optimize: a better way for return error

grpc.go

@@ -343,27 +343,22 @@ func (g *grpcServer) processRequest(stream grpc.ServerStream, service *service,
 		}
 
 		// define the handler func
-		fn := func(ctx context.Context, req server.Request, rsp interface{}) error {
-			ch := make(chan error, 1)
-			defer close(ch)
-
+		fn := func(ctx context.Context, req server.Request, rsp interface{}) (err error) {
 			defer func() {
 				if r := recover(); r != nil {
 					log.Log("panic recovered: ", r)
 					log.Logf(string(debug.Stack()))
-					ch <- errors.InternalServerError("go.micro.server", "panic recovered: %v", r)
+					err = errors.InternalServerError("go.micro.server", "panic recovered: %v", r)
 				}
 			}()
 			returnValues = function.Call([]reflect.Value{service.rcvr, mtype.prepareContext(ctx), reflect.ValueOf(argv.Interface()), reflect.ValueOf(rsp)})
 
 			// The return value for the method is an error.
-			if err := returnValues[0].Interface(); err != nil {
-				ch <- err.(error)
+			if rerr := returnValues[0].Interface(); rerr != nil {
+				err = rerr.(error)
 			}
 
-			ch <- nil
-
-			return <-ch
+			return err
 		}
 
 		// wrap the handler func