1.找到bin目錄，下面有elasticSearch的sh文件，查看執(zhí)行過(guò)程

exec \"$JAVA" \$ES_JAVA_OPTS \-Des.path.home="$ES_HOME" \-Des.path.conf="$ES_PATH_CONF" \-Des.distribution.flavor="$ES_DISTRIBUTION_FLAVOR" \-Des.distribution.type="$ES_DISTRIBUTION_TYPE" \-cp "$ES_CLASSPATH" \org.elasticsearch.bootstrap.Elasticsearch \"$@"

可以看到主類的名稱為：

Elasticsearch

2.主類Elasticsearch

找到main方法，父類

Command的execute()方法，ElasticSearch重寫了該方法 @Overrideprotected void execute(Terminal terminal, OptionSet options, Environment env) throws UserException {if (options.nonOptionArguments().isEmpty() == false) {throw new UserException(ExitCodes.USAGE, "Positional arguments not allowed, found " + options.nonOptionArguments());}if (options.has(versionOption)) {final String versionOutput = String.format(Locale.ROOT,"Version: %s, Build: %s/%s/%s/%s, JVM: %s",Version.displayVersion(Version.CURRENT, Build.CURRENT.isSnapshot()),Build.CURRENT.flavor().displayName(),Build.CURRENT.type().displayName(),Build.CURRENT.shortHash(),Build.CURRENT.date(),JvmInfo.jvmInfo().version());terminal.println(versionOutput);return;}final boolean daemonize = options.has(daemonizeOption);final Path pidFile = pidfileOption.value(options);final boolean quiet = options.has(quietOption);// a misconfigured java.io.tmpdir can cause hard-to-diagnose problems later, so reject it immediatelytry {env.validateTmpFile();} catch (IOException e) {throw new UserException(ExitCodes.CONFIG, e.getMessage());}try {init(daemonize, pidFile, quiet, env);} catch (NodeValidationException e) {throw new UserException(ExitCodes.CONFIG, e.getMessage());}}void init(final boolean daemonize, final Path pidFile, final boolean quiet, Environment initialEnv)throws NodeValidationException, UserException {try {Bootstrap.init(!daemonize, pidFile, quiet, initialEnv);} catch (BootstrapException | RuntimeException e) {// format exceptions to the console in a special way// to avoid 2MB stacktraces from guice, etc.throw new StartupException(e);}}

