package com.hadoopilluminated.examples;
/**
* The example below is taken from org.apache.hadoop.examples It is then
* commented and modified for the purposes of the book
*/
/**
* 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.
*/
import java.io.IOException;
import java.io.DataInput;
import java.io.DataOutput;
import java.util.Iterator;
import java.util.Random;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.SequenceFile;
import org.apache.hadoop.mapred.*;
import org.apache.hadoop.mapred.lib.NullOutputFormat;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;
/**
* Dummy class for testing MR framefork. Sleeps for a defined period of time in
* mapper and reducer. Generates fake input for map / reduce jobs. Note that
* generated number of input pairs is in the order of
* <code>numMappers * mapSleepTime / 100</code>, so the job uses some disk
* space.
*/
public class SleepJob extends Configured implements Tool,
Mapper<IntWritable, IntWritable, IntWritable, NullWritable>,
Reducer<IntWritable, NullWritable, NullWritable, NullWritable>,
Partitioner<IntWritable, NullWritable> {
private long mapSleepDuration = 100;
private long reduceSleepDuration = 100;
private int mapSleepCount = 1;
private int reduceSleepCount = 1;
private int count = 0;
public int getPartition(IntWritable k, NullWritable v, int numPartitions) {
return k.get() % numPartitions;
}
public static class EmptySplit implements InputSplit {
public void write(DataOutput out) throws IOException {
}
public void readFields(DataInput in) throws IOException {
}
public long getLength() {
return 0L;
}
public String[] getLocations() {
return new String[0];
}
}
public static class SleepInputFormat extends Configured
implements InputFormat<IntWritable, IntWritable> {
public InputSplit[] getSplits(JobConf conf, int numSplits) {
InputSplit[] ret = new InputSplit[numSplits];
for (int i = 0; i < numSplits; ++i) {
ret[i] = new EmptySplit();
}
return ret;
}
public RecordReader<IntWritable, IntWritable> getRecordReader(
InputSplit ignored, JobConf conf, Reporter reporter)
throws IOException {
final int count = conf.getInt("sleep.job.map.sleep.count", 1);
if (count < 0) {
throw new IOException("Invalid map count: " + count);
}
final int redcount = conf.getInt("sleep.job.reduce.sleep.count", 1);
if (redcount < 0) {
throw new IOException("Invalid reduce count: " + redcount);
}
final int emitPerMapTask = (redcount * conf.getNumReduceTasks());
return new RecordReader<IntWritable, IntWritable>() {
private int records = 0;
private int emitCount = 0;
public boolean next(IntWritable key, IntWritable value)
throws IOException {
key.set(emitCount);
int emit = emitPerMapTask / count;
if ((emitPerMapTask) % count > records) {
++emit;
}
emitCount += emit;
value.set(emit);
return records++ < count;
}
public IntWritable createKey() {
return new IntWritable();
}
public IntWritable createValue() {
return new IntWritable();
}
public long getPos() throws IOException {
return records;
}
public void close() throws IOException {
}
public float getProgress() throws IOException {
return records / ((float) count);
}
};
}
}
public void map(IntWritable key, IntWritable value,
OutputCollector<IntWritable, NullWritable> output, Reporter reporter)
throws IOException {
//it is expected that every map processes mapSleepCount number of records.
try {
reporter.setStatus("Sleeping... ("
+ (mapSleepDuration * (mapSleepCount - count)) + ") ms left");
Thread.sleep(mapSleepDuration);
} catch (InterruptedException ex) {
throw (IOException) new IOException(
"Interrupted while sleeping").initCause(ex);
}
++count;
// output reduceSleepCount * numReduce number of random values, so that
// each reducer will get reduceSleepCount number of keys.
