Use buf to detect for wire breaking changes

.github/workflows/build-check.yaml

@@ -82,3 +82,18 @@ jobs:
     steps:
     - uses: actions/checkout@v2
     - run: make gen-kotlin
+
+  breaking-change:
+    needs: docker-pull
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Fetch main branch for comparison
+      run: git fetch && git checkout main && git checkout -
+    - name: Run make lint with json output to annotate PR
+      # Formats JSON output into Github workflow commands
+      # https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#setting-an-error-message
+      run: >
+        BUF_FLAGS="--error-format json" make -s breaking-change
+        | jq -rs '.[] | "::error file=\(.path),line=\(.start_line),endLine=\(.end_line),title=Buf detected breaking change \(.type)::\(.message)"'
+        ; (exit ${PIPESTATUS[0]})

Makefile

@@ -18,7 +18,11 @@ endef
 gen-all: gen-cpp gen-csharp gen-go gen-java gen-kotlin gen-objc gen-openapi gen-php gen-python gen-ruby
 
 OTEL_DOCKER_PROTOBUF ?= otel/build-protobuf:0.9.0
+BUF_DOCKER ?= bufbuild/buf:1.7.0
+
 PROTOC := docker run --rm -u ${shell id -u} -v${PWD}:${PWD} -w${PWD} ${OTEL_DOCKER_PROTOBUF} --proto_path=${PWD}
+BUF := docker run --rm -v "${PWD}:/workspace" -w /workspace ${BUF_DOCKER}
+BUF_AGAINST ?= ".git\#branch=main"
 
 PROTO_GEN_CPP_DIR ?= $(GENDIR)/cpp
 PROTO_GEN_CSHARP_DIR ?= $(GENDIR)/csharp
@@ -36,6 +40,7 @@ PROTO_GEN_RUBY_DIR ?= $(GENDIR)/ruby
 .PHONY: docker-pull
 docker-pull:
 	docker pull $(OTEL_DOCKER_PROTOBUF)
+	docker pull $(BUF_DOCKER)
 
 # Generate gRPC/Protobuf implementation for C++.
 .PHONY: gen-cpp
@@ -139,3 +144,7 @@ gen-ruby:
 	$(PROTOC) --ruby_out=./$(PROTO_GEN_RUBY_DIR) --grpc-ruby_out=./$(PROTO_GEN_RUBY_DIR) opentelemetry/proto/collector/trace/v1/trace_service.proto
 	$(PROTOC) --ruby_out=./$(PROTO_GEN_RUBY_DIR) --grpc-ruby_out=./$(PROTO_GEN_RUBY_DIR) opentelemetry/proto/collector/metrics/v1/metrics_service.proto
 	$(PROTOC) --ruby_out=./$(PROTO_GEN_RUBY_DIR) --grpc-ruby_out=./$(PROTO_GEN_RUBY_DIR) opentelemetry/proto/collector/logs/v1/logs_service.proto
+
+.PHONY: lint
+breaking-change:
+	$(BUF) breaking --against $(BUF_AGAINST) $(BUF_FLAGS)

buf.yaml

@@ -0,0 +1,7 @@
+version: v1
+
+# See https://docs.buf.build/breaking/configuration
+breaking:
+  use:
+    - WIRE
+    - WIRE_JSON