ComputerListenerImpl.java

/*
 * The MIT License
 *
 * Copyright (c) 2004-2009, Sun Microsystems, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
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package hudson.plugins.hadoop;

import hudson.Extension;
import hudson.model.Computer;
import hudson.model.TaskListener;
import hudson.model.Hudson;
import hudson.slaves.ComputerListener;

import java.io.IOException;
import java.util.logging.Logger;

/**
 * When a new computer becomes online, starts a Hadoop data node and task tracker.
 *
 * <p>
 * This will be done on a separate JVM to allow administrators to control the JVM parameters better.
 * This JVM automatically kills itself when the slave JVM gets disconnected.
 *
 * @author Kohsuke Kawaguchi
 */
@Extension
public class ComputerListenerImpl extends ComputerListener {
    @Override
    public void onOnline(Computer c, TaskListener listener) {
        try {
            if(c==Hudson.getInstance().toComputer())
                return;   // this happens before the master is started.

            PluginImpl p = PluginImpl.get();
            String hdfsUrl = p.getHdfsUrl();
            if(hdfsUrl !=null) {
                String address = c.getHostName();
                if(address==null)
                    listener.getLogger().println("Unable to determine the hostname/IP address of this system. Skipping Hadoop deployment");
                else
                    c.getChannel().call(new SlaveStartTask(c, listener, hdfsUrl, address));
            }
        } catch (IOException e) {
            e.printStackTrace(listener.error("Failed to start Hadoop"));
        } catch (InterruptedException e) {
            e.printStackTrace(listener.error("Failed to start Hadoop"));
        }
    }

    private static final Logger LOGGER = Logger.getLogger(ComputerListenerImpl.class.getName());
}