/*
    *
    * 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.replication.regionserver;
  
  import java.io.IOException;
  import java.util.NavigableMap;
  import java.util.TreeMap;
  import java.util.concurrent.Executors;
  import java.util.concurrent.ScheduledExecutorService;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.atomic.AtomicBoolean;
  
  import com.google.common.util.concurrent.ThreadFactoryBuilder;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.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.HRegionInfo;
  import org.apache.hadoop.hbase.HTableDescriptor;
  import org.apache.hadoop.hbase.KeyValue;
  import org.apache.hadoop.hbase.Server;
  import org.apache.hadoop.hbase.regionserver.ReplicationSourceService;
  import org.apache.hadoop.hbase.regionserver.ReplicationSinkService;
  import org.apache.hadoop.hbase.regionserver.wal.HLog;
  import org.apache.hadoop.hbase.regionserver.wal.HLogKey;
  import org.apache.hadoop.hbase.regionserver.wal.WALEdit;
  import org.apache.hadoop.hbase.regionserver.wal.WALActionsListener;
  import org.apache.hadoop.hbase.replication.ReplicationQueues;
  import org.apache.hadoop.hbase.replication.ReplicationQueuesZKImpl;
  import org.apache.hadoop.hbase.replication.ReplicationZookeeper;
  import org.apache.hadoop.hbase.replication.master.ReplicationLogCleaner;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.apache.zookeeper.KeeperException;
  
  import static org.apache.hadoop.hbase.HConstants.HBASE_MASTER_LOGCLEANER_PLUGINS;
  import static org.apache.hadoop.hbase.HConstants.REPLICATION_ENABLE_KEY;
  import static org.apache.hadoop.hbase.HConstants.REPLICATION_SCOPE_LOCAL;
  
  /**
   * Gateway to Replication.  Used by {@link org.apache.hadoop.hbase.regionserver.HRegionServer}.
   */
  @InterfaceAudience.Private
  public class Replication implements WALActionsListener, 
    ReplicationSourceService, ReplicationSinkService {
    private static final Log LOG =
        LogFactory.getLog(Replication.class);
    private boolean replication;
    private ReplicationSourceManager replicationManager;
    private final AtomicBoolean replicating = new AtomicBoolean(true);
    private ReplicationZookeeper zkHelper;
    private ReplicationQueues replicationQueues;
    private Configuration conf;
    private ReplicationSink replicationSink;
    // Hosting server
    private Server server;
    /** Statistics thread schedule pool */
    private ScheduledExecutorService scheduleThreadPool;
    private int statsThreadPeriod;
  
    /**
     * Instantiate the replication management (if rep is enabled).
     * @param server Hosting server
     * @param fs handle to the filesystem
     * @param logDir
     * @param oldLogDir directory where logs are archived
     * @throws IOException
     */
    public Replication(final Server server, final FileSystem fs,
        final Path logDir, final Path oldLogDir) throws IOException{
      initialize(server, fs, logDir, oldLogDir);
    }
  
    /**
     * Empty constructor
     */
    public Replication() {
    }
  
    public void initialize(final Server server, final FileSystem fs,
        final Path logDir, final Path oldLogDir) throws IOException {
      this.server = server;
     this.conf = this.server.getConfiguration();
     this.replication = isReplication(this.conf);
     this.scheduleThreadPool = Executors.newScheduledThreadPool(1,
       new ThreadFactoryBuilder()
         .setNameFormat(server.getServerName() + "Replication Statistics #%d")
         .setDaemon(true)
         .build());
     if (replication) {
       try {
         this.zkHelper = new ReplicationZookeeper(server, this.replicating);
         this.replicationQueues =
             new ReplicationQueuesZKImpl(server.getZooKeeper(), this.conf, this.server);
         this.replicationQueues.init(this.server.getServerName().toString());
       } catch (KeeperException ke) {
         throw new IOException("Failed replication handler create " +
            "(replicating=" + this.replicating, ke);
       }
       this.replicationManager =
           new ReplicationSourceManager(zkHelper, replicationQueues, conf, this.server, fs,
               this.replicating, logDir, oldLogDir);
       this.statsThreadPeriod =
           this.conf.getInt("replication.stats.thread.period.seconds", 5 * 60);
       LOG.debug("ReplicationStatisticsThread " + this.statsThreadPeriod);
     } else {
       this.replicationManager = null;
       this.zkHelper = null;
       this.replicationQueues = null;
     }
   }
 
