RocketMQ源码分析之rocketmq-broker启动 (二)

本文章会从以下几个方面介绍rocketmq-broker启动流程
1. Broker简单介绍
1.1 initialize
1.2 start
2. broker启动代码分析
2.1 roketmq-broker启动入口
2.2 通过createBrokerController创建BrokerController对象
2.3 执行initialize方法进行初始化操作
2.4. 通过start启动broker信息

一，broker简单介绍

broker是消息接收处理，落地的核心模块。这个模块用于接收producer发送的消息以及consumer消费的消息。
broker启动主要分为initialize和start两个步骤。

broker的启动流程

图一、broker启动流程图
1.1 initialize

1) broker启动会获取外部传入的初始化参数，也会从配置文件中加载相关的配置参数，将参数保存在对应的Configuration类当中, Configuration类包含的消息如下

broker自身的配置: 包括根目录， namesrv地址，broker的IP和名称，消息队列数，收发消息线程池数等参数
netty启动配置: 包括监听端口, 工作线程数, 异步发送消息信号量数量等参数。
存储层配置：包括存储根目录，CommitLog 配置，持久化策略配置等参数

2) 当配置信息设置完毕后, broker会将这些信息传入brokerController控制器当中，这个控制器会初始化加载很多的管理器

rocketmq配置文件信息可以参考如下链接地址
- https://blog.csdn.net/w_x_z_/article/details/70225303
- rocketMQ配置文件信息
topicManager : 用于管理broker中存储的所有topic的配置
consumerOffsetManager: 管理Consumer的消费进度
subscriptionGroupManager: 用来管理订阅组，包括订阅权限等
messageStore: 用于broker层的消息落地存储

3) 当管理器全部加载完毕后，控制器将开始进入下一步初始化

启动netty服务器，用于接收消息
初始化多个线程池，包括sendMessageExecutor、pullMessageExecutor、adminBrokerExecutor、clientManagerExecutor, 分别用于发送消息执行器、拉取消息执行器、broker管理器执行器、客户端管理执行器，这些执行器回放如线程池中处理, 来做并发执行。

1.2 start
当broker初始化了配置参数后，就可以开始启动了

启动刚刚初始化的各个管理器以后：topicManager , consumerOffsetManager, subscriptionGroupManager, messgeStoreManager
开启定时调度线程，每隔30s向nameSrv上报自己的信息
启动线程处理无用的topic

二、broker启动代码分析

2.1 roketmq-broker启动入口

    public class BrokerStartup {
        //...
        public static void main(String[] args) {
            start(createBrokerController(args));
        }
        //...
    }

第3-5行， broker启动程序入口, 包含两部分, createBrokerController(args) 和 start(brokerController)

2.2 通过createBrokerController创建BrokerController对象

public static BrokerController createBrokerController(String[] args) {
        System.setProperty(RemotingCommand.REMOTING_VERSION_KEY, Integer.toString(MQVersion.CURRENT_VERSION));

        if (null == System.getProperty(NettySystemConfig.COM_ROCKETMQ_REMOTING_SOCKET_SNDBUF_SIZE)) {
            NettySystemConfig.socketSndbufSize = 131072;
        }

        if (null == System.getProperty(NettySystemConfig.COM_ROCKETMQ_REMOTING_SOCKET_RCVBUF_SIZE)) {
            NettySystemConfig.socketRcvbufSize = 131072;
        }

        try {
            //PackageConflictDetect.detectFastjson();
            Options options = ServerUtil.buildCommandlineOptions(new Options());
            commandLine = ServerUtil.parseCmdLine("mqbroker", args, buildCommandlineOptions(options),
                new PosixParser());
            if (null == commandLine) {
                System.exit(-1);
            }

            final BrokerConfig brokerConfig = new BrokerConfig();
            final NettyServerConfig nettyServerConfig = new NettyServerConfig();
            final NettyClientConfig nettyClientConfig = new NettyClientConfig();

            nettyClientConfig.setUseTLS(Boolean.parseBoolean(System.getProperty(TLS_ENABLE,
                String.valueOf(TlsSystemConfig.tlsMode == TlsMode.ENFORCING))));
            nettyServerConfig.setListenPort(10911);
            final MessageStoreConfig messageStoreConfig = new MessageStoreConfig();

