diff --git a/README.md b/README.md index 63f5539..20c8f41 100644 --- a/README.md +++ b/README.md @@ -271,6 +271,10 @@ - [Sentinel 底层 LongAdder 的计数实现](docs/Sentinel/Sentinel底层LongAdder的计数实现.md) - [Sentinel 限流算法的实现](docs/Sentinel/Sentinel限流算法的实现.md) +## RocketMQ + +- [rocketMQ NameServer与broker的通信](docs/rocketmq/rocketmq-nameserver-broker.md) + ## 番外篇（JDK 1.8） ### 基础类库 diff --git a/docs/rocketmq/rocketmq-nameserver-broker.md b/docs/rocketmq/rocketmq-nameserver-broker.md new file mode 100644 index 0000000..e6d343c --- /dev/null +++ b/docs/rocketmq/rocketmq-nameserver-broker.md @@ -0,0 +1,218 @@ +nameserver如何与broker进行通信的？ + +nameserver每隔10s扫描一次Broker，移除处于未激活状态的Broker + +核心代码： + +`this.scheduledExecutorService.scheduleAtFixedRate(NamesrvController.this.routeInfoManager::scanNotActiveBroker, 5, 10, TimeUnit.*SECONDS*);` + +``` +public int scanNotActiveBroker() { + int removeCount = 0; + Iterator> it = this.brokerLiveTable.entrySet().iterator(); + while (it.hasNext()) { + Entry next = it.next(); + long last = next.getValue().getLastUpdateTimestamp(); + if ((last +BROKER_CHANNEL_EXPIRED_TIME) < System.currentTimeMillis()) { + RemotingUtil.closeChannel(next.getValue().getChannel()); + it.remove(); + log.warn("The broker channel expired, {} {}ms", next.getKey(),BROKER_CHANNEL_EXPIRED_TIME); + this.onChannelDestroy(next.getKey(), next.getValue().getChannel()); + + removeCount++; + } + } + + return removeCount; +} +``` + +broker每隔30秒会向集群中所有的NameServer发送心跳包 + +核心代码： + +``` +this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() { + + @Override + public void run() { + try { + BrokerController.this.registerBrokerAll(true, false, brokerConfig.isForceRegister()); + } catch (Throwable e) { + log.error("registerBrokerAll Exception", e); + } + } +}, 1000 * 10, Math.max(10000, Math.min(brokerConfig.getRegisterNameServerPeriod(), 60000)), TimeUnit.MILLISECONDS); +``` + +``` +public synchronized void registerBrokerAll(final boolean checkOrderConfig, boolean oneway, boolean forceRegister) { + TopicConfigSerializeWrapper topicConfigWrapper = this.getTopicConfigManager().buildTopicConfigSerializeWrapper(); + + if (!PermName.isWriteable(this.getBrokerConfig().getBrokerPermission()) + || !PermName.isReadable(this.getBrokerConfig().getBrokerPermission())) { + ConcurrentHashMap topicConfigTable = new ConcurrentHashMap(); + for (TopicConfig topicConfig : topicConfigWrapper.getTopicConfigTable().values()) { + TopicConfig tmp = + new TopicConfig(topicConfig.getTopicName(), topicConfig.getReadQueueNums(), topicConfig.getWriteQueueNums(), + this.brokerConfig.getBrokerPermission()); + topicConfigTable.put(topicConfig.getTopicName(), tmp); + } + topicConfigWrapper.setTopicConfigTable(topicConfigTable); + } + + if (forceRegister || needRegister(this.brokerConfig.getBrokerClusterName(), + this.getBrokerAddr(), + this.brokerConfig.getBrokerName(), + this.brokerConfig.getBrokerId(), + this.brokerConfig.getRegisterBrokerTimeoutMills())) { + doRegisterBrokerAll(checkOrderConfig, oneway, topicConfigWrapper); + } +} +``` + +org.apache.rocketmq.namesrv.processor.DefaultRequestProcessor 是网络处理器解析请求类型，如果请求类型为`*RequestCode.REGISTER_BROKER`，则请求最终转发到org.apache.rocketmq.namesrv.routeinfo.RouteInfoManager#registerBroker* + +代码太多，文字来描述一下： + +第一步：路由注册需要加写锁，防止并发修改RouteInfoManager中的路由表。首先判断Broker所属集群是否存在，如果不存在，则创建集群，然后将broker名加入集群。 + +第二步：维护BrokerData信息，首先从brokerAddrTable中根据 broker名尝试获取Broker信息，如果不存在，则新建BrokerData放入brokerAddrTable，registerFirst设置为true；如果存在，直接替换原先的Broker信息，registerFirst设置为false，表示非第一次注册 + +第三步：如果Broker为主节点，并且Broker的topic配置信息发生变化或者是初次注册，则需要创建或者更新topic的路由元数据，并填充topicQueueTable + +根据topicConfig创建QueueData数据结构然后更新topicQueueTable + +``` +private void createAndUpdateQueueData(final String brokerName, final TopicConfig topicConfig) { + QueueData queueData = new QueueData(); + queueData.setBrokerName(brokerName); + queueData.setWriteQueueNums(topicConfig.getWriteQueueNums()); + queueData.setReadQueueNums(topicConfig.getReadQueueNums()); + queueData.setPerm(topicConfig.getPerm()); + queueData.setTopicSysFlag(topicConfig.getTopicSysFlag()); + + Map