Elasticsearch源码分析(一)启动流程 ModuleBuilder injector

http://blog.csdn.net/u010994304/article/details/50452890

es启动脚本是bin目录下的elasticsearch。

脚本内容不再赘述，java主类位于org.elasticsearch.bootstrap。主要逻辑是生成了一个InternalNode节点，并且启动了一个keepalive线程。结点的启动代表整个es进程启动了。

InternalNode节点是通过NodeBuilder来生成的，节点在构造函数中

通过ModuleBuilder类来进行模块的注入（是对Guice的一个封装而已），同时生成injector实例，如下

ModulesBuilder modules = new ModulesBuilder();
modules.add(new Version.Module(version));
modules.add(new CacheRecyclerModule(settings));
modules.add(new PageCacheRecyclerModule(settings));
modules.add(new BigArraysModule(settings));
modules.add(new PluginsModule(settings, pluginsService));
modules.add(new SettingsModule(settings));
modules.add(new NodeModule(this));
modules.add(new NetworkModule());
modules.add(new ScriptModule(settings));
modules.add(new EnvironmentModule(environment));
modules.add(new NodeEnvironmentModule(nodeEnvironment));
modules.add(new ClusterNameModule(settings));
modules.add(new ThreadPoolModule(settings));
modules.add(new DiscoveryModule(settings));
modules.add(new ClusterModule(settings));
modules.add(new RestModule(settings));
modules.add(new TransportModule(settings));
if (settings.getAsBoolean("http.enabled", true)) {
    modules.add(new HttpServerModule(settings));
}
modules.add(new RiversModule(settings));
modules.add(new IndicesModule(settings));
modules.add(new SearchModule());
modules.add(new ActionModule(false));
modules.add(new MonitorModule(settings));
modules.add(new GatewayModule(settings));
modules.add(new NodeClientModule());
modules.add(new BulkUdpModule());
modules.add(new ShapeModule());
modules.add(new PercolatorModule());
modules.add(new ResourceWatcherModule());
modules.add(new RepositoriesModule());
modules.add(new TribeModule());

            injector = modules.createInjector();

在InternalNode的start方法中，用injector对各个模块完成启动，各自负责各自的功能，如下：

 

injector.getInstance(Discovery.class).setAllocationService(injector.getInstance(AllocationService.class));

for (Class<? extends LifecycleComponent> plugin : pluginsService.services()) {
    injector.getInstance(plugin).start();
}

injector.getInstance(MappingUpdatedAction.class).start();
injector.getInstance(IndicesService.class).start();
injector.getInstance(IndexingMemoryController.class).start();
injector.getInstance(IndicesClusterStateService.class).start();
injector.getInstance(IndicesTTLService.class).start();
injector.getInstance(RiversManager.class).start();
injector.getInstance(SnapshotsService.class).start();
injector.getInstance(ClusterService.class).start();
injector.getInstance(RoutingService.class).start();
injector.getInstance(SearchService.class).start();
injector.getInstance(MonitorService.class).start();
injector.getInstance(RestController.class).start();
injector.getInstance(TransportService.class).start();
DiscoveryService discoService = injector.getInstance(DiscoveryService.class).start();
discoService.waitForInitialState();

// gateway should start after disco, so it can try and recovery from gateway on "start"
injector.getInstance(GatewayService.class).start();

if (settings.getAsBoolean("http.enabled", true)) {
    injector.getInstance(HttpServer.class).start();
}
injector.getInstance(BulkUdpService.class).start();
injector.getInstance(ResourceWatcherService.class).start();
injector.getInstance(TribeService.class).start();

至此，es进程启动完毕。

guice相关介绍可以参见以下链接：

关键点在于：

@inject注释---guice会扫描inject注释，并对方法中出现的参数实例寻找对应注册的实例进行初始化。

bind接口-----将接口跟具体实现类绑定

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