Merge pull request #11158 from yang-g/async_default_service

Add api to server builder plugin to modify the builder

include/grpc++/impl/server_builder_plugin.h

@@ -40,6 +40,7 @@
 
 namespace grpc {
 
+class ServerBuilder;
 class ServerInitializer;
 class ChannelArguments;
 
@@ -51,6 +52,10 @@ class ServerBuilderPlugin {
   virtual ~ServerBuilderPlugin() {}
   virtual grpc::string name() = 0;
 
+  /// UpdateServerBuilder will be called at the beginning of
+  /// \a ServerBuilder::BuildAndStart().
+  virtual void UpdateServerBuilder(ServerBuilder* builder) {}
+
   /// InitServer will be called in ServerBuilder::BuildAndStart(), after the
   /// Server instance is created.
   virtual void InitServer(ServerInitializer* si) = 0;

src/cpp/server/server_builder.cc

@@ -180,6 +180,10 @@ ServerBuilder& ServerBuilder::AddListeningPort(
 }
 
 std::unique_ptr<Server> ServerBuilder::BuildAndStart() {
+  for (auto plugin = plugins_.begin(); plugin != plugins_.end(); plugin++) {
+    (*plugin)->UpdateServerBuilder(this);
+  }
+
   ChannelArguments args;
   for (auto option = options_.begin(); option != options_.end(); ++option) {
     (*option)->UpdateArguments(&args);