Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.zookeeper.server; import java.io.IOException; import java.util.concurrent.CountDownLatch; import java.util.concurrent.TimeUnit; import javax.management.JMException; import org.apache.yetus.audience.InterfaceAudience; import org.apache.zookeeper.audit.ZKAuditProvider; import org.apache.zookeeper.jmx.ManagedUtil; import org.apache.zookeeper.metrics.MetricsProvider; import org.apache.zookeeper.metrics.MetricsProviderLifeCycleException; import org.apache.zookeeper.metrics.impl.MetricsProviderBootstrap; import org.apache.zookeeper.server.admin.AdminServer; import org.apache.zookeeper.server.admin.AdminServer.AdminServerException; import org.apache.zookeeper.server.admin.AdminServerFactory; import org.apache.zookeeper.server.persistence.FileTxnSnapLog; import org.apache.zookeeper.server.persistence.FileTxnSnapLog.DatadirException; import org.apache.zookeeper.server.quorum.QuorumPeerConfig.ConfigException; import org.apache.zookeeper.server.util.JvmPauseMonitor; import org.apache.zookeeper.util.ServiceUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * This class starts and runs a standalone ZooKeeperServer. */ @InterfaceAudience.Public public class ZooKeeperServerMain { private static final Logger LOG = LoggerFactory.getLogger(ZooKeeperServerMain.class); private static final String USAGE = "Usage: ZooKeeperServerMain configfile | port datadir [ticktime] [maxcnxns]"; // ZooKeeper server supports two kinds of connection: unencrypted and encrypted. private ServerCnxnFactory cnxnFactory; private ServerCnxnFactory secureCnxnFactory; private ContainerManager containerManager; private MetricsProvider metricsProvider; private AdminServer adminServer; /* * Start up the ZooKeeper server. * * @param args the configfile or the port datadir [ticktime] */ public static void main(String[] args) { ZooKeeperServerMain main = new ZooKeeperServerMain(); try { main.initializeAndRun(args); } catch (IllegalArgumentException e) { LOG.error("Invalid arguments, exiting abnormally", e); LOG.info(USAGE); System.err.println(USAGE); ZKAuditProvider.addServerStartFailureAuditLog(); ServiceUtils.requestSystemExit(ExitCode.INVALID_INVOCATION.getValue()); } catch (ConfigException e) { LOG.error("Invalid config, exiting abnormally", e); System.err.println("Invalid config, exiting abnormally"); ZKAuditProvider.addServerStartFailureAuditLog(); ServiceUtils.requestSystemExit(ExitCode.INVALID_INVOCATION.getValue()); } catch (DatadirException e) { LOG.error("Unable to access datadir, exiting abnormally", e); System.err.println("Unable to access datadir, exiting abnormally"); ZKAuditProvider.addServerStartFailureAuditLog(); ServiceUtils.requestSystemExit(ExitCode.UNABLE_TO_ACCESS_DATADIR.getValue()); } catch (AdminServerException e) { LOG.error("Unable to start AdminServer, exiting abnormally", e); System.err.println("Unable to start AdminServer, exiting abnormally"); ZKAuditProvider.addServerStartFailureAuditLog(); ServiceUtils.requestSystemExit(ExitCode.ERROR_STARTING_ADMIN_SERVER.getValue()); } catch (Exception e) { LOG.error("Unexpected exception, exiting abnormally", e); ZKAuditProvider.addServerStartFailureAuditLog(); ServiceUtils.requestSystemExit(ExitCode.UNEXPECTED_ERROR.getValue()); } LOG.info("Exiting normally"); ServiceUtils.requestSystemExit(ExitCode.EXECUTION_FINISHED.getValue()); } protected void initializeAndRun(String[] args) throws ConfigException, IOException, AdminServerException { try { ManagedUtil.registerLog4jMBeans(); } catch (JMException e) { LOG.warn("Unable to register log4j JMX control", e); } ServerConfig config = new ServerConfig(); if (args.length == 1) { config.parse(args[0]); } else { config.parse(args); } runFromConfig(config); } /** * Run from a ServerConfig. * @param config