/**
 * 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.mapred;

import junit.framework.TestCase;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hdfs.MiniDFSCluster;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.util.ToolRunner;
import org.apache.hadoop.examples.RandomWriter;
import org.apache.hadoop.examples.Sort;

/**
 * A JUnit test to test the Map-Reduce framework's sort 
 * with a Mini Map-Reduce Cluster with a Mini HDFS Clusters.
 */
public class TestMiniMRDFSSort extends TestCase {
  // Input/Output paths for sort
  private static final Path SORT_INPUT_PATH = new Path("/sort/input");
  private static final Path SORT_OUTPUT_PATH = new Path("/sort/output");

  // Knobs to control randomwriter; and hence sort
  private static final int NUM_HADOOP_SLAVES = 3;
  private static final int RW_BYTES_PER_MAP = 50000;
  private static final int RW_MAPS_PER_HOST = 5;
  
  private static void runRandomWriter(JobConf job, Path sortInput) 
  throws Exception {
    // Scale down the default settings for RandomWriter for the test-case
    // Generates NUM_HADOOP_SLAVES * RW_MAPS_PER_HOST * RW_BYTES_PER_MAP -> 1MB
    job.setInt("test.randomwrite.bytes_per_map", RW_BYTES_PER_MAP);
    job.setInt("test.randomwriter.maps_per_host", RW_MAPS_PER_HOST);
    String[] rwArgs = {sortInput.toString()};
    
    // Run RandomWriter
    assertEquals(ToolRunner.run(job, new RandomWriter(), rwArgs), 0);
  }
  
  private static void runSort(JobConf job, Path sortInput, Path sortOutput) 
  throws Exception {
    // Setup command-line arguments to 'sort'
    String[] sortArgs = {sortInput.toString(), sortOutput.toString()};
    
    // Run Sort
    assertEquals(ToolRunner.run(job, new Sort(), sortArgs), 0);
  }
  
  private static void runSortValidator(JobConf job, 
                                       Path sortInput, Path sortOutput) 
  throws Exception {
    String[] svArgs = {"-sortInput", sortInput.toString(), 
                       "-sortOutput", sortOutput.toString()};

    // Run Sort-Validator
    assertEquals(ToolRunner.run(job, new SortValidator(), svArgs), 0);
  }
  Configuration conf = new Configuration();
  public void testMapReduceSort() throws Exception {
    MiniDFSCluster dfs = null;
    MiniMRCluster mr = null;
    FileSystem fileSys = null;
    try {
      // set io.sort.mb and fsinmemory.size.mb to lower value in test
      conf.setInt("io.sort.mb", 5);
      conf.setInt("fs.inmemory.size.mb", 20);

      // Start the mini-MR and mini-DFS clusters
      dfs = new MiniDFSCluster(conf, NUM_HADOOP_SLAVES, true, null);
      fileSys = dfs.getFileSystem();
      mr = new MiniMRCluster(NUM_HADOOP_SLAVES, fileSys.getUri().toString(), 1);

      // Run randomwriter to generate input for 'sort'
      runRandomWriter(mr.createJobConf(), SORT_INPUT_PATH);
      
      // Run sort
      runSort(mr.createJobConf(), SORT_INPUT_PATH, SORT_OUTPUT_PATH);
      
      // Run sort-validator to check if sort worked correctly
      runSortValidator(mr.createJobConf(), SORT_INPUT_PATH, SORT_OUTPUT_PATH);
    } finally {
      if (dfs != null) { dfs.shutdown(); }
      if (mr != null) { mr.shutdown();
      }
    }
  }
  public void testMapReduceSortWithJvmReuse() throws Exception {
    conf.setInt("mapred.job.reuse.jvm.num.tasks", -1);
    testMapReduceSort();
  }
}