RocketMQ之NameServer学习笔记

org.apache.rocketmq.namesrv.NamesrvController

    NameserController,NameServer的核心控制类。

1.1 NamesrvConfig 

NamesrvConfig,主要指定nameserver的相关配置目录属性

1）kvConfigPath(kvConfig.json)

2）mqhome/namesrv/namesrv.properties

3）orderMessageEnable，是否开启顺序消息功能，默认为false

 

1.2 ScheduledExecutorService scheduledExecutorService

    private final ScheduledExecutorService scheduledExecutorService = Executors.newSingleThreadScheduledExecutor(new ThreadFactoryIm               pl("NSScheduledThread"));

   NameServer 定时任务执行线程池，一个线程，默认定时执行两个任务：

   任务一、每隔10s扫描broker,维护当前存活的Broker信息

   任务二、每隔10s打印KVConfig信息。

 

1.3 KVConfigManager 

   读取或变动NameServer的配置属性，加载NamesrvConfig中配置的配置文件到内存，此类一个亮点就是使用轻量级的非线程安全容器，再结合读写锁对资源读写进行保护。尽最大程度提升线程的并发度。

 

1.4 RouteInfoManager 

    NameServer数据的载体，记录Broker,Topic等信息。

//NameServer 与 Broker 空闲时长，默认2分钟，在2分钟内Nameserver没有收到Broker的心跳包，则关闭该链接。 
private final static long BROKER_CHANNEL_EXPIRED_TIME = 1000 * 60 * 2; //读写锁，用来保护非线程安全容器HashMap 
    private final ReadWriteLock lock = new ReentrantReadWriteLock(); //topicQueueTable，主题与队列关系，记录一个主题的队列分布在哪些Broker上，每一个Broker上存在该主题的队列个数 
    private final HashMap<String/* topic */, List<QueueData>> topicQueueTable; //brokerAddrTable,全部Broker信息，使用brokerName当key,BrokerData信息描述每个broker信息。
    private final HashMap<String/* brokerName */, BrokerData> brokerAddrTable; //clusterAddrTable，broker集群信息，每一个集群包含哪些Broker 
    private final HashMap<String/* clusterName */, Set<String/* brokerName */>> clusterAddrTable; //brokerLiveTable，当前存活的Broker,该信息不是实时的，NameServer每10S扫描一次全部的broker,根据心跳包的时间得知broker的状态，该机制也是致使当一个master Down掉后，消息生产者没法感知，可能继续向Down掉的Master发送消息，致使失败
    private final HashMap<String/* brokerAddr */, BrokerLiveInfo> brokerLiveTable; private final HashMap<String/* brokerAddr */, List<String>/* Filter Server */> filterServerTable;        

/** * Broker信息；key为brokerName，value为BrokerData */
private final HashMap<String/* brokerName */, BrokerData> brokerAddrTable; public class BrokerData implements Comparable<BrokerData> { /** * Cluster名称 */
    private String cluster; /** * broker名称 */
    private String brokerName; /** * 0->ip:port */
    private HashMap<Long/* brokerId */, String/* broker address */> brokerAddrs; }

• 注册topic信息topicQueueTable

/** * 消息队列路由信息；key为topic，value为QueueData */
private final HashMap<String/* topic */, List<QueueData>> topicQueueTable; public class QueueData implements Comparable<QueueData> { /** * Broker名称 */
    private String brokerName; /** * 读队列个数，默认4个 */
    private int readQueueNums; /** * 写队列个数，默认4个 */
    private int writeQueueNums; /** * 队列权限 */
    private int perm; /** * 配置的,同步复制仍是异步复制标记,对应TopicConfig.topicSysFlag * */
    private int topicSynFlag; }

/** * Broker状态信息，NameServer每次收到心跳包会替换该信息，每隔30秒更新一次 * brokerAddr: ip:port->{} */
private final HashMap<String/* brokerAddr */, BrokerLiveInfo> brokerLiveTable; class BrokerLiveInfo { /** * 存储上次收到心跳包的时间,每隔30秒更新一次 */
    private long lastUpdateTimestamp; private DataVersion dataVersion; private Channel channel; private String haServerAddr; }

 

 

• NamesrvStartup.java 启动入口类，NameServer 启动默认端口9876

nettyServerConfig.setListenPort(9876)