            if (BrokerRole.SLAVE == messageStoreConfig.getBrokerRole()) {
                int ratio = messageStoreConfig.getAccessMessageInMemoryMaxRatio() - 10;
                messageStoreConfig.setAccessMessageInMemoryMaxRatio(ratio);
            }

            if (commandLine.hasOption('c')) {
                String file = commandLine.getOptionValue('c');
                if (file != null) {
                    configFile = file;
                    InputStream in = new BufferedInputStream(new FileInputStream(file));
                    properties = new Properties();
                    properties.load(in);

                    properties2SystemEnv(properties);
                    MixAll.properties2Object(properties, brokerConfig);
                    MixAll.properties2Object(properties, nettyServerConfig);
                    MixAll.properties2Object(properties, nettyClientConfig);
                    MixAll.properties2Object(properties, messageStoreConfig);

                    BrokerPathConfigHelper.setBrokerConfigPath(file);
                    in.close();
                }
            }

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

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

            String namesrvAddr = brokerConfig.getNamesrvAddr();
            if (null != namesrvAddr) {
                try {
                    String[] addrArray = namesrvAddr.split(";");
                    for (String addr : addrArray) {
                        RemotingUtil.string2SocketAddress(addr);
                    }
                } catch (Exception e) {
                    System.out.printf(
                        "The Name Server Address[%s] illegal, please set it as follows, \"127.0.0.1:9876;192.168.0.1:9876\"%n",
                        namesrvAddr);
                    System.exit(-3);
                }
            }

            switch (messageStoreConfig.getBrokerRole()) {
                case ASYNC_MASTER:
                case SYNC_MASTER:
                    brokerConfig.setBrokerId(MixAll.MASTER_ID);
                    break;
                case SLAVE:
                    if (brokerConfig.getBrokerId() <= 0) {
                        System.out.printf("Slave's brokerId must be > 0");
                        System.exit(-3);
                    }

                    break;
                default:
                    break;
            }

            messageStoreConfig.setHaListenPort(nettyServerConfig.getListenPort() + 1);
            LoggerContext lc = (LoggerContext) LoggerFactory.getILoggerFactory();
            JoranConfigurator configurator = new JoranConfigurator();
            configurator.setContext(lc);
            lc.reset();
            configurator.doConfigure(brokerConfig.getRocketmqHome() + "/conf/logback_broker.xml");

            if (commandLine.hasOption('p')) {
                Logger console = LoggerFactory.getLogger(LoggerName.BROKER_CONSOLE_NAME);
                MixAll.printObjectProperties(console, brokerConfig);
                MixAll.printObjectProperties(console, nettyServerConfig);
                MixAll.printObjectProperties(console, nettyClientConfig);
                MixAll.printObjectProperties(console, messageStoreConfig);
                System.exit(0);
            } else if (commandLine.hasOption('m')) {
                Logger console = LoggerFactory.getLogger(LoggerName.BROKER_CONSOLE_NAME);
                MixAll.printObjectProperties(console, brokerConfig, true);
                MixAll.printObjectProperties(console, nettyServerConfig, true);
                MixAll.printObjectProperties(console, nettyClientConfig, true);
                MixAll.printObjectProperties(console, messageStoreConfig, true);
                System.exit(0);
            }

            log = LoggerFactory.getLogger(LoggerName.BROKER_LOGGER_NAME);
            MixAll.printObjectProperties(log, brokerConfig);
            MixAll.printObjectProperties(log, nettyServerConfig);
            MixAll.printObjectProperties(log, nettyClientConfig);
            MixAll.printObjectProperties(log, messageStoreConfig);

            final BrokerController controller = new BrokerController(
                brokerConfig,
                nettyServerConfig,
                nettyClientConfig,
                messageStoreConfig);
            // remember all configs to prevent discard
            controller.getConfiguration().registerConfig(properties);

            boolean initResult = controller.initialize();
            if (!initResult) {
                controller.shutdown();
                System.exit(-3);
            }

            Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {
                private volatile boolean hasShutdown = false;
                private AtomicInteger shutdownTimes = new AtomicInteger(0);

