Only build common protos with --grpc option for LRO.

config/common_protos.yml

@@ -33,4 +33,4 @@ packages:
     version: ''
 
 # semver is the semantic version of the common protos package.
-semver: 1.3.2
+semver: 1.3.3

config/dependencies.yml

@@ -67,7 +67,7 @@ protobuf:
 
 googleapis_common_protos:
   python:
-    version: '1.3.2'
+    version: '1.3.3'
   ruby:
     version: '1.2.0'
 

lib/api_repo.js

@@ -56,6 +56,9 @@ var DEFAULT_PROTO_COMPILER = 'protoc';
 // Python builds using grpcio-tools.
 var NO_PROTOC_PLUGIN = ['nodejs', 'java', 'python'];
 
+// common protos for which we build gRPC service methods
+var COMMON_GRPC_PROTOS = ['operations.proto'];
+
 // the default include path, where install the protobuf runtime installs its
 // protos.
 var DEFAULT_INCLUDE_PATH = Object.freeze(['/usr/local/include']);
@@ -1018,11 +1021,14 @@ ApiRepo.prototype._makeProtocFunc = function _makeProtocFunc(opts, language) {
           pluginOption = '--plugin=';
         } else {
           args.push('--' + language + '_out=' + outDir);
-          if (language === 'python') {
-            // required per https://github.com/grpc/grpc/issues/7857
-            args.push('--grpc_python_out=' + outDir);
-          } else {
-            args.push('--grpc_out=' + outDir);
+          if (!opts.buildCommonProtos ||
+              _.includes(COMMON_GRPC_PROTOS, protoPath)) {
+            if (language === 'python') {
+              // required per https://github.com/grpc/grpc/issues/7857
+              args.push('--grpc_python_out=' + outDir);
+            } else {
+              args.push('--grpc_out=' + outDir);
+            }
           }
         }
         if (!_.includes(NO_PROTOC_PLUGIN, language)) {