问题描述
在生产服务器搭了一套rocketmq环境,在生产服务器上能测试发送和接受消息都正常,并且观察namesrv和broker的日志,都没有发现异常日志。但就是在本地无法消费,网络是通的(ping和telnet都成功)
跟进问题总结
- 在跟代码发现订阅主题下的消费组的客户端数为空(为什么呢?)
1.1 观察消费端是否有下面的日志
if (null == cidAll) {
log.warn("doRebalance, {} {}, get consumer id list failed", consumerGroup, topic);
}
- (1)客户端日志打印位置留意下方代码(日志文件为rocketmq_client.log)
public class ClientLogger {
private static synchronized Appender createClientAppender() {
// 通过CLIENT_LOG_ROOT = "rocketmq.client.logRoot"可以指定路径
String clientLogRoot = System.getProperty(CLIENT_LOG_ROOT, System.getProperty("user.home") + "/logs/rocketmqlogs");
String clientLogFileName = System.getProperty(CLIENT_LOG_FILENAME, "rocketmq_client.log");
}
}
- 1.2 继续看rocketmq_client.log日志,会发现是因为访问不到broker,所以无法获取对应消费组信息
2021-11-17 16:52:03,364 WARN RocketmqClient - getConsumerIdListByGroup exception, xxx,xxx,xxx,xxx:10911 express
org.apache.rocketmq.remoting.exception.RemotingConnectException: connect to xxx,xxx,xxx,xxx:10911 failed
at org.apache.rocketmq.remoting.netty.NettyRemotingClient.invokeSync(NettyRemotingClient.java:394)
at org.apache.rocketmq.client.impl.MQClientAPIImpl.getConsumerIdListByGroup(MQClientAPIImpl.java:888)
at org.apache.rocketmq.client.impl.factory.MQClientInstance.findConsumerIdList(MQClientInstance.java:1067)
at org.apache.rocketmq.client.impl.consumer.RebalanceImpl.rebalanceByTopic(RebalanceImpl.java:260)
at org.apache.rocketmq.client.impl.consumer.RebalanceImpl.doRebalance(RebalanceImpl.java:223)
at org.apache.rocketmq.client.impl.consumer.DefaultMQPushConsumerImpl.doRebalance(DefaultMQPushConsumerImpl.java:1012)
at org.apache.rocketmq.client.impl.factory.MQClientInstance.doRebalance(MQClientInstance.java:958)
at org.apache.rocketmq.client.impl.consumer.RebalanceService.run(RebalanceService.java:41)
at java.lang.Thread.run(Thread.java:748)
- 把消费端部署在内网地址能通的环境就可以了
RocketMQ是如何消费的?
- 通过主题下的消息队列集合以及订阅该主题的消费组内的客户端数进行分配,获取该客户端分配的消息队列集合
- 通过指定消息队列的偏移量定义消息拉取请求pullRequest,拉取消息服务PullMessageService进行循环拉取任务
PullMessageService拉取消息
@Override
public void run() {
while (!this.isStopped()) {
try {
PullRequest pullRequest = this.pullRequestQueue.take();
this.pullMessage(pullRequest);
} catch (InterruptedException ignored) {
} catch (Exception e) {
log.error("Pull Message Service Run Method exception", e);
}
}
}
- pullRequestQueue是个阻塞队列,当pullRequestQueue队列里没有元素时,会一直阻塞
1.1 那pullRequestQueue中什么时候放入元素(关注下面RebalanceService的介绍)
RebalanceService放入拉取请求pullRequest
- 默认每2秒钟重新负载一次 MQClientInstance#doRebalance
public void doRebalance() {
// 以消费组的维度进行遍历负载
for (Map.Entry<String, MQConsumerInner> entry : this.consumerTable.entrySet()) {
MQConsumerInner impl = entry.getValue();
if (impl != null) {
try {
impl.doRebalance();
} catch (Throwable e) {
log.error("doRebalance exception", e);
}
}
}
}
- RebalanceImpl#doRebalance
public void doRebalance(final boolean isOrder) {
// 订阅信息(topic -> SubscriptionData)
Map<String, SubscriptionData> subTable = this.getSubscriptionInner();
if (subTable != null) {
for (final Map.Entry<String, SubscriptionData> entry : subTable.entrySet()) {
final String topic = entry.getKey();
try {
// 以主题维护进行负载
this.rebalanceByTopic(topic, isOrder);
} catch (Throwable e) {
if (!topic.startsWith(MixAll.RETRY_GROUP_TOPIC_PREFIX)) {
