/**
    * 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;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.conf.Configured;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.Cell;
  import org.apache.hadoop.hbase.CellUtil;
  import org.apache.hadoop.hbase.HBaseConfiguration;
  import org.apache.hadoop.hbase.KeyValue;
  import org.apache.hadoop.hbase.KeyValueUtil;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.classification.InterfaceStability;
  import org.apache.hadoop.hbase.client.Connection;
  import org.apache.hadoop.hbase.client.ConnectionFactory;
  import org.apache.hadoop.hbase.client.Delete;
  import org.apache.hadoop.hbase.client.Mutation;
  import org.apache.hadoop.hbase.client.Put;
  import org.apache.hadoop.hbase.client.RegionLocator;
  import org.apache.hadoop.hbase.client.Table;
  import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
  import org.apache.hadoop.hbase.regionserver.wal.WALEdit;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.apache.hadoop.hbase.wal.WALKey;
  import org.apache.hadoop.mapreduce.Job;
  import org.apache.hadoop.mapreduce.Mapper;
  import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
  import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
  import org.apache.hadoop.util.GenericOptionsParser;
  import org.apache.hadoop.util.Tool;
  import org.apache.hadoop.util.ToolRunner;
  
  import java.io.IOException;
  import java.text.ParseException;
  import java.text.SimpleDateFormat;
  import java.util.Map;
  import java.util.TreeMap;
  
  /**
   * A tool to replay WAL files as a M/R job.
   * The WAL can be replayed for a set of tables or all tables,
   * and a timerange can be provided (in milliseconds).
   * The WAL is filtered to the passed set of tables and  the output
   * can optionally be mapped to another set of tables.
   *
   * WAL replay can also generate HFiles for later bulk importing,
   * in that case the WAL is replayed for a single table only.
   */
  @InterfaceAudience.Public
  @InterfaceStability.Stable
  public class WALPlayer extends Configured implements Tool {
    final static Log LOG = LogFactory.getLog(WALPlayer.class);
    final static String NAME = "WALPlayer";
    final static String BULK_OUTPUT_CONF_KEY = "wal.bulk.output";
    final static String TABLES_KEY = "wal.input.tables";
    final static String TABLE_MAP_KEY = "wal.input.tablesmap";
  
    // This relies on Hadoop Configuration to handle warning about deprecated configs and
    // to set the correct non-deprecated configs when an old one shows up.
    static {
      Configuration.addDeprecation("hlog.bulk.output", BULK_OUTPUT_CONF_KEY);
      Configuration.addDeprecation("hlog.input.tables", TABLES_KEY);
      Configuration.addDeprecation("hlog.input.tablesmap", TABLE_MAP_KEY);
      Configuration.addDeprecation(HLogInputFormat.START_TIME_KEY, WALInputFormat.START_TIME_KEY);
      Configuration.addDeprecation(HLogInputFormat.END_TIME_KEY, WALInputFormat.END_TIME_KEY);
    }
  
    /**
     * A mapper that just writes out KeyValues.
     * This one can be used together with {@link KeyValueSortReducer}
     */
    static class WALKeyValueMapper
    extends Mapper<WALKey, WALEdit, ImmutableBytesWritable, KeyValue> {
      private byte[] table;
  
      @Override
      public void map(WALKey key, WALEdit value,
        Context context)
      throws IOException {
        try {
         // skip all other tables
         if (Bytes.equals(table, key.getTablename().getName())) {
           for (Cell cell : value.getCells()) {
             KeyValue kv = KeyValueUtil.ensureKeyValue(cell);
             if (WALEdit.isMetaEditFamily(kv.getFamily())) continue;
             context.write(new ImmutableBytesWritable(kv.getRow()), kv);
           }
         }
       } catch (InterruptedException e) {
         e.printStackTrace();
       }
     }
 
     @Override
     public void setup(Context context) throws IOException {
       // only a single table is supported when HFiles are generated with HFileOutputFormat
       String tables[] = context.getConfiguration().getStrings(TABLES_KEY);
       if (tables == null || tables.length != 1) {
         // this can only happen when WALMapper is used directly by a class other than WALPlayer
         throw new IOException("Exactly one table must be specified for bulk HFile case.");
       }
       table = Bytes.toBytes(tables[0]);
     }
   }
 
