/**
* 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.mahout.common;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Iterator;
import com.google.common.io.Closeables;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.filecache.DistributedCache;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.PathFilter;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.mapreduce.InputFormat;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.JobContext;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.OutputFormat;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.mahout.common.iterator.sequencefile.PathType;
import org.apache.mahout.common.iterator.sequencefile.SequenceFileDirValueIterator;
import org.apache.mahout.common.iterator.sequencefile.SequenceFileValueIterator;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public final class HadoopUtil {
private static final Logger log = LoggerFactory.getLogger(HadoopUtil.class);
private HadoopUtil() { }
/**
* Create a map-only Hadoop Job out of the passed in parameters. Does not set the
* Job name.
*
* @see #getCustomJobName(String, org.apache.hadoop.mapreduce.JobContext, Class, Class)
*/
public static Job prepareJob(Path inputPath,
Path outputPath,
Class<? extends InputFormat> inputFormat,
Class<? extends Mapper> mapper,
Class<? extends Writable> mapperKey,
Class<? extends Writable> mapperValue,
Class<? extends OutputFormat> outputFormat, Configuration conf) throws IOException {
Job job = new Job(new Configuration(conf));
Configuration jobConf = job.getConfiguration();
if (mapper.equals(Mapper.class)) {
throw new IllegalStateException("Can't figure out the user class jar file from mapper/reducer");
}
job.setJarByClass(mapper);
job.setInputFormatClass(inputFormat);
jobConf.set("mapred.input.dir", inputPath.toString());
job.setMapperClass(mapper);
job.setMapOutputKeyClass(mapperKey);
job.setMapOutputValueClass(mapperValue);
job.setOutputKeyClass(mapperKey);
job.setOutputValueClass(mapperValue);
jobConf.setBoolean("mapred.compress.map.output", true);
job.setNumReduceTasks(0);
job.setOutputFormatClass(outputFormat);
jobConf.set("mapred.output.dir", outputPath.toString());
return job;
}
/**
* Create a map and reduce Hadoop job. Does not set the name on the job.
* @param inputPath The input {@link org.apache.hadoop.fs.Path}
* @param outputPath The output {@link org.apache.hadoop.fs.Path}
* @param inputFormat The {@link org.apache.hadoop.mapreduce.InputFormat}
* @param mapper The {@link org.apache.hadoop.mapreduce.Mapper} class to use
* @param mapperKey The {@link org.apache.hadoop.io.Writable} key class. If the Mapper is a no-op, this value may be null
* @param mapperValue The {@link org.apache.hadoop.io.Writable} value class. If the Mapper is a no-op, this value may be null
* @param reducer The {@link org.apache.hadoop.mapreduce.Reducer} to use
* @param reducerKey The reducer key class.
* @param reducerValue The reducer value class.
* @param outputFormat The {@link org.apache.hadoop.mapreduce.OutputFormat}.
* @param conf The {@link org.apache.hadoop.conf.Configuration} to use.
* @return The {@link org.apache.hadoop.mapreduce.Job}.
* @throws IOException if there is a problem with the IO.
