org.apache.helix.agent.HelixAgentMain.java Source code

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Here is the source code for org.apache.helix.agent.HelixAgentMain.java

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package org.apache.helix.agent;

/*
 * 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.
 */

import java.util.Arrays;

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.helix.HelixManager;
import org.apache.helix.InstanceType;
import org.apache.helix.api.id.StateModelDefId;
import org.apache.helix.manager.zk.ZKHelixManager;
import org.apache.helix.participant.StateMachineEngine;
import org.apache.log4j.Logger;

public class HelixAgentMain {
    private static Logger LOG = Logger.getLogger(HelixAgentMain.class);

    public static final String zkAddr = "zkSvr";
    public static final String cluster = "cluster";
    public static final String help = "help";
    public static final String instanceName = "instanceName";
    public static final String stateModel = "stateModel";

    // hack: OptionalBuilder is not thread safe
    @SuppressWarnings("static-access")
    synchronized private static Options constructCommandLineOptions() {
        Option helpOption = OptionBuilder.withLongOpt(help).withDescription("Prints command-line options info")
                .create();

        Option zkAddrOption = OptionBuilder.withLongOpt(zkAddr).hasArgs(1).isRequired(true)
                .withArgName("ZookeeperServerAddress(Required)").withDescription("Provide zookeeper address")
                .create();

        Option clusterOption = OptionBuilder.withLongOpt(cluster).hasArgs(1).isRequired(true)
                .withArgName("Cluster name (Required)").withDescription("Provide cluster name").create();

        Option instanceNameOption = OptionBuilder.withLongOpt(instanceName).hasArgs(1).isRequired(true)
                .withArgName("Helix agent name (Required)").withDescription("Provide Helix agent name").create();

        Option stateModelOption = OptionBuilder.withLongOpt(stateModel).hasArgs(1).isRequired(true)
                .withArgName("State model name (Required)").withDescription("Provide state model name").create();

        Options options = new Options();
        options.addOption(helpOption);
        options.addOption(zkAddrOption);
        options.addOption(clusterOption);
        options.addOption(instanceNameOption);
        options.addOption(stateModelOption);

        return options;
    }

    public static void printUsage(Options cliOptions) {
        HelpFormatter helpFormatter = new HelpFormatter();
        helpFormatter.setWidth(1000);
        helpFormatter.printHelp("java " + HelixAgentMain.class.getName(), cliOptions);
    }

    public static CommandLine processCommandLineArgs(String[] cliArgs) throws Exception {
        CommandLineParser cliParser = new GnuParser();
        Options cliOptions = constructCommandLineOptions();

        try {
            return cliParser.parse(cliOptions, cliArgs);
        } catch (ParseException pe) {
            LOG.error("fail to parse command-line options. cliArgs: " + Arrays.toString(cliArgs), pe);
            printUsage(cliOptions);
            System.exit(1);
        }
        return null;
    }

    // NOT working for kill -9, working for kill -2/-15
    static class HelixAgentShutdownHook extends Thread {
        final HelixManager _manager;

        HelixAgentShutdownHook(HelixManager manager) {
            _manager = manager;
        }

        @Override
        public void run() {
            LOG.info("HelixAgentShutdownHook invoked. agent: " + _manager.getInstanceName());
            if (_manager != null && _manager.isConnected())
                _manager.disconnect();
        }
    }

    public static void main(String[] args) throws Exception {
        CommandLine cmd = processCommandLineArgs(args);
        String zkAddress = cmd.getOptionValue(zkAddr);
        String clusterName = cmd.getOptionValue(cluster);
        String instance = cmd.getOptionValue(instanceName);
        String stateModelName = cmd.getOptionValue(stateModel);

        HelixManager manager = new ZKHelixManager(clusterName, instance, InstanceType.PARTICIPANT, zkAddress);

        StateMachineEngine stateMach = manager.getStateMachineEngine();
        stateMach.registerStateModelFactory(StateModelDefId.from(stateModelName), new AgentStateModelFactory());

        Runtime.getRuntime().addShutdownHook(new HelixAgentShutdownHook(manager));

        try {
            manager.connect();
            Thread.currentThread().join();
        } catch (Exception e) {
            LOG.error(e);
        } finally {
            if (manager != null && manager.isConnected()) {
                manager.disconnect();
            }
        }
    }
}