webhcat/svr/src/main/java/org/apache/hcatalog/templeton/tool/HDFSCleanup.java

/**
 * 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.hcatalog.templeton.tool;

import java.io.IOException;
import java.util.Date;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hcatalog.templeton.tool.TempletonStorage.Type;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * This does periodic cleanup
 */
public class HDFSCleanup extends Thread {
    protected Configuration appConf;

    // The interval to wake up and check the queue
    public static final String HDFS_CLEANUP_INTERVAL =
        "templeton.hdfs.cleanup.interval"; // 12 hours

    // The max age of a task allowed
    public static final String HDFS_CLEANUP_MAX_AGE =
        "templeton.hdfs.cleanup.maxage"; // ~ 1 week

    protected static long interval = 1000L * 60L * 60L * 12L;
    protected static long maxage = 1000L * 60L * 60L * 24L * 7L;

    // The logger
    private static final Log LOG = LogFactory.getLog(HDFSCleanup.class);

    // Handle to cancel loop
    private boolean stop = false;

    // The instance
    private static HDFSCleanup thisclass = null;

    // Whether the cycle is running
    private static boolean isRunning = false;
    
    // The storage root
    private String storage_root;
    
    /**
     * Create a cleanup object. 
     */
    private HDFSCleanup(Configuration appConf) {
        this.appConf = appConf;
        interval = appConf.getLong(HDFS_CLEANUP_INTERVAL, interval);
        maxage = appConf.getLong(HDFS_CLEANUP_MAX_AGE, maxage);
        storage_root = appConf.get(TempletonStorage.STORAGE_ROOT);
    }
    
    public static HDFSCleanup getInstance(Configuration appConf) {
        if (thisclass != null) {
            return thisclass;
        }
        thisclass = new HDFSCleanup(appConf);
        return thisclass;
    }

    public static void startInstance(Configuration appConf) throws IOException {
        if (!isRunning) {
            getInstance(appConf).start();
        }
    }

    /**
     * Run the cleanup loop.
     *
     */
    public void run() {
        FileSystem fs = null;
        while (!stop) {
            try {
                // Put each check in a separate try/catch, so if that particular
                // cycle fails, it'll try again on the next cycle.
                try {
                    if (fs == null) {
                        fs = FileSystem.get(appConf);
                    }
                    checkFiles(fs);
                } catch (Exception e) {
                    LOG.error("Cleanup cycle failed: " + e.getMessage());
                }

                long sleepMillis = (long) (Math.random() * interval);
                LOG.info("Next execution: " + new Date(new Date().getTime()
                                                       + sleepMillis));
                Thread.sleep(sleepMillis);

            } catch (Exception e) {
                // If sleep fails, we should exit now before things get worse.
                isRunning = false;
                LOG.error("Cleanup failed: " + e.getMessage(), e);
            }
        }
        isRunning = false;
    }
    
    /**
     * Loop through all the files, deleting any that are older than
     * maxage.
     * 
     * @param fs
     * @throws IOException
     */
    private void checkFiles(FileSystem fs) throws IOException {
        long now = new Date().getTime();
        for (Type type : Type.values()) {
            try {
                for (FileStatus status : fs.listStatus(new Path(
                        HDFSStorage.getPath(type, storage_root)))) {
                    if (now - status.getModificationTime() > maxage) {
                        LOG.info("Deleting " + status.getPath().toString());
                        fs.delete(status.getPath(), true);
                    }
                }
            } catch (Exception e) {
                // Nothing to find for this type.
            }
        }
    }

    // Handle to stop this process from the outside if needed.
    public void exit() {
        stop = true;
    }

}