*
* @see #getCustomJobName(String, org.apache.hadoop.mapreduce.JobContext, Class, Class)
* @see #prepareJob(org.apache.hadoop.fs.Path, org.apache.hadoop.fs.Path, Class, Class, Class, Class, Class, org.apache.hadoop.conf.Configuration)
*/
public static Job prepareJob(Path inputPath,
Path outputPath,
Class<? extends InputFormat> inputFormat,
Class<? extends Mapper> mapper,
Class<? extends Writable> mapperKey,
Class<? extends Writable> mapperValue,
Class<? extends Reducer> reducer,
Class<? extends Writable> reducerKey,
Class<? extends Writable> reducerValue,
Class<? extends OutputFormat> outputFormat,
Configuration conf) throws IOException {
Job job = new Job(new Configuration(conf));
Configuration jobConf = job.getConfiguration();
if (reducer.equals(Reducer.class)) {
if (mapper.equals(Mapper.class)) {
throw new IllegalStateException("Can't figure out the user class jar file from mapper/reducer");
}
job.setJarByClass(mapper);
} else {
job.setJarByClass(reducer);
}
job.setInputFormatClass(inputFormat);
jobConf.set("mapred.input.dir", inputPath.toString());
job.setMapperClass(mapper);
if (mapperKey != null) {
job.setMapOutputKeyClass(mapperKey);
}
if (mapperValue != null) {
job.setMapOutputValueClass(mapperValue);
}
jobConf.setBoolean("mapred.compress.map.output", true);
job.setReducerClass(reducer);
job.setOutputKeyClass(reducerKey);
job.setOutputValueClass(reducerValue);
job.setOutputFormatClass(outputFormat);
jobConf.set("mapred.output.dir", outputPath.toString());
return job;
}
public static String getCustomJobName(String className, JobContext job,
Class<? extends Mapper> mapper,
Class<? extends Reducer> reducer) {
StringBuilder name = new StringBuilder(100);
String customJobName = job.getJobName();
if (customJobName == null || customJobName.trim().isEmpty()) {
name.append(className);
} else {
name.append(customJobName);
}
name.append('-').append(mapper.getSimpleName());
name.append('-').append(reducer.getSimpleName());
return name.toString();
}
public static void delete(Configuration conf, Iterable<Path> paths) throws IOException {
if (conf == null) {
conf = new Configuration();
}
for (Path path : paths) {
FileSystem fs = path.getFileSystem(conf);
if (fs.exists(path)) {
log.info("Deleting {}", path);
fs.delete(path, true);
}
}
}
public static void delete(Configuration conf, Path... paths) throws IOException {
delete(conf, Arrays.asList(paths));
}
public static long countRecords(Path path, Configuration conf) throws IOException {
long count = 0;
Iterator<?> iterator = new SequenceFileValueIterator<Writable>(path, true, conf);
while (iterator.hasNext()) {
iterator.next();
count++;
}
return count;
}
/**
* Count all the records in a directory using a {@link org.apache.mahout.common.iterator.sequencefile.SequenceFileDirValueIterator}
* @param path The {@link org.apache.hadoop.fs.Path} to count
* @param pt The {@link org.apache.mahout.common.iterator.sequencefile.PathType}
* @param filter Apply the {@link org.apache.hadoop.fs.PathFilter}. May be null
* @param conf The Hadoop {@link org.apache.hadoop.conf.Configuration}
* @return The number of records
* @throws IOException if there was an IO error
*/
public static long countRecords(Path path, PathType pt, PathFilter filter, Configuration conf) throws IOException {
long count = 0;
Iterator<?> iterator = new SequenceFileDirValueIterator<Writable>(path, pt, filter, null, true, conf);
while (iterator.hasNext()) {
iterator.next();
count++;
}
return count;
}
public static InputStream openStream(Path path, Configuration conf) throws IOException {
FileSystem fs = FileSystem.get(path.toUri(), conf);
return fs.open(path.makeQualified(fs));
}
public static FileStatus[] getFileStatus(Path path, PathType pathType, PathFilter filter, Comparator<FileStatus> ordering, Configuration conf) throws IOException {
FileStatus[] statuses;
FileSystem fs = path.getFileSystem(conf);
if (filter == null) {
statuses = pathType == PathType.GLOB ? fs.globStatus(path) : fs.listStatus(path);
} else {
statuses = pathType == PathType.GLOB ? fs.globStatus(path, filter) : fs.listStatus(path, filter);
}
if (ordering != null) {
Arrays.sort(statuses, ordering);
}
return statuses;
}
public static void cacheFiles(Path fileToCache, Configuration conf) {
DistributedCache.setCacheFiles(new URI[]{fileToCache.toUri()}, conf);
}
public static Path cachedFile(Configuration conf) throws IOException {
return new Path(DistributedCache.getCacheFiles(conf)[0].getPath());
}
public static void setSerializations(Configuration conf) {
conf.set("io.serializations", "org.apache.hadoop.io.serializer.JavaSerialization,"
+ "org.apache.hadoop.io.serializer.WritableSerialization");
}
public static void writeInt(int value, Path path, Configuration conf) throws IOException {
FileSystem fs = FileSystem.get(path.toUri(), conf);
FSDataOutputStream out = fs.create(path);
try {
out.writeInt(value);
} finally {
Closeables.closeQuietly(out);
}
}
public static int readInt(Path path, Configuration conf) throws IOException {
FileSystem fs = FileSystem.get(path.toUri(), conf);
FSDataInputStream in = fs.open(path);
try {
return in.readInt();
} finally {
Closeables.closeQuietly(in);
}
}
}