Feat:copy service comment to interfaces

Author: silves-xiang

balancer/grpclb/grpc_lb_v1/load_balancer_grpc.pb.go

@@ -187,6 +187,14 @@ func generateFileContent(gen *protogen.Plugin, file *protogen.File, g *protogen.
 	}
 }
 
+// Copy comments from proto file to _grpc.pb.go file
+func copyCommentsFromProto(g *protogen.GeneratedFile, service *protogen.Service) {
+	// Add empty comments line for godoc.
+	g.P("//")
+	// Pint comment without '\n', if comment has '\n', godoc considers this annotation to be non-service annotation.
+	g.P(strings.TrimSpace(service.Comments.Leading.String()))
+}
+
 func genService(gen *protogen.Plugin, file *protogen.File, g *protogen.GeneratedFile, service *protogen.Service) {
 	// Full methods constants.
 	helper.genFullMethods(g, service)
@@ -198,6 +206,9 @@ func genService(gen *protogen.Plugin, file *protogen.File, g *protogen.Generated
 	g.P("//")
 	g.P("// For semantics around ctx use and closing/ending streaming RPCs, please refer to https://pkg.go.dev/google.golang.org/grpc/?tab=doc#ClientConn.NewStream.")
 
+	// Copy comments from proto file.
+	copyCommentsFromProto(g, service)
+
 	if service.Desc.Options().(*descriptorpb.ServiceOptions).GetDeprecated() {
 		g.P("//")
 		g.P(deprecationComment)
@@ -251,6 +262,10 @@ func genService(gen *protogen.Plugin, file *protogen.File, g *protogen.Generated
 	g.P("// ", serverType, " is the server API for ", service.GoName, " service.")
 	g.P("// All implementations ", mustOrShould, " embed Unimplemented", serverType)
 	g.P("// for forward compatibility")
+
+	// Copy comments from proto file.
+	copyCommentsFromProto(g, service)
+
 	if service.Desc.Options().(*descriptorpb.ServiceOptions).GetDeprecated() {
 		g.P("//")
 		g.P(deprecationComment)