04 RocketMQ - Producer 源码分析
Producer 启动流程
整体脉络
启动入口
DefaultMQProducer producer = new DefaultMQProducer("ProducerGroupName");
producer.setNamesrvAddr("192.0.0.1:9876");
// 启动 producer
producer.start();
DefaultMQProducer::start()
- 组装 producerGroup
- 启动 producer
- 启动并发处理队列任务
public void start() throws MQClientException {
//1.组装 producerGroup
this.setProducerGroup(withNamespace(this.producerGroup));
//2.启动 producer
this.defaultMQProducerImpl.start();
//3.启动并发处理队列任务
if (null != traceDispatcher) {
try {
traceDispatcher.start(this.getNamesrvAddr(), this.getAccessChannel());
} catch (MQClientException e) {
log.warn("acl dispatcher start failed ", e);
}
}
}
DefaultMQProducerImpl::start()
- 检查生产者组是否满足要求
- 更改当前 instanceName为进程ID
- 创建或获得MQ客户端实例(
IP@instanceName@unitName相同则为同一实例) - 注册当前生产者到 MQClientInstance 中，方便后续调用网路请求
- 启动生产者
- 发送心跳到所有的 broker
- 定时清除过期请求
public void start() throws MQClientException {
this.start(true);
}
public void start(final boolean startFactory) throws MQClientException {
switch (this.serviceState) {
//第一次创建
case CREATE_JUST:
this.serviceState = ServiceState.START_FAILED;
//1.检查生产者组是否满足要求
this.checkConfig();
//2.更改当前instanceName为进程ID
if (!this.defaultMQProducer.getProducerGroup().equals(MixAll.CLIENT_INNER_PRODUCER_GROUP)) {
this.defaultMQProducer.changeInstanceNameToPID();
}
//3.创建或获得MQ客户端实例
// IP@instanceName@unitName 相同则为同一实例
this.mQClientFactory = MQClientManager.getInstance().getOrCreateMQClientInstance(this.defaultMQProducer, rpcHook);
//4.注册当前生产者到MQClientInstance中,方便后续调用网路请求
boolean registerOK = mQClientFactory.registerProducer(this.defaultMQProducer.getProducerGroup(), this);
if (!registerOK) {
this.serviceState = ServiceState.CREATE_JUST;
throw new MQClientException("The producer group[" + this.defaultMQProducer.getProducerGroup()
+ "] has been created before, specify another name please." + FAQUrl.suggestTodo(FAQUrl.GROUP_NAME_DUPLICATE_URL),
null);
}
this.topicPublishInfoTable.put(this.defaultMQProducer.getCreateTopicKey(), new TopicPublishInfo());
//5.启动生产者
if (startFactory) {
//最终还是调用MQClientInstance
mQClientFactory.start();
}
log.info("the producer [{}] start OK. sendMessageWithVIPChannel={}", this.defaultMQProducer.getProducerGroup(),
this.defaultMQProducer.isSendMessageWithVIPChannel());
this.serviceState = ServiceState.RUNNING;
break;
case RUNNING:
case START_FAILED:
case SHUTDOWN_ALREADY:
throw new MQClientException("The producer service state not OK, maybe started once, "
+ this.serviceState
+ FAQUrl.suggestTodo(FAQUrl.CLIENT_SERVICE_NOT_OK),
null);
default:
break;
}
//6.发送心跳到所有的broker
this.mQClientFactory.sendHeartbeatToAllBrokerWithLock();
//7.定时清除过期请求
this.timer.scheduleAtFixedRate(new TimerTask() {
@Override
public void run() {
try {
RequestFutureTable.scanExpiredRequest();
} catch (Throwable e) {
log.error("scan RequestFutureTable exception", e);
}
}
}, 1000 * 3, 1000);
}
MQClientInstance::start()
- 如果 namesrvAddr 为空，通过 http 调用获取一下
- 开启消息发送服务 NRC
- 开启一系列定时任务（获取路由地址，修改路由信息，发送心跳等）
- 开启拉消息服务
- 开启负载均衡服务
- 再次调用 DefaultMQProducerImpl::start(false)
public void start() throws MQClientException {
synchronized (this) {
switch (this.serviceState) {
case CREATE_JUST:
this.serviceState = ServiceState.START_FAILED;
//1.如果 namesrvAddr 为空，通过http调用获取一下
if (null == this.clientConfig.getNamesrvAddr()) {
this.mQClientAPIImpl.fetchNameServerAddr();
}
//2.开启消息发送服务 NRC
this.mQClientAPIImpl.start();
//3.开启一系列定时任务（获取路由地址，修改路由信息，发送心跳等）
this.startScheduledTask();
//4.开启拉消息服务
this.pullMessageService.start();
//5.开启负载均衡服务
this.rebalanceService.start();
//6.再次调用 DefaultMQProducerImpl::start()??
