摘要：關(guān)注我轉(zhuǎn)載請務必注明原創(chuàng)地址為前提上篇文章寫完了流程啟動的一部分，方法都入口，以及創(chuàng)建運行的必須環(huán)境以及相關(guān)配置，接著就是創(chuàng)建該環(huán)境的節(jié)點了。的創(chuàng)建看下新建節(jié)點的代碼代碼比較多，這里是比較關(guān)鍵的地方，我就把注釋直接寫在代碼上面了，實在不好

轉(zhuǎn)載請務必注明原創(chuàng)地址為：http://www.54tianzhisheng.cn/2018/08/12/es-code03/

上篇文章寫完了 ES 流程啟動的一部分，main 方法都入口，以及創(chuàng)建 Elasticsearch 運行的必須環(huán)境以及相關(guān)配置，接著就是創(chuàng)建該環(huán)境的節(jié)點了。

看下新建節(jié)點的代碼：(代碼比較多，這里是比較關(guān)鍵的地方，我就把注釋直接寫在代碼上面了，實在不好拆開這段代碼，300 多行代碼)

public Node(Environment environment) {
        this(environment, Collections.emptyList()); //執(zhí)行下面的代碼
    }

protected Node(final Environment environment, Collection> classpathPlugins) {
    final List resourcesToClose = new ArrayList<>(); // register everything we need to release in the case of an error
    boolean success = false;
    {
// use temp logger just to say we are starting. we can"t use it later on because the node name might not be set
        Logger logger = Loggers.getLogger(Node.class, NODE_NAME_SETTING.get(environment.settings()));
        logger.info("initializing ...");
    }
    try {
        originalSettings = environment.settings();
        Settings tmpSettings = Settings.builder().put(environment.settings())
            .put(Client.CLIENT_TYPE_SETTING_S.getKey(), CLIENT_TYPE).build();

// create the node environment as soon as possible, to recover the node id and enable logging
        try {
            nodeEnvironment = new NodeEnvironment(tmpSettings, environment); //1、創(chuàng)建節(jié)點環(huán)境,比如節(jié)點名稱,節(jié)點ID,分片信息,存儲元,以及分配內(nèi)存準備給節(jié)點使用
            resourcesToClose.add(nodeEnvironment);
        } catch (IOException ex) {
        throw new IllegalStateException("Failed to create node environment", ex);
        }
        final boolean hadPredefinedNodeName = NODE_NAME_SETTING.exists(tmpSettings);
        final String nodeId = nodeEnvironment.nodeId();
        tmpSettings = addNodeNameIfNeeded(tmpSettings, nodeId);
        final Logger logger = Loggers.getLogger(Node.class, tmpSettings);
// this must be captured after the node name is possibly added to the settings
        final String nodeName = NODE_NAME_SETTING.get(tmpSettings);
        if (hadPredefinedNodeName == false) {
            logger.info("node name derived from node ID [{}]; set [{}] to override", nodeId, NODE_NAME_SETTING.getKey());
        } else {
            logger.info("node name [{}], node ID [{}]", nodeName, nodeId);
        }

        //2、打印出JVM相關(guān)信息
        final JvmInfo jvmInfo = JvmInfo.jvmInfo();
        logger.info(
"version[{}], pid[{}], build[{}/{}/{}/{}], OS[{}/{}/{}], JVM[{}/{}/{}/{}]",
            Version.displayVersion(Version.CURRENT, Build.CURRENT.isSnapshot()),
            jvmInfo.pid(), Build.CURRENT.flavor().displayName(),
            Build.CURRENT.type().displayName(), Build.CURRENT.shortHash(),
            Build.CURRENT.date(), Constants.OS_NAME, Constants.OS_VERSION,
            Constants.OS_ARCH,Constants.JVM_VENDOR,Constants.JVM_NAME,
            Constants.JAVA_VERSION,Constants.JVM_VERSION);
        logger.info("JVM arguments {}", Arrays.toString(jvmInfo.getInputArguments()));
        //檢查當前版本是不是 pre-release 版本（Snapshot），
        warnIfPreRelease(Version.CURRENT, Build.CURRENT.isSnapshot(), logger);
        。。。
        this.pluginsService = new PluginsService(tmpSettings, environment.configFile(), environment.modulesFile(), environment.pluginsFile(), classpathPlugins);   //3、利用PluginsService加載相應的模塊和插件
        this.settings = pluginsService.updatedSettings();
        localNodeFactory = new LocalNodeFactory(settings, nodeEnvironment.nodeId());

// create the environment based on the finalized (processed) view of the settings
// this is just to makes sure that people get the same settings, no matter where they ask them from
        this.environment = new Environment(this.settings, environment.configFile());
        Environment.assertEquivalent(environment, this.environment);

        final List> executorBuilders = pluginsService.getExecutorBuilders(settings);        //線程池

        final ThreadPool threadPool = new ThreadPool(settings, executorBuilders.toArray(new ExecutorBuilder[0]));
        resourcesToClose.add(() -> ThreadPool.terminate(threadPool, 10, TimeUnit.SECONDS));
        // adds the context to the DeprecationLogger so that it does not need to be injected everywhere
        DeprecationLogger.setThreadContext(threadPool.getThreadContext());
        resourcesToClose.add(() -> DeprecationLogger.removeThreadContext(threadPool.getThreadContext()));

        final List> additionalSettings = new ArrayList<>(pluginsService.getPluginSettings());       //額外配置
        final List additionalSettingsFilter = new ArrayList<>(pluginsService.getPluginSettingsFilter());
        for (final ExecutorBuilder builder : threadPool.builders()) {
            //4、加載一些額外配置
            additionalSettings.addAll(builder.getRegisteredSettings());
        }
        client = new NodeClient(settings, threadPool);//5、創(chuàng)建一個節(jié)點客戶端                                                                                  