   /**
    * A mapper that writes out {@link Mutation} to be directly applied to
    * a running HBase instance.
    */
   protected static class WALMapper
   extends Mapper<WALKey, WALEdit, ImmutableBytesWritable, Mutation> {
     private Map<TableName, TableName> tables = new TreeMap<TableName, TableName>();
 
     @Override
     public void map(WALKey key, WALEdit value, Context context)
     throws IOException {
       try {
         if (tables.isEmpty() || tables.containsKey(key.getTablename())) {
           TableName targetTable = tables.isEmpty() ?
                 key.getTablename() :
                 tables.get(key.getTablename());
           ImmutableBytesWritable tableOut = new ImmutableBytesWritable(targetTable.getName());
           Put put = null;
           Delete del = null;
           Cell lastCell = null;
           for (Cell cell : value.getCells()) {
             // filtering WAL meta entries
             if (WALEdit.isMetaEditFamily(cell.getFamily())) continue;
 
             // Allow a subclass filter out this cell.
             if (filter(context, cell)) {
               // A WALEdit may contain multiple operations (HBASE-3584) and/or
               // multiple rows (HBASE-5229).
               // Aggregate as much as possible into a single Put/Delete
               // operation before writing to the context.
               if (lastCell == null || lastCell.getTypeByte() != cell.getTypeByte()
                   || !CellUtil.matchingRow(lastCell, cell)) {
                 // row or type changed, write out aggregate KVs.
                 if (put != null) context.write(tableOut, put);
                 if (del != null) context.write(tableOut, del);
                 if (CellUtil.isDelete(cell)) {
                   del = new Delete(cell.getRow());
                 } else {
                   put = new Put(cell.getRow());
                 }
               }
               if (CellUtil.isDelete(cell)) {
                 del.addDeleteMarker(cell);
               } else {
                 put.add(cell);
               }
             }
             lastCell = cell;
           }
           // write residual KVs
           if (put != null) context.write(tableOut, put);
           if (del != null) context.write(tableOut, del);
         }
       } catch (InterruptedException e) {
         e.printStackTrace();
       }
     }
 
     /**
      * @param cell
      * @return Return true if we are to emit this cell.
      */
     protected boolean filter(Context context, final Cell cell) {
       return true;
     }
 
     @Override
     public void setup(Context context) throws IOException {
       String[] tableMap = context.getConfiguration().getStrings(TABLE_MAP_KEY);
       String[] tablesToUse = context.getConfiguration().getStrings(TABLES_KEY);
       if (tablesToUse == null && tableMap == null) {
         // Then user wants all tables.
       } else if (tablesToUse == null || tableMap == null || tablesToUse.length != tableMap.length) {
         // this can only happen when WALMapper is used directly by a class other than WALPlayer
         throw new IOException("No tables or incorrect table mapping specified.");
       }
       int i = 0;
       if (tablesToUse != null) {
         for (String table : tablesToUse) {
           tables.put(TableName.valueOf(table),
             TableName.valueOf(tableMap[i++]));
         }
       }
     }
   }
 
   /**
    * @param conf The {@link Configuration} to use.
    */
   public WALPlayer(Configuration conf) {
     super(conf);
   }
 
   void setupTime(Configuration conf, String option) throws IOException {
     String val = conf.get(option);
     if (null == val) return;
     long ms;
     try {
       // first try to parse in user friendly form
       ms = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SS").parse(val).getTime();
     } catch (ParseException pe) {
       try {
         // then see if just a number of ms's was specified
         ms = Long.parseLong(val);
       } catch (NumberFormatException nfe) {
         throw new IOException(option
             + " must be specified either in the form 2001-02-20T16:35:06.99 "
             + "or as number of milliseconds");
       }
     }
     conf.setLong(option, ms);
   }
 