this.defaultMQProducer.getDefaultMQProducerImpl().start(false);
log.info("the client factory [{}] start OK", this.clientId);
this.serviceState = ServiceState.RUNNING;
break;
case START_FAILED:
throw new MQClientException("The Factory object[" + this.getClientId() + "] has been created before, and failed.", null);
default:
break;
}
}
}
startScheduledTask() - 开启定时任务
- 2分钟一次获取路由地址
- 30s一次修改路由信息
- 30s一次心跳
- 5s一次持久化消费进度
- 60s一次调整线程池
private void startScheduledTask() {
//1. 2分钟一次获取路由地址
if (null == this.clientConfig.getNamesrvAddr()) {
this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
try {
MQClientInstance.this.mQClientAPIImpl.fetchNameServerAddr();
} catch (Exception e) {
log.error("ScheduledTask fetchNameServerAddr exception", e);
}
}
}, 1000 * 10, 1000 * 60 * 2, TimeUnit.MILLISECONDS);
}
//2. 30s一次修改路由信息
this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
try {
MQClientInstance.this.updateTopicRouteInfoFromNameServer();
} catch (Exception e) {
log.error("ScheduledTask updateTopicRouteInfoFromNameServer exception", e);
}
}
}, 10, this.clientConfig.getPollNameServerInterval(), TimeUnit.MILLISECONDS);
//3. 30s一次心跳
this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
try {
MQClientInstance.this.cleanOfflineBroker();
MQClientInstance.this.sendHeartbeatToAllBrokerWithLock();
} catch (Exception e) {
log.error("ScheduledTask sendHeartbeatToAllBroker exception", e);
}
}
}, 1000, this.clientConfig.getHeartbeatBrokerInterval(), TimeUnit.MILLISECONDS);
//4. 5s一次持久化消费进度
this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
try {
MQClientInstance.this.persistAllConsumerOffset();
} catch (Exception e) {
log.error("ScheduledTask persistAllConsumerOffset exception", e);
}
}
}, 1000 * 10, this.clientConfig.getPersistConsumerOffsetInterval(), TimeUnit.MILLISECONDS);
//5. 60s一次调整线程池
this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
try {
MQClientInstance.this.adjustThreadPool();
} catch (Exception e) {
log.error("ScheduledTask adjustThreadPool exception", e);
}
}
}, 1, 1, TimeUnit.MINUTES);
}
Producer 消息发送
整体脉络
发送入口
try {
Message msg = new Message("TopicTest",
"TagA",
"Hello world".getBytes(RemotingHelper.DEFAULT_CHARSET));
SendResult sendResult = producer.send(msg);
System.out.printf("%s%n", sendResult);
}catch (Exception e){
e.printStackTrace();
}
DefaultMQProducer::send()
public SendResult send(
Message msg) throws MQClientException, RemotingException, MQBrokerException, InterruptedException {
//校验消息
Validators.checkMessage(msg, this);
msg.setTopic(withNamespace(msg.getTopic()));
return this.defaultMQProducerImpl.send(msg);
}
DefaultMQProducerImpl::send()
public SendResult send(
Message msg) throws MQClientException, RemotingException, MQBrokerException, InterruptedException {
return send(msg, this.defaultMQProducer.getSendMsgTimeout());
}
public SendResult send(Message msg,
long timeout) throws MQClientException, RemotingException, MQBrokerException, InterruptedException {
return this.sendDefaultImpl(msg, CommunicationMode.SYNC, null, timeout);
}
DefaultMQProducerImpl::sendDefaultImpl()
