From 0bfcf1ca8fdbe0c7f964a63ce84f51998fe1d4c2 Mon Sep 17 00:00:00 2001
From: Aaron Abbott <aaronabbott@google.com>
Date: Wed, 3 Aug 2022 04:13:20 -0400
Subject: [PATCH] Use buf to detect for wire breaking changes (#415)

---
 .github/workflows/build-check.yaml | 13 +++++++++++++
 Makefile                           | 11 +++++++++++
 buf.yaml                           |  6 ++++++
 3 files changed, 30 insertions(+)
 create mode 100644 buf.yaml

diff --git a/.github/workflows/build-check.yaml b/.github/workflows/build-check.yaml
index 914e201..7f26bf3 100644
--- a/.github/workflows/build-check.yaml
+++ b/.github/workflows/build-check.yaml
@@ -82,3 +82,16 @@ 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: Run make breaking-change 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]})
diff --git a/Makefile b/Makefile
index 54c234d..1d8c996 100755
--- a/Makefile
+++ b/Makefile
@@ -18,7 +18,13 @@ 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}
+# When checking for protobuf breaking changes, check against the upstream repo's main branch.
+# Options are described in https://docs.buf.build/breaking/usage#git
+BUF_AGAINST ?= "https://github.com/open-telemetry/opentelemetry-proto.git"
 
 PROTO_GEN_CPP_DIR ?= $(GENDIR)/cpp
 PROTO_GEN_CSHARP_DIR ?= $(GENDIR)/csharp
@@ -36,6 +42,7 @@ 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 +146,7 @@ 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: breaking-change
+breaking-change:
+	$(BUF) breaking --against $(BUF_AGAINST) $(BUF_FLAGS)
diff --git a/buf.yaml b/buf.yaml
new file mode 100644
index 0000000..86ed2c4
--- /dev/null
+++ b/buf.yaml
@@ -0,0 +1,6 @@
+version: v1
+
+# See https://docs.buf.build/breaking/configuration
+breaking:
+  use:
+    - WIRE