Java tutorial
/* * Copyright 2010 The Apache Software Foundation * * 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.hadoop.hbase.rest; import org.apache.commons.cli.CommandLine; import org.apache.commons.cli.HelpFormatter; import org.apache.commons.cli.Options; import org.apache.commons.cli.PosixParser; import org.apache.commons.cli.ParseException; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.hbase.HBaseConfiguration; import org.apache.hadoop.hbase.rest.filter.GzipFilter; import org.apache.hadoop.hbase.security.User; import org.apache.hadoop.hbase.util.Strings; import org.apache.hadoop.hbase.util.VersionInfo; import org.apache.hadoop.net.DNS; import java.util.List; import java.util.ArrayList; import org.mortbay.jetty.Connector; import org.mortbay.jetty.Server; import org.mortbay.jetty.nio.SelectChannelConnector; import org.mortbay.jetty.servlet.Context; import org.mortbay.jetty.servlet.ServletHolder; import org.mortbay.thread.QueuedThreadPool; import com.sun.jersey.spi.container.servlet.ServletContainer; /** * Main class for launching REST gateway as a servlet hosted by Jetty. * <p> * The following options are supported: * <ul> * <li>-p --port : service port</li> * <li>-ro --readonly : server mode</li> * </ul> */ public class Main implements Constants { private static void printUsageAndExit(Options options, int exitCode) { HelpFormatter formatter = new HelpFormatter(); formatter.printHelp("bin/hbase rest start", "", options, "\nTo run the REST server as a daemon, execute " + "bin/hbase-daemon.sh start|stop rest [-p <port>] [-ro]\n", true); System.exit(exitCode); } /** * The main method for the HBase rest server. * @param args command-line arguments * @throws Exception exception */ public static void main(String[] args) throws Exception { Log LOG = LogFactory.getLog("RESTServer"); VersionInfo.logVersion(); Configuration conf = HBaseConfiguration.create(); RESTServlet servlet = RESTServlet.getInstance(conf); Options options = new Options(); options.addOption("p", "port", true, "Port to bind to [default: 8080]"); options.addOption("ro", "readonly", false, "Respond only to GET HTTP " + "method requests [default: false]"); CommandLine commandLine = null; try { commandLine = new PosixParser().parse(options, args); } catch (ParseException e) { LOG.error("Could not parse: ", e); printUsageAndExit(options, -1); } // check for user-defined port setting, if so override the conf if (commandLine != null && commandLine.hasOption("port")) { String val = commandLine.getOptionValue("port"); servlet.getConfiguration().setInt("hbase.rest.port", Integer.valueOf(val)); LOG.debug("port set to " + val); } // check if server should only process GET requests, if so override the conf if (commandLine != null && commandLine.hasOption("readonly")) { servlet.getConfiguration().setBoolean("hbase.rest.readonly", true); LOG.debug("readonly set to true"); } @SuppressWarnings("unchecked") List<String> remainingArgs = commandLine != null ? commandLine.getArgList() : new ArrayList<String>(); if (remainingArgs.size() != 1) { printUsageAndExit(options, 1); } String command = remainingArgs.get(0); if ("start".equals(command)) { // continue and start container } else if ("stop".equals(command)) { System.exit(1); } else { printUsageAndExit(options, 1); } // set up the Jersey servlet container for Jetty ServletHolder sh = new ServletHolder(ServletContainer.class); sh.setInitParameter("com.sun.jersey.config.property.resourceConfigClass", ResourceConfig.class.getCanonicalName()); sh.setInitParameter("com.sun.jersey.config.property.packages", "jetty"); // set up Jetty and run the embedded server Server server = new Server(); Connector connector = new SelectChannelConnector(); connector.setPort(servlet.getConfiguration().getInt("hbase.rest.port", 8080)); connector.setHost(servlet.getConfiguration().get("hbase.rest.host", "0.0.0.0")); server.addConnector(connector); // Set the default max thread number to 100 to limit // the number of concurrent requests so that REST server doesn't OOM easily. // Jetty set the default max thread number to 250, if we don't set it. // // Our default min thread number 2 is the same as that used by Jetty. int maxThreads = servlet.getConfiguration().getInt("hbase.rest.threads.max", 100); int minThreads = servlet.getConfiguration().getInt("hbase.rest.threads.min", 2); QueuedThreadPool threadPool = new QueuedThreadPool(maxThreads); threadPool.setMinThreads(minThreads); server.setThreadPool(threadPool); server.setSendServerVersion(false); server.setSendDateHeader(false); server.setStopAtShutdown(true); // set up context Context context = new Context(server, "/", Context.SESSIONS); context.addServlet(sh, "/*"); context.addFilter(GzipFilter.class, "/*", 0); // login the server principal (if using secure Hadoop) if (User.isSecurityEnabled() && User.isHBaseSecurityEnabled(conf)) { String machineName = Strings .domainNamePointerToHostName(DNS.getDefaultHost(conf.get("hbase.rest.dns.interface", "default"), conf.get("hbase.rest.dns.nameserver", "default"))); User.login(conf, "hbase.rest.keytab.file", "hbase.rest.kerberos.principal", machineName); } // start server server.start(); server.join(); } }