RocketMQ中Broker的启动源码分析（一）

在RocketMQ中，使用BrokerStartup作为启动类，相较于NameServer的启动，Broker作为RocketMQ的核心可复杂得多

主函数作为其启动的入口：

1 public static void main(String[] args) {
2     start(createBrokerController(args));
3 }

首先通过createBrokerController方法生成Broker的控制器BrokerController

createBrokerController方法：

  1 public static BrokerController createBrokerController(String[] args) {
  2     System.setProperty(RemotingCommand.REMOTING_VERSION_KEY, Integer.toString(MQVersion.CURRENT_VERSION));
  3 
  4     if (null == System.getProperty(NettySystemConfig.COM_ROCKETMQ_REMOTING_SOCKET_SNDBUF_SIZE)) {
  5         NettySystemConfig.socketSndbufSize = 131072;
  6     }
  7 
  8     if (null == System.getProperty(NettySystemConfig.COM_ROCKETMQ_REMOTING_SOCKET_RCVBUF_SIZE)) {
  9         NettySystemConfig.socketRcvbufSize = 131072;
 10     }
 11 
 12     try {
 13         //PackageConflictDetect.detectFastjson();
 14         Options options = ServerUtil.buildCommandlineOptions(new Options());
 15         commandLine = ServerUtil.parseCmdLine("mqbroker", args, buildCommandlineOptions(options),
 16             new PosixParser());
 17         if (null == commandLine) {
 18             System.exit(-1);
 19         }
 20 
 21         final BrokerConfig brokerConfig = new BrokerConfig();
 22         final NettyServerConfig nettyServerConfig = new NettyServerConfig();
 23         final NettyClientConfig nettyClientConfig = new NettyClientConfig();
 24 
 25         nettyClientConfig.setUseTLS(Boolean.parseBoolean(System.getProperty(TLS_ENABLE,
 26             String.valueOf(TlsSystemConfig.tlsMode == TlsMode.ENFORCING))));
 27         nettyServerConfig.setListenPort(10911);
 28         final MessageStoreConfig messageStoreConfig = new MessageStoreConfig();
 29 
 30         if (BrokerRole.SLAVE == messageStoreConfig.getBrokerRole()) {
 31             int ratio = messageStoreConfig.getAccessMessageInMemoryMaxRatio() - 10;
 32             messageStoreConfig.setAccessMessageInMemoryMaxRatio(ratio);
 33         }
 34 
 35         if (commandLine.hasOption('c')) {
 36             String file = commandLine.getOptionValue('c');
 37             if (file != null) {
 38                 configFile = file;
 39                 InputStream in = new BufferedInputStream(new FileInputStream(file));
 40                 properties = new Properties();
 41                 properties.load(in);
 42 
 43                 properties2SystemEnv(properties);
 44                 MixAll.properties2Object(properties, brokerConfig);
 45                 MixAll.properties2Object(properties, nettyServerConfig);
 46                 MixAll.properties2Object(properties, nettyClientConfig);
 47                 MixAll.properties2Object(properties, messageStoreConfig);
 48 
 49                 BrokerPathConfigHelper.setBrokerConfigPath(file);
 50                 in.close();
 51             }
 52         }
 53 
 54         MixAll.properties2Object(ServerUtil.commandLine2Properties(commandLine), brokerConfig);
 55 
 56         if (null == brokerConfig.getRocketmqHome()) {
 57             System.out.printf("Please set the %s variable in your environment to match the location of the RocketMQ installation", MixAll.ROCKETMQ_HOME_ENV);
 58             System.exit(-2);
 59         }
 60 
 61         String namesrvAddr = brokerConfig.getNamesrvAddr();
 62         if (null != namesrvAddr) {
 63             try {
 64                 String[] addrArray = namesrvAddr.split(";");
 65                 for (String addr : addrArray) {
 66                     RemotingUtil.string2SocketAddress(addr);
 67                 }
 68             } catch (Exception e) {
 69                 System.out.printf(
 70                     "The Name Server Address[%s] illegal, please set it as follows, "127.0.0.1:9876;192.168.0.1:9876"%n",
 71                     namesrvAddr);
 72                 System.exit(-3);
 73             }
 74         }
 75 
 76         switch (messageStoreConfig.getBrokerRole()) {
 77             case ASYNC_MASTER:
 78             case SYNC_MASTER:
 79                 brokerConfig.setBrokerId(MixAll.MASTER_ID);
 80                 break;
 81             case SLAVE:
 82                 if (brokerConfig.getBrokerId() <= 0) {
 83                     System.out.printf("Slave's brokerId must be > 0");
 84                     System.exit(-3);
 85                 }
 86 
 87                 break;
 88             default:
 89                 break;
 90         }
 91 
 92         messageStoreConfig.setHaListenPort(nettyServerConfig.getListenPort() + 1);
 93         LoggerContext lc = (LoggerContext) LoggerFactory.getILoggerFactory();
 94         JoranConfigurator configurator = new JoranConfigurator();
 95         configurator.setContext(lc);
 96         lc.reset();
 97         configurator.doConfigure(brokerConfig.getRocketmqHome() + "/conf/logback_broker.xml");
 98 
 99         if (commandLine.hasOption('p')) {
100             InternalLogger console = InternalLoggerFactory.getLogger(LoggerName.BROKER_CONSOLE_NAME);
101             MixAll.printObjectProperties(console, brokerConfig);
102             MixAll.printObjectProperties(console, nettyServerConfig);
103             MixAll.printObjectProperties(console, nettyClientConfig);
104             MixAll.printObjectProperties(console, messageStoreConfig);
105             System.exit(0);
106         } else if (commandLine.hasOption('m')) {
107             InternalLogger console = InternalLoggerFactory.getLogger(LoggerName.BROKER_CONSOLE_NAME);
108             MixAll.printObjectProperties(console, brokerConfig, true);
109             MixAll.printObjectProperties(console, nettyServerConfig, true);
110             MixAll.printObjectProperties(console, nettyClientConfig, true);
111             MixAll.printObjectProperties(console, messageStoreConfig, true);
112             System.exit(0);
113         }
114 
115         log = InternalLoggerFactory.getLogger(LoggerName.BROKER_LOGGER_NAME);
116         MixAll.printObjectProperties(log, brokerConfig);
117         MixAll.printObjectProperties(log, nettyServerConfig);
118         MixAll.printObjectProperties(log, nettyClientConfig);
119         MixAll.printObjectProperties(log, messageStoreConfig);
120 
121         final BrokerController controller = new BrokerController(
122             brokerConfig,
123             nettyServerConfig,
124             nettyClientConfig,
125             messageStoreConfig);
126         // remember all configs to prevent discard
127         controller.getConfiguration().registerConfig(properties);
128 
129         boolean initResult = controller.initialize();
130         if (!initResult) {
131             controller.shutdown();
132             System.exit(-3);
133         }
134 
135         Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {
136             private volatile boolean hasShutdown = false;
137             private AtomicInteger shutdownTimes = new AtomicInteger(0);
138 
139             @Override
140             public void run() {
141                 synchronized (this) {
142                     log.info("Shutdown hook was invoked, {}", this.shutdownTimes.incrementAndGet());
143                     if (!this.hasShutdown) {
144                         this.hasShutdown = true;
145                         long beginTime = System.currentTimeMillis();
146                         controller.shutdown();
147                         long consumingTimeTotal = System.currentTimeMillis() - beginTime;
148                         log.info("Shutdown hook over, consuming total time(ms): {}", consumingTimeTotal);
149                     }
150                 }
151             }
152         }, "ShutdownHook"));
153 
154         return controller;
155     } catch (Throwable e) {
156         e.printStackTrace();
157         System.exit(-1);
158     }
159 
160     return null;
161 }

