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WacMapReduceHBaseWrapperDemo.java
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Wed, Sep 25, 23:26

WacMapReduceHBaseWrapperDemo.java
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package org.warcbase.demo;
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.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.KeyValue;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.hbase.mapreduce.TableMapReduceUtil;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Counters;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;
import org.apache.log4j.Logger;
import org.archive.io.arc.ARCRecord;
import org.warcbase.data.ArcRecordUtils;
import org.warcbase.mapreduce.lib.TableChainMapper;
public class WacMapReduceHBaseWrapperDemo extends Configured implements Tool {
private static final Logger LOG = Logger.getLogger(WacMapReduceHBaseDemo.class);
private static enum Records {
ROWS, URLS
};
private static class MyMapper1 extends Mapper<ImmutableBytesWritable, Result, LongWritable, Text> {
@Override
public void map(ImmutableBytesWritable row, Result result, Context context)
throws IOException, InterruptedException {
context.getCounter(Records.ROWS).increment(1);
for (KeyValue kv : result.list()) {
ARCRecord record = ArcRecordUtils.getRecord(kv.getValue());
context.write(new LongWritable(0), new Text(record.getMetaData().getUrl()));
}
}
}
private static class MyMapper2 extends Mapper<LongWritable, Text, Text, Text> {
@Override
public void map(LongWritable key, Text url, Context context) throws IOException,
InterruptedException {
context.getCounter(Records.URLS).increment(1);
context.write(new Text(url), new Text(""));
}
}
public WacMapReduceHBaseWrapperDemo() {
}
public static final String INPUT_OPTION = "input";
public static final String OUTPUT_OPTION = "output";
/**
* 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_OPTION));
options.addOption(OptionBuilder.withArgName("path").hasArg().withDescription("output path")
.create(OUTPUT_OPTION));
CommandLine cmdline;
CommandLineParser parser = new GnuParser();
try {
cmdline = parser.parse(options, args);
} catch (ParseException exp) {
HelpFormatter formatter = new HelpFormatter();
formatter.printHelp(this.getClass().getName(), options);
ToolRunner.printGenericCommandUsage(System.out);
System.err.println("Error parsing command line: " + exp.getMessage());
return -1;
}
if (!cmdline.hasOption(INPUT_OPTION) || !cmdline.hasOption(OUTPUT_OPTION)) {
HelpFormatter formatter = new HelpFormatter();
formatter.printHelp(this.getClass().getName(), options);
ToolRunner.printGenericCommandUsage(System.out);
return -1;
}
String input = cmdline.getOptionValue(INPUT_OPTION);
Path output = new Path(cmdline.getOptionValue(OUTPUT_OPTION));
LOG.info("Tool name: " + WacMapReduceHBaseWrapperDemo.class.getSimpleName());
LOG.info(" - input: " + input);
LOG.info(" - output: " + output);
Configuration config = HBaseConfiguration.create(getConf());
// This should be fetched from external config files,
// but not working due to weirdness in current config.
config.set("hbase.zookeeper.quorum", "bespinrm.umiacs.umd.edu");
Job job = Job.getInstance(config, WacMapReduceHBaseWrapperDemo.class.getSimpleName() + ":" + input);
job.setJarByClass(WacMapReduceHBaseWrapperDemo.class);
Scan scan = new Scan();
scan.addFamily("c".getBytes());
// Very conservative settings because a single row might not fit in memory
// if we have many captured version of a URL.
scan.setCaching(1); // Controls the number of rows to pre-fetch
scan.setBatch(10); // Controls the number of columns to fetch on a per row basis
scan.setCacheBlocks(false); // Don't set to true for MR jobs
scan.setMaxVersions(); // We want all versions
TableMapReduceUtil.initTableMapperJob(input, // input HBase table name
scan, // Scan instance to control CF and attribute selection
TableChainMapper.class, // mapper
Text.class, // mapper output key
Text.class, // mapper output value
job);
TableChainMapper.addMapper(job, MyMapper1.class, ImmutableBytesWritable.class, Result.class,
LongWritable.class, Text.class, job.getConfiguration());
TableChainMapper.addMapper(job, MyMapper2.class, LongWritable.class, Text.class,
Text.class, Text.class, job.getConfiguration());
job.setNumReduceTasks(0);
FileOutputFormat.setOutputPath(job, output);
job.setOutputFormatClass(TextOutputFormat.class);
FileSystem fs = FileSystem.get(getConf());
if (FileSystem.get(getConf()).exists(output)) {
fs.delete(output, true);
}
job.waitForCompletion(true);
Counters counters = job.getCounters();
LOG.info("Read " + (int) counters.findCounter(Records.ROWS).getValue() + " rows.");
LOG.info("Read " + (int) counters.findCounter(Records.URLS).getValue() + " URLs.");
return 0;
}
/**
* Dispatches command-line arguments to the tool via the <code>ToolRunner</code>.
*/
public static void main(String[] args) throws Exception {
LOG.info("Running " + WacMapReduceHBaseWrapperDemo.class.getCanonicalName() + " with args "
+ Arrays.toString(args));
ToolRunner.run(new WacMapReduceHBaseWrapperDemo(), args);
}
}

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