/**
    * 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.hbase.master.cleaner;
  
  import static org.apache.hadoop.hbase.HConstants.HBASE_MASTER_LOGCLEANER_PLUGINS;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Map;
  import java.util.concurrent.LinkedBlockingQueue;
  import java.util.concurrent.TimeUnit;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.fs.FileStatus;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.Stoppable;
  import org.apache.hadoop.hbase.conf.ConfigurationObserver;
  import org.apache.hadoop.hbase.wal.DefaultWALProvider;
  
  /**
   * This Chore, every time it runs, will attempt to delete the WALs in the old logs folder. The WAL
   * is only deleted if none of the cleaner delegates says otherwise.
   * @see BaseLogCleanerDelegate
   */
  @InterfaceAudience.Private
  public class LogCleaner extends CleanerChore<BaseLogCleanerDelegate>
          implements ConfigurationObserver {
    private static final Log LOG = LogFactory.getLog(LogCleaner.class.getName());
  
    public static final String OLD_WALS_CLEANER_THREAD_SIZE = "hbase.oldwals.cleaner.thread.size";
    public static final int DEFAULT_OLD_WALS_CLEANER_THREAD_SIZE = 2;
  
    public static final String OLD_WALS_CLEANER_THREAD_TIMEOUT_MSEC =
        "hbase.oldwals.cleaner.thread.timeout.msec";
    static final long DEFAULT_OLD_WALS_CLEANER_THREAD_TIMEOUT_MSEC = 60 * 1000L;
  
    public static final String OLD_WALS_CLEANER_THREAD_CHECK_INTERVAL_MSEC =
        "hbase.oldwals.cleaner.thread.check.interval.msec";
    static final long DEFAULT_OLD_WALS_CLEANER_THREAD_CHECK_INTERVAL_MSEC = 500L;
  
    private final LinkedBlockingQueue<CleanerContext> pendingDelete;
    private List<Thread> oldWALsCleaner;
    private long cleanerThreadTimeoutMsec;
    private long cleanerThreadCheckIntervalMsec;
  
    /**
     * @param p the period of time to sleep between each run
     * @param s the stopper
     * @param conf configuration to use
     * @param fs handle to the FS
     * @param oldLogDir the path to the archived logs
     */
    public LogCleaner(final int p, final Stoppable s, Configuration conf, FileSystem fs,
        Path oldLogDir, DirScanPool pool, Map<String, Object> params) {
      super("LogsCleaner", p, s, conf, fs, oldLogDir, HBASE_MASTER_LOGCLEANER_PLUGINS, pool, params);
      this.pendingDelete = new LinkedBlockingQueue<>();
      int size = conf.getInt(OLD_WALS_CLEANER_THREAD_SIZE, DEFAULT_OLD_WALS_CLEANER_THREAD_SIZE);
      this.oldWALsCleaner = createOldWalsCleaner(size);
      this.cleanerThreadTimeoutMsec = conf.getLong(OLD_WALS_CLEANER_THREAD_TIMEOUT_MSEC,
          DEFAULT_OLD_WALS_CLEANER_THREAD_TIMEOUT_MSEC);
      this.cleanerThreadCheckIntervalMsec = conf.getLong(OLD_WALS_CLEANER_THREAD_CHECK_INTERVAL_MSEC,
          DEFAULT_OLD_WALS_CLEANER_THREAD_CHECK_INTERVAL_MSEC);
    }
  
    @Override
    protected boolean validate(Path file) {
      return DefaultWALProvider.validateWALFilename(file.getName());
    }
  
    @Override
    public void onConfigurationChange(Configuration conf) {
      int newSize = conf.getInt(OLD_WALS_CLEANER_THREAD_SIZE, DEFAULT_OLD_WALS_CLEANER_THREAD_SIZE);
      if (newSize == oldWALsCleaner.size()) {
        if (LOG.isDebugEnabled()) {
          LOG.debug("Size from configuration is the same as previous which is " +
              newSize + ", no need to update.");
        }
        return;
     }
     interruptOldWALsCleaner();
     oldWALsCleaner = createOldWalsCleaner(newSize);
     cleanerThreadTimeoutMsec = conf.getLong(OLD_WALS_CLEANER_THREAD_TIMEOUT_MSEC,
         DEFAULT_OLD_WALS_CLEANER_THREAD_TIMEOUT_MSEC);
     cleanerThreadCheckIntervalMsec = conf.getLong(OLD_WALS_CLEANER_THREAD_CHECK_INTERVAL_MSEC,
         DEFAULT_OLD_WALS_CLEANER_THREAD_CHECK_INTERVAL_MSEC);
   }
 
