ElasticSearch源码解读二：启动过程详解

    /**
     * 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(foreground, pidFile, keystore, initialEnv.settings(), initialEnv.configFile());

        if (Node.NODE_NAME_SETTING.exists(environment.settings())) {
            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
            // setDefaultUncaughtExceptionHandler
            Thread.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 otherwise
            if (e instanceof CreationException) {
                // guice: log the shortened exc to the log file
                ByteArrayOutputStream 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 exception
                logger.error("Exception", e);
            }
            // re-enable it if appropriate, so they can see any logging during the shutdown process
            if (foreground && maybeConsoleAppender != null) {
                Loggers.addAppender(rootLogger, maybeConsoleAppender);
            }

            throw e;
        }
    }

    private void setup(boolean addShutdownHook, Environment environment) throws BootstrapException {
        Settings settings = environment.settings();

        try {
            spawner.spawnNativeControllers(environment);
        } catch (IOException e) {
            throw new BootstrapException(e);
        }

        initializeNatives(
                environment.tmpFile(),
                BootstrapSettings.MEMORY_LOCK_SETTING.get(settings),
                BootstrapSettings.SYSTEM_CALL_FILTER_SETTING.get(settings),
                BootstrapSettings.CTRLHANDLER_SETTING.get(settings));

        // initialize probes before the security manager is installed
        initializeProbes();

        if (addShutdownHook) {
            Runtime.getRuntime().addShutdownHook(new Thread() {
                @Override
                public void run() {
                    try {
                        IOUtils.close(node, spawner);
                        LoggerContext context = (LoggerContext) LogManager.getContext(false);
                        Configurator.shutdown(context);
                    } catch (IOException ex) {
                        throw new ElasticsearchException("failed to stop node", ex);
                    }
                }
            });
        }

        try {
            // look for jar hell
            final Logger logger = LogManager.getLogger(JarHell.class);
            JarHell.checkJarHell(logger::debug);
        } catch (IOException | URISyntaxException e) {
            throw new BootstrapException(e);
        }

        // Log ifconfig output before SecurityManager is installed
        IfConfig.logIfNecessary();

        // install SM after natives, shutdown hooks, etc.
        try {
            Security.configure(environment, BootstrapSettings.SECURITY_FILTER_BAD_DEFAULTS_SETTING.get(settings));
        } catch (IOException | NoSuchAlgorithmException e) {
            throw new BootstrapException(e);
        }

        node = new Node(environment) {
            @Override
            protected void validateNodeBeforeAcceptingRequests(
                final BootstrapContext context,
                final BoundTransportAddress boundTransportAddress, List<BootstrapCheck> checks) throws NodeValidationException {
                BootstrapChecks.check(context, boundTransportAddress, checks);
            }

            @Override
            protected void registerDerivedNodeNameWithLogger(String nodeName) {
                LogConfigurator.setNodeName(nodeName);
            }
        };
    }

    /**
     * Constructs a node
     *
     * @param environment                the environment for this node
     * @param classpathPlugins           the plugins to be loaded from the classpath
     * @param forbidPrivateIndexSettings whether or not private index settings are forbidden when creating an index; this is used in the
     *                                   test framework for tests that rely on being able to set private settings
     */
    protected Node(
            final Environment environment, Collection<Class<? extends Plugin>> classpathPlugins, boolean forbidPrivateIndexSettings) {
        logger = LogManager.getLogger(Node.class);
        final List<Closeable> resourcesToClose = new ArrayList<>(); // register everything we need to release in the case of an error
        boolean success = false;
        try {
            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 so we can
             * recover the node id which we might have to use to derive the
             * node name. And it is important to get *that* as soon as possible
             * so that log lines can contain it.
             */
            boolean nodeNameExplicitlyDefined = NODE_NAME_SETTING.exists(tmpSettings);
            try {
                Consumer<String> nodeIdConsumer = nodeNameExplicitlyDefined ?
                        nodeId -> {} : nodeId -> registerDerivedNodeNameWithLogger(nodeIdToNodeName(nodeId));
                nodeEnvironment = new NodeEnvironment(tmpSettings, environment, nodeIdConsumer);
                resourcesToClose.add(nodeEnvironment);
            } catch (IOException ex) {
                throw new IllegalStateException("Failed to create node environment", ex);
            }
            if (nodeNameExplicitlyDefined) {
                logger.info("node name [{}], node ID [{}]",
                        NODE_NAME_SETTING.get(tmpSettings), nodeEnvironment.nodeId());
            } else {
                tmpSettings = Settings.builder()
                        .put(tmpSettings)
                        .put(NODE_NAME_SETTING.getKey(), nodeIdToNodeName(nodeEnvironment.nodeId()))
                        .build();
                logger.info("node name derived from node ID [{}]; set [{}] to override",
                        nodeEnvironment.nodeId(), NODE_NAME_SETTING.getKey());
            }


            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()));
            warnIfPreRelease(Version.CURRENT, Build.CURRENT.isSnapshot(), logger);

            if (logger.isDebugEnabled()) {
                logger.debug("using config [{}], data [{}], logs [{}], plugins [{}]",
                    environment.configFile(), Arrays.toString(environment.dataFiles()), environment.logsFile(), environment.pluginsFile());
            }
            ...
        }

    // get a bundle for a single plugin dir
    private static Bundle readPluginBundle(final Set<Bundle> bundles, final Path plugin, String type) throws IOException {
        LogManager.getLogger(PluginsService.class).trace("--- adding [{}] [{}]", type, plugin.toAbsolutePath());
        final PluginInfo info;
        try {
            info = PluginInfo.readFromProperties(plugin);
        } catch (final IOException e) {
            throw new IllegalStateException("Could not load plugin descriptor for " + type +
                                            " directory [" + plugin.getFileName() + "]", e);
        }
        final Bundle bundle = new Bundle(info, plugin);
        if (bundles.add(bundle) == false) {
            throw new IllegalStateException("duplicate " + type + ": " + info);
        }
        return bundle;
    }