                @Override
                public void run() {
                    synchronized (this) {
                        log.info("Shutdown hook was invoked, {}", this.shutdownTimes.incrementAndGet());
                        if (!this.hasShutdown) {
                            this.hasShutdown = true;
                            long beginTime = System.currentTimeMillis();
                            controller.shutdown();
                            long consumingTimeTotal = System.currentTimeMillis() - beginTime;
                            log.info("Shutdown hook over, consuming total time(ms): {}", consumingTimeTotal);
                        }
                    }
                }
            }, "ShutdownHook"));

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

        return null;
    }

第2行，设置rocketMQ版本信息
第4-10行，校验远程通信的发送缓存和接收缓存是否为空, 如果为空则设置默认值大小为131072
- NettySystemConfig.socketSndbufSize = 131072;
- NettySystemConfig.socketRcvbufSize = 131072;
第14-19行，buildCommandlineOptions()构造命令行解析Options, 这个过程已经设置了h(help)、n(namesrvAddr)两个参数, 后面还会配置c(configFile), p(printConfigItem), m(printImportantConfig)；parseCmdLine()方法会对mqbroker启动命令进行解析(*nix系统), 比如: nohup ./mqbroker -n 192.168.2.1:9876 ; 如果解析的commandLine==null, 则退出
第35-52行，如果启动命令行参数包含 -c 参数，会读取配置到Propertis中, 让后通过MixAll.properties2Object(), 将读取的配置文件信息存入brokerConfig, nettyServerConfig, nettyClientConfig, messageStoreConfig对应的实体类中，最后将配置文件路径信息保存到BrokerPathConfigHelper中brokerConfigPath变量中
第54行，将其它命令行参数读取到Properties中，并将信息保存到brokerConfig对象中
第62-75行，从brokerConfig获取namesrvAddr信息，并将地址信息转为SocketAddress对象
第77-91行，设置当前broker的角色(master,slave), 如果是同步/异步MASTER信息，brokerId=0 ;如果是SLAVE信息，brokerId > 0 ; 如果brokerId < 0 , 会抛出异常
第116-121行，将log的信息配置到brokerConfig，nettyServerConfig，nettyClientConfig，messageStoreConfig对象中
第122-128行，通过brokerConfig，nettyServerConfig，nettyClientConfig，messageStoreConfig对象创建BrokerController对象，并将propertis中保存的信息保存到brokerController的Configuration属性中
第136-159行，通过Runtime.getRuntime().addShutdownHook()设置，在jvm关闭之前需要处理的一些事情，系统会处理内存清理、对象销毁等一系列操作, 这里是对brokerController进行关闭操作。

2.3 执行initialize方法进行初始化操作

public boolean initialize() throws CloneNotSupportedException {
        boolean result = this.topicConfigManager.load();

        result = result && this.consumerOffsetManager.load();
        result = result && this.subscriptionGroupManager.load();
        result = result && this.consumerFilterManager.load();

        if (result) {
            try {
                this.messageStore =
                    new DefaultMessageStore(this.messageStoreConfig, this.brokerStatsManager, this.messageArrivingListener,
                        this.brokerConfig);
                this.brokerStats = new BrokerStats((DefaultMessageStore) this.messageStore);
                //load plugin
                MessageStorePluginContext context = new MessageStorePluginContext(messageStoreConfig, brokerStatsManager, messageArrivingListener, brokerConfig);
                this.messageStore = MessageStoreFactory.build(context, this.messageStore);
                this.messageStore.getDispatcherList().addFirst(new CommitLogDispatcherCalcBitMap(this.brokerConfig, this.consumerFilterManager));
            } catch (IOException e) {
                result = false;
                log.error("Failed to initialize", e);
            }
        }

        result = result && this.messageStore.load();

        if (result) {
            this.remotingServer = new NettyRemotingServer(this.nettyServerConfig, this.clientHousekeepingService);
            NettyServerConfig fastConfig = (NettyServerConfig) this.nettyServerConfig.clone();
            fastConfig.setListenPort(nettyServerConfig.getListenPort() - 2);
            this.fastRemotingServer = new NettyRemotingServer(fastConfig, this.clientHousekeepingService);
            this.sendMessageExecutor = new BrokerFixedThreadPoolExecutor(
                this.brokerConfig.getSendMessageThreadPoolNums(),
                this.brokerConfig.getSendMessageThreadPoolNums(),
                1000 * 60,
                TimeUnit.MILLISECONDS,
                this.sendThreadPoolQueue,
                new ThreadFactoryImpl("SendMessageThread_"));