   /**
    * Sets up the actual job.
    *
    * @param args  The command line parameters.
    * @return The newly created job.
    * @throws IOException When setting up the job fails.
    */
   public Job createSubmittableJob(String[] args)
   throws IOException {
     Configuration conf = getConf();
     setupTime(conf, HLogInputFormat.START_TIME_KEY);
     setupTime(conf, HLogInputFormat.END_TIME_KEY);
     Path inputDir = new Path(args[0]);
     String[] tables = args[1].split(",");
     String[] tableMap;
     if (args.length > 2) {
       tableMap = args[2].split(",");
       if (tableMap.length != tables.length) {
         throw new IOException("The same number of tables and mapping must be provided.");
       }
     } else {
       // if not mapping is specified map each table to itself
       tableMap = tables;
     }
     conf.setStrings(TABLES_KEY, tables);
     conf.setStrings(TABLE_MAP_KEY, tableMap);
     Job job = new Job(conf, NAME + "_" + inputDir);
     job.setJarByClass(WALPlayer.class);
     FileInputFormat.setInputPaths(job, inputDir);
     job.setInputFormatClass(WALInputFormat.class);
     job.setMapOutputKeyClass(ImmutableBytesWritable.class);
     String hfileOutPath = conf.get(BULK_OUTPUT_CONF_KEY);
     if (hfileOutPath != null) {
       // the bulk HFile case
       if (tables.length != 1) {
         throw new IOException("Exactly one table must be specified for the bulk export option");
       }
       TableName tableName = TableName.valueOf(tables[0]);
       job.setMapperClass(WALKeyValueMapper.class);
       job.setReducerClass(KeyValueSortReducer.class);
       Path outputDir = new Path(hfileOutPath);
       FileOutputFormat.setOutputPath(job, outputDir);
       job.setMapOutputValueClass(KeyValue.class);
       try (Connection conn = ConnectionFactory.createConnection(conf);
           Table table = conn.getTable(tableName);
           RegionLocator regionLocator = conn.getRegionLocator(tableName)) {
         HFileOutputFormat2.configureIncrementalLoad(job, table.getTableDescriptor(), regionLocator);
       }
       TableMapReduceUtil.addDependencyJars(job.getConfiguration(),
           com.google.common.base.Preconditions.class);
     } else {
       // output to live cluster
       job.setMapperClass(WALMapper.class);
       job.setOutputFormatClass(MultiTableOutputFormat.class);
       TableMapReduceUtil.addDependencyJars(job);
       TableMapReduceUtil.initCredentials(job);
       // No reducers.
       job.setNumReduceTasks(0);
     }
     return job;
   }
 
   /*
    * @param errorMsg Error message.  Can be null.
    */
   private void usage(final String errorMsg) {
     if (errorMsg != null && errorMsg.length() > 0) {
       System.err.println("ERROR: " + errorMsg);
     }
     System.err.println("Usage: " + NAME + " [options] <wal inputdir> <tables> [<tableMappings>]");
     System.err.println("Read all WAL entries for <tables>.");
     System.err.println("If no tables (\"\") are specific, all tables are imported.");
     System.err.println("(Careful, even -ROOT- and hbase:meta entries will be imported in that case.)");
     System.err.println("Otherwise <tables> is a comma separated list of tables.\n");
     System.err.println("The WAL entries can be mapped to new set of tables via <tableMapping>.");
     System.err.println("<tableMapping> is a command separated list of targettables.");
     System.err.println("If specified, each table in <tables> must have a mapping.\n");
     System.err.println("By default " + NAME + " will load data directly into HBase.");
     System.err.println("To generate HFiles for a bulk data load instead, pass the option:");
     System.err.println("  -D" + BULK_OUTPUT_CONF_KEY + "=/path/for/output");
     System.err.println("  (Only one table can be specified, and no mapping is allowed!)");
     System.err.println("Other options: (specify time range to WAL edit to consider)");
     System.err.println("  -D" + WALInputFormat.START_TIME_KEY + "=[date|ms]");
     System.err.println("  -D" + WALInputFormat.END_TIME_KEY + "=[date|ms]");
     System.err.println("For performance also consider the following options:\n"
         + "  -Dmapreduce.map.speculative=false\n"
         + "  -Dmapreduce.reduce.speculative=false");
   }
 
   /**
    * Main entry point.
    *
    * @param args  The command line parameters.
    * @throws Exception When running the job fails.
    */
   public static void main(String[] args) throws Exception {
     int ret = ToolRunner.run(new WALPlayer(HBaseConfiguration.create()), args);
     System.exit(ret);
   }
 
   @Override
   public int run(String[] args) throws Exception {
     String[] otherArgs = new GenericOptionsParser(getConf(), args).getRemainingArgs();
     if (otherArgs.length < 2) {
       usage("Wrong number of arguments: " + otherArgs.length);
       System.exit(-1);
     }
     Job job = createSubmittableJob(otherArgs);
     return job.waitForCompletion(true) ? 0 : 1;
   }
 }