func newTraceInterceptor()

in producer/interceptor.go [45:106]
53 lines of code
8 McCabe index (conditional complexity)

func newTraceInterceptor(dispatcher internal.TraceDispatcher) primitive.Interceptor {
	if dispatcher != nil {
		dispatcher.Start()
	}

	return func(ctx context.Context, req, reply interface{}, next primitive.Invoker) error {
		if dispatcher == nil {
			return fmt.Errorf("GetOrNewRocketMQClient faild")
		}
		beginT := time.Now()
		producerCtx, ok := primitive.GetProducerCtx(ctx)
		if !ok {
			return fmt.Errorf("ProducerCtx Not Exist")
		}
		err := next(ctx, req, reply)

		if producerCtx.Message.Topic == dispatcher.GetTraceTopicName() {
			return err
		}

		// SendOneway && SendAsync has no reply.
		if reply == nil {
			return err
		}

		result := reply.(*primitive.SendResult)
		if result.RegionID == "" || !result.TraceOn {
			return err
		}

		sendSuccess := result.Status == primitive.SendOK
		costT := time.Since(beginT).Nanoseconds() / int64(time.Millisecond)
		storeT := beginT.UnixNano()/int64(time.Millisecond) + costT/2

		traceBean := internal.TraceBean{
			Topic:       producerCtx.Message.Topic,
			Tags:        producerCtx.Message.GetTags(),
			Keys:        producerCtx.Message.GetKeys(),
			StoreHost:   producerCtx.BrokerAddr,
			ClientHost:  utils.LocalIP,
			BodyLength:  len(producerCtx.Message.Body),
			MsgType:     producerCtx.MsgType,
			MsgId:       result.MsgID,
			OffsetMsgId: result.OffsetMsgID,
			StoreTime:   storeT,
		}

		traceCtx := internal.TraceContext{
			RequestId: primitive.CreateUniqID(), // set id
			TimeStamp: time.Now().UnixNano() / int64(time.Millisecond),

			TraceType:  internal.Pub,
			GroupName:  producerCtx.ProducerGroup,
			RegionId:   result.RegionID,
			TraceBeans: []internal.TraceBean{traceBean},
			CostTime:   costT,
			IsSuccess:  sendSuccess,
		}
		dispatcher.Append(traceCtx)
		return err
	}
}