/**
    *
    * 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.mapreduce.replication;
  
  import java.io.IOException;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hbase.*;
  import org.apache.hadoop.hbase.client.HConnectable;
  import org.apache.hadoop.hbase.client.HConnection;
  import org.apache.hadoop.hbase.client.HConnectionManager;
  import org.apache.hadoop.hbase.client.HTable;
  import org.apache.hadoop.hbase.client.Put;
  import org.apache.hadoop.hbase.client.Result;
  import org.apache.hadoop.hbase.client.ResultScanner;
  import org.apache.hadoop.hbase.client.Scan;
  import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
  import org.apache.hadoop.hbase.mapreduce.TableInputFormat;
  import org.apache.hadoop.hbase.mapreduce.TableMapReduceUtil;
  import org.apache.hadoop.hbase.mapreduce.TableMapper;
  import org.apache.hadoop.hbase.replication.ReplicationPeer;
  import org.apache.hadoop.hbase.replication.ReplicationPeers;
  import org.apache.hadoop.hbase.replication.ReplicationPeersZKImpl;
  import org.apache.hadoop.hbase.replication.ReplicationZookeeper;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
  import org.apache.hadoop.mapreduce.Job;
  import org.apache.hadoop.mapreduce.lib.output.NullOutputFormat;
  import org.apache.zookeeper.KeeperException;
  
  /**
   * This map-only job compares the data from a local table with a remote one.
   * Every cell is compared and must have exactly the same keys (even timestamp)
   * as well as same value. It is possible to restrict the job by time range and
   * families. The peer id that's provided must match the one given when the
   * replication stream was setup.
   * <p>
   * Two counters are provided, Verifier.Counters.GOODROWS and BADROWS. The reason
   * for a why a row is different is shown in the map's log.
   */
  public class VerifyReplication {
  
    private static final Log LOG =
        LogFactory.getLog(VerifyReplication.class);
  
    public final static String NAME = "verifyrep";
    static long startTime = 0;
    static long endTime = 0;
    static String tableName = null;
    static String families = null;
    static String peerId = null;
  
    /**
     * Map-only comparator for 2 tables
     */
    public static class Verifier
        extends TableMapper<ImmutableBytesWritable, Put> {
  
      public static enum Counters {GOODROWS, BADROWS}
  
      private ResultScanner replicatedScanner;
  
      /**
       * Map method that compares every scanned row with the equivalent from
       * a distant cluster.
       * @param row  The current table row key.
       * @param value  The columns.
       * @param context  The current context.
       * @throws IOException When something is broken with the data.
       */
      @Override
      public void map(ImmutableBytesWritable row, final Result value,
                      Context context)
          throws IOException {
        if (replicatedScanner == null) {
          Configuration conf = context.getConfiguration();
          final Scan scan = new Scan();
          scan.setCaching(conf.getInt(TableInputFormat.SCAN_CACHEDROWS, 1));
          long startTime = conf.getLong(NAME + ".startTime", 0);
          long endTime = conf.getLong(NAME + ".endTime", 0);
          String families = conf.get(NAME + ".families", null);
         if(families != null) {
           String[] fams = families.split(",");
           for(String fam : fams) {
             scan.addFamily(Bytes.toBytes(fam));
           }
         }
         if (startTime != 0) {
           scan.setTimeRange(startTime,
               endTime == 0 ? HConstants.LATEST_TIMESTAMP : endTime);
         }
         HConnectionManager.execute(new HConnectable<Void>(conf) {
           @Override
           public Void connect(HConnection conn) throws IOException {
             ZooKeeperWatcher localZKW = null;
             ReplicationZookeeper zk = null;
             ReplicationPeer peer = null;
             try {
               localZKW = new ZooKeeperWatcher(
                 conf, "VerifyReplication", new Abortable() {
                 @Override public void abort(String why, Throwable e) {}
                 @Override public boolean isAborted() {return false;}
               });
               ReplicationPeers rp = new ReplicationPeersZKImpl(localZKW, conf, localZKW);
               rp.init();
               Configuration peerConf = rp.getPeerConf(peerId);
               if (peerConf == null) {
                 throw new IOException("Couldn't get peer conf!");
               }
               HTable replicatedTable = new HTable(peerConf, conf.get(NAME + ".tableName"));
               scan.setStartRow(value.getRow());
               replicatedScanner = replicatedTable.getScanner(scan);
             } catch (KeeperException e) {
               throw new IOException("Got a ZK exception", e);
             } finally {
               if (peer != null) {
                 peer.close();
               }
               if (zk != null) {
                 zk.close();
               }
               if (localZKW != null) {
                 localZKW.close();
               }
             }
             return null;
           }
         });
       }
       Result res = replicatedScanner.next();
       try {
         Result.compareResults(value, res);
         context.getCounter(Counters.GOODROWS).increment(1);
       } catch (Exception e) {
         LOG.warn("Bad row", e);
         context.getCounter(Counters.BADROWS).increment(1);
       }
     }
 
     protected void cleanup(Context context) {
       if (replicatedScanner != null) {
         replicatedScanner.close();
         replicatedScanner = null;
       }
     }
   }
 
