kafka.etl.impl.SimpleKafkaETLJob.java Source code

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Here is the source code for kafka.etl.impl.SimpleKafkaETLJob.java

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/*
 * Copyright 2010 LinkedIn
 * 
 * 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 kafka.etl.impl;

import kafka.etl.KafkaETLInputFormat;
import kafka.etl.KafkaETLJob;
import kafka.etl.Props;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.JobClient;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.RunningJob;
import org.apache.hadoop.mapred.TextOutputFormat;

/**
 * This is a simple Kafka ETL job which pull text events generated by
 * DataGenerator and store them in hdfs
 */
@SuppressWarnings("deprecation")
public class SimpleKafkaETLJob {

    protected String _name;
    protected Props _props;
    protected String _input;
    protected String _output;
    protected String _topic;

    public SimpleKafkaETLJob(String name, Props props) throws Exception {
        _name = name;
        _props = props;

        _input = _props.getProperty("input");
        _output = _props.getProperty("output");

        _topic = props.getProperty("kafka.etl.topic");
    }

    protected JobConf createJobConf() throws Exception {
        JobConf jobConf = KafkaETLJob.createJobConf("SimpleKafakETL", _topic, _props, getClass());

        jobConf.setMapperClass(SimpleKafkaETLMapper.class);
        KafkaETLInputFormat.setInputPaths(jobConf, new Path(_input));

        jobConf.setOutputKeyClass(LongWritable.class);
        jobConf.setOutputValueClass(Text.class);
        jobConf.setOutputFormat(TextOutputFormat.class);
        TextOutputFormat.setCompressOutput(jobConf, false);
        Path output = new Path(_output);
        FileSystem fs = output.getFileSystem(jobConf);
        if (fs.exists(output))
            fs.delete(output);
        TextOutputFormat.setOutputPath(jobConf, output);

        jobConf.setNumReduceTasks(0);
        return jobConf;
    }

    public void execute() throws Exception {
        JobConf conf = createJobConf();
        RunningJob runningJob = new JobClient(conf).submitJob(conf);
        String id = runningJob.getJobID();
        System.out.println("Hadoop job id=" + id);
        runningJob.waitForCompletion();

        if (!runningJob.isSuccessful())
            throw new Exception("Hadoop ETL job failed! Please check status on http://"
                    + conf.get("mapred.job.tracker") + "/jobdetails.jsp?jobid=" + id);
    }

    /**
     * for testing only
     * 
     * @param args
     * @throws Exception
     */
    public static void main(String[] args) throws Exception {

        if (args.length < 1)
            throw new Exception("Usage: - config_file");

        Props props = new Props(args[0]);
        SimpleKafkaETLJob job = new SimpleKafkaETLJob("SimpleKafkaETLJob", props);
        job.execute();
    }

}