2.啟動(dòng)類Bootstrap

init方法

/*** This method is invoked by {@link Elasticsearch#main(String[])} to startup elasticsearch.*/static void init(final boolean foreground,final Path pidFile,final boolean quiet,final Environment initialEnv) throws BootstrapException, NodeValidationException, UserException {// force the class initializer for BootstrapInfo to run before// the security manager is installed BootstrapInfo.init();INSTANCE = new Bootstrap();final SecureSettings keystore = loadSecureSettings(initialEnv);final Environment environment = createEnvironment(pidFile, keystore, initialEnv.settings(), initialEnv.configFile());LogConfigurator.setNodeName(Node.NODE_NAME_SETTING.get(environment.settings()));try {LogConfigurator.configure(environment);} catch (IOException e) {throw new BootstrapException(e);}if (environment.pidFile() != null) {try {PidFile.create(environment.pidFile(), true);} catch (IOException e) {throw new BootstrapException(e);}}final boolean closeStandardStreams = (foreground == false) || quiet;try {if (closeStandardStreams) {final Logger rootLogger = LogManager.getRootLogger();final Appender maybeConsoleAppender = Loggers.findAppender(rootLogger, ConsoleAppender.class);if (maybeConsoleAppender != null) {Loggers.removeAppender(rootLogger, maybeConsoleAppender);}closeSystOut();}// fail if somebody replaced the lucene jars checkLucene();// install the default uncaught exception handler; must be done before security is// initialized as we do not want to grant the runtime permission// setDefaultUncaughtExceptionHandlerThread.setDefaultUncaughtExceptionHandler(new ElasticsearchUncaughtExceptionHandler());INSTANCE.setup(true, environment);try {// any secure settings must be read during node construction IOUtils.close(keystore);} catch (IOException e) {throw new BootstrapException(e);}INSTANCE.start();if (closeStandardStreams) {closeSysError();}} catch (NodeValidationException | RuntimeException e) {// disable console logging, so user does not see the exception twice (jvm will show it already)final Logger rootLogger = LogManager.getRootLogger();final Appender maybeConsoleAppender = Loggers.findAppender(rootLogger, ConsoleAppender.class);if (foreground && maybeConsoleAppender != null) {Loggers.removeAppender(rootLogger, maybeConsoleAppender);}Logger logger = LogManager.getLogger(Bootstrap.class);// HACK, it sucks to do this, but we will run users out of disk space otherwiseif (e instanceof CreationException) {// guice: log the shortened exc to the log fileByteArrayOutputStream os = new ByteArrayOutputStream();PrintStream ps = null;try {ps = new PrintStream(os, false, "UTF-8");} catch (UnsupportedEncodingException uee) {assert false;e.addSuppressed(uee);}new StartupException(e).printStackTrace(ps);ps.flush();try {logger.error("Guice Exception: {}", os.toString("UTF-8"));} catch (UnsupportedEncodingException uee) {assert false;e.addSuppressed(uee);}} else if (e instanceof NodeValidationException) {logger.error("node validation exception\n{}", e.getMessage());} else {// full exceptionlogger.error("Exception", e);}// re-enable it if appropriate, so they can see any logging during the shutdown processif (foreground && maybeConsoleAppender != null) {Loggers.addAppender(rootLogger, maybeConsoleAppender);}throw e;}}

找到紅色的啟動(dòng)方法start，進(jìn)去看，是Node的start方法

private void start() throws NodeValidationException {node.start();keepAliveThread.start();}