    /**
     * @param c Configuration to look at
     * @return True if replication is enabled.
     */
   public static boolean isReplication(final Configuration c) {
     return c.getBoolean(REPLICATION_ENABLE_KEY, false);
   }
 
    /*
     * Returns an object to listen to new hlog changes
     **/
   public WALActionsListener getWALActionsListener() {
     return this;
   }
   /**
    * Stops replication service.
    */
   public void stopReplicationService() {
     join();
   }
 
   /**
    * Join with the replication threads
    */
   public void join() {
     if (this.replication) {
       this.replicationManager.join();
       if (this.replicationSink != null) {
         this.replicationSink.stopReplicationSinkServices();
       }
     }
   }
 
   /**
    * Carry on the list of log entries down to the sink
    * @param entries list of entries to replicate
    * @throws IOException
    */
   public void replicateLogEntries(HLog.Entry[] entries) throws IOException {
     if (this.replication) {
       this.replicationSink.replicateEntries(entries);
     }
   }
 
   /**
    * If replication is enabled and this cluster is a master,
    * it starts
    * @throws IOException
    */
   public void startReplicationService() throws IOException {
     if (this.replication) {
       this.replicationManager.init();
       this.replicationSink = new ReplicationSink(this.conf, this.server);
       this.scheduleThreadPool.scheduleAtFixedRate(
         new ReplicationStatisticsThread(this.replicationSink, this.replicationManager),
         statsThreadPeriod, statsThreadPeriod, TimeUnit.SECONDS);
     }
   }
 
   /**
    * Get the replication sources manager
    * @return the manager if replication is enabled, else returns false
    */
   public ReplicationSourceManager getReplicationManager() {
     return this.replicationManager;
   }
 
   @Override
   public void visitLogEntryBeforeWrite(HRegionInfo info, HLogKey logKey,
       WALEdit logEdit) {
     // Not interested
   }
 
   @Override
   public void visitLogEntryBeforeWrite(HTableDescriptor htd, HLogKey logKey,
                                        WALEdit logEdit) {
     NavigableMap<byte[], Integer> scopes =
         new TreeMap<byte[], Integer>(Bytes.BYTES_COMPARATOR);
     byte[] family;
     for (KeyValue kv : logEdit.getKeyValues()) {
       family = kv.getFamily();
       int scope = htd.getFamily(family).getScope();
       if (scope != REPLICATION_SCOPE_LOCAL &&
           !scopes.containsKey(family)) {
         scopes.put(family, scope);
       }
     }
     if (!scopes.isEmpty()) {
       logKey.setScopes(scopes);
     }
   }
 
   @Override
   public void preLogRoll(Path oldPath, Path newPath) throws IOException {
     getReplicationManager().preLogRoll(newPath);
   }
 
   @Override
   public void postLogRoll(Path oldPath, Path newPath) throws IOException {
     getReplicationManager().postLogRoll(newPath);
   }
 
   @Override
   public void preLogArchive(Path oldPath, Path newPath) throws IOException {
     // Not interested
   }
 
   @Override
   public void postLogArchive(Path oldPath, Path newPath) throws IOException {
     // Not interested
   }
 
   /**
    * This method modifies the master's configuration in order to inject
    * replication-related features
    * @param conf
    */
   public static void decorateMasterConfiguration(Configuration conf) {
     if (!isReplication(conf)) {
       return;
     }
     String plugins = conf.get(HBASE_MASTER_LOGCLEANER_PLUGINS);
     String cleanerClass = ReplicationLogCleaner.class.getCanonicalName();
     if (!plugins.contains(cleanerClass)) {
       conf.set(HBASE_MASTER_LOGCLEANER_PLUGINS, plugins + "," + cleanerClass);
     }
   }
 
   @Override
   public void logRollRequested() {
     // Not interested
   }
 
   @Override
   public void logCloseRequested() {
     // not interested
   }
 
   /*
    * Statistics thread. Periodically prints the cache statistics to the log.
    */
   static class ReplicationStatisticsThread extends Thread {
 
     private final ReplicationSink replicationSink;
     private final ReplicationSourceManager replicationManager;
 
     public ReplicationStatisticsThread(final ReplicationSink replicationSink,
                             final ReplicationSourceManager replicationManager) {
       super("ReplicationStatisticsThread");
       this.replicationManager = replicationManager;
       this.replicationSink = replicationSink;
     }
 
     @Override
     public void run() {
       printStats(this.replicationManager.getStats());
       printStats(this.replicationSink.getStats());
     }
 
     private void printStats(String stats) {
       if (!stats.isEmpty()) {
         LOG.info(stats);
       }
     }
   }
 }