TableDumper.java

/*
   Copyright 2011, Lightbox Technologies, Inc

   Licensed 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 com.lightboxtechnologies.nsrl;

import java.io.IOException;
import java.util.Map;
import java.util.NavigableMap;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.hbase.mapreduce.TableMapper;
import org.apache.hadoop.hbase.mapreduce.TableMapReduceUtil;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
import org.apache.hadoop.util.GenericOptionsParser;

import org.apache.commons.codec.binary.Hex;

/**
 * A MR job to dump an HBase table to a text file.
 *
 * @author Joel Uckelman
 */
public class TableDumper {

  static class TableDumperMapper extends TableMapper<Text,Text> {

    private final Hex hex = new Hex();

    @Override
    public void map(ImmutableBytesWritable key, Result values, Context context)
                                     throws IOException, InterruptedException {

      final byte[] keyb = key.get();

      final NavigableMap<byte[],NavigableMap<byte[],NavigableMap<Long,byte[]>>> map1 = values.getMap();

      final StringBuilder sb = new StringBuilder();

      for (Map.Entry<byte[],NavigableMap<byte[],NavigableMap<Long,byte[]>>> e1 : map1.entrySet()) {
        final String family = new String(e1.getKey());
        sb.append(family).append(" => [");

        boolean e2_first = true;
        for (Map.Entry<byte[],NavigableMap<Long,byte[]>> e2 : e1.getValue().entrySet()) {
          if (e2_first) {
            e2_first = false;
          }
          else {
            sb.append(", ");
          }

          final String col = new String(e2.getKey());
          sb.append(col).append(" => [");
          for (Map.Entry<Long,byte[]> e3 : e2.getValue().entrySet()) {
            sb.append(e3.getKey()).append(" => ");

            if (col.equals("crc32") || col.equals("md5") || col.equals("sha1")) {
              sb.append(new String(hex.encode(e3.getValue())));
            }
            else if (col.equals("filesize")) {
              sb.append(Bytes.toLong(e3.getValue()));
            }
            else {
              sb.append('1');
            }
          }
          sb.append("]");
        }
        sb.append(']');
      }

      context.write(new Text(hex.encode(key.get())), new Text(sb.toString()));
    }
  }

  public static void main(String[] args) throws Exception {
    final Configuration conf = HBaseConfiguration.create();

    final String[] otherArgs =
      new GenericOptionsParser(conf, args).getRemainingArgs();

    if (otherArgs.length != 2) {
      System.err.println(
        "Usage: TableDumper <table> <outpath>"
      );
      System.exit(2);
    }

    final String table_name = otherArgs[0];
    final String output_filename = otherArgs[1];

    final Job job = new Job(conf, "TableDumper");
    job.setJarByClass(TableDumper.class);

    final Scan scan = new Scan();

    TableMapReduceUtil.initTableMapperJob(
      table_name,
      scan,
      TableDumperMapper.class,
      Text.class,
      Text.class,
      job
    );

    job.setOutputFormatClass(TextOutputFormat.class);

    TextOutputFormat.setOutputPath(job, new Path(output_filename));

    System.exit(job.waitForCompletion(true) ? 0 : 1);
  }
}