queueDataMap = this.topicQueueTable.get(topicConfig.getTopicName()); + if (null == queueDataMap) { + queueDataMap = new HashMap<>(); + queueDataMap.put(queueData.getBrokerName(), queueData); + this.topicQueueTable.put(topicConfig.getTopicName(), queueDataMap); + log.info("new topic registered, {} {}", topicConfig.getTopicName(), queueData); + } else { + QueueData old = queueDataMap.put(queueData.getBrokerName(), queueData); + if (old != null && !old.equals(queueData)) { + log.info("topic changed, {} OLD: {} NEW: {}", topicConfig.getTopicName(), old, + queueData); + } + } +} +``` + +第四步：更新BrokerLiveInfo,存储状态正常的Broker信息表，BrokerLiveInfo是执行路由删除操作的重要依据。 + +``` +BrokerLiveInfo prevBrokerLiveInfo = this.brokerLiveTable.put(brokerAddr, + new BrokerLiveInfo( + System.currentTimeMillis(), + topicConfigWrapper.getDataVersion(), + channel, + haServerAddr)); +``` + +第五步：注册Broker的过滤器Server地址列表，一个Broker上会关联多个 FilterServer消息过滤服务器。如果此Broker为从节点，则需要查找该Broker的主节点信息，并更新对应的masterAddr属性 + +``` +if (MixAll.MASTER_ID!= brokerId) { + String masterAddr = brokerData.getBrokerAddrs().get(MixAll.MASTER_ID); + if (masterAddr != null) { + BrokerLiveInfo brokerLiveInfo = this.brokerLiveTable.get(masterAddr); + if (brokerLiveInfo != null) { + result.setHaServerAddr(brokerLiveInfo.getHaServerAddr()); + result.setMasterAddr(masterAddr); + } + } +} +``` + +总结： + + NameServer与Broker保持长连接，Broker的状态信息存储在BrokerLiveTable中，NameServer每收到一个心跳包，将更新brokerLiveTable中关于broker的状态信息以及路由表（topicQueueTable、brokerAddrTable、brokerLiveTable、filterServerTable）。更新上述路由表使用了锁粒度较少的读写锁，允许多个消息发送者并发读操作，保证消息发送时的高并发，同一时刻NameServer只处理一个Broker心跳包，多个心跳包请求串行执行。 + +NameServer如何剔除失效的Broker？ + +1、NameServer每隔十秒注册一次brokerLiveTable状态表，如果BrokerLive的lastUpdateTimestamp + +时间戳距当前时间超过120秒，则认为Broker失效，移除该Broker，关闭与broker的连接，同时更新topicQueueTable、brokerAddrTable、brokerLiveTable、filterServerTable。 + +2、如果broker在正常关闭的情况下，会发送unRegisterBroker指令。 + +不管是哪一种方式触发的路由删除，处理逻辑是一样的 + +第一步：申请写锁，移除brokerLiveTable、filterServerTable中Broker相关的信息 + +``` +this.lock.writeLock().lockInterruptibly(); +BrokerLiveInfo brokerLiveInfo = this.brokerLiveTable.remove(brokerAddr); +log.info("unregisterBroker, remove from brokerLiveTable {}, {}",brokerLiveInfo != null ? "OK" : "Failed",brokerAddr); +this.filterServerTable.remove(brokerAddr); +``` + +第二步：维护brokerAddrTable，找到具体的broker，将其从brokerData中移除，如果移除之后不再包含其他broker，则在brokerAddrtable移除该brokerName对应的数据 + +``` +BrokerData brokerData = this.brokerAddrTable.get(brokerName); +if (null != brokerData) { + String addr = brokerData.getBrokerAddrs().remove(brokerId); + log.info("unregisterBroker, remove addr from brokerAddrTable {}, {}",addr != null ? "OK" : "Failed",brokerAddr); + + if (brokerData.getBrokerAddrs().isEmpty()) { + this.brokerAddrTable.remove(brokerName); + log.info("unregisterBroker, remove name from brokerAddrTable OK, {}",brokerName); + removeBrokerName = true; + } +} +``` + +第三步：根据brokerName从clusterAddrTable中找到Broker并将其中集群中移除，如果移除后集群中不包含任何Broker，则将该集群从clusterAddrTable中移除 + +``` +if (removeBrokerName) { + Set nameSet = this.clusterAddrTable.get(clusterName); + if (nameSet != null) { + boolean removed = nameSet.remove(brokerName); + log.info("unregisterBroker, remove name from clusterAddrTable {}, {}",removed ? "OK" : "Failed",brokerName); + + if (nameSet.isEmpty()) { + this.clusterAddrTable.remove(clusterName); + log.info("unregisterBroker, remove cluster from clusterAddrTable {}",clusterName); + } + } + +} +``` + +第四步： 根据brokerName，遍历所有主题的队列，如果队列中包含当前broker的队列，则移除，如果topic中包含待移除的Broker的队列，从路由表中删除该topic + +``` +this.topicQueueTable.forEach((topic, queueDataMap) -> { + QueueData old = queueDataMap.remove(brokerName); + if (old != null) { + log.info("removeTopicByBrokerName, remove one broker's topic {} {}", topic, old); + } + + if (queueDataMap.size() == 0) { + noBrokerRegisterTopic.add(topic); + log.info("removeTopicByBrokerName, remove the topic all queue {}", topic); + } +}); +``` + +第五步： + +释放锁，完成路由删除 + +``` + finally { + this.lock.writeLock().unlock(); +} +``` \ No newline at end of file