package com.twitter.elephantbird.examples;
import java.io.IOException;
import com.twitter.elephantbird.examples.proto.AddressBookProtos.Person;
import com.twitter.elephantbird.examples.proto.AddressBookProtos.Person.PhoneNumber;
import com.twitter.elephantbird.mapreduce.input.MultiInputFormat;
import com.twitter.elephantbird.mapreduce.io.ProtobufWritable;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
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.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* For a file of LZO-compressed protobufs of type Person (see address_book.proto), generate a count of
* phone numbers for each person.
*
* To write the data file, use a ProtobufBlockWriter<Person> as specified in the documentation for
* ProtobufBlockWriter.java. It will write blocks of 100 Person protobufs at a time to a file which will
* be lzo compressed.
*/
public class PhoneNumberCounter extends Configured implements Tool {
private static final Logger LOG = LoggerFactory.getLogger(PhoneNumberCounter.class);
private PhoneNumberCounter() {}
public static class PhoneNumberCounterMapper extends Mapper<LongWritable, ProtobufWritable<Person>, Text, Text> {
private final Text name_ = new Text();
private final Text phoneNumber_ = new Text();
@Override
protected void map(LongWritable key, ProtobufWritable<Person> value, Context context) throws IOException, InterruptedException {
Person p = value.get();
name_.set(p.getName());
for (PhoneNumber phoneNumber: p.getPhoneList()) {
// Could do something with the PhoneType here; note that the protobuf data structure is fully preserved
// inside the writable, including nesting.
// PhoneType type = phoneNumber.getType()
phoneNumber_.set(phoneNumber.getNumber());
context.write(name_, phoneNumber_);
}
}
}
public static class PhoneNumberCounterReducer extends Reducer<Text, Text, Text, LongWritable> {
private final LongWritable count_ = new LongWritable();
@Override
protected void reduce(Text key, Iterable<Text> values, Context context) throws IOException, InterruptedException {
int count = 0;
for (Text phoneNumber: values) {
count++;
}
count_.set(count);
context.write(key, count_);
}
}
public int run(String[] args) throws Exception {
if (args.length != 1) {
System.out.println("Usage: hadoop jar path/to/this.jar " + getClass() + " <input dir> <output dir>");
System.exit(1);
}
Configuration conf = getConf();
Job job = new Job(conf);
job.setJobName("Protobuf Person Phone Number Counter");
job.setOutputKeyClass(NullWritable.class);
job.setOutputValueClass(LongWritable.class);
job.setJarByClass(getClass());
job.setMapperClass(PhoneNumberCounterMapper.class);
job.setCombinerClass(PhoneNumberCounterReducer.class);
job.setReducerClass(PhoneNumberCounterReducer.class);
// tell inputformat the name of protbuf class corresponding to input records.
MultiInputFormat.setClassConf(Person.class, conf);
job.setInputFormatClass(MultiInputFormat.class);
job.setOutputFormatClass(TextOutputFormat.class);
FileInputFormat.setInputPaths(job, new Path(args[0]));
FileOutputFormat.setOutputPath(job, new Path(args[1]));
return job.waitForCompletion(true) ? 0 : 1;
}
public static void main(String[] args) throws Exception {
int exitCode = ToolRunner.run(new PhoneNumberCounter(), args);
System.exit(exitCode);
}
}