
+          retention-days: 1
+  upload:
+    runs-on: ubuntu-latest
+    if: (github.ref == 'refs/heads/master') && (github.repository == 'citra-emu/citra-multiplayer-dedicated')
+    needs:
+      - build
+    steps:
+      - name: Download digests
+        uses: actions/download-artifact@v3
+        with:
+          name: digests
+          path: /tmp/digests
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+      - name: Create Docker Image Label
+        id: meta
+        uses: docker/metadata-action@v4
+        with:
+          images: ${{ env.REGISTRY_IMAGE }}
+      - name: Login to Docker Hub
+        uses: docker/login-action@v2
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+      - name: Create manifest list and push
+        working-directory: /tmp/digests
+        run: |
+          docker buildx imagetools create $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
+            $(printf '${{ env.REGISTRY_IMAGE }}@sha256:%s ' *)
+      - name: Inspect image
+        run: |
+          docker buildx imagetools inspect ${{ env.REGISTRY_IMAGE }}:${{ steps.meta.outputs.version }}