【八】RocketMQ源码之-produce发送流程_defaultmqproducerimpl.send-优快云博客

本文链接：https://blog.youkuaiyun.com/u014535922/article/details/129465368

Producer

消息生产者的代码都在client模块中，相对于RocketMQ来讲，消息生产者就是客户端，也是消息
的提供者。

发送流程

在这里插入图片描述

总结

1. DefaultMQProducerImpl调用本类方法send()方法中的send()方法。
2. send()方法调用sendDefaultImpl()从缓存中查找topicPublishInfo的信息，如果没有，调用MQClientInstance从Namesrv获取路由信息实际是从NameServer中获取的路由信息。
3. DefaultMQProducerImpl 读取路由的写队列，填充TopicPublishInfo。
4. DefaultMQProducerImpl调用MQFaultStrategy类中的方法，再调用LatencyFaultTolerance，获取到TopicPublishInfo中消息队列的信息。
5. DefaultMQProducerImpl执行sendKemelimpl方法，获取broker的地址，
6. DefaultMQProducerImpl调用MessageClientIDSetter给MSG设置唯一ID
7. DefaultMQProducerImpl调用SendMessageHook给消息增强后，发送消息。

核心代码

DefaultMQProducerImpl#send(Message msg)

//发送消息
public SendResult send(Message msg) {
return send(msg, this.defaultMQProducer.getSendMsgTimeout());
}

DefaultMQProducerImpl#send(Message msg,long timeout)

//发送消息,默认超时时间为3s
public SendResult send(Message msg,long timeout){
return this.sendDefaultImpl(msg, CommunicationMode.SYNC, null, timeout);
}

DefaultMQProducerImpl#sendDefaultImpl

//校验消息
Validators.checkMessage(msg, this.defaultMQProducer);

验证消息

代码：Validators#checkMessage

public static void checkMessage(Message msg, DefaultMQProducer defaultMQProducer)
        throws MQClientException {
        if (null == msg) {
            throw new MQClientException(ResponseCode.MESSAGE_ILLEGAL, "the message is null");
        }
        // topic
        Validators.checkTopic(msg.getTopic());

        // body
        if (null == msg.getBody()) {
            throw new MQClientException(ResponseCode.MESSAGE_ILLEGAL, "the message body is null");
        }

        if (0 == msg.getBody().length) {
            throw new MQClientException(ResponseCode.MESSAGE_ILLEGAL, "the message body length is zero");
        }

        if (msg.getBody().length > defaultMQProducer.getMaxMessageSize()) {
            throw new MQClientException(ResponseCode.MESSAGE_ILLEGAL,
                "the message body size over max value, MAX: " + defaultMQProducer.getMaxMessageSize());
        }
    }

查找路由

DefaultMQProducerImpl#tryToFindTopicPublishInfo

private TopicPublishInfo tryToFindTopicPublishInfo(final String topic) {
        //首先从本地缓存中获取
        TopicPublishInfo topicPublishInfo = this.topicPublishInfoTable.get(topic);
        //如果本地缓存没有,先占座，一会填充
        if (null == topicPublishInfo || !topicPublishInfo.ok()) {
            this.topicPublishInfoTable.putIfAbsent(topic, new TopicPublishInfo());
            //从命名服务器获取路由信息
            this.mQClientFactory.updateTopicRouteInfoFromNameServer(topic);
            topicPublishInfo = this.topicPublishInfoTable.get(topic);
        }

        if (topicPublishInfo.isHaveTopicRouterInfo() || topicPublishInfo.ok()) {
            return topicPublishInfo;
        } else {
            //以tryLock的方式更新主题的路由信息（Update Pub info||Update sub info）
            this.mQClientFactory.updateTopicRouteInfoFromNameServer(topic, true, this.defaultMQProducer);
            topicPublishInfo = this.topicPublishInfoTable.get(topic);
            return topicPublishInfo;
        }
    }

TopicPublishInfo

public class TopicPublishInfo {
private boolean orderTopic = false; //是否是顺序消息
private boolean haveTopicRouterInfo = false;
private List<MessageQueue> messageQueueList = new ArrayList<MessageQueue>
(); //该主题消息队列
private volatile ThreadLocalIndex sendWhichQueue = new
ThreadLocalIndex();//每选择一次消息队列,该值+1
private TopicRouteData topicRouteData;//关联Topic路由元信息
}