3.節(jié)點(diǎn)啟動(dòng)Node

start方法

/*** Start the node. If the node is already started, this method is no-op.*/public Node start() throws NodeValidationException {if (!lifecycle.moveToStarted()) {return this;}logger.info("starting ...");pluginLifecycleComponents.forEach(LifecycleComponent::start);injector.getInstance(MappingUpdatedAction.class).setClient(client);injector.getInstance(IndicesService.class).start();injector.getInstance(IndicesClusterStateService.class).start();injector.getInstance(SnapshotsService.class).start();injector.getInstance(SnapshotShardsService.class).start();injector.getInstance(RoutingService.class).start();injector.getInstance(SearchService.class).start();nodeService.getMonitorService().start();final ClusterService clusterService = injector.getInstance(ClusterService.class);final NodeConnectionsService nodeConnectionsService = injector.getInstance(NodeConnectionsService.class);nodeConnectionsService.start();clusterService.setNodeConnectionsService(nodeConnectionsService);injector.getInstance(ResourceWatcherService.class).start();injector.getInstance(GatewayService.class).start();Discovery discovery = injector.getInstance(Discovery.class);clusterService.getMasterService().setClusterStatePublisher(discovery::publish);// Start the transport service now so the publish address will be added to the local disco node in ClusterServiceTransportService transportService = injector.getInstance(TransportService.class);transportService.getTaskManager().setTaskResultsService(injector.getInstance(TaskResultsService.class));transportService.start();assert localNodeFactory.getNode() != null;assert transportService.getLocalNode().equals(localNodeFactory.getNode()): "transportService has a different local node than the factory provided";final MetaData onDiskMetadata;try {// we load the global state here (the persistent part of the cluster state stored on disk) to// pass it to the bootstrap checks to allow plugins to enforce certain preconditions based on the recovered state.if (DiscoveryNode.isMasterNode(settings) || DiscoveryNode.isDataNode(settings)) {onDiskMetadata = injector.getInstance(GatewayMetaState.class).loadMetaState();} else {onDiskMetadata = MetaData.EMPTY_META_DATA;}assert onDiskMetadata != null : "metadata is null but shouldn't"; // this is never null} catch (IOException e) {throw new UncheckedIOException(e);}validateNodeBeforeAcceptingRequests(new BootstrapContext(settings, onDiskMetadata), transportService.boundAddress(), pluginsService.filterPlugins(Plugin.class).stream().flatMap(p -> p.getBootstrapChecks().stream()).collect(Collectors.toList()));clusterService.addStateApplier(transportService.getTaskManager());// start after transport service so the local disco is knowndiscovery.start(); // start before cluster service so that it can set initial state on ClusterApplierService clusterService.start();assert clusterService.localNode().equals(localNodeFactory.getNode()): "clusterService has a different local node than the factory provided";transportService.acceptIncomingRequests();discovery.startInitialJoin();final TimeValue initialStateTimeout = DiscoverySettings.INITIAL_STATE_TIMEOUT_SETTING.get(settings);if (initialStateTimeout.millis() > 0) {final ThreadPool thread = injector.getInstance(ThreadPool.class);ClusterState clusterState = clusterService.state();ClusterStateObserver observer = new ClusterStateObserver(clusterState, clusterService, null, logger, thread.getThreadContext());if (clusterState.nodes().getMasterNodeId() == null) {logger.debug("waiting to join the cluster. timeout [{}]", initialStateTimeout);final CountDownLatch latch = new CountDownLatch(1);observer.waitForNextChange(new ClusterStateObserver.Listener() {@Overridepublic void onNewClusterState(ClusterState state) { latch.countDown(); }@Overridepublic void onClusterServiceClose() {latch.countDown();}@Overridepublic void onTimeout(TimeValue timeout) {logger.warn("timed out while waiting for initial discovery state - timeout: {}",initialStateTimeout);latch.countDown();}}, state -> state.nodes().getMasterNodeId() != null, initialStateTimeout);try {latch.await();} catch (InterruptedException e) {throw new ElasticsearchTimeoutException("Interrupted while waiting for initial discovery state");}}}injector.getInstance(HttpServerTransport.class).start();if (WRITE_PORTS_FILE_SETTING.get(settings)) {TransportService transport = injector.getInstance(TransportService.class);writePortsFile("transport", transport.boundAddress());HttpServerTransport http = injector.getInstance(HttpServerTransport.class);writePortsFile("http", http.boundAddress());}logger.info("started");pluginsService.filterPlugins(ClusterPlugin.class).forEach(ClusterPlugin::onNodeStarted);return this;}

里面一個(gè)非常重要的對(duì)象Injector，我們看看它的定義：

/*** Builds the graphs of objects that make up your application. The injector tracks the dependencies* for each type and uses bindings to inject them. This is the core of Guice, although you rarely* interact with it directly. This "behind-the-scenes" operation is what distinguishes dependency* injection from its cousin, the service locator pattern.* <p>* Contains several default bindings:* <ul>* <li>This {@link Injector} instance itself* <li>A {@code Provider<T>} for each binding of type {@code T}* <li>The {@link java.util.logging.Logger} for the class being injected* <li>The {@link Stage} in which the Injector was created* </ul>* <p>* Injectors are created using the facade class {@link Guice}.* <p>* An injector can also {@link #injectMembers(Object) inject the dependencies} of* already-constructed instances. This can be used to interoperate with objects created by other* frameworks or services.** @author crazybob@google.com (Bob Lee)* @author jessewilson@google.com (Jesse Wilson)*/

簡(jiǎn)單的說(shuō)，Injector是一個(gè)實(shí)例管理器，和spring中IOC的beanfactory功能相當(dāng)。

需要啟動(dòng)的服務(wù)如下：

后續(xù)會(huì)針對(duì)每個(gè)服務(wù)做單獨(dú)的分析

轉(zhuǎn)載于:https://www.cnblogs.com/davidwang456/p/10038579.html

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