• 每10秒钟扫描一次，移除失效的broker，同时删除缓存元数据信息

//初始化NameServer
boolean initResult = controller.initialize(); public boolean initialize() { //加载KV配置
    this.kvConfigManager.load(); this.remotingServer = new NettyRemotingServer(this.nettyServerConfig, this.brokerHousekeepingService); this.remotingExecutor = Executors.newFixedThreadPool(nettyServerConfig.getServerWorkerThreads(), new ThreadFactoryImpl("RemotingExecutorThread_")); this.registerProcessor(); //每10秒钟扫描一次，移除失效的broker
    this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() { @Override public void run() { NamesrvController.this.routeInfoManager.scanNotActiveBroker(); } }, 5, 10, TimeUnit.SECONDS); //每隔10秒钟打印一次KV配置信息
    this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() { @Override public void run() { NamesrvController.this.kvConfigManager.printAllPeriodically(); } }, 1, 10, TimeUnit.MINUTES); return true; }

 

• 失效时间为2分钟，即：Broker在2分钟内未上报心跳会被移除

/** * 失效时间为2分钟，即：Broker在2分钟内未上报心跳会被移除 */
public void scanNotActiveBroker() { Iterator<Entry<String, BrokerLiveInfo>> it = this.brokerLiveTable.entrySet().iterator(); while (it.hasNext()) { Entry<String, BrokerLiveInfo> 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()); } } } private final static long BROKER_CHANNEL_EXPIRED_TIME = 1000 * 60 * 2;

2.DefaultRequestProcessor

• 用于响应客户端、Broker的请求。主要向NameServer发送心跳包、获取Cluster、Broker、Topic元数据信息。
• 调用链：
  在NameServer启动时注册，NamesrvController.initialize()->registerProcessor()

public RemotingCommand processRequest(ChannelHandlerContext ctx, RemotingCommand request) throws RemotingCommandException { if (log.isDebugEnabled()) { log.debug("receive request, {} {} {}", request.getCode(), RemotingHelper.parseChannelRemoteAddr(ctx.channel()), request); } switch (request.getCode()) { case RequestCode.PUT_KV_CONFIG://增长NameServer配置信息；由DefaultMQAdminExt使用
            return this.putKVConfig(ctx, request); case RequestCode.GET_KV_CONFIG://根据NameSpace和key获取NameServer配置信息；由DefaultMQAdminExt使用
            return this.getKVConfig(ctx, request); case RequestCode.DELETE_KV_CONFIG: //据NameSapce和Key删除NameServerr配置信息
            return this.deleteKVConfig(ctx, request); case RequestCode.REGISTER_BROKER: //注册Broker信息；由BrokerOuterAPI.registerBroker使用，在BrokerController启动时调用
            Version brokerVersion = MQVersion.value2Version(request.getVersion()); if (brokerVersion.ordinal() >= MQVersion.Version.V3_0_11.ordinal()) { return this.registerBrokerWithFilterServer(ctx, request); } else { return this.registerBroker(ctx, request); } case RequestCode.UNREGISTER_BROKER://移除注销broker信息；由BrokerOuterAPI.unregisterBroker使用，在BrokerController.shutdown时调用
            return this.unregisterBroker(ctx, request); case RequestCode.GET_ROUTEINTO_BY_TOPIC: //获取Topic路由信息 TopicRouteData
            return this.getRouteInfoByTopic(ctx, request); case RequestCode.GET_BROKER_CLUSTER_INFO://获取Cluster及Broker信息
            return this.getBrokerClusterInfo(ctx, request); case RequestCode.WIPE_WRITE_PERM_OF_BROKER: //去除该broker上全部topic的写权限
            return this.wipeWritePermOfBroker(ctx, request); case RequestCode.GET_ALL_TOPIC_LIST_FROM_NAMESERVER: //获取全部的Topic列表
            return getAllTopicListFromNameserver(ctx, request); case RequestCode.DELETE_TOPIC_IN_NAMESRV: //从nameServer中删除topic
            return deleteTopicInNamesrv(ctx, request); case RequestCode.GET_KVLIST_BY_NAMESPACE: //获取配置信息 configTable
            return this.getKVListByNamespace(ctx, request); case RequestCode.GET_TOPICS_BY_CLUSTER: //获取该集群下的全部topic list
            return this.getTopicsByCluster(ctx, request); case RequestCode.GET_SYSTEM_TOPIC_LIST_FROM_NS: // 此处意思为：系统会将集群名称、broker名称做为默认topic建立。如今获取这类topic
            return this.getSystemTopicListFromNs(ctx, request); case RequestCode.GET_UNIT_TOPIC_LIST: //暂无使用
            return this.getUnitTopicList(ctx, request); case RequestCode.GET_HAS_UNIT_SUB_TOPIC_LIST: //暂无使用
            return this.getHasUnitSubTopicList(ctx, request); case RequestCode.GET_HAS_UNIT_SUB_UNUNIT_TOPIC_LIST://暂无使用
            return this.getHasUnitSubUnUnitTopicList(ctx, request); case RequestCode.UPDATE_NAMESRV_CONFIG: //更新properties请求
            return this.updateConfig(ctx, request); case RequestCode.GET_NAMESRV_CONFIG: //获取properties内容
            return this.getConfig(ctx, request); default: break; } return null; }