这里和NameServer中的createNamesrvController方法作用类似，对Broker所需做了一系列的配置

先设置了Netty通信时的缓冲区大小，这里默认是128K

接着会创建了几个实体类
BrokerConfig，用来封装其绝大多数基本配置信息
NettyServerConfig，封装了其作为对外暴露的消息队列服务器的信息
NettyClientConfig，则封装了其作为NameServer客户端的信息
这里面封装的信息和NameServer一个道理，都是映射了配置文件相应的配置

然后对NettyClientConfig的TLS进行设置
让NettyServerConfig默认监听10911端口

紧接着创建了一个MessageStoreConfig，这个就是用来封装Store的信息，

MessageStoreConfig会默认配置BrokerRole为ASYNC_MASTER
Broker有三种身份，用BrokerRole枚举来表示：

1 public enum BrokerRole {
2     ASYNC_MASTER,
3     SYNC_MASTER,
4     SLAVE;
5 }

也就是异步Master，同步Master，以及Slave

这里会对其身份进行检查，若是Slave，则需要调整其允许的消息最大内存占比，默认值是40，也就是说Master允许消息最大内存占用40%，而Slave则只允许30%

接着会对”-c“指令进行相应配置的加载

往后看到对namesrvAddr进行了检查，只是简单地检查NameServer集群地址信息是否合法

往下看到有个switch块，其根据Broker的身份，进行设置
只要是Master，将其BrokerId设为0，而Slave的BrokerId需要大于0
（一个Master可以对应多个Slave，但是一个Slave只能对应一个Master，Master与Slave的对应关系通过指定相同的BrokerName，不同的BrokerId来定义，BrokerId为0表示Master，大于0表示Slave，Master也可以部署多个）

继续往下，这里会对Store设置HA的监听端口，是NettyServer侦听端口加1

往下是对“-p”，”-m“指令进行相应配置的加载，以及日志的相关配置

之后就会创建了一个BrokerController：

 1 public BrokerController(
 2         final BrokerConfig brokerConfig,
 3         final NettyServerConfig nettyServerConfig,
 4         final NettyClientConfig nettyClientConfig,
 5         final MessageStoreConfig messageStoreConfig
 6     ) {
 7     this.brokerConfig = brokerConfig;
 8     this.nettyServerConfig = nettyServerConfig;
 9     this.nettyClientConfig = nettyClientConfig;
10     this.messageStoreConfig = messageStoreConfig;
11     this.consumerOffsetManager = new ConsumerOffsetManager(this);
12     this.topicConfigManager = new TopicConfigManager(this);
13     this.pullMessageProcessor = new PullMessageProcessor(this);
14     this.pullRequestHoldService = new PullRequestHoldService(this);
15     this.messageArrivingListener = new NotifyMessageArrivingListener(this.pullRequestHoldService);
16     this.consumerIdsChangeListener = new DefaultConsumerIdsChangeListener(this);
17     this.consumerManager = new ConsumerManager(this.consumerIdsChangeListener);
18     this.consumerFilterManager = new ConsumerFilterManager(this);
19     this.producerManager = new ProducerManager();
20     this.clientHousekeepingService = new ClientHousekeepingService(this);
21     this.broker2Client = new Broker2Client(this);
22     this.subscriptionGroupManager = new SubscriptionGroupManager(this);
23     this.brokerOuterAPI = new BrokerOuterAPI(nettyClientConfig);
24     this.filterServerManager = new FilterServerManager(this);
25 
26     this.slaveSynchronize = new SlaveSynchronize(this);
27 
28     this.sendThreadPoolQueue = new LinkedBlockingQueue<Runnable>(this.brokerConfig.getSendThreadPoolQueueCapacity());
29     this.pullThreadPoolQueue = new LinkedBlockingQueue<Runnable>(this.brokerConfig.getPullThreadPoolQueueCapacity());
30     this.queryThreadPoolQueue = new LinkedBlockingQueue<Runnable>(this.brokerConfig.getQueryThreadPoolQueueCapacity());
31     this.clientManagerThreadPoolQueue = new LinkedBlockingQueue<Runnable>(this.brokerConfig.getClientManagerThreadPoolQueueCapacity());
32     this.consumerManagerThreadPoolQueue = new LinkedBlockingQueue<Runnable>(this.brokerConfig.getConsumerManagerThreadPoolQueueCapacity());
33     this.heartbeatThreadPoolQueue = new LinkedBlockingQueue<Runnable>(this.brokerConfig.getHeartbeatThreadPoolQueueCapacity());
34     this.endTransactionThreadPoolQueue = new LinkedBlockingQueue<Runnable>(this.brokerConfig.getEndTransactionPoolQueueCapacity());
35 
36     this.brokerStatsManager = new BrokerStatsManager(this.brokerConfig.getBrokerClusterName());
37     this.setStoreHost(new InetSocketAddress(this.getBrokerConfig().getBrokerIP1(), this.getNettyServerConfig().getListenPort()));
38 
39     this.brokerFastFailure = new BrokerFastFailure(this);
40     this.configuration = new Configuration(
41         log,
42         BrokerPathConfigHelper.getBrokerConfigPath(),
43         this.brokerConfig, this.nettyServerConfig, this.nettyClientConfig, this.messageStoreConfig
44     );
45 }