    /**
     * Reads the plugin descriptor file.
     *
     * @param path           the path to the root directory for the plugin
     * @return the plugin info
     * @throws IOException if an I/O exception occurred reading the plugin descriptor
     */
    public static PluginInfo readFromProperties(final Path path) throws IOException {
        final Path descriptor = path.resolve(ES_PLUGIN_PROPERTIES);

        final Map<String, String> propsMap;
        {
            final Properties props = new Properties();
            try (InputStream stream = Files.newInputStream(descriptor)) {
                props.load(stream);
            }
            propsMap = props.stringPropertyNames().stream().collect(Collectors.toMap(Function.identity(), props::getProperty));
        }

        final String name = propsMap.remove("name");
        if (name == null || name.isEmpty()) {
            throw new IllegalArgumentException(
                    "property [name] is missing in [" + descriptor + "]");
        }
        final String description = propsMap.remove("description");
        if (description == null) {
            throw new IllegalArgumentException(
                    "property [description] is missing for plugin [" + name + "]");
        }
        final String version = propsMap.remove("version");
        if (version == null) {
            throw new IllegalArgumentException(
                    "property [version] is missing for plugin [" + name + "]");
        }

        final String esVersionString = propsMap.remove("elasticsearch.version");
        if (esVersionString == null) {
            throw new IllegalArgumentException(
                    "property [elasticsearch.version] is missing for plugin [" + name + "]");
        }
        final Version esVersion = Version.fromString(esVersionString);
        final String javaVersionString = propsMap.remove("java.version");
        if (javaVersionString == null) {
            throw new IllegalArgumentException(
                    "property [java.version] is missing for plugin [" + name + "]");
        }
        JarHell.checkVersionFormat(javaVersionString);
        final String classname = propsMap.remove("classname");
        if (classname == null) {
            throw new IllegalArgumentException(
                    "property [classname] is missing for plugin [" + name + "]");
        }

        final String extendedString = propsMap.remove("extended.plugins");
        final List<String> extendedPlugins;
        if (extendedString == null) {
            extendedPlugins = Collections.emptyList();
        } else {
            extendedPlugins = Arrays.asList(Strings.delimitedListToStringArray(extendedString, ","));
        }

        final String hasNativeControllerValue = propsMap.remove("has.native.controller");
        final boolean hasNativeController;
        if (hasNativeControllerValue == null) {
            hasNativeController = false;
        } else {
            switch (hasNativeControllerValue) {
                case "true":
                    hasNativeController = true;
                    break;
                case "false":
                    hasNativeController = false;
                    break;
                default:
                    final String message = String.format(
                            Locale.ROOT,
                            "property [%s] must be [%s], [%s], or unspecified but was [%s]",
                            "has_native_controller",
                            "true",
                            "false",
                            hasNativeControllerValue);
                    throw new IllegalArgumentException(message);
            }
        }

        if (esVersion.before(Version.V_6_3_0) && esVersion.onOrAfter(Version.V_6_0_0_beta2)) {
            propsMap.remove("requires.keystore");
        }

        if (propsMap.isEmpty() == false) {
            throw new IllegalArgumentException("Unknown properties in plugin descriptor: " + propsMap.keySet());
        }

        return new PluginInfo(name, description, version, esVersion, javaVersionString,
                              classname, extendedPlugins, hasNativeController);
    }

    public static final String ES_PLUGIN_PROPERTIES = "plugin-descriptor.properties";
    public static final String ES_PLUGIN_POLICY = "plugin-security.policy";

    public enum ThreadPoolType {
        DIRECT("direct"),
        FIXED("fixed"),
        FIXED_AUTO_QUEUE_SIZE("fixed_auto_queue_size"),
        SCALING("scaling");

        private final String type;

        public String getType() {
            return type;
        }

        ThreadPoolType(String type) {
            this.type = type;
        }

        private static final Map<String, ThreadPoolType> TYPE_MAP;

        static {
            Map<String, ThreadPoolType> typeMap = new HashMap<>();
            for (ThreadPoolType threadPoolType : ThreadPoolType.values()) {
                typeMap.put(threadPoolType.getType(), threadPoolType);
            }
            TYPE_MAP = Collections.unmodifiableMap(typeMap);
        }

        public static ThreadPoolType fromType(String type) {
            ThreadPoolType threadPoolType = TYPE_MAP.get(type);
            if (threadPoolType == null) {
                throw new IllegalArgumentException("no ThreadPoolType for " + type);
            }
            return threadPoolType;
        }
    }

    public static class Names {
        public static final String SAME = "same";
        public static final String GENERIC = "generic";
        public static final String LISTENER = "listener";
        public static final String GET = "get";
        public static final String ANALYZE = "analyze";
        public static final String INDEX = "index";
        public static final String WRITE = "write";
        public static final String SEARCH = "search";
        public static final String SEARCH_THROTTLED = "search_throttled";
        public static final String MANAGEMENT = "management";
        public static final String FLUSH = "flush";
        public static final String REFRESH = "refresh";
        public static final String WARMER = "warmer";
        public static final String SNAPSHOT = "snapshot";
        public static final String FORCE_MERGE = "force_merge";
        public static final String FETCH_SHARD_STARTED = "fetch_shard_started";
        public static final String FETCH_SHARD_STORE = "fetch_shard_store";
    }