校验消息、查找路由、选择队列、发送消息、计算不可用时长
private SendResult sendDefaultImpl(
Message msg,
final CommunicationMode communicationMode,
final SendCallback sendCallback,
final long timeout
) throws MQClientException, RemotingException, MQBrokerException, InterruptedException {
this.makeSureStateOK();
//1.校验消息
Validators.checkMessage(msg, this.defaultMQProducer);
final long invokeID = random.nextLong();
long beginTimestampFirst = System.currentTimeMillis();
long beginTimestampPrev = beginTimestampFirst;
long endTimestamp = beginTimestampFirst;
//2.查找路由
TopicPublishInfo topicPublishInfo = this.tryToFindTopicPublishInfo(msg.getTopic());
if (topicPublishInfo != null && topicPublishInfo.ok()) {
boolean callTimeout = false;
MessageQueue mq = null;
Exception exception = null;
SendResult sendResult = null;
//重试次数 2次 ，实际最大的发送3次 +1
int timesTotal = communicationMode == CommunicationMode.SYNC ? 1 + this.defaultMQProducer.getRetryTimesWhenSendFailed() : 1;
int times = 0;
String[] brokersSent = new String[timesTotal];
for (; times < timesTotal; times++) {
String lastBrokerName = null == mq ? null : mq.getBrokerName();
//3.选择队列
MessageQueue mqSelected = this.selectOneMessageQueue(topicPublishInfo, lastBrokerName);
if (mqSelected != null) {
mq = mqSelected;
brokersSent[times] = mq.getBrokerName();
try {
beginTimestampPrev = System.currentTimeMillis();
if (times > 0) {
//Reset topic with namespace during resend.
msg.setTopic(this.defaultMQProducer.withNamespace(msg.getTopic()));
}
long costTime = beginTimestampPrev - beginTimestampFirst;
if (timeout < costTime) {
callTimeout = true;
break;
}
//4.发送消息
sendResult = this.sendKernelImpl(msg, mq, communicationMode, sendCallback, topicPublishInfo, timeout - costTime);
endTimestamp = System.currentTimeMillis();
//5.成功或失败都计算不可用时长（故障延迟用）
this.updateFaultItem(mq.getBrokerName(), endTimestamp - beginTimestampPrev, false);
//todo 发送正常，使根据发送时长计算broker不可用时长(duration)
switch (communicationMode) {
case ASYNC:
return null;
case ONEWAY:
return null;
case SYNC:
if (sendResult.getSendStatus() != SendStatus.SEND_OK) {
if (this.defaultMQProducer.isRetryAnotherBrokerWhenNotStoreOK()) {
continue;
}
}
return sendResult;
default:
break;
}
} catch (RemotingException e) {
endTimestamp = System.currentTimeMillis();
//todo 发送异常，默认当前发送时长为30000L
this.updateFaultItem(mq.getBrokerName(), endTimestamp - beginTimestampPrev, true);
log.warn(String.format("sendKernelImpl exception, resend at once, InvokeID: %s, RT: %sms, Broker: %s", invokeID, endTimestamp - beginTimestampPrev, mq), e);
log.warn(msg.toString());
exception = e;
continue;
} catch (MQClientException e) {
endTimestamp = System.currentTimeMillis();
this.updateFaultItem(mq.getBrokerName(), endTimestamp - beginTimestampPrev, true);
log.warn(String.format("sendKernelImpl exception, resend at once, InvokeID: %s, RT: %sms, Broker: %s", invokeID, endTimestamp - beginTimestampPrev, mq), e);
log.warn(msg.toString());
exception = e;
continue;
} catch (MQBrokerException e) {
endTimestamp = System.currentTimeMillis();
this.updateFaultItem(mq.getBrokerName(), endTimestamp - beginTimestampPrev, true);