可以看到，这里实例化了许多成员，我就不一一分析，挑几个重要的介绍

ConsumerOffsetManager：用来管理消费者的消费消息的进度，主要通过一张map来缓存

1 private ConcurrentMap<String/* topic@group */, ConcurrentMap<Integer, Long>> offsetTable =
2         new ConcurrentHashMap<String, ConcurrentMap<Integer, Long>>(512);

由topic@group的形式构成键，而值中的map的Integer代表具体的哪条消息队列，Long表示该消息队列的偏移量offset

TopicConfigManager：管理Topic和消息队列的信息，主要通过一张map来缓存

1 private final ConcurrentMap<String, TopicConfig> topicConfigTable =
2         new ConcurrentHashMap<String, TopicConfig>(1024);
3     private final DataVersion dataVersion = new DataVersion();

键就是Topic，值TopicConfig用来记录对应的消息队列的个数

PullMessageProcessor、PullRequestHoldService、NotifyMessageArrivingListener这三个来管理Pull消息请求，关于Pull消息在后续博客再细说

ConsumerManager：管理Consumer，主要通过一张map来缓存

1 private final ConcurrentMap<String/* Group */, ConsumerGroupInfo> consumerTable =
2         new ConcurrentHashMap<String, ConsumerGroupInfo>(1024);

键值就是Consumer的GroupName，
而ConsumerGroupInfo由如下构成：

1 private final ConcurrentMap<String/* Topic */, SubscriptionData> subscriptionTable =
2         new ConcurrentHashMap<String, SubscriptionData>();
3 private final ConcurrentMap<Channel, ClientChannelInfo> channelInfoTable =
4 new ConcurrentHashMap<Channel, ClientChannelInfo>(16);
5 private volatile ConsumeType consumeType;
6 private volatile MessageModel messageModel;

可以看到封装了一个subscriptionTable ，这个map记录Topic和订阅内容
以及一个channelInfoTable，记录Consumer的物理连接
ConsumeType是一个枚举，表明两种消费方式：

1 public enum ConsumeType {
2     CONSUME_ACTIVELY("PULL"),
3     CONSUME_PASSIVELY("PUSH");
4 }

MessageModel 也是一个枚举，表明两种消费模式：

 1 public enum MessageModel {
 2     /**
 3      * broadcast
 4      */
 5     BROADCASTING("BROADCASTING"),
 6     /**
 7      * clustering
 8      */
 9     CLUSTERING("CLUSTERING");
10 }

Broadcasting：同一个ConsumerGroup里的每个Consumer都能消费到所订阅Topic的全部消息，也就是一个消息会被多次分发，被多个Consumer消费
Clustering：同一个ConsumerGroup里的每个Consumer只消费所订阅消息的一部分内容，同一个ConsumerGroup里所有的Consumer消费的内容合起来才是所订阅Topic内容的整体，从而达到负载均衡的目的

结合着来看，也就是说使用相同GroupName的一组Consumer，其ConsumeType和MessageModel必定相同，其订阅的Topic会根据ConsumeType和MessageModel来完成相应的方式的消息处理

回到BrokerController的构造

ProducerManager：管理Producer，主要通过一张map来缓存

1 private final HashMap<String /* group name */, HashMap<Channel, ClientChannelInfo>> groupChannelTable =
2         new HashMap<String, HashMap<Channel, ClientChannelInfo>>();

相比ConsumerManager，对Producer的管理简单的多，只需要记录group name 和物理连接的映射

再回到createBrokerController方法，在完成BrokerController的创建后，会调用BrokerController的initialize方法：

