MQTT---HiveMQ源码详解(二)结构与启动

来源：互联网发布：明道软件个人版怎么样编辑：程序博客网时间：2024/04/26 19:14

源博客地址:http://blog.csdn.net/pipinet123

MQTT交流群:221405150

目录结构

在官网中也有更详细的介绍，下面我只对目录结构做一个简单介绍即可，感兴趣的朋友可以参考官网文档.http://www.hivemq.com/docs/hivemq/latest/#installation

目录结构

bin

包含hivemq.jar以及一些启动脚本

conf

包含config.xml、logback.xml以及plugin的配置文件
examples是一些示例组网场景的示例配置

data

metadata存放版本信息(加密过)
persistence存放着所有持久化信息的文件、以及备份文件。包含client_session_subscriptions、client_sessions、outgoing_message_flow、incomming_message_flow、publish_payloads、queued_messages、retained_messages等。

diagnostics

存放着诊断模式下诊断信息，包括系统信息、网络接口信息、jvm信息、插件信息等等。方便开发者排查问题。

license

存放hivemq授权license文件。

log

存放日志

plugins

第三方插件目录

启动

既然它是一个java程序,那么我们就从它的main方法开始我们的hivemq源码之路。

main

public class HiveMQServer {    private static final Logger LOGGER = LoggerFactory.getLogger(HiveMQServer.class);    private final NettyServer nettyServer;    private final ClusterConfigurationService clusterConfigurationService;    private final PluginBrokerCallbackHandler pluginBrokerCallbackHandler;    private final PluginInformationStore pluginInformationStore;    private final Provider<ClusterJoiner> clusterJoinerProvider;    @Inject    HiveMQServer(NettyServer nettyServer,                 ClusterConfigurationService clusterConfigurationService,                 PluginBrokerCallbackHandler pluginBrokerCallbackHandler,                 PluginInformationStore pluginInformationStore,                 Provider<ClusterJoiner> clusterJoinerProvider) {        this.nettyServer = nettyServer;        this.clusterConfigurationService = clusterConfigurationService;        this.pluginBrokerCallbackHandler = pluginBrokerCallbackHandler;        this.pluginInformationStore = pluginInformationStore;        this.clusterJoinerProvider = clusterJoinerProvider;    }    public void start() throws InterruptedException, ExecutionException {        //启动netty server        this.nettyServer.start().sync();        //通知OnBrokerStart事件        fireOnBrokerStart();        //加入cluster        joinCluster();        //启动对应承载在netty上的Listener，并打印出这些Listener启动结果信息。请参考Linstener配置请参考http://www.hivemq.com/docs/hivemq/latest/#configuration-chapter        ListenableFuture<List<ListenerStartResult>> startFuture = this.nettyServer.startListeners();        List<ListenerStartResult> startResults = startFuture.get();        new ListenerStartResultLogger(startResults).log();    }    private void joinCluster() {        //根据配置确定是否加入cluster        if (!this.clusterConfigurationService.isEnabled()) {            return;        }        try {        //使用ClusterJoiner类进行连接jgroup，组成cluster。            ClusterJoiner clusterJoiner = this.clusterJoinerProvider.get();            ListenableFuture<Void> future = clusterJoiner.join();            future.get();        } catch (Exception e) {            if (e.getCause() instanceof DuplicateOrInvalidLicenseException) {                LOGGER.error("Found duplicate or invalid license file in the cluster. Shutting down HiveMQ");            } else if (e.getCause() instanceof DifferentConfigurationException) {                LOGGER.error("The configuration of this HiveMQ instance is different form the other instances in the cluster. Shutting down HiveMQ");            } else {                LOGGER.error("Could not join cluster. Shutting down HiveMQ.", e);            }            if (e.getCause() instanceof UnrecoverableException) {                throw ((UnrecoverableException) e.getCause());            }            throw new UnrecoverableException(false);        }    }    //通知对应plugin broker已经启动    private void fireOnBrokerStart() {        LOGGER.trace("Calling all OnBrokerStart Callbacks");        printPluginInformations();        this.pluginBrokerCallbackHandler.onStart();    }    public static void main(String[] args) throws InterruptedException, ExecutionException {        LOGGER.info("Starting HiveMQ Server");        long startTime = System.nanoTime();        //初始化SystemInformation，可以通过环境变量来分别设置conf、plugins、log、license等目录。        //请参考hivemq spi SystemInformation        LOGGER.trace("Initializing HiveMQ home directory");        HiveMQSystemInformation systemInformation = new HiveMQSystemInformation(true);        //创建MetricRegistry        //请参考开源框架Metrics        LOGGER.trace("Creating MetricRegistry");        MetricRegistry metricRegistry = new MetricRegistry();        //增加统计Listener        metricRegistry.addListener(new StatisticsListener());        //初始化日志        LOGGER.trace("Initializing Logging");        LogConfigurator.init(systemInformation.getConfigFolder(), metricRegistry);        //增加未处理异常拦截,并对其进行优雅处理        LOGGER.trace("Initializing Exception handlers");        RecoverableExceptionHandler.init();        //初始化ConfigurationService,并读取conf/config.xml文件，加载用户配置        //请参考hivemq spi ConfigurationService,        LOGGER.trace("Initializing configuration");        HiveMQConfigurationService hiveMQConfigurationService = HiveMQConfigurationServiceFactory.create(systemInformation);        //创建Clusterid提供者。        ClusterIdProducer clusterIdProducer = new ClusterIdProducer();        if (hiveMQConfigurationService.clusterConfiguration().isEnabled()) {            LOGGER.info("This node's cluster-ID is {}", clusterIdProducer.get());        }        //根据原有版本，判断是否需要做持久化数据的migration，如需要进行migration，因为可以配置每个数据的使用策略(file/memory)，所以每个数据分别进行migration        LOGGER.trace("Checking for migrations");        Map<MigrationType, Set<String>> neededMigrations = Migrations.getNeededMigrations(systemInformation);        Injector injector = null;        if (neededMigrations.size() > 0) {            LOGGER.warn("HiveMQ has been updated, migrating persistent data to new version !");            neededMigrations.keySet().forEach(type -> LOGGER.debug("{} needs to be migrated", type));            //因为migration也是依赖guice来做容器，所以migration也会创建一个injector            injector = Bootstrap.createInjector(systemInformation, hiveMQConfigurationService, clusterIdProducer);            Migrations.start(injector, neededMigrations);        }        //升级完成,将升级的最新版本信息，持久化到文件中，以便下次启动进行判断        Migrations.finish(systemInformation, hiveMQConfigurationService);        //初始化guice        LOGGER.trace("Initializing Guice");        injector = Bootstrap.createInjector(systemInformation, metricRegistry, hiveMQConfigurationService, clusterIdProducer, injector);        //从guice中获得HiveMQServer实例，并启动它        HiveMQServer server = injector.getInstance(HiveMQServer.class);        server.start();        //对EXodus日志级别做修改        LogConfigurator.addXodusLogModificator();        LOGGER.info("Started HiveMQ in {}ms", TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startTime));        //hivemq版本升级检查器，会连接hivemq官网判断是否有新版本升级。可以在配置文件中设置不检查        UpdateChecker updateChecker = injector.getInstance(UpdateChecker.class);        updateChecker.start();    }    //根据加载出来的所有plugin打印plugin信息    //请参考hivemq spi @Information    private void printPluginInformations() {        Set<PluginInformation> pluginInformations = this.pluginInformationStore.getPluginInformations();        pluginInformations.forEach(pluginInformation ->                LOGGER.info("Loaded Plugin {} - v{}", pluginInformation.getName(), pluginInformation.getVersion())        );    }}