log.warn("rebalanceByTopic Exception", e);
}
}
}
}
this.truncateMessageQueueNotMyTopic();
}
- 集群消息负载算法介绍RebalanceImpl#rebalanceByTopic
private void rebalanceByTopic(final String topic, final boolean isOrder) {
switch (messageModel) {
case CLUSTERING: {
// 获取主题下队列列表
Set<MessageQueue> mqSet = this.topicSubscribeInfoTable.get(topic);
// 订阅该主题消费组内的客户端数(topic -> brokerAddr && brokerAddr + group -> cidAll)
List<String> cidAll = this.mQClientFactory.findConsumerIdList(topic, consumerGroup);
// 分配算法(默认平均分配:AllocateMessageQueueAveragely)为该客户端分配对应消息队列
allocateResult = strategy.allocate(
this.consumerGroup,
this.mQClientFactory.getClientId(),
mqAll,
cidAll);
// 见下方3.1的介绍
boolean changed = this.updateProcessQueueTableInRebalance(topic, allocateResultSet, isOrder);
}
}
}
- 3.1 RebalanceImpl#updateProcessQueueTableInRebalance
(1)按照消息队列MessageQueue的维度定义拉取请求PullRequest
(2)对拉取请求集合添加到拉取服务PullMessageService的pullRequestQueue队列中(见上方PullMessageService介绍)
private boolean updateProcessQueueTableInRebalance(final String topic, final Set<MessageQueue> mqSet,
final boolean isOrder) {
List<PullRequest> pullRequestList = new ArrayList<PullRequest>();
for (MessageQueue mq : mqSet) {
if (!this.processQueueTable.containsKey(mq)) {
ProcessQueue pq = new ProcessQueue();
// 消息队列的偏移量
long nextOffset = this.computePullFromWhereWithException(mq);
if (nextOffset >= 0) {
// pq在上方会new初始化
ProcessQueue pre = this.processQueueTable.putIfAbsent(mq, pq);
if(pre == null){
// 新建拉取请求
PullRequest pullRequest = new PullRequest();
pullRequest.setConsumerGroup(consumerGroup);
pullRequest.setNextOffset(nextOffset);
pullRequest.setMessageQueue(mq);
pullRequest.setProcessQueue(pq);
pullRequestList.add(pullRequest);
changed = true;
}
}
}
}
// 分发拉取请求
this.dispatchPullRequest(pullRequestList);
}
获取订阅主题消费组内消费者
- 通过注册中心namesrv获取主题的路由信息(包含主题对应broker集合),随机返回其中一个broker
- 向broker请求消费组的消费者信息
// MQClientInstance
public List<String> findConsumerIdList(final String topic, final String group) {
// 获取主题相关的broker(问题点:返回的是内网地址,在外面访问不了)
String brokerAddr = this.findBrokerAddrByTopic(topic);
if (null != brokerAddr) {
// 向broker发送信息,获取消费组的消费者信息
return this.mQClientAPIImpl.getConsumerIdListByGroup(brokerAddr, group, 3000);
}
}
- 获取topic的broker信息
public String findBrokerAddrByTopic(final String topic) {
// 获取topic的路由信息(topicRouteTable在哪里初始化? -->关注下方主题路由信息的介绍)
TopicRouteData topicRouteData = this.topicRouteTable.get(topic);
if (topicRouteData != null) {
// 获取主题的broker列表
List<BrokerData> brokers = topicRouteData.getBrokerDatas();
if (!brokers.isEmpty()) {
// 随机返回一个broker
int index = random.nextInt(brokers.size());
BrokerData bd = brokers.get(index % brokers.size());
return bd.selectBrokerAddr();
}
}
}
主题路由信息
- 在客户端实例MQClientInstance中有个定时任务,默认每30秒更新路由信息(通过pollNameServerInterval可以配置)
// MQClientInstance
public boolean updateTopicRouteInfoFromNameServer(final String topic, boolean isDefault,
DefaultMQProducer defaultMQProducer) {
if (this.lockNamesrv.tryLock(LOCK_TIMEOUT_MILLIS, TimeUnit.MILLISECONDS)) {
// 从注册中心namesrv获取主题的路由信息
TopicRouteData topicRouteData = this.mQClientAPIImpl.getTopicRouteInfoFromNameServer(topic, 1000 * 3);
if (topicRouteData != null) {
// 将topic的路由信息缓存到本地
this.topicRouteTable.put(topic, cloneTopicRouteData);
}
}
}