BrokerController的initialize方法：

  1 public boolean initialize() throws CloneNotSupportedException {
  2     boolean result = this.topicConfigManager.load();
  3 
  4     result = result && this.consumerOffsetManager.load();
  5     result = result && this.subscriptionGroupManager.load();
  6     result = result && this.consumerFilterManager.load();
  7 
  8     if (result) {
  9         try {
 10             this.messageStore =
 11                 new DefaultMessageStore(this.messageStoreConfig, this.brokerStatsManager, this.messageArrivingListener,
 12                     this.brokerConfig);
 13             if (messageStoreConfig.isEnableDLegerCommitLog()) {
 14                 DLedgerRoleChangeHandler roleChangeHandler = new DLedgerRoleChangeHandler(this, (DefaultMessageStore) messageStore);
 15                 ((DLedgerCommitLog)((DefaultMessageStore) messageStore).getCommitLog()).getdLedgerServer().getdLedgerLeaderElector().addRoleChangeHandler(roleChangeHandler);
 16             }
 17             this.brokerStats = new BrokerStats((DefaultMessageStore) this.messageStore);
 18             //load plugin
 19             MessageStorePluginContext context = new MessageStorePluginContext(messageStoreConfig, brokerStatsManager, messageArrivingListener, brokerConfig);
 20             this.messageStore = MessageStoreFactory.build(context, this.messageStore);
 21             this.messageStore.getDispatcherList().addFirst(new CommitLogDispatcherCalcBitMap(this.brokerConfig, this.consumerFilterManager));
 22         } catch (IOException e) {
 23             result = false;
 24             log.error("Failed to initialize", e);
 25         }
 26     }
 27 
 28     result = result && this.messageStore.load();
 29 
 30     if (result) {
 31         this.remotingServer = new NettyRemotingServer(this.nettyServerConfig, this.clientHousekeepingService);
 32         NettyServerConfig fastConfig = (NettyServerConfig) this.nettyServerConfig.clone();
 33         fastConfig.setListenPort(nettyServerConfig.getListenPort() - 2);
 34         this.fastRemotingServer = new NettyRemotingServer(fastConfig, this.clientHousekeepingService);
 35         this.sendMessageExecutor = new BrokerFixedThreadPoolExecutor(
 36             this.brokerConfig.getSendMessageThreadPoolNums(),
 37             this.brokerConfig.getSendMessageThreadPoolNums(),
 38             1000 * 60,
 39             TimeUnit.MILLISECONDS,
 40             this.sendThreadPoolQueue,
 41             new ThreadFactoryImpl("SendMessageThread_"));
 42 
 43         this.pullMessageExecutor = new BrokerFixedThreadPoolExecutor(
 44             this.brokerConfig.getPullMessageThreadPoolNums(),
 45             this.brokerConfig.getPullMessageThreadPoolNums(),
 46             1000 * 60,
 47             TimeUnit.MILLISECONDS,
 48             this.pullThreadPoolQueue,
 49             new ThreadFactoryImpl("PullMessageThread_"));
 50 
 51         this.queryMessageExecutor = new BrokerFixedThreadPoolExecutor(
 52             this.brokerConfig.getQueryMessageThreadPoolNums(),
 53             this.brokerConfig.getQueryMessageThreadPoolNums(),
 54             1000 * 60,
 55             TimeUnit.MILLISECONDS,
 56             this.queryThreadPoolQueue,
 57             new ThreadFactoryImpl("QueryMessageThread_"));
 58 
 59         this.adminBrokerExecutor =
 60             Executors.newFixedThreadPool(this.brokerConfig.getAdminBrokerThreadPoolNums(), new ThreadFactoryImpl(
 61                 "AdminBrokerThread_"));
 62 
 63         this.clientManageExecutor = new ThreadPoolExecutor(
 64             this.brokerConfig.getClientManageThreadPoolNums(),
 65             this.brokerConfig.getClientManageThreadPoolNums(),
 66             1000 * 60,
 67             TimeUnit.MILLISECONDS,
 68             this.clientManagerThreadPoolQueue,
 69             new ThreadFactoryImpl("ClientManageThread_"));
 70 
 71         this.heartbeatExecutor = new BrokerFixedThreadPoolExecutor(
 72             this.brokerConfig.getHeartbeatThreadPoolNums(),
 73             this.brokerConfig.getHeartbeatThreadPoolNums(),
 74             1000 * 60,
 75             TimeUnit.MILLISECONDS,
 76             this.heartbeatThreadPoolQueue,
 77             new ThreadFactoryImpl("HeartbeatThread_", true));
 78 
 79         this.endTransactionExecutor = new BrokerFixedThreadPoolExecutor(
 80             this.brokerConfig.getEndTransactionThreadPoolNums(),
 81             this.brokerConfig.getEndTransactionThreadPoolNums(),
 82             1000 * 60,
 83             TimeUnit.MILLISECONDS,
 84             this.endTransactionThreadPoolQueue,
 85             new ThreadFactoryImpl("EndTransactionThread_"));
 86 
 87         this.consumerManageExecutor =
 88             Executors.newFixedThreadPool(this.brokerConfig.getConsumerManageThreadPoolNums(), new ThreadFactoryImpl(
 89                 "ConsumerManageThread_"));
 90 
 91         this.registerProcessor();
 92 
 93         final long initialDelay = UtilAll.computNextMorningTimeMillis() - System.currentTimeMillis();
 94         final long period = 1000 * 60 * 60 * 24;
 95         this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
 96             @Override
 97             public void run() {
 98                 try {
 99                     BrokerController.this.getBrokerStats().record();
100                 } catch (Throwable e) {
101                     log.error("schedule record error.", e);
102                 }
103             }
104         }, initialDelay, period, TimeUnit.MILLISECONDS);
105 
106         this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
107             @Override
108             public void run() {
109                 try {
110                     BrokerController.this.consumerOffsetManager.persist();
111                 } catch (Throwable e) {
112                     log.error("schedule persist consumerOffset error.", e);
113                 }
114             }
115         }, 1000 * 10, this.brokerConfig.getFlushConsumerOffsetInterval(), TimeUnit.MILLISECONDS);
116 
117         this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
118             @Override
119             public void run() {
120                 try {
121                     BrokerController.this.consumerFilterManager.persist();
122                 } catch (Throwable e) {
123                     log.error("schedule persist consumer filter error.", e);
124                 }
125             }
126         }, 1000 * 10, 1000 * 10, TimeUnit.MILLISECONDS);
127 
128         this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
129             @Override
130             public void run() {
131                 try {
132                     BrokerController.this.protectBroker();
133                 } catch (Throwable e) {
134                     log.error("protectBroker error.", e);
135                 }
136             }
137         }, 3, 3, TimeUnit.MINUTES);
138 
139         this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
140             @Override
141             public void run() {
142                 try {
143                     BrokerController.this.printWaterMark();
144                 } catch (Throwable e) {
145                     log.error("printWaterMark error.", e);
146                 }
147             }
148         }, 10, 1, TimeUnit.SECONDS);
149 
150         this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
151 
152             @Override
153             public void run() {
154                 try {
155                     log.info("dispatch behind commit log {} bytes", BrokerController.this.getMessageStore().dispatchBehindBytes());
156                 } catch (Throwable e) {
157                     log.error("schedule dispatchBehindBytes error.", e);
158                 }
159             }
160         }, 1000 * 10, 1000 * 60, TimeUnit.MILLISECONDS);
161 
162         if (this.brokerConfig.getNamesrvAddr() != null) {
163             this.brokerOuterAPI.updateNameServerAddressList(this.brokerConfig.getNamesrvAddr());
164             log.info("Set user specified name server address: {}", this.brokerConfig.getNamesrvAddr());
165         } else if (this.brokerConfig.isFetchNamesrvAddrByAddressServer()) {
166             this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
167 
168                 @Override
169                 public void run() {
170                     try {
171                         BrokerController.this.brokerOuterAPI.fetchNameServerAddr();
172                     } catch (Throwable e) {
173                         log.error("ScheduledTask fetchNameServerAddr exception", e);
174                     }
175                 }
176             }, 1000 * 10, 1000 * 60 * 2, TimeUnit.MILLISECONDS);
177         }
178 
179         if (!messageStoreConfig.isEnableDLegerCommitLog()) {
180             if (BrokerRole.SLAVE == this.messageStoreConfig.getBrokerRole()) {
181                 if (this.messageStoreConfig.getHaMasterAddress() != null && this.messageStoreConfig.getHaMasterAddress().length() >= 6) {
182                     this.messageStore.updateHaMasterAddress(this.messageStoreConfig.getHaMasterAddress());
183                     this.updateMasterHAServerAddrPeriodically = false;
184                 } else {
185                     this.updateMasterHAServerAddrPeriodically = true;
186                 }
187             } else {
188                 this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
189                     @Override
190                     public void run() {
191                         try {
192                             BrokerController.this.printMasterAndSlaveDiff();
193                         } catch (Throwable e) {
194                             log.error("schedule printMasterAndSlaveDiff error.", e);
195                         }
196                     }
197                 }, 1000 * 10, 1000 * 60, TimeUnit.MILLISECONDS);
198             }
199         }
200 
201         if (TlsSystemConfig.tlsMode != TlsMode.DISABLED) {
202             // Register a listener to reload SslContext
203             try {
204                 fileWatchService = new FileWatchService(
205                     new String[] {
206                         TlsSystemConfig.tlsServerCertPath,
207                         TlsSystemConfig.tlsServerKeyPath,
208                         TlsSystemConfig.tlsServerTrustCertPath
209                     },
210                     new FileWatchService.Listener() {
211                         boolean certChanged, keyChanged = false;
212 
213                         @Override
214                         public void onChanged(String path) {
215                             if (path.equals(TlsSystemConfig.tlsServerTrustCertPath)) {
216                                 log.info("The trust certificate changed, reload the ssl context");
217                                 reloadServerSslContext();
218                             }
219                             if (path.equals(TlsSystemConfig.tlsServerCertPath)) {
220                                 certChanged = true;
221                             }
222                             if (path.equals(TlsSystemConfig.tlsServerKeyPath)) {
223                                 keyChanged = true;
224                             }
225                             if (certChanged && keyChanged) {
226                                 log.info("The certificate and private key changed, reload the ssl context");
227                                 certChanged = keyChanged = false;
228                                 reloadServerSslContext();
229                             }
230                         }
231 
232                         private void reloadServerSslContext() {
233                             ((NettyRemotingServer) remotingServer).loadSslContext();
234                             ((NettyRemotingServer) fastRemotingServer).loadSslContext();
235                         }
236                     });
237             } catch (Exception e) {
238                 log.warn("FileWatchService created error, can't load the certificate dynamically");
239             }
240         }
241         initialTransaction();
242         initialAcl();
243         initialRpcHooks();
244     }
245     return result;
246 }