int k = key.get();
for (int i = 0; i < value.get(); ++i) {
output.collect(new IntWritable(k + i), NullWritable.get());
}
}
public void reduce(IntWritable key, Iterator<NullWritable> values,
OutputCollector<NullWritable, NullWritable> output, Reporter reporter)
throws IOException {
try {
reporter.setStatus("Sleeping... ("
+ (reduceSleepDuration * (reduceSleepCount - count)) + ") ms left");
Thread.sleep(reduceSleepDuration);
} catch (InterruptedException ex) {
throw (IOException) new IOException(
"Interrupted while sleeping").initCause(ex);
}
count++;
}
public void configure(JobConf job) {
this.mapSleepCount =
job.getInt("sleep.job.map.sleep.count", mapSleepCount);
this.reduceSleepCount =
job.getInt("sleep.job.reduce.sleep.count", reduceSleepCount);
this.mapSleepDuration =
job.getLong("sleep.job.map.sleep.time", 100) / mapSleepCount;
this.reduceSleepDuration =
job.getLong("sleep.job.reduce.sleep.time", 100) / reduceSleepCount;
}
public void close() throws IOException {
}
public static void main(String[] args) throws Exception {
int res = ToolRunner.run(new Configuration(), new SleepJob(), args);
System.exit(res);
}
public int run(int numMapper, int numReducer, long mapSleepTime,
int mapSleepCount, long reduceSleepTime,
int reduceSleepCount) throws IOException {
JobConf job = setupJobConf(numMapper, numReducer, mapSleepTime,
mapSleepCount, reduceSleepTime, reduceSleepCount);
JobClient.runJob(job);
return 0;
}
public JobConf setupJobConf(int numMapper, int numReducer,
long mapSleepTime, int mapSleepCount,
long reduceSleepTime, int reduceSleepCount) {
JobConf job = new JobConf(getConf(), SleepJob.class);
job.setNumMapTasks(numMapper);
job.setNumReduceTasks(numReducer);
job.setMapperClass(SleepJob.class);
job.setMapOutputKeyClass(IntWritable.class);
job.setMapOutputValueClass(NullWritable.class);
job.setReducerClass(SleepJob.class);
job.setOutputFormat(NullOutputFormat.class);
job.setInputFormat(SleepInputFormat.class);
job.setPartitionerClass(SleepJob.class);
job.setSpeculativeExecution(false);
job.setJobName("Sleep job");
FileInputFormat.addInputPath(job, new Path("ignored"));
job.setLong("sleep.job.map.sleep.time", mapSleepTime);
job.setLong("sleep.job.reduce.sleep.time", reduceSleepTime);
job.setInt("sleep.job.map.sleep.count", mapSleepCount);
job.setInt("sleep.job.reduce.sleep.count", reduceSleepCount);
return job;
}
public int run(String[] args) throws Exception {
if (args.length < 1) {
System.err.println("SleepJob [-m numMapper] [-r numReducer]"
+ " [-mt mapSleepTime (msec)] [-rt reduceSleepTime (msec)]"
+ " [-recordt recordSleepTime (msec)]");
ToolRunner.printGenericCommandUsage(System.err);
return -1;
}
int numMapper = 1, numReducer = 1;
long mapSleepTime = 100, reduceSleepTime = 100, recSleepTime = 100;
int mapSleepCount = 1, reduceSleepCount = 1;
for (int i = 0; i < args.length; i++) {
if (args[i].equals("-m")) {
numMapper = Integer.parseInt(args[++i]);
} else if (args[i].equals("-r")) {
numReducer = Integer.parseInt(args[++i]);
} else if (args[i].equals("-mt")) {
mapSleepTime = Long.parseLong(args[++i]);
} else if (args[i].equals("-rt")) {
reduceSleepTime = Long.parseLong(args[++i]);
} else if (args[i].equals("-recordt")) {
recSleepTime = Long.parseLong(args[++i]);
}
}
// sleep for *SleepTime duration in Task by recSleepTime per record
mapSleepCount = (int) Math.ceil(mapSleepTime / ((double) recSleepTime));
reduceSleepCount = (int) Math.ceil(reduceSleepTime / ((double) recSleepTime));
return run(numMapper, numReducer, mapSleepTime, mapSleepCount,
reduceSleepTime, reduceSleepCount);
}
}
