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.hadoop.hdfs.tools; import org.apache.commons.cli.CommandLine; import org.apache.commons.cli.CommandLineParser; import org.apache.commons.cli.GnuParser; import org.apache.commons.cli.HelpFormatter; import org.apache.commons.cli.Option; import org.apache.commons.cli.OptionBuilder; import org.apache.commons.cli.Options; import org.apache.commons.cli.ParseException; import org.apache.hadoop.classification.InterfaceAudience; import javax.management.AttributeNotFoundException; import javax.management.MBeanAttributeInfo; import javax.management.MBeanInfo; import javax.management.MBeanServerConnection; import javax.management.ObjectName; import javax.management.ReflectionException; import javax.management.remote.JMXConnector; import javax.management.remote.JMXConnectorFactory; import javax.management.remote.JMXServiceURL; import java.lang.management.ManagementFactory; import java.util.ArrayList; import java.util.Arrays; import java.util.Set; import java.util.TreeSet; import org.apache.hadoop.util.ExitUtil; /** * tool to get data from NameNode or DataNode using MBeans currently the * following MBeans are available (under hadoop domain): * hadoop:service=NameNode,name=FSNamesystemState (static) * hadoop:service=NameNode,name=NameNodeActivity (dynamic) * hadoop:service=NameNode,name=RpcActivityForPort9000 (dynamic) * hadoop:service=DataNode,name=RpcActivityForPort50020 (dynamic) * hadoop:name=service=DataNode,FSDatasetState-UndefinedStorageId663800459 * (static) * hadoop:service=DataNode,name=DataNodeActivity-UndefinedStorageId-520845215 * (dynamic) * <p/> * <p/> * implementation note: all logging is sent to System.err (since it is a * command * line tool) */ @InterfaceAudience.Private public class JMXGet { private static final String format = "%s=%s%n"; private ArrayList<ObjectName> hadoopObjectNames; private MBeanServerConnection mbsc; private String service = "NameNode", port = "", server = "localhost"; private String localVMUrl = null; public JMXGet() { } public void setService(String service) { this.service = service; } public void setPort(String port) { this.port = port; } public void setServer(String server) { this.server = server; } public void setLocalVMUrl(String url) { this.localVMUrl = url; } /** * print all attributes' values */ public void printAllValues() throws Exception { err("List of all the available keys:"); Object val = null; for (ObjectName oname : hadoopObjectNames) { err(">>>>>>>>jmx name: " + oname.getCanonicalKeyPropertyListString()); MBeanInfo mbinfo = mbsc.getMBeanInfo(oname); MBeanAttributeInfo[] mbinfos = mbinfo.getAttributes(); for (MBeanAttributeInfo mb : mbinfos) { val = mbsc.getAttribute(oname, mb.getName()); System.out.format(format, mb.getName(), (val == null) ? "" : val.toString()); } } } /** * get single value by key */ public String getValue(String key) throws Exception { Object val = null; for (ObjectName oname : hadoopObjectNames) { try { val = mbsc.getAttribute(oname, key); } catch (AttributeNotFoundException anfe) { /* just go to the next */ continue; } catch (ReflectionException re) { if (re.getCause() instanceof NoSuchMethodException) { continue; } } err("Info: key = " + key + "; val = " + (val == null ? "null" : val.getClass()) + ":" + val); break; } return (val == null) ? "" : val.toString(); } /** * @throws Exception * initializes MBeanServer */ public void init() throws Exception { err("init: server=" + server + ";port=" + port + ";service=" + service + ";localVMUrl=" + localVMUrl); String url_string = null; // build connection url if (localVMUrl != null) { // use // jstat -snap <vmpid> | grep sun.management.JMXConnectorServer.address // to get url url_string = localVMUrl; err("url string for local pid = " + localVMUrl + " = " + url_string); } else if (!port.isEmpty() && !server.isEmpty()) { // using server and port url_string = "service:jmx:rmi:///jndi/rmi://" + server + ":" + port + "/jmxrmi"; } // else url stays null // Create an RMI connector client and // connect it to the RMI connector server if (url_string == null) { // assume local vm (for example for Testing) mbsc = ManagementFactory.getPlatformMBeanServer(); } else { JMXServiceURL url = new JMXServiceURL(url_string); err("Create RMI connector and connect to the RMI connector server" + url); JMXConnector jmxc = JMXConnectorFactory.connect(url, null); // Get an MBeanServerConnection // err("\nGet an MBeanServerConnection"); mbsc = jmxc.getMBeanServerConnection(); } // Get domains from MBeanServer // err("\nDomains:"); String domains[] = mbsc.getDomains(); Arrays.sort(domains); for (String domain : domains) { err("\tDomain = " + domain); } // Get MBeanServer's default domain // err("\nMBeanServer default domain = " + mbsc.getDefaultDomain()); // Get MBean count // err("\nMBean count = " + mbsc.getMBeanCount()); // Query MBean names for specific domain "hadoop" and service ObjectName query = new ObjectName("Hadoop:service=" + service + ",*"); hadoopObjectNames = new ArrayList<>(5); err("\nQuery MBeanServer MBeans:"); Set<ObjectName> names = new TreeSet<>(mbsc.queryNames(query, null)); for (ObjectName name : names) { hadoopObjectNames.add(name); err("Hadoop service: " + name); } } /** * Print JMXGet usage information */ static void printUsage(Options opts) { HelpFormatter formatter = new HelpFormatter(); formatter.printHelp("jmxget options are: ", opts); } /** * @param msg */ private static void err(String msg) { System.err.println(msg); } /** * parse args */ private static CommandLine parseArgs(Options opts, String... args) throws IllegalArgumentException { OptionBuilder.withArgName("NameNode|DataNode"); OptionBuilder.hasArg(); OptionBuilder.withDescription("specify jmx service (NameNode by default)"); Option jmx_service = OptionBuilder.create("service"); OptionBuilder.withArgName("mbean server"); OptionBuilder.hasArg(); OptionBuilder.withDescription("specify mbean server (localhost by default)"); Option jmx_server = OptionBuilder.create("server"); OptionBuilder.withDescription("print help"); Option jmx_help = OptionBuilder.create("help"); OptionBuilder.withArgName("mbean server port"); OptionBuilder.hasArg(); OptionBuilder.withDescription("specify mbean server port, " + "if missing - it will try to connect to MBean Server in the same VM"); Option jmx_port = OptionBuilder.create("port"); OptionBuilder.withArgName("VM's connector url"); OptionBuilder.hasArg(); OptionBuilder.withDescription("connect to the VM on the same machine;" + "\n use:\n jstat -J-Djstat.showUnsupported=true -snap <vmpid> | " + "grep sun.management.JMXConnectorServer.address\n " + "to find the url"); Option jmx_localVM = OptionBuilder.create("localVM"); opts.addOption(jmx_server); opts.addOption(jmx_help); opts.addOption(jmx_service); opts.addOption(jmx_port); opts.addOption(jmx_localVM); CommandLine commandLine = null; CommandLineParser parser = new GnuParser(); try { commandLine = parser.parse(opts, args, true); } catch (ParseException e) { printUsage(opts); throw new IllegalArgumentException("invalid args: " + e.getMessage()); } return commandLine; } /** * main * * @param args */ public static void main(String[] args) { int res = -1; // parse arguments Options opts = new Options(); CommandLine commandLine = null; try { commandLine = parseArgs(opts, args); } catch (IllegalArgumentException iae) { commandLine = null; } if (commandLine == null) { // invalid arguments err("Invalid args"); printUsage(opts); ExitUtil.terminate(-1); } JMXGet jm = new JMXGet(); if (commandLine.hasOption("port")) { jm.setPort(commandLine.getOptionValue("port")); } if (commandLine.hasOption("service")) { jm.setService(commandLine.getOptionValue("service")); } if (commandLine.hasOption("server")) { jm.setServer(commandLine.getOptionValue("server")); } if (commandLine.hasOption("localVM")) { // from the file /tmp/hsperfdata* jm.setLocalVMUrl(commandLine.getOptionValue("localVM")); } if (commandLine.hasOption("help")) { printUsage(opts); ExitUtil.terminate(0); } // rest of args args = commandLine.getArgs(); try { jm.init(); if (args.length == 0) { jm.printAllValues(); } else { for (String key : args) { err("key = " + key); String val = jm.getValue(key); if (val != null) { System.out.format(JMXGet.format, key, val); } } } res = 0; } catch (Exception re) { re.printStackTrace(); res = -1; } ExitUtil.terminate(res); } }