首先完成对.../store/config/topics.json、.../store/config/consumerOffset.json、
.../store/config/subscriptionGroup.json、.../store/config/consumerFilter.json这几个文件的加载

接着创建一个DefaultMessageStore，这是Broker的核心存储

DefaultMessageStore的构造：

 1 private final ConcurrentMap<String/* topic */, ConcurrentMap<Integer/* queueId */, ConsumeQueue>> consumeQueueTable;
 2 ......
 3 public DefaultMessageStore(final MessageStoreConfig messageStoreConfig, final BrokerStatsManager brokerStatsManager,
 4         final MessageArrivingListener messageArrivingListener, final BrokerConfig brokerConfig) throws IOException {
 5     this.messageArrivingListener = messageArrivingListener;
 6     this.brokerConfig = brokerConfig;
 7     this.messageStoreConfig = messageStoreConfig;
 8     this.brokerStatsManager = brokerStatsManager;
 9     // 请求定位服务
10     this.allocateMappedFileService = new AllocateMappedFileService(this);
11     // 存储服务
12     if (messageStoreConfig.isEnableDLegerCommitLog()) {
13         this.commitLog = new DLedgerCommitLog(this);
14     } else {
15         this.commitLog = new CommitLog(this);
16     }
17     // 消费队列信息
18     this.consumeQueueTable = new ConcurrentHashMap<>(32);
19     // 刷新队列服务
20     this.flushConsumeQueueService = new FlushConsumeQueueService();
21     // 清除CommitLog数据服务
22     this.cleanCommitLogService = new CleanCommitLogService();
23     // 清除消费队列服务
24     this.cleanConsumeQueueService = new CleanConsumeQueueService();
25     this.storeStatsService = new StoreStatsService();
26     // 索引服务
27     this.indexService = new IndexService(this);
28     
29     // HA服务，主从复制
30     if (!messageStoreConfig.isEnableDLegerCommitLog()) {
31         this.haService = new HAService(this);
32     } else {
33         this.haService = null;
34     }
35     this.reputMessageService = new ReputMessageService();
36     this.scheduleMessageService = new ScheduleMessageService(this);
37 
38     this.transientStorePool = new TransientStorePool(messageStoreConfig);
39 
40     if (messageStoreConfig.isTransientStorePoolEnable()) {
41         this.transientStorePool.init();
42     }
43 
44     this.allocateMappedFileService.start();
45 
46     this.indexService.start();
47 
48     this.dispatcherList = new LinkedList<>();
49     this.dispatcherList.addLast(new CommitLogDispatcherBuildConsumeQueue());
50     this.dispatcherList.addLast(new CommitLogDispatcherBuildIndex());
51 
52     File file = new File(StorePathConfigHelper.getLockFile(messageStoreConfig.getStorePathRootDir()));
53     MappedFile.ensureDirOK(file.getParent());
54     lockFile = new RandomAccessFile(file, "rw");
55 }

可以看到DefaultMessageStore的构造会创建很多服务，来管理store的存储

其中isEnableDLegerCommitLog用来判断是否使用DLeger，默认false是关闭的
所以在默认情况下使用CommitLog + HAService

关于DLeger可参考这篇博客【Dledger-RocketMQ 基于Raft协议的commitlog存储库】

后续的主从复制还是以CommitLog + HAService为主

回到initialize方法，接着会调用DefaultMessageStore的load方法：

 1 public boolean load() {
 2     boolean result = true;
 3 
 4     try {
 5         boolean lastExitOK = !this.isTempFileExist();
 6         log.info("last shutdown {}", lastExitOK ? "normally" : "abnormally");
 7 
 8         if (null != scheduleMessageService) {
 9             result = result && this.scheduleMessageService.load();
10         }
11 
12         // load Commit Log
13         result = result && this.commitLog.load();
14 
15         // load Consume Queue
16         result = result && this.loadConsumeQueue();
17 
18         if (result) {
19             this.storeCheckpoint =
20                 new StoreCheckpoint(StorePathConfigHelper.getStoreCheckpoint(this.messageStoreConfig.getStorePathRootDir()));
21 
22             this.indexService.load(lastExitOK);
23 
24             this.recover(lastExitOK);
25 
26             log.info("load over, and the max phy offset = {}", this.getMaxPhyOffset());
27         }
28     } catch (Exception e) {
29         log.error("load exception", e);
30         result = false;
31     }
32 
33     if (!result) {
34         this.allocateMappedFileService.shutdown();
35     }
36 
37     return result;
38 }

这里会加载CommitLog和ConsumeQueue对应的文件

接着创建熟悉的NettyRemotingServer，在前面博客中介绍过了，就不再展开
这里会根据nettyServerConfig克隆一份服务端配置，以此创建fastRemotingServer服务端，只不过这个服务端侦听的是上面服务端端口减2的端口号

看过我前面的博客就会发现这个fastRemotingServer的端口号其实就是之前提到过的VIP通道
详见：

【RocketMQ中Producer的启动源码分析】

【RocketMQ中Producer消息的发送源码分析】

接着会根据不同的需求创建很多不同的线程池

然后调用registerProcessor方法：

registerProcessor方法：

 1 public void registerProcessor() {
 2    /**
 3      * SendMessageProcessor
 4      */
 5     SendMessageProcessor sendProcessor = new SendMessageProcessor(this);
 6     sendProcessor.registerSendMessageHook(sendMessageHookList);
 7     sendProcessor.registerConsumeMessageHook(consumeMessageHookList);
 8 
 9     this.remotingServer.registerProcessor(RequestCode.SEND_MESSAGE, sendProcessor, this.sendMessageExecutor);
10     this.remotingServer.registerProcessor(RequestCode.SEND_MESSAGE_V2, sendProcessor, this.sendMessageExecutor);
11     this.remotingServer.registerProcessor(RequestCode.SEND_BATCH_MESSAGE, sendProcessor, this.sendMessageExecutor);
12     this.remotingServer.registerProcessor(RequestCode.CONSUMER_SEND_MSG_BACK, sendProcessor, this.sendMessageExecutor);
13     this.fastRemotingServer.registerProcessor(RequestCode.SEND_MESSAGE, sendProcessor, this.sendMessageExecutor);
14     this.fastRemotingServer.registerProcessor(RequestCode.SEND_MESSAGE_V2, sendProcessor, this.sendMessageExecutor);
15     this.fastRemotingServer.registerProcessor(RequestCode.SEND_BATCH_MESSAGE, sendProcessor, this.sendMessageExecutor);
16     this.fastRemotingServer.registerProcessor(RequestCode.CONSUMER_SEND_MSG_BACK, sendProcessor, this.sendMessageExecutor);
17     /**
18      * PullMessageProcessor
19      */
20     this.remotingServer.registerProcessor(RequestCode.PULL_MESSAGE, this.pullMessageProcessor, this.pullMessageExecutor);
21     this.pullMessageProcessor.registerConsumeMessageHook(consumeMessageHookList);
22 
23     /**
24      * QueryMessageProcessor
25      */
26     NettyRequestProcessor queryProcessor = new QueryMessageProcessor(this);
27     this.remotingServer.registerProcessor(RequestCode.QUERY_MESSAGE, queryProcessor, this.queryMessageExecutor);
28     this.remotingServer.registerProcessor(RequestCode.VIEW_MESSAGE_BY_ID, queryProcessor, this.queryMessageExecutor);
29 
30     this.fastRemotingServer.registerProcessor(RequestCode.QUERY_MESSAGE, queryProcessor, this.queryMessageExecutor);
31     this.fastRemotingServer.registerProcessor(RequestCode.VIEW_MESSAGE_BY_ID, queryProcessor, this.queryMessageExecutor);
32 
33     /**
34      * ClientManageProcessor
35      */
36     ClientManageProcessor clientProcessor = new ClientManageProcessor(this);
37     this.remotingServer.registerProcessor(RequestCode.HEART_BEAT, clientProcessor, this.heartbeatExecutor);
38     this.remotingServer.registerProcessor(RequestCode.UNREGISTER_CLIENT, clientProcessor, this.clientManageExecutor);
39     this.remotingServer.registerProcessor(RequestCode.CHECK_CLIENT_CONFIG, clientProcessor, this.clientManageExecutor);
40 
41     this.fastRemotingServer.registerProcessor(RequestCode.HEART_BEAT, clientProcessor, this.heartbeatExecutor);
42     this.fastRemotingServer.registerProcessor(RequestCode.UNREGISTER_CLIENT, clientProcessor, this.clientManageExecutor);
43     this.fastRemotingServer.registerProcessor(RequestCode.CHECK_CLIENT_CONFIG, clientProcessor, this.clientManageExecutor);
44 
45     /**
46      * ConsumerManageProcessor
47      */
48     ConsumerManageProcessor consumerManageProcessor = new ConsumerManageProcessor(this);
49     this.remotingServer.registerProcessor(RequestCode.GET_CONSUMER_LIST_BY_GROUP, consumerManageProcessor, this.consumerManageExecutor);
50     this.remotingServer.registerProcessor(RequestCode.UPDATE_CONSUMER_OFFSET, consumerManageProcessor, this.consumerManageExecutor);
51     this.remotingServer.registerProcessor(RequestCode.QUERY_CONSUMER_OFFSET, consumerManageProcessor, this.consumerManageExecutor);
52 
53     this.fastRemotingServer.registerProcessor(RequestCode.GET_CONSUMER_LIST_BY_GROUP, consumerManageProcessor, this.consumerManageExecutor);
54     this.fastRemotingServer.registerProcessor(RequestCode.UPDATE_CONSUMER_OFFSET, consumerManageProcessor, this.consumerManageExecutor);
55     this.fastRemotingServer.registerProcessor(RequestCode.QUERY_CONSUMER_OFFSET, consumerManageProcessor, this.consumerManageExecutor);
56 
57     /**
58      * EndTransactionProcessor
59      */
60     this.remotingServer.registerProcessor(RequestCode.END_TRANSACTION, new EndTransactionProcessor(this), this.endTransactionExecutor);
61     this.fastRemotingServer.registerProcessor(RequestCode.END_TRANSACTION, new EndTransactionProcessor(this), this.endTransactionExecutor);
62 
63     /**
64      * Default
65      */
66     AdminBrokerProcessor adminProcessor = new AdminBrokerProcessor(this);
67     this.remotingServer.registerDefaultProcessor(adminProcessor, this.adminBrokerExecutor);
68     this.fastRemotingServer.registerDefaultProcessor(adminProcessor, this.adminBrokerExecutor);
69 }

这里会创建好几种Processor，通过registerProcessor方法同时注册到remotingServer和fastRemotingServer中

registerProcessor方法：

1 public void registerProcessor(int requestCode, NettyRequestProcessor processor, ExecutorService executor) {
2         ExecutorService executorThis = executor;
3     if (null == executor) {
4         executorThis = this.publicExecutor;
5     }
6 
7     Pair<NettyRequestProcessor, ExecutorService> pair = new Pair<NettyRequestProcessor, ExecutorService>(processor, executorThis);
8     this.processorTable.put(requestCode, pair);
9 }

这里实际上就是向processorTable进行了记录的添加，为的是后续收到请求能做出对应的处理

processorTable：

1 protected final HashMap<Integer/* request code */, Pair<NettyRequestProcessor, ExecutorService>> processorTable =
2         new HashMap<Integer, Pair<NettyRequestProcessor, ExecutorService>>(64);

这里的SendMessageProcessor很重要，后续会详细介绍

在完成registerProcessor后，会创建8个定时任务

①

1 BrokerController.this.getBrokerStats().record();

定时打印Broker的状态

②

1 BrokerController.this.consumerOffsetManager.persist();

定时向consumerOffset.json文件中写入消费者偏移量

③

1 BrokerController.this.consumerFilterManager.persist();

定时向consumerFilter.json文件写入消费者过滤器信息

④

1 BrokerController.this.protectBroker();

定时禁用消费慢的consumer，保护Broker，需要设置disableConsumeIfConsumerReadSlowly属性，默认false

⑤

1 BrokerController.this.printWaterMark();

定时打印Send、Pull、Query、Transaction队列信息

⑥

1 public void run() {
2     try {
3         log.info("dispatch behind commit log {} bytes", BrokerController.this.getMessageStore().dispatchBehindBytes());
4     } catch (Throwable e) {
5         log.error("schedule dispatchBehindBytes error.", e);
6     }
7 }

定时打印已存储在提交日志中但尚未调度到消费队列的字节数

⑦

 1 if (this.brokerConfig.getNamesrvAddr() != null) {
 2     this.brokerOuterAPI.updateNameServerAddressList(this.brokerConfig.getNamesrvAddr());
 3     log.info("Set user specified name server address: {}", this.brokerConfig.getNamesrvAddr());
 4 } else if (this.brokerConfig.isFetchNamesrvAddrByAddressServer()) {
 5     this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
 6 
 7         @Override
 8         public void run() {
 9             try {
10                 BrokerController.this.brokerOuterAPI.fetchNameServerAddr();
11             } catch (Throwable e) {
12                 log.error("ScheduledTask fetchNameServerAddr exception", e);
13             }
14         }
15     }, 1000 * 10, 1000 * 60 * 2, TimeUnit.MILLISECONDS);
16 }

若是设置了NamesrvAddr，需要通过updateNameServerAddressList完成一次NameServer地址的跟新（updateNameServerAddressList在前面博客介绍过了）
若是设置了NamesrvAddr，并且设置了fetchNamesrvAddrByAddressServer属性（默认关闭），需要定时获取更新NameServer地址（fetchNameServerAddr方法在之前博客也介绍过）

