ci: build multiplatform Docker images

.github/workflows/docker.yml

@@ -1,22 +1,114 @@
-name: ci
+name: Docker
 
 on:
   push:
-    branches:
-      - 'main'
+    branches: ['main']
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}
+
+permissions:
+  contents: read
+  packages: write
 
 jobs:
-  docker:
+  build:
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        platform:
+          - linux/arm64
+          - linux/amd64
+
     steps:
-      - name: Login to GitHub Container Registry
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+        if: ${{ matrix.platform != 'linux/amd64' }}
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Log in to the Container registry
         uses: docker/login-action@v2
         with:
-          registry: ghcr.io
-          username: ${{ github.repository_owner }}
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
-      - name: Build and push
-        uses: docker/build-push-action@v4
+
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@v4
         with:
-          push: true
-          tags: ghcr.io/prismlauncher/refraction:latest
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          tags: |
+            type=ref,event=branch
+            type=raw,value=latest
+
+      - name: Build and push by digest
+        uses: docker/build-push-action@v4
+        id: build
+        with:
+          context: .
+          provenance: false
+          labels: ${{ steps.meta.outputs.labels }}
+          platforms: ${{ matrix.platform }}
+          outputs: type=image,name=${{ env.REGISTRY }}/${{ env.IMAGE_NAME }},push-by-digest=true,name-canonical=true,push=true
+
+      - name: Export digests
+        run: |
+          mkdir -p /tmp/digests
+          digest="${{ steps.build.outputs.digest }}"
+          touch "/tmp/digests/${digest#sha256:}"
+
+      - name: Upload digests
+        uses: actions/upload-artifact@v3
+        with:
+          name: digests
+          path: /tmp/digests/*
+          if-no-files-found: error
+          retention-days: 1
+
+  push:
+    runs-on: ubuntu-latest
+    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: Log in to the Container registry
+        uses: docker/login-action@v2
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@v4
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          tags: |
+            type=ref,event=branch
+            type=raw,value=latest
+
+      - 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 }}/${{ env.IMAGE_NAME }}@sha256:%s ' *)
+
+      - name: Inspect image
+        run: |
+          docker buildx imagetools inspect ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ steps.meta.outputs.version }}

.github/workflows/lint.yml

@@ -2,7 +2,9 @@ name: Lint
 
 on:
   push:
+    branches: ['main']
   pull_request:
+    branches: ['main']
 
 jobs:
   lint: