Rocket MQ 2 - Namesrv

通过上文中使用可以看到，主要逻辑还是在NamesrvController中包含KVConfigManager负责配置相关的读写，RouteInfoManager负责路由信息的管理;

启动定时任务定时打印配置信息，另一个定时任务去检测是broker是否超时，整个远程通信是利用NettyRemotingServer

package org.apache.rocketmq.namesrv;
......
/**
 * it-worker's comments: 主要包含了各种配置的读取，配置管理和路由管理，远程调度依赖remoteserver，通过两个定时任务打印配置项并且扫描Broker是否下线
 */
public class NamesrvController {
    private static final Logger log = LoggerFactory.getLogger(LoggerName.NAMESRV_LOGGER_NAME);
    private final NamesrvConfig namesrvConfig;
    private final NettyServerConfig nettyServerConfig;
    private final ScheduledExecutorService scheduledExecutorService = Executors.newSingleThreadScheduledExecutor(new ThreadFactoryImpl(
        "NSScheduledThread"));
    private final KVConfigManager kvConfigManager;
    private final RouteInfoManager routeInfoManager;
    private RemotingServer remotingServer;
    private BrokerHousekeepingService brokerHousekeepingService;
    private ExecutorService remotingExecutor;
    private Configuration configuration;
    ......
    public boolean initialize() {
        this.kvConfigManager.load();
        this.remotingServer = new NettyRemotingServer(this.nettyServerConfig, this.brokerHousekeepingService);
        this.remotingExecutor =
            Executors.newFixedThreadPool(nettyServerConfig.getServerWorkerThreads(), new ThreadFactoryImpl("RemotingExecutorThread_"));
        this.registerProcessor();
        this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
            @Override
            public void run() {
                NamesrvController.this.routeInfoManager.scanNotActiveBroker();
            }
        }, 5, 10, TimeUnit.SECONDS);

        this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
            @Override
            public void run() {
                NamesrvController.this.kvConfigManager.printAllPeriodically();
            }
        }, 1, 10, TimeUnit.MINUTES);

        return true;
    }

    private void registerProcessor() {
        if (namesrvConfig.isClusterTest()) {
            this.remotingServer.registerDefaultProcessor(new ClusterTestRequestProcessor(this, namesrvConfig.getProductEnvName()),
                this.remotingExecutor);
        } else {

            this.remotingServer.registerDefaultProcessor(new DefaultRequestProcessor(this), this.remotingExecutor);
        }
    }

    public void start() throws Exception {
        this.remotingServer.start();
        this.fileWatchService.start();

    }

    public void shutdown() {
        this.remotingServer.shutdown();
        this.remotingExecutor.shutdown();
        this.scheduledExecutorService.shutdown();
    }
    ......
}

检测broker，遍历，看最后修改时间，如果时间过长则删除，标记为不可用Broker

    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());
            }
        }
    }

新版本增加了对于Tls的文件监听和自动重新加载，启动的时候在启动remoteserver的同时也启动this.fileWatchService.start();

        if (TlsSystemConfig.tlsMode != TlsMode.DISABLED) {
            // Register a listener to reload SslContext
            try {
                fileWatchService = new FileWatchService(
                    new String[] {
                        TlsSystemConfig.tlsServerCertPath,
                        TlsSystemConfig.tlsServerKeyPath,
                        TlsSystemConfig.tlsServerTrustCertPath
                    },
                    new FileWatchService.Listener() {
                        boolean certChanged, keyChanged = false;
                        @Override
                        public void onChanged(String path) {
                            if (path.equals(TlsSystemConfig.tlsServerTrustCertPath)) {
                                log.info("The trust certificate changed, reload the ssl context");
                                reloadServerSslContext();
                            }
                            if (path.equals(TlsSystemConfig.tlsServerCertPath)) {
                                certChanged = true;
                            }
                            if (path.equals(TlsSystemConfig.tlsServerKeyPath)) {
                                keyChanged = true;
                            }
                            if (certChanged && keyChanged) {
                                log.info("The certificate and private key changed, reload the ssl context");
                                certChanged = keyChanged = false;
                                reloadServerSslContext();
                            }
                        }
                        private void reloadServerSslContext() {
                            ((NettyRemotingServer) remotingServer).loadSslContext();
                        }
                    });
            } catch (Exception e) {
                log.warn("FileWatchService created error, can't load the certificate dynamically");
            }
        }

对于配置管理其实没啥好说的，主要看下路由管理可以看到主要数据还是保存在一个hashmap中

从RocketMQ技术内幕书上截取的运行时系统存储信息示意图，非常清楚，可以看出内存结构中，包含了不同纬度的信息