org.apache.karaf.main.lock.SimpleFileLock Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of org.apache.karaf.main
This bundle is the main Karaf launcher. It's responsible of the Karaf startup including the console, branding, etc bootstrap.
There is a newer version: 4.4.6
Show newest version
/*
 * 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.karaf.main.lock;

import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.channels.FileLock;
import org.apache.felix.utils.properties.Properties;
import java.util.logging.Logger;

import org.apache.karaf.main.util.BootstrapLogManager;

public class SimpleFileLock implements Lock {

    private static final Logger LOG = Logger.getLogger(SimpleFileLock.class.getName());
    private static final String PROPERTY_LOCK_DIR = "karaf.lock.dir";
    private static final String PROP_KARAF_BASE = "karaf.base";
    private RandomAccessFile lockFile;
    private File lockPath;
    private FileLock lock;

    public SimpleFileLock(Properties props) {
        try {

            LOG.addHandler( BootstrapLogManager.getDefaultHandler() );
            String lock = props.getProperty(PROPERTY_LOCK_DIR);

            if (lock != null) {
                File karafLock = getKarafLock(new File(lock), props);
                props.setProperty(PROPERTY_LOCK_DIR, karafLock.getPath());
            } else {
                props.setProperty(PROPERTY_LOCK_DIR, System.getProperty(PROP_KARAF_BASE));
            }

            File base = new File(props.getProperty(PROPERTY_LOCK_DIR));
            lockPath = new File(base, "lock"); 
            lockFile = new RandomAccessFile(lockPath, "rw");
        } catch (IOException ioe){
            throw new RuntimeException("Karaf can't startup, make sure the log file can be accessed and written by the user starting Karaf : " + ioe.getMessage(), ioe);
        } catch (Exception e){
            throw new RuntimeException("Could not create file lock: " + e.getMessage(), e);
        }
    }

    public boolean lock() throws Exception {
        LOG.info("Trying to lock " + lockPath.getPath());
        if (lock == null) {
            lock = lockFile.getChannel().tryLock();
        }
        if (lock != null) {
            LOG.info("Lock acquired");
        } else {
            LOG.info("Lock failed");
        }
        return lock != null;
    }

    public void release() throws Exception {
        if (lock != null && lock.isValid()) {
            LOG.info("Releasing lock " + lockPath.getPath());
            lock.release();
            lock.channel().close();
        }
        lock = null;
    }
 
    public boolean isAlive() throws Exception {
        return lock != null && lock.isValid() && lockPath.exists();
    }

    private static File getKarafLock(File lock,Properties props) {
        File rc = null;

        String path = lock.getPath();
        if (path != null) {
            rc = validateDirectoryExists(path, "Invalid " + PROPERTY_LOCK_DIR + " system property");
        }

        if (rc == null) {
            path = props.getProperty(PROP_KARAF_BASE);
            if (path != null) {
                rc = validateDirectoryExists(path, "Invalid " + PROP_KARAF_BASE + " property");
            }
        }

        if (rc == null) {
            rc = lock;
        }
        return rc;
    }

    private static File validateDirectoryExists(String path, String errPrefix) {
        File rc;
        try {
            rc = new File(path).getCanonicalFile();
        } catch (IOException e) {
            throw new IllegalArgumentException(errPrefix + " '" + path + "' : " + e.getMessage());
        }
        if (!rc.exists()) {
            throw new IllegalArgumentException(errPrefix + " '" + path + "' : does not exist");
        }
        if (!rc.isDirectory()) {
            throw new IllegalArgumentException(errPrefix + " '" + path + "' : is not a directory");
        }
        return rc;
    }

}