ServerConfig to use. * @throws IOException * @throws AdminServerException */ public void runFromConfig(ServerConfig config) throws IOException, AdminServerException { LOG.info("Starting server"); FileTxnSnapLog txnLog = null; try { try { metricsProvider = MetricsProviderBootstrap.startMetricsProvider( config.getMetricsProviderClassName(), config.getMetricsProviderConfiguration()); } catch (MetricsProviderLifeCycleException error) { throw new IOException("Cannot boot MetricsProvider " + config.getMetricsProviderClassName(), error); } ServerMetrics.metricsProviderInitialized(metricsProvider); // Note that this thread isn't going to be doing anything else, // so rather than spawning another thread, we will just call // run() in this thread. // create a file logger url from the command line args txnLog = new FileTxnSnapLog(config.dataLogDir, config.dataDir); JvmPauseMonitor jvmPauseMonitor = null; if (config.jvmPauseMonitorToRun) { jvmPauseMonitor = new JvmPauseMonitor(config); } final ZooKeeperServer zkServer = new ZooKeeperServer(jvmPauseMonitor, txnLog, config.tickTime, config.minSessionTimeout, config.maxSessionTimeout, config.listenBacklog, null, config.initialConfig); txnLog.setServerStats(zkServer.serverStats()); // Registers shutdown handler which will be used to know the // server error or shutdown state changes. final CountDownLatch shutdownLatch = new CountDownLatch(1); zkServer.registerServerShutdownHandler(new ZooKeeperServerShutdownHandler(shutdownLatch)); // Start Admin server adminServer = AdminServerFactory.createAdminServer(); adminServer.setZooKeeperServer(zkServer); adminServer.start(); boolean needStartZKServer = true; if (config.getClientPortAddress() != null) { cnxnFactory = ServerCnxnFactory.createFactory(); cnxnFactory.configure(config.getClientPortAddress(), config.getMaxClientCnxns(), config.getClientPortListenBacklog(), false); cnxnFactory.startup(zkServer); // zkServer has been started. So we don't need to start it again in secureCnxnFactory. needStartZKServer = false; } if (config.getSecureClientPortAddress() != null) { secureCnxnFactory = ServerCnxnFactory.createFactory(); secureCnxnFactory.configure(config.getSecureClientPortAddress(), config.getMaxClientCnxns(), config.getClientPortListenBacklog(), true); secureCnxnFactory.startup(zkServer, needStartZKServer); } containerManager = new ContainerManager(zkServer.getZKDatabase(), zkServer.firstProcessor, Integer.getInteger("znode.container.checkIntervalMs", (int) TimeUnit.MINUTES.toMillis(1)), Integer.getInteger("znode.container.maxPerMinute", 10000), Long.getLong("znode.container.maxNeverUsedIntervalMs", 0)); containerManager.start(); ZKAuditProvider.addZKStartStopAuditLog(); // Watch status of ZooKeeper server. It will do a graceful shutdown // if the server is not running or hits an internal error. shutdownLatch.await(); shutdown(); if (cnxnFactory != null) { cnxnFactory.join(); } if (secureCnxnFactory != null) { secureCnxnFactory.join(); } if (zkServer.canShutdown()) { zkServer.shutdown(true); } } catch (InterruptedException e) { // warn, but generally this is ok LOG.warn("Server interrupted", e); } finally { if (txnLog != null) { txnLog.close(); } if (metricsProvider != null) { try { metricsProvider.stop(); } catch (Throwable error) { LOG.warn("Error while stopping metrics", error); } } } } /** * Shutdown the serving instance */ protected void shutdown() { if (containerManager != null) { containerManager.stop(); } if (cnxnFactory != null) { cnxnFactory.shutdown(); } if (secureCnxnFactory != null) { secureCnxnFactory.shutdown(); } try { if (adminServer != null) { adminServer.shutdown(); } } catch (AdminServerException e) { LOG.warn("Problem stopping AdminServer", e); } } // VisibleForTesting ServerCnxnFactory getCnxnFactory() { return cnxnFactory; } }