IMO, The most popular scenario of MQ System is that decouple complex distributed system and process message asynchronous. If a user wants low latency or explicit response from downstream, he should use an RPC Framework instead of MQ, like Dubbo, gRPC, etc. so I vote for -1.
heng du <[email protected]> 于2019年8月27日周二 下午5:54写道： > Dear Apache RocketMQ Community: > > We would like to propose a RIP[16] about RocketMQ RPC(Request-Response > model) Support. Many companies use the MQ system to constructing their > service bus, especially in the financial industry. We wish RocketMQ can > provide an RPC client implement to help developers building their > applications conveniently and effectively. > > > Status > > Current State: Proposed > > Authors: qqeasonchen > > Shepherds: duhengforever > > Mailing List discussion: dev, users > > Pull Request: none > > Released: 4.6.0 > > Background & Motivation > > RPC is a powerful technique for constructing distributed, client-server > based applications. Many companies use the MQ system to constructing their > service bus, especially in the financial industry. We need to implement an > RPC client based on MQ system ourselves because the MQ system doesn’t > support RPC naturally. In the current version of rocketmq project, producer > client only support to send a message to the broker and cannot wait a > response message replied from the consumer. We wish RocketMQ can provide an > RPC client implement to help developers building their applications > conveniently and effectively. > > Goals > > - What problem is this proposal designed to solve? > > (1) Design and implement an RPC interface based on RocketMQ Producer, > which support send a message and then wait a response message replied from > the consumer. > > (2) Design and Implement a consumer which can automatically or manually > send a reply message. > > (3) Enable the broker to push a message to an explicit producer. > > > > - To what degree should we solve the problem? > > We wish developers can use RocketMQ easily to constructing their > distributed applications which need RPC call. > > Non-Goals > > - What problem is this proposal NOT designed to solve? > > In this phase, this rip only supports a usable RPC call in most common > scenarios. > > - Are there any limits to this proposal? > > Users may need to tune some client and broker’s configurations to achieve > better performance. > > Changes > > Architecture > > We plan to add RPC implement into client and broker modules. In client > modules, we will add an RPC interface into DefaultMQProducer, and add reply > logic into DefaultMQPushConsumer. In broker modules, we will add a > processor to push reply message from consumer to explicit producer. > > Interface Design/Change > > - Method signature changes > > Plan to add interfaces as follow: > > > Message request(final Message msg, final long timeout) throws > MQClientException, RemotingException, MQBrokerException, InterruptedException; > > > > Message request(final Message msg, final SendCallback sendCallback, final > long timeout) throws MQClientException, RemotingException, > InterruptedException; > > > > Message request(final Message msg, final MessageQueueSelector selector, > final Object arg, final long timeout) throws MQClientException, > RemotingException, MQBrokerException, InterruptedException; > > > > Message request(final Message msg, final MessageQueueSelector selector, > final Object arg, final SendCallback sendCallback, final long timeout) > throws MQClientException, RemotingException, InterruptedException; > > > > Message request(final Message msg, final MessageQueue MQ, final long > timeout) throws MQClientException, RemotingException, MQBrokerException, > InterruptedException; > > > > Message request(final Message msg, final MessageQueue mq, final > SendCallback sendCallback, long timeout) throws MQClientException, > RemotingException, InterruptedException; > > > > - Method behavior changes > > No issue > > - CLI command changes > > No issue > > - Log format or content changes > > No issue > > Compatibility, Deprecation, and Migration Plan > > - No issue > > Implementation Outline > > We will implement the proposed changes by *1* phase. > > Phase 1 > > 1. Implement RPC feature in Producer > 2. Implement RPC feature in Consumer > 3. Implement RPC feature in Broker > >
