add PreCall and PostCall plugins of server

server/plugin.go

@@ -26,6 +26,8 @@ type PluginContainer interface {
 	DoPostReadRequest(ctx context.Context, r *protocol.Message, e error) error
 
 	DoPreHandleRequest(ctx context.Context, req *protocol.Message) error
+	DoPreCall(ctx context.Context, args interface{}) (interface{}, error)
+	DoPostCall(ctx context.Context, args, reply interface{}) (interface{}, error)
 
 	DoPreWriteResponse(context.Context, *protocol.Message, *protocol.Message) error
 	DoPostWriteResponse(context.Context, *protocol.Message, *protocol.Message, error) error
@@ -77,6 +79,14 @@ type (
 		PreHandleRequest(ctx context.Context, r *protocol.Message) error
 	}
 
+	PreCallPlugin interface {
+		PreCall(ctx context.Context, args interface{}) (interface{}, error)
+	}
+
+	PostCallPlugin interface {
+		PostCall(ctx context.Context, args, reply interface{}) (interface{}, error)
+	}
+
 	//PreWriteResponsePlugin represents .
 	PreWriteResponsePlugin interface {
 		PreWriteResponse(context.Context, *protocol.Message, *protocol.Message) error
@@ -253,6 +263,36 @@ func (p *pluginContainer) DoPreHandleRequest(ctx context.Context, r *protocol.Me
 	return nil
 }
 
+// DoPreCall invokes PreCallPlugin plugin.
+func (p *pluginContainer) DoPreCall(ctx context.Context, args interface{}) (interface{}, error) {
+	var err error
+	for i := range p.plugins {
+		if plugin, ok := p.plugins[i].(PreCallPlugin); ok {
+			args, err = plugin.PreCall(ctx, args)
+			if err != nil {
+				return args, err
+			}
+		}
+	}
+
+	return args, err
+}
+
+// DoPostCall invokes PostCallPlugin plugin.
+func (p *pluginContainer) DoPostCall(ctx context.Context, args, reply interface{}) (interface{}, error) {
+	var err error
+	for i := range p.plugins {
+		if plugin, ok := p.plugins[i].(PostCallPlugin); ok {
+			reply, err = plugin.PostCall(ctx, args, reply)
+			if err != nil {
+				return reply, err
+			}
+		}
+	}
+
+	return reply, err
+}
+
 // DoPreWriteResponse invokes PreWriteResponse plugin.
 func (p *pluginContainer) DoPreWriteResponse(ctx context.Context, req *protocol.Message, res *protocol.Message) error {
 	for i := range p.plugins {

server/server.go

@@ -529,12 +529,22 @@ func (s *Server) handleRequest(ctx context.Context, req *protocol.Message) (res
 
 	replyv := argsReplyPools.Get(mtype.ReplyType)
 
+	argv, err = s.Plugins.DoPreCall(ctx, argv)
+	if err != nil {
+		argsReplyPools.Put(mtype.ReplyType, replyv)
+		return handleError(res, err)
+	}
+
 	if mtype.ArgType.Kind() != reflect.Ptr {
 		err = service.call(ctx, mtype, reflect.ValueOf(argv).Elem(), reflect.ValueOf(replyv))
 	} else {
 		err = service.call(ctx, mtype, reflect.ValueOf(argv), reflect.ValueOf(replyv))
 	}
 
+	if err == nil {
+		replyv, err = s.Plugins.DoPostCall(ctx, argv, replyv)
+	}
+
 	argsReplyPools.Put(mtype.ArgType, argv)
 	if err != nil {
 		argsReplyPools.Put(mtype.ReplyType, replyv)