⑧

 1 if (!messageStoreConfig.isEnableDLegerCommitLog()) {
 2     if (BrokerRole.SLAVE == this.messageStoreConfig.getBrokerRole()) {
 3         if (this.messageStoreConfig.getHaMasterAddress() != null && this.messageStoreConfig.getHaMasterAddress().length() >= 6) {
 4             this.messageStore.updateHaMasterAddress(this.messageStoreConfig.getHaMasterAddress());
 5             this.updateMasterHAServerAddrPeriodically = false;
 6         } else {
 7             this.updateMasterHAServerAddrPeriodically = true;
 8         }
 9     } else {
10         this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
11             @Override
12             public void run() {
13                 try {
14                     BrokerController.this.printMasterAndSlaveDiff();
15                 } catch (Throwable e) {
16                     log.error("schedule printMasterAndSlaveDiff error.", e);
17                 }
18             }
19         }, 1000 * 10, 1000 * 60, TimeUnit.MILLISECONDS);
20     }
21 }

在非DLeger模式下
若是SLAVE，则需要检查是否设置了HA的Master地址
若设置了Master地址要通过updateHaMasterAddress方法向更新Master地址
updateHaMasterAddress方法实则是在HAClient中实现的：

1 public void updateMasterAddress(final String newAddr) {
2     String currentAddr = this.masterAddress.get();
3     if (currentAddr == null || !currentAddr.equals(newAddr)) {
4         this.masterAddress.set(newAddr);
5         log.info("update master address, OLD: " + currentAddr + " NEW: " + newAddr);
6     }
7 }

非常简单，只是一个比较替换的操作

若没有设置需要更改updateMasterHAServerAddrPeriodically为true，在后面会有用

若是MASTER，则需要定时打印slave落后的字节数

设置完定时任务后，和NameServer中一样设置了对SslContext的监听

接着通过initialTransaction方法，加载事务需要的实例
initialTransaction方法：

 1 private void initialTransaction() {
 2     this.transactionalMessageService = ServiceProvider.loadClass(ServiceProvider.TRANSACTION_SERVICE_ID, TransactionalMessageService.class);
 3     if (null == this.transactionalMessageService) {
 4         this.transactionalMessageService = new TransactionalMessageServiceImpl(new TransactionalMessageBridge(this, this.getMessageStore()));
 5         log.warn("Load default transaction message hook service: {}", TransactionalMessageServiceImpl.class.getSimpleName());
 6     }
 7     this.transactionalMessageCheckListener = ServiceProvider.loadClass(ServiceProvider.TRANSACTION_LISTENER_ID, AbstractTransactionalMessageCheckListener.class);
 8     if (null == this.transactionalMessageCheckListener) {
 9         this.transactionalMessageCheckListener = new DefaultTransactionalMessageCheckListener();
10         log.warn("Load default discard message hook service: {}", DefaultTransactionalMessageCheckListener.class.getSimpleName());
11     }
12     this.transactionalMessageCheckListener.setBrokerController(this);
13     this.transactionalMessageCheckService = new TransactionalMessageCheckService(this);
14 }

这里动态加载了TransactionalMessageService和AbstractTransactionalMessageCheckListener的实现类，位于如下
"META-INF/service/org.apache.rocketmq.broker.transaction.TransactionalMessageService"
"META-INF/service/org.apache.rocketmq.broker.transaction.AbstractTransactionalMessageCheckListener"
还创建了TransactionalMessageCheckService

initialAcl会创建ACL权限检查：

 1 private void initialAcl() {
 2    if (!this.brokerConfig.isAclEnable()) {
 3         log.info("The broker dose not enable acl");
 4         return;
 5     }
 6 
 7     List<AccessValidator> accessValidators = ServiceProvider.load(ServiceProvider.ACL_VALIDATOR_ID, AccessValidator.class);
 8     if (accessValidators == null || accessValidators.isEmpty()) {
 9         log.info("The broker dose not load the AccessValidator");
10         return;
11     }
12 
13     for (AccessValidator accessValidator: accessValidators) {
14         final AccessValidator validator = accessValidator;
15         this.registerServerRPCHook(new RPCHook() {
16 
17             @Override
18             public void doBeforeRequest(String remoteAddr, RemotingCommand request) {
19                 //Do not catch the exception
20                 validator.validate(validator.parse(request, remoteAddr));
21             }
22 
23             @Override
24             public void doAfterResponse(String remoteAddr, RemotingCommand request, RemotingCommand response) {
25             }
26         });
27     }
28 }

需要设置aclEnable属性，默认关闭
若是设置了，同样会加载"META-INF/service/org.apache.rocketmq.acl.AccessValidator"配置的AccessValidator实体类
然后将其包装成RPC钩子，注册到remotingServer和fastRemotingServer中，用于请求的调用validate方法进行ACL权限检查

initialRpcHooks方法则会注册配置了的RPC钩子：

1 private void initialRpcHooks() {
2     List<RPCHook> rpcHooks = ServiceProvider.load(ServiceProvider.RPC_HOOK_ID, RPCHook.class);
3     if (rpcHooks == null || rpcHooks.isEmpty()) {
4         return;
5     }
6     for (RPCHook rpcHook: rpcHooks) {
7         this.registerServerRPCHook(rpcHook);
8     }
9 }

加载"META-INF/service/org.apache.rocketmq.remoting.RPCHook"下的配置的实体类

到此Broker启动前的准备工作已经完成，后面start方法会进行真正的启动，在下一篇博客继续分析

相关阅读:
IOS学习笔记 ---- 15/09/14
IOS学习笔记 ---- 15/09/07
IOS学习笔记 ---- 15/09/06
IOS学习笔记 ---- 15/09/02
IOS学习笔记 ---- 15/09/01
IOS学习笔记 ---- 15/08/31
IOS学习笔记 ---- 15/08/30之前
 ios之UITableViewController(二) tableView的编辑模式
 ios之UIPageController和UIScrollView配合使用
 ios之UIScrollView
原文地址：https://www.cnblogs.com/a526583280/p/11297099.html