/*
* Cloud9: A Hadoop toolkit for working with big data
*
* 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.example.pagerank;
import java.io.IOException;
import java.util.Arrays;
import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.CommandLineParser;
import org.apache.commons.cli.GnuParser;
import org.apache.commons.cli.HelpFormatter;
import org.apache.commons.cli.OptionBuilder;
import org.apache.commons.cli.Options;
import org.apache.commons.cli.ParseException;
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.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;
import org.apache.log4j.Logger;
import edu.umd.cloud9.io.array.ArrayListOfIntsWritable;
/**
* <p>
* Driver program that takes a plain-text encoding of a directed graph and builds corresponding
* Hadoop structures for representing the graph.
* </p>
*
* @author Jimmy Lin
* @author Michael Schatz
*/
public class BuildPageRankRecords extends Configured implements Tool {
private static final Logger LOG = Logger.getLogger(BuildPageRankRecords.class);
private static final String NODE_CNT_FIELD = "node.cnt";
private static class MyMapper extends Mapper<LongWritable, Text, IntWritable, PageRankNode> {
private static final IntWritable nid = new IntWritable();
private static final PageRankNode node = new PageRankNode();
@Override
public void setup(Mapper<LongWritable, Text, IntWritable, PageRankNode>.Context context) {
int n = context.getConfiguration().getInt(NODE_CNT_FIELD, 0);
if (n == 0) {
throw new RuntimeException(NODE_CNT_FIELD + " cannot be 0!");
}
node.setType(PageRankNode.Type.Complete);
node.setPageRank((float) -StrictMath.log(n));
}
@Override
public void map(LongWritable key, Text t, Context context) throws IOException,
InterruptedException {
String[] arr = t.toString().trim().split("\\s+");
nid.set(Integer.parseInt(arr[0]));
if (arr.length == 1) {
node.setNodeId(Integer.parseInt(arr[0]));
node.setAdjacencyList(new ArrayListOfIntsWritable());
} else {
node.setNodeId(Integer.parseInt(arr[0]));
int[] neighbors = new int[arr.length - 1];
for (int i = 1; i < arr.length; i++) {
neighbors[i - 1] = Integer.parseInt(arr[i]);
}
node.setAdjacencyList(new ArrayListOfIntsWritable(neighbors));
}
context.getCounter("graph", "numNodes").increment(1);
context.getCounter("graph", "numEdges").increment(arr.length - 1);
if (arr.length > 1) {
context.getCounter("graph", "numActiveNodes").increment(1);
}
context.write(nid, node);
}
}
public BuildPageRankRecords() {}
private static final String INPUT = "input";
private static final String OUTPUT = "output";
private static final String NUM_NODES = "numNodes";
/**
* Runs this tool.
*/
@SuppressWarnings({ "static-access" })
public int run(String[] args) throws Exception {
Options options = new Options();
options.addOption(OptionBuilder.withArgName("path").hasArg()
.withDescription("input path").create(INPUT));
options.addOption(OptionBuilder.withArgName("path").hasArg()
.withDescription("output path").create(OUTPUT));
options.addOption(OptionBuilder.withArgName("num").hasArg()
.withDescription("number of nodes").create(NUM_NODES));
CommandLine cmdline;
CommandLineParser parser = new GnuParser();
try {
cmdline = parser.parse(options, args);
} catch (ParseException exp) {
System.err.println("Error parsing command line: " + exp.getMessage());
return -1;
}
if (!cmdline.hasOption(INPUT) || !cmdline.hasOption(OUTPUT) || !cmdline.hasOption(NUM_NODES)) {
System.out.println("args: " + Arrays.toString(args));
HelpFormatter formatter = new HelpFormatter();
formatter.setWidth(120);
formatter.printHelp(this.getClass().getName(), options);
ToolRunner.printGenericCommandUsage(System.out);
return -1;
}
String inputPath = cmdline.getOptionValue(INPUT);
String outputPath = cmdline.getOptionValue(OUTPUT);
int n = Integer.parseInt(cmdline.getOptionValue(NUM_NODES));
LOG.info("Tool name: " + BuildPageRankRecords.class.getSimpleName());
LOG.info(" - inputDir: " + inputPath);
LOG.info(" - outputDir: " + outputPath);
LOG.info(" - numNodes: " + n);
Configuration conf = getConf();
conf.setInt(NODE_CNT_FIELD, n);
conf.setInt("mapred.min.split.size", 1024 * 1024 * 1024);
Job job = Job.getInstance(conf);
job.setJobName(BuildPageRankRecords.class.getSimpleName() + ":" + inputPath);
job.setJarByClass(BuildPageRankRecords.class);
job.setNumReduceTasks(0);
FileInputFormat.addInputPath(job, new Path(inputPath));
FileOutputFormat.setOutputPath(job, new Path(outputPath));
job.setInputFormatClass(TextInputFormat.class);
job.setOutputFormatClass(SequenceFileOutputFormat.class);
job.setMapOutputKeyClass(IntWritable.class);
job.setMapOutputValueClass(PageRankNode.class);
job.setOutputKeyClass(IntWritable.class);
job.setOutputValueClass(PageRankNode.class);
job.setMapperClass(MyMapper.class);
// Delete the output directory if it exists already.
FileSystem.get(conf).delete(new Path(outputPath), true);
job.waitForCompletion(true);
return 0;
}
/**
* Dispatches command-line arguments to the tool via the {@code ToolRunner}.
*/
public static void main(String[] args) throws Exception {
ToolRunner.run(new BuildPageRankRecords(), args);
}
}