RocketMq nameServer 启动流程

  启动源：

　　nameServer 启动是使用 org.apache.rocketmq.namesrv.NamesrvStartup main 方法启动的，脚手架这里就不多说了。

　　配置文件的配置信息请看这两个配置类的字段：

　　　　org.apache.rocketmq.remoting.netty.NettyServerConfig

　　　　org.apache.rocketmq.common.namesrv.NamesrvConfig 

启动流程：

　　1.设置脚手架进行初始化

　　2.设置nameService Netty 默认启动端口为9876 ，也可以通过 -n 或者配置文件进行修改

　　3.执行一些脚手架命令，进行配置NameSrvConfig 以及NettyServerConfig

　　4.实例化 NamesrvController

　　5.init NameSrv

　　6.启动NameSrv

public static NamesrvController main0(String[] args) {
         String rocketmqHome = System.getProperty(MixAll.ROCKETMQ_HOME_PROPERTY, System.getenv(MixAll.ROCKETMQ_HOME_ENV));
         System.out.println(rocketmqHome);

        System.setProperty(RemotingCommand.REMOTING_VERSION_KEY, Integer.toString(MQVersion.CURRENT_VERSION));
        try {
            //PackageConflictDetect.detectFastjson();
            //1.脚手架命令
            Options options = ServerUtil.buildCommandlineOptions(new Options());
            commandLine = ServerUtil.parseCmdLine("mqnamesrv", args, buildCommandlineOptions(options), new PosixParser());
            if (null == commandLine) {
                System.exit(-1);
                return null;
            }

            final NamesrvConfig namesrvConfig = new NamesrvConfig();
            final NettyServerConfig nettyServerConfig = new NettyServerConfig();
            //2.nameService 地址默认是9876 端口
            nettyServerConfig.setListenPort(9876);
            if (commandLine.hasOption('c')) {
                String file = commandLine.getOptionValue('c');
                if (file != null) {
                    InputStream in = new BufferedInputStream(new FileInputStream(file));
                    properties = new Properties();
                    properties.load(in);
                    //3. -c 命令文件配置信息初始化到NamesrvConfig NettyServerConfig 中
                    MixAll.properties2Object(properties, namesrvConfig);
                    MixAll.properties2Object(properties, nettyServerConfig);

                    namesrvConfig.setConfigStorePath(file);

                    System.out.printf("load config properties file OK, " + file + "%n");
                    in.close();
                }
            }

            if (commandLine.hasOption('p')) {
                MixAll.printObjectProperties(null, namesrvConfig);
                MixAll.printObjectProperties(null, nettyServerConfig);
                System.exit(0);
            }

            MixAll.properties2Object(ServerUtil.commandLine2Properties(commandLine), namesrvConfig);

            if (null == namesrvConfig.getRocketmqHome()) {
                System.out.printf("Please set the %s variable in your environment to match the location of the RocketMQ installation%n", MixAll.ROCKETMQ_HOME_ENV);
                System.exit(-2);
            }

            LoggerContext lc = (LoggerContext) LoggerFactory.getILoggerFactory();
            JoranConfigurator configurator = new JoranConfigurator();
            configurator.setContext(lc);
            lc.reset();
            configurator.doConfigure(namesrvConfig.getRocketmqHome() + "/conf/logback_namesrv.xml");
            final Logger log = LoggerFactory.getLogger(LoggerName.NAMESRV_LOGGER_NAME);

            MixAll.printObjectProperties(log, namesrvConfig);
            MixAll.printObjectProperties(log, nettyServerConfig);
            //4.实例化 NamesrvController 
            final NamesrvController controller = new NamesrvController(namesrvConfig, nettyServerConfig);

            // remember all configs to prevent discard
            controller.getConfiguration().registerConfig(properties);
            //5.初始化NameSrv 的信息
            boolean initResult = controller.initialize();
            if (!initResult) {
                controller.shutdown();
                System.exit(-3);
            }

