Kafka Consumer Test - implements kafka examples for testing

kafka_consumer_test.groovy

@Grab("org.apache.kafka:kafka_2.10:0.8.1")
@GrabExclude("com.sun.jmx:jmxri")
@GrabExclude("javax.jms:jms")
@GrabExclude("com.sun.jdmk:jmxtools")
@GrabExclude("junit:junit")

import kafka.consumer.ConsumerConfig;
import kafka.consumer.ConsumerIterator;
import kafka.consumer.KafkaStream;
import kafka.javaapi.consumer.ConsumerConnector;
 
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.concurrent.*

/**
 * Kafka examples taken from website. This allows simple testing of kafka consumer configuration.
 */
// zookeeper-server-start.sh /usr/local/Cellar/kafka/0.8.1.1/libexec/config/zookeeper.properties
// kafka-server-start.sh /usr/local/Cellar/kafka/0.8.1.1/libexec/config/server.properties
// kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 1 --partitions 1 --topic test_topic
// kafka-console-producer.sh --broker-list localhost:9092 --topic test_topic


String zooKeeper = "localhost"
String groupId = "g2"
String topic = "test_topic"
int threads = 1

ConsumerGroupExample example = new ConsumerGroupExample(zooKeeper, groupId, topic);
example.run(threads);

try {
    Thread.sleep(10000);
} catch (InterruptedException ie) {

}
example.shutdown();

println 'done'

public class ConsumerTest implements Runnable {
    private KafkaStream m_stream;
    private int m_threadNumber;
 
    public ConsumerTest(KafkaStream a_stream, int a_threadNumber) {
        m_threadNumber = a_threadNumber;
        m_stream = a_stream;
    }
 
    public void run() {
        ConsumerIterator<byte[], byte[]> it = m_stream.iterator();
        while (it.hasNext())
            System.out.println("Thread " + m_threadNumber + ": " + new String(it.next().message()));
        System.out.println("Shutting down Thread: " + m_threadNumber);
    }
}

public class ConsumerGroupExample {
    private final ConsumerConnector consumer;
    private final String topic;
    private  ExecutorService executor;
 
    public ConsumerGroupExample(String a_zookeeper, String a_groupId, String a_topic) {
        consumer = kafka.consumer.Consumer.createJavaConsumerConnector(
                createConsumerConfig(a_zookeeper, a_groupId));
        this.topic = a_topic;
    }
 
    public void shutdown() {
        if (consumer != null) consumer.shutdown();
        if (executor != null) executor.shutdown();
        try {
            if (!executor.awaitTermination(5000, TimeUnit.MILLISECONDS)) {
                System.out.println("Timed out waiting for consumer threads to shut down, exiting uncleanly");
            }
        } catch (InterruptedException e) {
            System.out.println("Interrupted during shutdown, exiting uncleanly");
        }
   }
 
    public void run(int a_numThreads) {
        Map<String, Integer> topicCountMap = new HashMap<String, Integer>();
        topicCountMap.put(topic, new Integer(a_numThreads));
        Map<String, List<KafkaStream<byte[], byte[]>>> consumerMap = consumer.createMessageStreams(topicCountMap);
        List<KafkaStream<byte[], byte[]>> streams = consumerMap.get(topic);
 
        // now launch all the threads
        //
        executor = Executors.newFixedThreadPool(a_numThreads);
 
        // now create an object to consume the messages
        //
        int threadNumber = 0;
        for (final KafkaStream stream : streams) {
            executor.submit(new ConsumerTest(stream, threadNumber));
            threadNumber++;
        }
    }
 
    private static ConsumerConfig createConsumerConfig(String a_zookeeper, String a_groupId) {
        Properties props = new Properties();
        props.put("zookeeper.connect", a_zookeeper);
        props.put("group.id", a_groupId);
        props.put("zookeeper.session.timeout.ms", "400");
        props.put("zookeeper.sync.time.ms", "200");
        props.put("auto.commit.interval.ms", "1000");
        props.put("auto.offset.reset", "smallest")
 
        return new ConsumerConfig(props);
    }
}