            this.pullMessageExecutor = new BrokerFixedThreadPoolExecutor(
                this.brokerConfig.getPullMessageThreadPoolNums(),
                this.brokerConfig.getPullMessageThreadPoolNums(),
                1000 * 60,
                TimeUnit.MILLISECONDS,
                this.pullThreadPoolQueue,
                new ThreadFactoryImpl("PullMessageThread_"));

            this.queryMessageExecutor = new BrokerFixedThreadPoolExecutor(
                this.brokerConfig.getQueryMessageThreadPoolNums(),
                this.brokerConfig.getQueryMessageThreadPoolNums(),
                1000 * 60,
                TimeUnit.MILLISECONDS,
                this.queryThreadPoolQueue,
                new ThreadFactoryImpl("QueryMessageThread_"));

            this.adminBrokerExecutor =
                Executors.newFixedThreadPool(this.brokerConfig.getAdminBrokerThreadPoolNums(), new ThreadFactoryImpl(
                    "AdminBrokerThread_"));

            this.clientManageExecutor = new ThreadPoolExecutor(
                this.brokerConfig.getClientManageThreadPoolNums(),
                this.brokerConfig.getClientManageThreadPoolNums(),
                1000 * 60,
                TimeUnit.MILLISECONDS,
                this.clientManagerThreadPoolQueue,
                new ThreadFactoryImpl("ClientManageThread_"));

            this.consumerManageExecutor =
                Executors.newFixedThreadPool(this.brokerConfig.getConsumerManageThreadPoolNums(), new ThreadFactoryImpl(
                    "ConsumerManageThread_"));

            this.registerProcessor();

            final long initialDelay = UtilAll.computNextMorningTimeMillis() - System.currentTimeMillis();
            final long period = 1000 * 60 * 60 * 24;
            this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
                @Override
                public void run() {
                    try {
                        BrokerController.this.getBrokerStats().record();
                    } catch (Throwable e) {
                        log.error("schedule record error.", e);
                    }
                }
            }, initialDelay, period, TimeUnit.MILLISECONDS);

            this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
                @Override
                public void run() {
                    try {
                        BrokerController.this.consumerOffsetManager.persist();
                    } catch (Throwable e) {
                        log.error("schedule persist consumerOffset error.", e);
                    }
                }
            }, 1000 * 10, this.brokerConfig.getFlushConsumerOffsetInterval(), TimeUnit.MILLISECONDS);

            this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
                @Override
                public void run() {
                    try {
                        BrokerController.this.consumerFilterManager.persist();
                    } catch (Throwable e) {
                        log.error("schedule persist consumer filter error.", e);
                    }
                }
            }, 1000 * 10, 1000 * 10, TimeUnit.MILLISECONDS);

            this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
                @Override
                public void run() {
                    try {
                        BrokerController.this.protectBroker();
                    } catch (Throwable e) {
                        log.error("protectBroker error.", e);
                    }
                }
            }, 3, 3, TimeUnit.MINUTES);

            this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
                @Override
                public void run() {
                    try {
                        BrokerController.this.printWaterMark();
                    } catch (Throwable e) {
                        log.error("printWaterMark error.", e);
                    }
                }
            }, 10, 1, TimeUnit.SECONDS);

            this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {

                @Override
                public void run() {
                    try {
                        log.info("dispatch behind commit log {} bytes", BrokerController.this.getMessageStore().dispatchBehindBytes());
                    } catch (Throwable e) {
                        log.error("schedule dispatchBehindBytes error.", e);
                    }
                }
            }, 1000 * 10, 1000 * 60, TimeUnit.MILLISECONDS);

            if (this.brokerConfig.getNamesrvAddr() != null) {
                this.brokerOuterAPI.updateNameServerAddressList(this.brokerConfig.getNamesrvAddr());
                log.info("Set user specified name server address: {}", this.brokerConfig.getNamesrvAddr());
            } else if (this.brokerConfig.isFetchNamesrvAddrByAddressServer()) {
                this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {

                    @Override
                    public void run() {
                        try {
                            BrokerController.this.brokerOuterAPI.fetchNameServerAddr();
                        } catch (Throwable e) {
                            log.error("ScheduledTask fetchNameServerAddr exception", e);
                        }
                    }
                }, 1000 * 10, 1000 * 60 * 2, TimeUnit.MILLISECONDS);
            }

            if (BrokerRole.SLAVE == this.messageStoreConfig.getBrokerRole()) {
                if (this.messageStoreConfig.getHaMasterAddress() != null && this.messageStoreConfig.getHaMasterAddress().length() >= 6) {
                    this.messageStore.updateHaMasterAddress(this.messageStoreConfig.getHaMasterAddress());
                    this.updateMasterHAServerAddrPeriodically = false;
                } else {
                    this.updateMasterHAServerAddrPeriodically = true;
                }

                this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {

                    @Override
                    public void run() {
                        try {
                            BrokerController.this.slaveSynchronize.syncAll();
                        } catch (Throwable e) {
                            log.error("ScheduledTask syncAll slave exception", e);
                        }
                    }
                }, 1000 * 10, 1000 * 60, TimeUnit.MILLISECONDS);
            } else {
                this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {

                    @Override
                    public void run() {
                        try {
                            BrokerController.this.printMasterAndSlaveDiff();
                        } catch (Throwable e) {
                            log.error("schedule printMasterAndSlaveDiff error.", e);
                        }
                    }
                }, 1000 * 10, 1000 * 60, TimeUnit.MILLISECONDS);
            }
        }

        return result;
    }

第2-6行, 加载topicConfigManager、consumerOffsetManager、subscriptionGroupManager、consumerFilterManager ，将加载结果成功与否存储在result中
第8-22行，如果前面的资源加载成功，会构建messageStore对象信息，在加载插件plugins到content后，会通过MessageStoreFactory.build()再次处理messageStore信息，最后通过load()方法加载messageStore信息
第26-191行，校验资源加载result是否成功，如果不成功，则直接返回result结果false, 如果result = true,
1) 创建sendMessageExecutor、pullMessageExecutor、queryMessageExecutor、adminBrokerExecutor、clientManageExecutor、consumerManageExecutor执行器信息
2) 通过registerProcessor()方法向remotingServer, fastRemotingServer对象中注册刚刚创建的执行器(Excuter)信息
3) 通过scheduledExecutorService:ScheduledExecutorService 对象，定期查询如下信息
- BrokerController.this.getBrokerStats().record(); 记录broker的状态
- BrokerController.this.consumerOffsetManager.persist(); 消费者当前信息的offset位置
- BrokerController.this.consumerFilterManager.persist(); 消费者filterManaer信息
- BrokerController.this.protectBroker(); Broker信息
- BrokerController.this.printWaterMark();
- BrokerController.this.getMessageStore().dispatchBehindBytes() 打印日志信息
- BrokerController.this.brokerOuterAPI.fetchNameServerAddr(); 获取namesrv地址信息
- BrokerController.this.slaveSynchronize.syncAll(); 同步从broker信息，

2.4. 通过start启动broker信息

public static BrokerController start(BrokerController controller) {
        try {
            controller.start();
            // ...
            return controller;
        } catch (Throwable e) {
            e.printStackTrace();
            System.exit(-1);
        }
        return null;
    }

第3行，启动brokerControler

public void start() throws Exception {
        if (this.messageStore != null) {
            this.messageStore.start();
        }

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

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

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

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

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

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

        this.registerBrokerAll(true, false);
        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);
        //...
    }

第2-28行，如果参数校验不为空，则启动messageStore、remotingServer、fastRemotingServer、brokerOuterAPI、pullRequestHoldService、clientHousekeepingService、filterServerManager相关信息
第30-40行，通过方法registerBrokerAll()开启调度线程，每隔30s,向namesrv上报自己的信息，处理无用的topic

上面是关于broker启动的源码分析, 后面有新的理解会在此文章的基础上进行修改。