注册broker信息

• Broker每隔30秒向全部的NameServer上报Topic注册信息
• Broker调用链

  BrokerController.start()->this.registerBrokerAll()->this.brokerOuterAPI.registerBrokerAll()

//每隔30秒向全部的NameServer上报Topic注册信息
this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() { @Override public void run() { try { BrokerController.this.registerBrokerAll(true, false); } catch (Throwable e) { log.error("registerBrokerAll Exception", e); } } }, 1000 * 10, 1000 * 30, TimeUnit.MILLISECONDS);

• 服务端处理主要包括：注册集群信息clusterAddrTable、注册broker信息brokerAddrTable、
  注册topic信息topicQueueTable、broker心跳包brokerLiveTable
• NameServer处理链

  DefaultRequestProcessor->processRequest->RequestCode.REGISTER_BROKER->this.registerBroker->RouteInfoManager.registerBroker()

public RegisterBrokerResult registerBroker( final String clusterName, final String brokerAddr, final String brokerName, final long brokerId, final String haServerAddr, final TopicConfigSerializeWrapper topicConfigWrapper, final List<String> filterServerList, final Channel channel) { RegisterBrokerResult result = new RegisterBrokerResult(); try { try { //加写锁，防止并发修改
            this.lock.writeLock().lockInterruptibly(); //注册集群信息
            Set<String> brokerNames = this.clusterAddrTable.get(clusterName); if (null == brokerNames) { brokerNames = new HashSet<String>(); this.clusterAddrTable.put(clusterName, brokerNames); } brokerNames.add(brokerName); boolean registerFirst = false; //注册broker信息
            BrokerData brokerData = this.brokerAddrTable.get(brokerName); if (null == brokerData) { registerFirst = true; brokerData = new BrokerData(clusterName, brokerName, new HashMap<Long, String>()); this.brokerAddrTable.put(brokerName, brokerData); } String oldAddr = brokerData.getBrokerAddrs().put(brokerId, brokerAddr); registerFirst = registerFirst || (null == oldAddr); //Topic配置变化了；Master Broker第一次注册或者Topic dataVersion不相同时更新路由信息 //有Topic新增时dataVersion会递增
            if (null != topicConfigWrapper //                 && MixAll.MASTER_ID == brokerId) { if (this.isBrokerTopicConfigChanged(brokerAddr, topicConfigWrapper.getDataVersion())//                     || registerFirst) { ConcurrentMap<String, TopicConfig> tcTable = topicConfigWrapper.getTopicConfigTable(); if (tcTable != null) { for (Map.Entry<String, TopicConfig> entry : tcTable.entrySet()) { this.createAndUpdateQueueData(brokerName, entry.getValue()); //更新topicQueueTable
 } } } } //更新broker心跳信息
            BrokerLiveInfo prevBrokerLiveInfo = this.brokerLiveTable.put(brokerAddr, new BrokerLiveInfo( System.currentTimeMillis(), topicConfigWrapper.getDataVersion(), channel, haServerAddr)); //新broker注册时会有日志输出
            if (null == prevBrokerLiveInfo) { log.info("new broker registerd, {} HAServer: {}", brokerAddr, haServerAddr); } //更新filterServer信息
            if (filterServerList != null) { if (filterServerList.isEmpty()) { this.filterServerTable.remove(brokerAddr); } else { this.filterServerTable.put(brokerAddr, filterServerList); } } //Slave设置MasterAddr和HaServerAddr
            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); } } } } finally { this.lock.writeLock().unlock(); } } catch (Exception e) { log.error("registerBroker Exception", e); } return result; }