   @Override
   protected int deleteFiles(Iterable<FileStatus> filesToDelete) {
     List<CleanerContext> results = new LinkedList<>();
     for (FileStatus toDelete : filesToDelete) {
       CleanerContext context = CleanerContext.createCleanerContext(toDelete,
           cleanerThreadTimeoutMsec);
       if (context != null) {
         pendingDelete.add(context);
         results.add(context);
       }
     }
 
     int deletedFiles = 0;
     for (CleanerContext res : results) {
       deletedFiles += res.getResult(cleanerThreadCheckIntervalMsec) ? 1 : 0;
     }
     return deletedFiles;
   }
 
   @Override
   public synchronized void cleanup() {
     super.cleanup();
     interruptOldWALsCleaner();
   }
 
   int getSizeOfCleaners() {
     return oldWALsCleaner.size();
   }
 
   long getCleanerThreadTimeoutMsec() {
     return cleanerThreadTimeoutMsec;
   }
 
   long getCleanerThreadCheckIntervalMsec() {
     return cleanerThreadCheckIntervalMsec;
   }
 
   private List<Thread> createOldWalsCleaner(int size) {
     LOG.info("Creating OldWALs cleaners with size=" + size);
 
     List<Thread> oldWALsCleaner = new ArrayList<>(size);
     for (int i = 0; i < size; i++) {
       Thread cleaner = new Thread(new Runnable() {
         @Override
         public void run() {
           deleteFile();
         }
       });
       cleaner.setName("OldWALsCleaner-" + i);
       cleaner.setDaemon(true);
       cleaner.start();
       oldWALsCleaner.add(cleaner);
     }
     return oldWALsCleaner;
   }
 
   private void interruptOldWALsCleaner() {
     for (Thread cleaner : oldWALsCleaner) {
       cleaner.interrupt();
     }
     oldWALsCleaner.clear();
   }
 
   private void deleteFile() {
     while (true) {
       CleanerContext context = null;
       boolean succeed = false;
       boolean interrupted = false;
       try {
         context = pendingDelete.take();
         if (context != null) {
           FileStatus toClean = context.getTargetToClean();
           succeed = this.fs.delete(toClean.getPath(), false);
         }
       } catch (InterruptedException ite) {
         // It's most likely from configuration changing request
         if (context != null) {
           LOG.warn("Interrupted while cleaning oldWALs " +
               context.getTargetToClean() + ", try to clean it next round.");
         }
         interrupted = true;
       } catch (IOException e) {
         // fs.delete() fails.
         LOG.warn("Failed to clean oldwals with exception: " + e);
         succeed = false;
       } finally {
         if (context != null) {
           context.setResult(succeed);
         }
         if (interrupted) {
           // Restore interrupt status
           Thread.currentThread().interrupt();
           break;
         }
       }
     }
     if (LOG.isDebugEnabled()) {
       LOG.debug("Exiting cleaner.");
     }
   }
 
   @Override
   public synchronized void cancel(boolean mayInterruptIfRunning) {
     super.cancel(mayInterruptIfRunning);
     for (Thread t : oldWALsCleaner) {
       t.interrupt();
     }
   }
 
   private static final class CleanerContext {
 
     final FileStatus target;
     volatile boolean result;
     volatile boolean setFromCleaner = false;
     long timeoutMsec;
 
     static CleanerContext createCleanerContext(FileStatus status, long timeoutMsec) {
       return status != null ? new CleanerContext(status, timeoutMsec) : null;
     }
 
     private CleanerContext(FileStatus status, long timeoutMsec) {
       this.target = status;
       this.result = false;
       this.timeoutMsec = timeoutMsec;
     }
 
     synchronized void setResult(boolean res) {
       this.result = res;
       this.setFromCleaner = true;
       notify();
     }
 
     synchronized boolean getResult(long waitIfNotFinished) {
       long totalTimeMsec = 0;
       try {
         while (!setFromCleaner) {
           long startTimeNanos = System.nanoTime();
           wait(waitIfNotFinished);
           totalTimeMsec += TimeUnit.MILLISECONDS.convert(System.nanoTime() - startTimeNanos,
               TimeUnit.NANOSECONDS);
           if (totalTimeMsec >= timeoutMsec) {
             LOG.warn("Spend too much time " + totalTimeMsec + " ms to delete oldwals " + target);
             return result;
           }
         }
       } catch (InterruptedException e) {
         LOG.warn("Interrupted while waiting deletion of " + target);
         return result;
       }
       return result;
     }
 
     FileStatus getTargetToClean() {
       return target;
     }
   }
 }