   /**
    * Sets up the actual job.
    *
    * @param conf  The current configuration.
    * @param args  The command line parameters.
    * @return The newly created job.
    * @throws java.io.IOException When setting up the job fails.
    */
   public static Job createSubmittableJob(Configuration conf, String[] args)
   throws IOException {
     if (!doCommandLine(args)) {
       return null;
     }
     if (!conf.getBoolean(HConstants.REPLICATION_ENABLE_KEY, false)) {
       throw new IOException("Replication needs to be enabled to verify it.");
     }
     conf.set(NAME+".peerId", peerId);
     conf.set(NAME+".tableName", tableName);
     conf.setLong(NAME+".startTime", startTime);
     conf.setLong(NAME+".endTime", endTime);
     if (families != null) {
       conf.set(NAME+".families", families);
     }
     Job job = new Job(conf, NAME + "_" + tableName);
     job.setJarByClass(VerifyReplication.class);
 
     Scan scan = new Scan();
     if (startTime != 0) {
       scan.setTimeRange(startTime,
           endTime == 0 ? HConstants.LATEST_TIMESTAMP : endTime);
     }
     if(families != null) {
       String[] fams = families.split(",");
       for(String fam : fams) {
         scan.addFamily(Bytes.toBytes(fam));
       }
     }
     TableMapReduceUtil.initTableMapperJob(tableName, scan,
         Verifier.class, null, null, job);
     job.setOutputFormatClass(NullOutputFormat.class);
     job.setNumReduceTasks(0);
     return job;
   }
 
   private static boolean doCommandLine(final String[] args) {
     if (args.length < 2) {
       printUsage(null);
       return false;
     }
     try {
       for (int i = 0; i < args.length; i++) {
         String cmd = args[i];
         if (cmd.equals("-h") || cmd.startsWith("--h")) {
           printUsage(null);
           return false;
         }
 
         final String startTimeArgKey = "--starttime=";
         if (cmd.startsWith(startTimeArgKey)) {
           startTime = Long.parseLong(cmd.substring(startTimeArgKey.length()));
           continue;
         }
 
         final String endTimeArgKey = "--endtime=";
         if (cmd.startsWith(endTimeArgKey)) {
           endTime = Long.parseLong(cmd.substring(endTimeArgKey.length()));
           continue;
         }
 
         final String familiesArgKey = "--families=";
         if (cmd.startsWith(familiesArgKey)) {
           families = cmd.substring(familiesArgKey.length());
           continue;
         }
 
         if (i == args.length-2) {
           peerId = cmd;
         }
 
         if (i == args.length-1) {
           tableName = cmd;
         }
       }
     } catch (Exception e) {
       e.printStackTrace();
       printUsage("Can't start because " + e.getMessage());
       return false;
     }
     return true;
   }
 
   /*
    * @param errorMsg Error message.  Can be null.
    */
   private static void printUsage(final String errorMsg) {
     if (errorMsg != null && errorMsg.length() > 0) {
       System.err.println("ERROR: " + errorMsg);
     }
     System.err.println("Usage: verifyrep [--starttime=X]" +
         " [--stoptime=Y] [--families=A] <peerid> <tablename>");
     System.err.println();
     System.err.println("Options:");
     System.err.println(" starttime    beginning of the time range");
     System.err.println("              without endtime means from starttime to forever");
     System.err.println(" stoptime     end of the time range");
     System.err.println(" families     comma-separated list of families to copy");
     System.err.println();
     System.err.println("Args:");
     System.err.println(" peerid       Id of the peer used for verification, must match the one given for replication");
     System.err.println(" tablename    Name of the table to verify");
     System.err.println();
     System.err.println("Examples:");
     System.err.println(" To verify the data replicated from TestTable for a 1 hour window with peer #5 ");
     System.err.println(" $ bin/hbase " +
         "org.apache.hadoop.hbase.mapreduce.replication.VerifyReplication" +
         " --starttime=1265875194289 --stoptime=1265878794289 5 TestTable ");
   }
 
   /**
    * Main entry point.
    *
    * @param args  The command line parameters.
    * @throws Exception When running the job fails.
    */
   public static void main(String[] args) throws Exception {
     Configuration conf = HBaseConfiguration.create();
     Job job = createSubmittableJob(conf, args);
     if (job != null) {
       System.exit(job.waitForCompletion(true) ? 0 : 1);
     }
   }
 }