        //6、緩存一系列模塊,如NodeModule,ClusterModule,IndicesModule,ActionModule,GatewayModule,SettingsModule,RepositioriesModule，scriptModule，analysisModule
        final ResourceWatcherService resourceWatcherService = new ResourceWatcherService(settings, threadPool);
        final ScriptModule scriptModule = new ScriptModule(settings, pluginsService.filterPlugins(ScriptPlugin.class));
        AnalysisModule analysisModule = new AnalysisModule(this.environment, pluginsService.filterPlugins(AnalysisPlugin.class));
        // this is as early as we can validate settings at this point. we already pass them to ScriptModule as well as ThreadPool so we might be late here already
        final SettingsModule settingsModule = new SettingsModule(this.settings, additionalSettings, additionalSettingsFilter);
scriptModule.registerClusterSettingsListeners(settingsModule.getClusterSettings());
        resourcesToClose.add(resourceWatcherService);
        final NetworkService networkService = new NetworkService(
  getCustomNameResolvers(pluginsService.filterPlugins(DiscoveryPlugin.class)));
        List clusterPlugins = pluginsService.filterPlugins(ClusterPlugin.class);
        final ClusterService clusterService = new ClusterService(settings, settingsModule.getClusterSettings(), threadPool,                                                      ClusterModule.getClusterStateCustomSuppliers(clusterPlugins));
        clusterService.addStateApplier(scriptModule.getScriptService());
        resourcesToClose.add(clusterService);
        final IngestService ingestService = new IngestService(settings, threadPool, this.environment,                                                  scriptModule.getScriptService(), analysisModule.getAnalysisRegistry(), pluginsService.filterPlugins(IngestPlugin.class));
        final DiskThresholdMonitor listener = new DiskThresholdMonitor(settings, clusterService::state, clusterService.getClusterSettings(), client);
        final ClusterInfoService clusterInfoService = newClusterInfoService(settings, clusterService, threadPool, client,
listener::onNewInfo);
        final UsageService usageService = new UsageService(settings);

        ModulesBuilder modules = new ModulesBuilder();
// plugin modules must be added here, before others or we can get crazy injection errors...
        for (Module pluginModule : pluginsService.createGuiceModules()) {
            modules.add(pluginModule);
        }
        final MonitorService monitorService = new MonitorService(settings, nodeEnvironment, threadPool, clusterInfoService);
        ClusterModule clusterModule = new ClusterModule(settings, clusterService, clusterPlugins, clusterInfoService);
        modules.add(clusterModule);
        IndicesModule indicesModule = new IndicesModule(pluginsService.filterPlugins(MapperPlugin.class));
        modules.add(indicesModule);

        SearchModule searchModule = new SearchModule(settings, false, pluginsService.filterPlugins(SearchPlugin.class));
        CircuitBreakerService circuitBreakerService = createCircuitBreakerService(settingsModule.getSettings(),
                                                                                  settingsModule.getClusterSettings());
        resourcesToClose.add(circuitBreakerService);
        modules.add(new GatewayModule());

        PageCacheRecycler pageCacheRecycler = createPageCacheRecycler(settings);
        BigArrays bigArrays = createBigArrays(pageCacheRecycler, circuitBreakerService);
        resourcesToClose.add(bigArrays);
        modules.add(settingsModule);
        List namedWriteables = Stream.of(
            NetworkModule.getNamedWriteables().stream(),
            indicesModule.getNamedWriteables().stream(),
            searchModule.getNamedWriteables().stream(),
            pluginsService.filterPlugins(Plugin.class).stream()
            .flatMap(p -> p.getNamedWriteables().stream()),
            ClusterModule.getNamedWriteables().stream())
            .flatMap(Function.identity()).collect(Collectors.toList());
        final NamedWriteableRegistry namedWriteableRegistry = new NamedWriteableRegistry(namedWriteables);
        NamedXContentRegistry xContentRegistry = new NamedXContentRegistry(Stream.of(
            NetworkModule.getNamedXContents().stream(),
            searchModule.getNamedXContents().stream(),
            pluginsService.filterPlugins(Plugin.class).stream()
            .flatMap(p -> p.getNamedXContent().stream()),
            ClusterModule.getNamedXWriteables().stream())
.flatMap(Function.identity()).collect(toList()));
        modules.add(new RepositoriesModule(this.environment, pluginsService.filterPlugins(RepositoryPlugin.class), xContentRegistry));
        final MetaStateService metaStateService = new MetaStateService(settings, nodeEnvironment, xContentRegistry);
        final IndicesService indicesService = new IndicesService(settings, pluginsService, nodeEnvironment, xContentRegistry,
analysisModule.getAnalysisRegistry(),                                                                clusterModule.getIndexNameExpressionResolver(), indicesModule.getMapperRegistry(), namedWriteableRegistry,threadPool, settingsModule.getIndexScopedSettings(), circuitBreakerService, bigArrays, scriptModule.getScriptService(),client, metaStateService);

        Collection