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 com.trendmicro.hdfs.webdav; import java.io.IOException; import java.net.InetSocketAddress; import java.util.concurrent.TimeUnit; import org.apache.commons.cli.CommandLine; import org.apache.commons.cli.HelpFormatter; import org.apache.commons.cli.Options; import org.apache.commons.cli.ParseException; import org.apache.commons.cli.PosixParser; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.net.NetUtils; import org.apache.hadoop.security.SecurityUtil; import org.apache.hadoop.security.UserGroupInformation; import org.apache.log4j.Level; import org.apache.log4j.Logger; 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.FilterHolder; import org.mortbay.jetty.servlet.ServletHolder; import com.yammer.metrics.reporting.GangliaReporter; import com.yammer.metrics.web.DefaultWebappMetricsFilter; public class Main { private static final Log LOG = LogFactory.getLog(Main.class); private static void printUsageAndExit(Options options, int exitCode) { HelpFormatter formatter = new HelpFormatter(); formatter .printHelp( "Usage: webdav [options]", "", options, "\nTo run the WebDAV server as a daemon, execute " + "bin/hadoop-daemon.sh start " + Main.class.getCanonicalName() + " [options]\n", true); System.exit(exitCode); } private static InetSocketAddress getAddress(Configuration conf) { return NetUtils.createSocketAddr(conf.get("hadoop.webdav.bind.address", "0.0.0.0"), conf.getInt("hadoop.webdav.port", 8080)); } public static void main(String[] args) { HDFSWebDAVServlet servlet = HDFSWebDAVServlet.getServlet(); Configuration conf = servlet.getConfiguration(); // Process command line Options options = new Options(); options.addOption("d", "debug", false, "Enable debug logging"); options.addOption("p", "port", true, "Port to bind to [default: 8080]"); options.addOption("b", "bind-address", true, "Address or hostname to bind to [default: 0.0.0.0]"); options.addOption("g", "ganglia", true, "Send Ganglia metrics to host:port [default: none]"); CommandLine cmd = null; try { cmd = new PosixParser().parse(options, args); } catch (ParseException e) { printUsageAndExit(options, -1); } if (cmd.hasOption('d')) { Logger rootLogger = Logger.getLogger("com.trendmicro"); rootLogger.setLevel(Level.DEBUG); } if (cmd.hasOption('b')) { conf.set("hadoop.webdav.bind.address", cmd.getOptionValue('b')); } if (cmd.hasOption('p')) { conf.setInt("hadoop.webdav.port", Integer.valueOf(cmd.getOptionValue('p'))); } String gangliaHost = null; int gangliaPort = 8649; if (cmd.hasOption('g')) { String val = cmd.getOptionValue('g'); if (val.indexOf(':') != -1) { String[] split = val.split(":"); gangliaHost = split[0]; gangliaPort = Integer.valueOf(split[1]); } else { gangliaHost = val; } } InetSocketAddress addr = getAddress(conf); // Log in the server principal from keytab UserGroupInformation.setConfiguration(conf); if (UserGroupInformation.isSecurityEnabled()) try { SecurityUtil.login(conf, "hadoop.webdav.server.kerberos.keytab", "hadoop.webdav.server.kerberos.principal", addr.getHostName()); } catch (IOException e) { LOG.fatal("Could not log in", e); System.err.println("Could not log in"); System.exit(-1); } // Set up embedded Jetty Server server = new Server(); server.setSendServerVersion(false); server.setSendDateHeader(false); server.setStopAtShutdown(true); // Set up connector Connector connector = new SelectChannelConnector(); connector.setPort(addr.getPort()); connector.setHost(addr.getHostName()); server.addConnector(connector); LOG.info("Listening on " + addr); // Set up context Context context = new Context(server, "/", Context.SESSIONS); // WebDAV servlet ServletHolder servletHolder = new ServletHolder(servlet); servletHolder.setInitParameter("authenticate-header", "Basic realm=\"Hadoop WebDAV Server\""); context.addServlet(servletHolder, "/*"); // metrics instrumentation filter context.addFilter(new FilterHolder(new DefaultWebappMetricsFilter()), "/*", 0); // auth filter context.addFilter(new FilterHolder(new AuthFilter(conf)), "/*", 0); server.setHandler(context); // Set up Ganglia metrics reporting if (gangliaHost != null) { GangliaReporter.enable(1, TimeUnit.MINUTES, gangliaHost, gangliaPort); } // Start and join the server thread try { server.start(); server.join(); } catch (Exception e) { LOG.fatal("Failed to start Jetty", e); System.err.println("Failed to start Jetty"); System.exit(-1); } } }