log.warn(String.format("sendKernelImpl exception, resend at once, InvokeID: %s, RT: %sms, Broker: %s", invokeID, endTimestamp - beginTimestampPrev, mq), e);
log.warn(msg.toString());
exception = e;
switch (e.getResponseCode()) {
case ResponseCode.TOPIC_NOT_EXIST:
case ResponseCode.SERVICE_NOT_AVAILABLE:
case ResponseCode.SYSTEM_ERROR:
case ResponseCode.NO_PERMISSION:
case ResponseCode.NO_BUYER_ID:
case ResponseCode.NOT_IN_CURRENT_UNIT:
continue;
default:
if (sendResult != null) {
return sendResult;
}
throw e;
}
} catch (InterruptedException e) {
endTimestamp = System.currentTimeMillis();
this.updateFaultItem(mq.getBrokerName(), endTimestamp - beginTimestampPrev, false);
log.warn(String.format("sendKernelImpl exception, throw exception, InvokeID: %s, RT: %sms, Broker: %s", invokeID, endTimestamp - beginTimestampPrev, mq), e);
log.warn(msg.toString());
log.warn("sendKernelImpl exception", e);
log.warn(msg.toString());
throw e;
}
} else {
break;
}
}
if (sendResult != null) {
return sendResult;
}
String info = String.format("Send [%d] times, still failed, cost [%d]ms, Topic: %s, BrokersSent: %s",
times,
System.currentTimeMillis() - beginTimestampFirst,
msg.getTopic(),
Arrays.toString(brokersSent));
info += FAQUrl.suggestTodo(FAQUrl.SEND_MSG_FAILED);
MQClientException mqClientException = new MQClientException(info, exception);
if (callTimeout) {
throw new RemotingTooMuchRequestException("sendDefaultImpl call timeout");
}
if (exception instanceof MQBrokerException) {
mqClientException.setResponseCode(((MQBrokerException) exception).getResponseCode());
} else if (exception instanceof RemotingConnectException) {
mqClientException.setResponseCode(ClientErrorCode.CONNECT_BROKER_EXCEPTION);
} else if (exception instanceof RemotingTimeoutException) {
mqClientException.setResponseCode(ClientErrorCode.ACCESS_BROKER_TIMEOUT);
} else if (exception instanceof MQClientException) {
mqClientException.setResponseCode(ClientErrorCode.BROKER_NOT_EXIST_EXCEPTION);
}
throw mqClientException;
}
validateNameServerSetting();
throw new MQClientException("No route info of this topic: " + msg.getTopic() + FAQUrl.suggestTodo(FAQUrl.NO_TOPIC_ROUTE_INFO),
null).setResponseCode(ClientErrorCode.NOT_FOUND_TOPIC_EXCEPTION);
}
checkMessage() - 校验消息
// 校验消息
public static void checkMessage(Message msg, DefaultMQProducer defaultMQProducer)
throws MQClientException {
//判断是否为空
if (null == msg) {
throw new MQClientException(ResponseCode.MESSAGE_ILLEGAL, "the message is null");
}
// 校验主题
Validators.checkTopic(msg.getTopic());
Validators.isNotAllowedSendTopic(msg.getTopic());
// 校验消息体
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");
}
// 不能超过4M
if (msg.getBody().length > defaultMQProducer.getMaxMessageSize()) {
throw new MQClientException(ResponseCode.MESSAGE_ILLEGAL,
"the message body size over max value, MAX: " + defaultMQProducer.getMaxMessageSize());
}
}
tryToFindTopicPublishInfo() - 查找路由
private TopicPublishInfo tryToFindTopicPublishInfo(final String topic) {
//从缓存中获得主题的路由信息
TopicPublishInfo topicPublishInfo = this.topicPublishInfoTable.get(topic);
