org.apache.hadoop.chukwa.util.PidFile.java Source code

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Here is the source code for org.apache.hadoop.chukwa.util.PidFile.java

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/*
 * 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.chukwa.util;

import java.io.*;
import java.lang.management.ManagementFactory;
import java.nio.channels.*;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class PidFile extends Thread {

    String name;
    private static Log log = LogFactory.getLog(PidFile.class);
    private static FileLock lock = null;
    private static FileOutputStream pidFileOutput = null;

    public PidFile(String name) {
        this.name = name;
        try {
            init();
        } catch (IOException ex) {
            clean();
            System.exit(-1);
        }
    }

    public void init() throws IOException {
        String pidLong = ManagementFactory.getRuntimeMXBean().getName();
        String[] items = pidLong.split("@");
        String pid = items[0];
        String chukwaPath = System.getProperty("CHUKWA_HOME");
        StringBuffer pidFilesb = new StringBuffer();
        String pidDir = System.getenv("CHUKWA_PID_DIR");
        if (pidDir == null) {
            pidDir = chukwaPath + File.separator + "var" + File.separator + "run";
        }
        pidFilesb.append(pidDir).append(File.separator).append(name).append(".pid");
        try {
            File existsFile = new File(pidDir);
            if (!existsFile.exists()) {
                boolean success = (new File(pidDir)).mkdirs();
                if (!success) {
                    throw (new IOException());
                }
            }
            File pidFile = new File(pidFilesb.toString());

            pidFileOutput = new FileOutputStream(pidFile);
            pidFileOutput.write(pid.getBytes());
            pidFileOutput.flush();
            FileChannel channel = pidFileOutput.getChannel();
            PidFile.lock = channel.tryLock();
            if (PidFile.lock != null) {
                log.debug("Initlization succeeded...");
            } else {
                throw (new IOException("Can not get lock on pid file: " + pidFilesb));
            }
        } catch (IOException ex) {
            System.out.println("Initialization failed: can not write pid file to " + pidFilesb);
            log.error("Initialization failed...");
            log.error(ex.getMessage());
            System.exit(-1);
            throw ex;

        }

    }

    public void clean() {
        String chukwaPath = System.getenv("CHUKWA_HOME");
        StringBuffer pidFilesb = new StringBuffer();
        String pidDir = System.getenv("CHUKWA_PID_DIR");
        if (pidDir == null) {
            pidDir = chukwaPath + File.separator + "var" + File.separator + "run";
        }
        pidFilesb.append(pidDir).append(File.separator).append(name).append(".pid");
        String pidFileName = pidFilesb.toString();

        File pidFile = new File(pidFileName);
        if (!pidFile.exists()) {
            log.error("Delete pid file, No such file or directory: " + pidFileName);
        } else {
            try {
                lock.release();
                pidFileOutput.close();
            } catch (IOException e) {
                log.error("Unable to release file lock: " + pidFileName);
            }
        }

        boolean result = pidFile.delete();
        if (!result) {
            log.error("Delete pid file failed, " + pidFileName);
        }
    }

    public void run() {
        clean();
    }
}