/*
* Cloud9: A MapReduce Library for Hadoop
*
* 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 edu.umd.cloud9.webgraph;
import java.io.IOException;
import java.net.URI;
import java.util.Collections;
import java.util.Iterator;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.SequenceFile;
import org.apache.hadoop.mapred.FileOutputFormat;
import org.apache.hadoop.mapred.JobClient;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.MapReduceBase;
import org.apache.hadoop.mapred.Mapper;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Partitioner;
import org.apache.hadoop.mapred.Reducer;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.mapred.SequenceFileInputFormat;
import org.apache.hadoop.mapred.SequenceFileOutputFormat;
import org.apache.log4j.Logger;
import tl.lin.data.array.ArrayListWritable;
import tl.lin.data.pair.PairOfIntString;
import edu.umd.cloud9.util.PowerTool;
import edu.umd.cloud9.webgraph.data.AnchorText;
import edu.umd.cloud9.webgraph.data.AnchorTextConstants;
/**
*
* @author Nima Asadi
*
*/
public class CollectHostnames extends PowerTool {
private static final Logger sLogger = Logger.getLogger(CollectHostnames.class);
public static class Map extends MapReduceBase implements
Mapper<IntWritable, ArrayListWritable<AnchorText>, PairOfIntString, IntWritable> {
private static final PairOfIntString keyWord = new PairOfIntString();
private static final IntWritable valueWord = new IntWritable();
private static String host;
public void map(IntWritable key, ArrayListWritable<AnchorText> anchors,
OutputCollector<PairOfIntString, IntWritable> output, Reporter reporter) throws IOException {
for(AnchorText data : anchors) {
if(data.isURL())
try {
//extract the hostname for a given URL
host = new URI(data.getText()).getHost();
}catch(Exception e) {
return;
}
}
for(AnchorText data : anchors) {
if(!data.isExternalOutLink())
continue;
valueWord.set(key.get());
for(int target : data) {
keyWord.set(target, host);
output.collect(keyWord, valueWord);
}
}
}
}
protected static class Partition implements Partitioner<PairOfIntString, IntWritable> {
public void configure(JobConf job) {
}
public int getPartition(PairOfIntString key, IntWritable value, int numReduceTasks) {
return Math.abs(key.getLeftElement() % numReduceTasks);
}
}
public static class Reduce extends MapReduceBase implements
Reducer<PairOfIntString, IntWritable, IntWritable, ArrayListWritable<AnchorText>> {
private static OutputCollector<IntWritable, ArrayListWritable<AnchorText>> outputCollector;
private static final ArrayListWritable<AnchorText> arrayList =
new ArrayListWritable<AnchorText>();
private static final IntWritable keyWord = new IntWritable();
private static boolean firstTime = true;
private static int currentDocument, packet;
public void reduce(PairOfIntString key, Iterator<IntWritable> values,
OutputCollector<IntWritable, ArrayListWritable<AnchorText>> output, Reporter reporter) throws IOException {
if(firstTime) {
outputCollector = output;
firstTime = false;
arrayList.clear();
currentDocument = key.getLeftElement();
} else if(currentDocument != key.getLeftElement()) {
Collections.sort(arrayList);
keyWord.set(currentDocument);
output.collect(keyWord, arrayList);
currentDocument = key.getLeftElement();
arrayList.clear();
}
arrayList.add(new AnchorText(AnchorTextConstants.Type.OTHER_TYPES.val, key.getRightElement()));
int currentIndex = arrayList.size() - 1;
while(values.hasNext()) {
packet = values.next().get();
//break larger chunks of data to smaller packets - reduces the underlying HashMap costs
if(arrayList.get(currentIndex).getSize() < AnchorTextConstants.MAXIMUM_SOURCES_PER_PACKET) {
arrayList.get(currentIndex).addDocument(packet);
} else {
arrayList.add(new AnchorText(AnchorTextConstants.Type.OTHER_TYPES.val, key.getRightElement(), packet));
currentIndex = arrayList.size() - 1;
}
}
}
public void close() throws IOException {
Collections.sort(arrayList);
keyWord.set(currentDocument);
outputCollector.collect(keyWord, arrayList);
}
}
public static final String[] RequiredParameters = {
"Cloud9.InputPath",
"Cloud9.OutputPath",
"Cloud9.Mappers",
"Cloud9.Reducers"
};
public String[] getRequiredParameters() {
return RequiredParameters;
}
public CollectHostnames(Configuration conf) {
super(conf);
}
public int runTool() throws Exception {
JobConf conf = new JobConf(getConf(), CollectHostnames.class);
FileSystem fs = FileSystem.get(conf);
int numMappers = conf.getInt("Cloud9.Mappers", 1);
int numReducers = conf.getInt("Cloud9.Reducers", 200);
String inputPath = conf.get("Cloud9.InputPath");
String outputPath = conf.get("Cloud9.OutputPath");
conf.setJobName("CollectHostnames");
conf.set("mapred.child.java.opts", "-Xmx4096m");
conf.setInt("mapred.task.timeout", 60000000);
conf.setNumMapTasks(numMappers);
conf.setNumReduceTasks(numReducers);
conf.setMapperClass(Map.class);
conf.setPartitionerClass(Partition.class);
conf.setReducerClass(Reduce.class);
conf.setOutputKeyClass(IntWritable.class);
conf.setOutputValueClass(ArrayListWritable.class);
conf.setMapOutputKeyClass(PairOfIntString.class);
conf.setMapOutputValueClass(IntWritable.class);
conf.setInputFormat(SequenceFileInputFormat.class);
conf.setOutputFormat(SequenceFileOutputFormat.class);
SequenceFileOutputFormat.setCompressOutput(conf, true);
SequenceFileOutputFormat.setOutputCompressionType(conf, SequenceFile.CompressionType.BLOCK);
SequenceFileInputFormat.setInputPaths(conf, inputPath);
FileOutputFormat.setOutputPath(conf, new Path(outputPath));
sLogger.info("PropagateHostname");
sLogger.info(" - input path: " + inputPath);
sLogger.info(" - output path: " + outputPath);
if(!fs.exists(new Path(outputPath))) {
JobClient.runJob(conf);
} else {
sLogger.info(outputPath + " already exists! Skipping this step...");
}
return 0;
}
}