RocketMq源码学习（一） nameService

public class NamesrvStartup {
    public static Properties properties = null;
    public static CommandLine commandLine = null;

    public static void main(String[] args) {
        main0(args);
    }

    public static NamesrvController main0(String[] args) {
        System.setProperty(RemotingCommand.REMOTING_VERSION_KEY, Integer.toString(MQVersion.CURRENT_VERSION));
        try {
            //PackageConflictDetect.detectFastjson();

            Options options = ServerUtil.buildCommandlineOptions(new Options());------------args是用java -jar 后面输入的字符串，按照键值对输入的，这一步是解析命令行的参数，c是指定config的配置文件，p看样子是退出？
            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();
            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);
                    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);
----------------这个controller是关键类，传入两个配置文件进去
            final NamesrvController controller = new NamesrvController(namesrvConfig, nettyServerConfig);

            // remember all configs to prevent discard
            controller.getConfiguration().registerConfig(properties);
--------------看下面的start方法，实际是调用controller中的一个叫remotingServer的参数的start方法，而remotingServer的赋值就是在这个initialize方法中，new一个NettyRemotingServer出来，是调用netty的入口（见下文）
            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;
                }
            }));

            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;
    }

    public static Options buildCommandlineOptions(final Options options) {
        Option opt = new Option("c", "configFile", true, "Name server config properties file");
        opt.setRequired(false);
        options.addOption(opt);

        opt = new Option("p", "printConfigItem", false, "Print all config item");
        opt.setRequired(false);
        options.addOption(opt);

        return options;
    }
}

sh ${ROCKETMQ_HOME}/bin/runserver.sh com.alibaba.rocketmq.namesrv.NamesrvStartup $@--------上面这行代码是bin目录下的mqnamesrv文件中的命令，执行NamesrvStartup 的Main方法，启动nameServer，既然是用netty作为io框架来做服务端，必然有netty两个线程池的eventloop

 @Override------------NettyRemotingServer的start方法，eventLoopGroupBoss是父线程池，管理端口监控连接的，eventLoopGroupSelector 是子线程池，select channel的读写，处理业务逻辑的
    public void start() {
        this.defaultEventExecutorGroup = new DefaultEventExecutorGroup(
            nettyServerConfig.getServerWorkerThreads(),
            new ThreadFactory() {

                private AtomicInteger threadIndex = new AtomicInteger(0);

                @Override
                public Thread newThread(Runnable r) {
                    return new Thread(r, "NettyServerCodecThread_" + this.threadIndex.incrementAndGet());
                }
            });

        ServerBootstrap childHandler =
            this.serverBootstrap.group(this.eventLoopGroupBoss, this.eventLoopGroupSelector)
                .channel(useEpoll() ? EpollServerSocketChannel.class : NioServerSocketChannel.class)
                .option(ChannelOption.SO_BACKLOG, 1024)
                .option(ChannelOption.SO_REUSEADDR, true)
                .option(ChannelOption.SO_KEEPALIVE, false)
                .childOption(ChannelOption.TCP_NODELAY, true)
                .childOption(ChannelOption.SO_SNDBUF, nettyServerConfig.getServerSocketSndBufSize())
                .childOption(ChannelOption.SO_RCVBUF, nettyServerConfig.getServerSocketRcvBufSize())
                .localAddress(new InetSocketAddress(this.nettyServerConfig.getListenPort()))-----------根据之前分析netty可以知道，initchannel方法中添加的handler，每一个channel在accept生成的时候，都会把childHandler给添加到自己的pipeline当中去，当然initChannel方法中的handler也会添加进去，这几个handler一定有处理服务注册和服务发现相关逻辑的。
                .childHandler(new ChannelInitializer<SocketChannel>() {
                    @Override
                    public void initChannel(SocketChannel ch) throws Exception {
                        ch.pipeline()
                            .addLast(defaultEventExecutorGroup, HANDSHAKE_HANDLER_NAME,
                                new HandshakeHandler(TlsSystemConfig.tlsMode))
                            .addLast(defaultEventExecutorGroup,//这里用的netty的第三个线程池，把channel的读写和在pipeline中的数据处理分开-----------------Encoder和Decoder的encode/decode方法之所以能使用，是被继承的适配器中的channelread/write调用了
                                new NettyEncoder(),
                                new NettyDecoder(),-----------------------检测心跳，长时间没有数据的连接关闭掉
                                new IdleStateHandler(0, 0, nettyServerConfig.getServerChannelMaxIdleTimeSeconds()),-----------------------------重写了register，active等方法
                                new NettyConnectManageHandler(),-----------------------------核心的数据处理类，明天再看
                                new NettyServerHandler()
                            );
                    }
                });

        if (nettyServerConfig.isServerPooledByteBufAllocatorEnable()) {
            childHandler.childOption(ChannelOption.ALLOCATOR, PooledByteBufAllocator.DEFAULT);
        }

        try {
            ChannelFuture sync = this.serverBootstrap.bind().sync();
            InetSocketAddress addr = (InetSocketAddress) sync.channel().localAddress();
            this.port = addr.getPort();
        } catch (InterruptedException e1) {
            throw new RuntimeException("this.serverBootstrap.bind().sync() InterruptedException", e1);
        }

        if (this.channelEventListener != null) {
            this.nettyEventExecutor.start();
        }

        this.timer.scheduleAtFixedRate(new TimerTask() {

            @Override
            public void run() {
                try {
                    NettyRemotingServer.this.scanResponseTable();
                } catch (Throwable e) {
                    log.error("scanResponseTable exception", e);
                }
            }
        }, 1000 * 3, 1000);
    }