//路由信息为空,则从NameServer获取路由
if (null == topicPublishInfo || !topicPublishInfo.ok()) {
this.topicPublishInfoTable.putIfAbsent(topic, new TopicPublishInfo());
this.mQClientFactory.updateTopicRouteInfoFromNameServer(topic);
topicPublishInfo = this.topicPublishInfoTable.get(topic);
}
if (topicPublishInfo.isHaveTopicRouterInfo() || topicPublishInfo.ok()) {
return topicPublishInfo;
} else {
//如果未找到当前主题的路由信息,则用默认主题继续查找
this.mQClientFactory.updateTopicRouteInfoFromNameServer(topic, true, this.defaultMQProducer);
topicPublishInfo = this.topicPublishInfoTable.get(topic);
return topicPublishInfo;
}
}
TopicPublishInfo - 路由信息
selectOneMessageQueue() - 选择队列
MQFaultStrategy::selectOneMessageQueue()，选择队列时存在两种策略：
- 轮询（默认）
消息第一次发送时，用private volatile ThreadLocalIndex sendWhichQueue = new ThreadLocalIndex();取模队列数，得到发送的队列，小心重试发送时，规避上次发送失败的broker队列进行发送 - 故障延迟
发送消息时计算服务不可用时长，当选择队列时会跳过“不可用”的服务
public MessageQueue selectOneMessageQueue(final TopicPublishInfo tpInfo, final String lastBrokerName) {
//故障延迟机制
if (this.sendLatencyFaultEnable) {
try {
int index = tpInfo.getSendWhichQueue().getAndIncrement();
//对消息队列轮询获取一个队列
for (int i = 0; i < tpInfo.getMessageQueueList().size(); i++) {
//基于index和队列数量取余，确定位置
int pos = Math.abs(index++) % tpInfo.getMessageQueueList().size();
if (pos < 0)
pos = 0;
MessageQueue mq = tpInfo.getMessageQueueList().get(pos);
if (latencyFaultTolerance.isAvailable(mq.getBrokerName()))
return mq;
}
//如果预测的所有broker都不可用，则随机选择一个broker,随机选择该Broker下一个队列进行发送
final String notBestBroker = latencyFaultTolerance.pickOneAtLeast();
//获得Broker的写队列集合
int writeQueueNums = tpInfo.getQueueIdByBroker(notBestBroker);
if (writeQueueNums > 0) {
final MessageQueue mq = tpInfo.selectOneMessageQueue();
if (notBestBroker != null) {
//获得一个队列,指定broker和队列ID并返回
mq.setBrokerName(notBestBroker);
mq.setQueueId(tpInfo.getSendWhichQueue().getAndIncrement() % writeQueueNums);
}
return mq;
} else {
latencyFaultTolerance.remove(notBestBroker);
}
} catch (Exception e) {
log.error("Error occurred when selecting message queue", e);
}
return tpInfo.selectOneMessageQueue();
}
//轮询
return tpInfo.selectOneMessageQueue(lastBrokerName);
}
TopicPublishInfo::selectOneMessageQueue()
public MessageQueue selectOneMessageQueue(final String lastBrokerName) {
//todo lastBrokerName 是每次发送一条消息时保存的临时变量
//第一次选择队列（非重试）
if (lastBrokerName == null) {
return selectOneMessageQueue();
} else {
//重试发送时的消息发送
for (int i = 0; i < this.messageQueueList.size(); i++) {
int index = this.sendWhichQueue.getAndIncrement();
//遍历消息队列集合
int pos = Math.abs(index) % this.messageQueueList.size();
if (pos < 0)
pos = 0;
//重试中，规避上次Broker队列
MessageQueue mq = this.messageQueueList.get(pos);
if (!mq.getBrokerName().equals(lastBrokerName)) {
return mq;
}
}
//如果没有集群，或者没得选，还是按照第一次选择队列
return selectOneMessageQueue();
}
}
//默认选择选择队列
public MessageQueue selectOneMessageQueue() {
//sendWhichQueue自增(这里使用的 ThreadLocal)
int index = this.sendWhichQueue.getAndIncrement();
//对队列大小取模
int pos = Math.abs(index) % this.messageQueueList.size();
if (pos < 0)
pos = 0;
//返回对应的队列
return this.messageQueueList.get(pos);
}