Bootstrap & Guice Modules

它是采用Guice作为di框架，那么我们就从Bootstrap开始看它包含了哪些Module以及简单介绍下这些Module主要是注入哪些对应处理代码。

public class Bootstrap {    private static final Logger LOGGER = LoggerFactory.getLogger(Bootstrap.class);    public static Injector createInjector(SystemInformation systemInformation, MetricRegistry metricRegistry, HiveMQConfigurationService hiveMQConfigurationService, ClusterIdProducer clusterIdProducer, Injector injector) {    //根据系统变量判断是否开启诊断模式        if (!Boolean.parseBoolean(System.getProperty("diagnosticMode"))) {            LOGGER.trace("Turning Guice stack traces off");            System.setProperty("guice_include_stack_traces", "OFF");        }        //加载所有PluginModule        //请参考hivemq spi PluginModule        //后续会专门讲解plugin是如何加载的        List<PluginModule> pluginModules = new PluginBootstrap().create(systemInformation.getPluginFolder());        ImmutableList.Builder<AbstractModule> builder = ImmutableList.builder();        builder.add(        //系统信息                new SystemInformationModule(systemInformation),           //注册cache的生命周期范围                new ScopeModule(),                //增加@PostConstruct、@PreDestroy注解处理                new LifecycleModule(),                //配置的Module                new ConfigurationModule(hiveMQConfigurationService, clusterIdProducer),                //netty所有handler、以及listenser等module                new NettyModule(),                //内部module                new InternalModule(),                //plugin callback module，主要处理plugin注册cabllback后回调                new PluginCallbackModule(),                //为方法增加cache的module                new MethodCacheModule(),                //持久化module                new PersistenceModule(injector),                //统计的module                new MetricModule(metricRegistry),                //流量监控module                new TrafficShapingModule(),                //cluster module                new ClusterModule(),                //plugin提供service的module                new ServiceModule(pluginModules),                //license的解析、验证、限制module                new LicensingModule(),                //更新hivemq程序的module                new UpdateModule(),                //诊断模式module                new DiagnosticModule());        builder.addAll(pluginModules);        return Guice.createInjector(Stage.PRODUCTION, builder.build());    }//创建数据升级的Injector，这个较上面的module加载的少点而已。    public static Injector createInjector(SystemInformation systemInformation,                                          HiveMQConfigurationService hiveMQConfigurationService,                                          ClusterIdProducer clusterIdProducer) {        ImmutableList.Builder<AbstractModule> builder = ImmutableList.builder();        builder.add(                new SystemInformationModule(systemInformation),                new ConfigurationModule(hiveMQConfigurationService, clusterIdProducer),                new BridgeModule(),                new ScopeModule(),                new LifecycleModule());        return Guice.createInjector(Stage.PRODUCTION, builder.build());    }}

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