MQClientInstance#updateTopicRouteInfoFromNameServer

if (isDefault && defaultMQProducer != null) {
                        topicRouteData = this.mQClientAPIImpl.getDefaultTopicRouteInfoFromNameServer(defaultMQProducer.getCreateTopicKey(),
                            1000 * 3);
                        if (topicRouteData != null) {
                            for (QueueData data : topicRouteData.getQueueDatas()) {
                                int queueNums = Math.min(defaultMQProducer.getDefaultTopicQueueNums(), data.getReadQueueNums());
                                data.setReadQueueNums(queueNums);
                                data.setWriteQueueNums(queueNums);
                            }
                        }
                    }

MQClientInstance#updateTopicRouteInfoFromNameServer

//判断路由是否需要更改
TopicRouteData old = this.topicRouteTable.get(topic);
boolean changed = topicRouteDataIsChange(old, topicRouteData);
if (!changed) {
changed = this.isNeedUpdateTopicRouteInfo(topic);
} else {
log.info("the topic[{}] route info changed, old[{}] ,new[{}]", topic,
old, topicRouteData);
}

MQClientInstance#updateTopicRouteInfoFromNameServer

if (changed) {
//将topicRouteData转换为发布队列
TopicPublishInfo publishInfo = topicRouteData2TopicPublishInfo(topic,topicRouteData);
publishInfo.setHaveTopicRouterInfo(true);
//遍历生产
Iterator<Entry<String, MQProducerInner>> it =this.producerTable.entrySet().iterator();
while (it.hasNext()) {
Entry<String, MQProducerInner> entry = it.next();
MQProducerInner impl = entry.getValue();
if (impl != null) {
//生产者不为空时,更新publishInfo信息
impl.updateTopicPublishInfo(topic, publishInfo);
    }
  }
}

MQClientInstance#topicRouteData2TopicPublishInfo

 TopicPublishInfo info = new TopicPublishInfo();
        info.setTopicRouteData(route);
        if (route.getOrderTopicConf() != null && route.getOrderTopicConf().length() > 0) {
            String[] brokers = route.getOrderTopicConf().split(";");
            for (String broker : brokers) {
                String[] item = broker.split(":");
                int nums = Integer.parseInt(item[1]);
                for (int i = 0; i < nums; i++) {
                    MessageQueue mq = new MessageQueue(topic, item[0], i);
                    info.getMessageQueueList().add(mq);
                }
            }

            info.setOrderTopic(true);
        } else {
            List<QueueData> qds = route.getQueueDatas();
            Collections.sort(qds);
            for (QueueData qd : qds) {
                if (PermName.isWriteable(qd.getPerm())) {
                    BrokerData brokerData = null;
                    for (BrokerData bd : route.getBrokerDatas()) {
                        if (bd.getBrokerName().equals(qd.getBrokerName())) {
                            brokerData = bd;
                            break;
                        }
                    }

                    if (null == brokerData) {
                        continue;
                    }

                    if (!brokerData.getBrokerAddrs().containsKey(MixAll.MASTER_ID)) {
                        continue;
                    }

                    for (int i = 0; i < qd.getWriteQueueNums(); i++) {
                        MessageQueue mq = new MessageQueue(topic, qd.getBrokerName(), i);
                        info.getMessageQueueList().add(mq);
                    }
                }
            }

            info.setOrderTopic(false);
        }

        return info;

选择队列

默认不启用Broker故障延迟机制
TopicPublishInfo#selectOneMessageQueue(lastBrokerName)

public MessageQueue selectOneMessageQueue(final String lastBrokerName) {
        if (lastBrokerName == null) {
            return selectOneMessageQueue();
        } else {
            int index = this.sendWhichQueue.getAndIncrement();
            for (int i = 0; i < this.messageQueueList.size(); i++) {
                int pos = Math.abs(index++) % this.messageQueueList.size();
                if (pos < 0)
                    pos = 0;
                MessageQueue mq = this.messageQueueList.get(pos);
                if (!mq.getBrokerName().equals(lastBrokerName)) {
                    return mq;
                }
            }
            return selectOneMessageQueue();
        }
    }

    public MessageQueue selectOneMessageQueue() {
        int index = this.sendWhichQueue.getAndIncrement();
        int pos = Math.abs(index) % this.messageQueueList.size();
        if (pos < 0)
            pos = 0;
        return this.messageQueueList.get(pos);
    }

发送消息

消息发送API核心入口DefaultMQProducerImpl#sendKernelImpl

private SendResult sendKernelImpl(
	final Message msg, //待发送消息
	final MessageQueue mq, //消息发送队列
	final CommunicationMode communicationMode, //消息发送内模式
	final SendCallback sendCallback, pp //异步消息回调函数
	final TopicPublishInfo topicPublishInfo, //主题路由信息
	final long timeout //超时时间
)