Consumer not receiving message in Apache Kafka

Question

I am building an Apache Kafka consumer to subscribe to another already running Kafka. Now, my problem is that when my producer pushes message to a server...my consumer does not receive them. Here I give Producer code,

        Properties properties = new Properties();
        properties.put("metadata.broker.list","Running kafka ip addr:9092");
        properties.put("serializer.class","kafka.serializer.StringEncoder");
        ProducerConfig producerConfig = new ProducerConfig(properties);
        kafka.javaapi.producer.Producer<String,String> producer = new kafka.javaapi.producer.Producer<String, String>(producerConfig);
        String filePath="filepath";
        File rootFile= new File(filePath);
        Collection<File> allFiles = FileUtils.listFiles(rootFile, CanReadFileFilter.CAN_READ, TrueFileFilter.INSTANCE);
        for(File file : allFiles) {
            StringBuilder sb = new StringBuilder();
            sb.append(file);
            KeyedMessage<String, String> message =new KeyedMessage<String, String>(TOPIC,sb.toString());
            System.out.println("sending msg from producer.."+sb.toString());
            producer.send(message);
        }
           producer.close();

Here Consumer code,

         properties.put("bootstrap.servers","Running zookeaper ip addr:2181");
         properties.put("group.id","test-group");
         properties.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
         properties.put("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
         properties.put("enable.auto.commit", "false");

         KafkaConsumer<String, String> consumer = new KafkaConsumer<String, String>(properties);
         consumer.subscribe(Collections.singletonList(topicName)); 
         while (true) {
                ConsumerRecords<String, String> records = consumer.poll(100);
                for (ConsumerRecord<String, String> record : records)
                {
                    System.out.println("topic = "+record.topic());
                    System.out.println("topic = "+record.partition());
                    System.out.println("topic = "+record.offset());
                }
                try {
                  consumer.commitSync(); 
                } catch (CommitFailedException e) {
                    System.out.printf("commit failed", e) ;
                }
            }

I use this dependency:

    <dependency>
        <groupId>org.apache.kafka</groupId>
        <artifactId>kafka_2.11</artifactId>
        <version>0.10.0.0</version>
    </dependency>
    <dependency>
        <groupId>org.apache.kafka</groupId>
        <artifactId>kafka-clients</artifactId>
        <version>0.10.1.0</version>
    </dependency>

I get all information from that link:
https://kafka.apache.org/0100/javadoc/index.html?org/apache/kafka/clients/consumer/KafkaConsumer.html

When we running consumer, we didn't get any notification from the consumer side. Please give me any idea.

Answer 1

For producer:

  properties.put("metadata.broker.list","Running kafka ip addr:9092"); 

I guess, this should be "bootstrap.servers".

For consumer:

 properties.put("bootstrap.servers","Running zookeaper ip addr:2181"); 

bootstrap.servers must point to a broker, not to ZK.

The "problem" is, that the consumer will just wait for a broker but not fail if there is no broker at the specified host/port.

Answer 2

I'm a newb at Kafka and Java, but i'll like to suggest the following approach

• Verify that the producer is actually writing to the topic using the following command /usr/bin/kafka-avro-console-consumer --new-consumer --bootstrap-server localhost:9092 --topic KumarTopic --from-beginning .
• If it is, you'll probably need to focus on your consumer code. Confluent's guides are pretty helpful.