Build & push demo binaries on main

Also attempts building on PRs for testing.

.github/workflows/docker.yaml

@@ -0,0 +1,62 @@
+name: docker
+on:
+  push:
+    - main
+  pull_request:
+permissions:
+  contents: read
+env:
+  REGISTRY_HOST: ${{ secrets.RELEASE_REGISTRY_HOST }}
+  REGISTRY_URL: ${{ secrets.RELEASE_REGISTRY_URL }}
+concurrency:
+  group: docker-${{ github.ref }}
+  cancel-in-progress: false
+jobs:
+  docker-build-push:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      # Needed for Github GCP WIF
+      id-token: write
+    strategy:
+      matrix:
+        dockerfile:
+          - Dockerfile.produce
+          - Dockerfile.consume
+    steps:
+      - name: Checkout Code
+        uses: actions/checkout@v4
+      - id: ar-auth
+        name: Authenticate to GCP Release Artifact Registry through WIF
+        uses: google-github-actions/auth@v2
+        with:
+          token_format: 'access_token'
+          workload_identity_provider: ${{ secrets.RELEASE_REGISTRY_WIF_PROVIDER }}
+          service_account: ${{ secrets.RELEASE_REGISTRY_SERVICE_ACCOUNT }}
+          export_environment_variables: false
+          create_credentials_file: false
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+        with:
+          driver-opts: |
+            network=host
+      - name: login-ar
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY_HOST }}
+          username: oauth2accesstoken
+          password: ${{ steps.ar-auth.outputs.access_token }}
+      - name: Build and push docker image
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          file: ${{ matrix.dockerfile }}
+          platforms: linux/amd64,linux/arm64
+          # Don't publish images on PR runs
+          push: ${{ github.event_name != 'pull_request' }}
+          tags: |
+            ${{ env.REGISTRY_URL }}/bufstream-demo:git.${{ github.sha }}
+            ${{ env.REGISTRY_URL }}/bufstream-demo:latest
+          # With provenance: true, docker ends up pushing the image separately into
+          # multiple files and manifests, which not all clients can read.
+          provenance: false

Makefile

@@ -14,14 +14,20 @@ docker-bufstream-run: # Run Bufstream within Docker.
 		"us-docker.pkg.dev/buf-images-1/bufstream-public/images/bufstream:$(BUFSTREAM_VERSION)" \
 			--config /bufstream.yaml
 
-.PHONY: docker-produce-run
-docker-produce-run: # Run the demo producer within Docker. If you have Go installed, you can call produce-run.
+.PHONY: docker-produce-build
+docker-produce-build:
 	docker build -t bufstream/demo-produce -f Dockerfile.produce .
+
+.PHONY: docker-consume-build
+docker-consume-build:
+	docker build -t bufstream/demo-consume -f Dockerfile.consume .
+
+.PHONY: docker-produce-run
+docker-produce-run: docker-produce-build # Run the demo producer within Docker. If you have Go installed, you can call produce-run.
 	docker run --rm --network=host bufstream/demo-produce
 
 .PHONY: docker-consume-run
-docker-consume-run: # Run the demo consumer within Docker. If you have Go installed, you can call consume-run.
-	docker build -t bufstream/demo-consume -f Dockerfile.consume .
+docker-consume-run: docker-consume-build # Run the demo consumer within Docker. If you have Go installed, you can call consume-run.
 	docker run --rm --network=host bufstream/demo-consume
 
 .PHONY: produce-run