            Runtime.getRuntime().addShutdownHook(new ShutdownHookThread(log, new Callable<Void>() {
                @Override
                public Void call() throws Exception {
                    controller.shutdown();
                    return null;
                }
            }));
            //6.启动NameSrv
            controller.start();

            String tip = "The Name Server boot success. serializeType=" + RemotingCommand.getSerializeTypeConfigInThisServer();
            log.info(tip);
            System.out.printf(tip + "%n");

            return controller;
        } catch (Throwable e) {
            e.printStackTrace();
            System.exit(-1);
        }

        return null;
    }

实例化Srv：

  public NamesrvController(NamesrvConfig namesrvConfig, NettyServerConfig nettyServerConfig) {
        this.namesrvConfig = namesrvConfig;
        //nettyServer 配置信息
        this.nettyServerConfig = nettyServerConfig;
        this.kvConfigManager = new KVConfigManager(this);
        //broker 路由信息管理器，用来管理存储broker 给我们发送的toipc 信息，这个很重要
        this.routeInfoManager = new RouteInfoManager();
        //连接检测
        this.brokerHousekeepingService = new BrokerHousekeepingService(this);
        this.configuration = new Configuration(
            log,
            this.namesrvConfig, this.nettyServerConfig
        );
        this.configuration.setStorePathFromConfig(this.namesrvConfig, "configStorePath");
    }

init NameSrv:

 public boolean initialize() {
        //加载 kvConfig.json 文件
        this.kvConfigManager.load();
        //Netty Server 初始化
        this.remotingServer = new NettyRemotingServer(this.nettyServerConfig, this.brokerHousekeepingService);

        this.remotingExecutor =
            Executors.newFixedThreadPool(nettyServerConfig.getServerWorkerThreads(), new ThreadFactoryImpl("RemotingExecutorThread_"));
        //注册nameSrv处理器
        this.registerProcessor();

        this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {

            @Override
            public void run() {
                NamesrvController.this.routeInfoManager.scanNotActiveBroker();
            }
        }, 5, 10, TimeUnit.SECONDS);
        //kv 打印定时任务
        this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {

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

        return true;
    }

启动NameSrv

    public void start() throws Exception {
        //Netty 服务端bind 9876 开始服务
        this.remotingServer.start();
    }

 从启动流程可以看到，NameSrv 只有一个服务端，没有客户端，不会主动与broker 以及consumer producer 进行交互 。

RouteInfoManager

 RouteInfoManager 维护了broker 中topic  ip  queue 等信息，是namesrv 重要的一个组成部分，Broker 向 namesrv 报告自身信息全部维护在 RouteInfoManager 中，以及consumer 

producter 都会从这里取到相关的信息。

private static final Logger log = LoggerFactory.getLogger(LoggerName.NAMESRV_LOGGER_NAME);
    private final static long BROKER_CHANNEL_EXPIRED_TIME = 1000 * 60 * 2;
    private final ReadWriteLock lock = new ReentrantReadWriteLock();
    //topic 对应的queueData 信息
    private final HashMap<String/* topic */, List<QueueData>> topicQueueTable;
    //brokerName 与Broker信息映射
    private final HashMap<String/* brokerName */, BrokerData> brokerAddrTable;
    //clipperName 与brokerName 映射
    private final HashMap<String/* clusterName */, Set<String/* brokerName */>> clusterAddrTable;
    private final HashMap<String/* brokerAddr */, BrokerLiveInfo> brokerLiveTable;
    private final HashMap<String/* brokerAddr */, List<String>/* Filter Server */> filterServerTable;

    public RouteInfoManager() {
        this.topicQueueTable = new HashMap<String, List<QueueData>>(1024);
        this.brokerAddrTable = new HashMap<String, BrokerData>(128);
        this.clusterAddrTable = new HashMap<String, Set<String>>(32);
        this.brokerLiveTable = new HashMap<String, BrokerLiveInfo>(256);
        this.filterServerTable = new HashMap<String, List<String>>(256);
    }