Running Kafka locally with Docker

There are two popular Docker images for Kafka that I have come across:

• Bitmami/kafka (Github)
• wurstmeister/kafka (Github)

I chose these instead of via Confluent Platform because they’re more vanilla compared to the components Confluent Platform includes.

You can run both the Bitmami/kafka and wurstmeister/kafka images locally using the docker-compose config below, I’ll duplicate it with the name of each image inserted:

• Bitmami/kafka:

  version: "3"
  services:
    zookeeper:
      image: 'bitnami/zookeeper:latest'
      ports:
        - '2181:2181'
      environment:
        - ALLOW_ANONYMOUS_LOGIN=yes
    kafka:
      image: 'bitnami/kafka:latest'
      ports:
        - '9092:9092'
      environment:
        - KAFKA_BROKER_ID=1
        - KAFKA_LISTENERS=PLAINTEXT://:9092
        - KAFKA_ADVERTISED_LISTENERS=PLAINTEXT://127.0.0.1:9092
        - KAFKA_ZOOKEEPER_CONNECT=zookeeper:2181
        - ALLOW_PLAINTEXT_LISTENER=yes
      depends_on:
        - zookeeper

  The Bitnami image is well documented and is where I pulled this nice docker-compose config from.

• wurstmeister/kafka:

  version: "3"
  services:
    zookeeper:
      image: 'wurstmeister/zookeeper:latest'
      ports:
        - '2181:2181'
      environment:
        - ALLOW_ANONYMOUS_LOGIN=yes
    kafka:
      image: 'wurstmeister/kafka:latest'
      ports:
        - '9092:9092'
      environment:
        - KAFKA_BROKER_ID=1
        - KAFKA_LISTENERS=PLAINTEXT://:9092
        - KAFKA_ADVERTISED_LISTENERS=PLAINTEXT://127.0.0.1:9092
        - KAFKA_ZOOKEEPER_CONNECT=zookeeper:2181
        - ALLOW_PLAINTEXT_LISTENER=yes
      depends_on:
        - zookeeper

It is important to have KAFKA_ADVERTISED_LISTENERS set or you won’t be able to connect to Kafka from an external application. More information on this topic can be found here, which I found extremely useful when I did this incorrectly.

Once you have started the Kafka and Zookeeper containers, you’re good to go. You can start connecting to Kafka either directly or from an application.

• Directly, via Kafka’s consumer and producer scripts:

  # Create topic
  docker exec -it kafka_kafka_1 kafka-topics.sh --create --bootstrap-server kafka:9092 --topic my-topic
  # Create events
  docker exec -it kafka_kafka_1 kafka-console-producer.sh --bootstrap-server kafka:9092 --topic my-topic
  # Read events
  docker exec -it kafka_kafka_1 kafka-console-consumer.sh --bootstrap-server kafka:9092 --topic my-topic --from-beginning

• From an application (in Kotlin):

  fun createProducer(): Producer<String, String> {
    val props = Properties()
    props["bootstrap.servers"] = "localhost:9092"
    props["acks"] = "all"
    props["retries"] = 0
    props["linger.ms"] = 1
    props["key.serializer"] = "org.apache.kafka.common.serialization.StringSerializer"
    props["value.serializer"] = "org.apache.kafka.common.serialization.StringSerializer"
    return KafkaProducer(props)
  }
  
  fun Producer<String, String>.produceMessages(topic: String) {
    fixedRateTimer(daemon = true, period = Duration.ofSeconds(2).toMillis()) {
      val time = LocalDateTime.now()
      val message = ProducerRecord(
        topic, // topic
        time.toString(), // key
        "Message sent at ${LocalDateTime.now()}" // value
      )
      send(message)
    }
  }
  
  fun createConsumer(): Consumer<String, String> {
    val props = Properties()
    props.setProperty("bootstrap.servers", "localhost:9092")
    props.setProperty("group.id", "test")
    props.setProperty("enable.auto.commit", "true")
    props.setProperty("auto.commit.interval.ms", "1000")
    props.setProperty("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer")
    props.setProperty("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer")
    return KafkaConsumer(props)
  }
  
  fun Consumer<String, String>.consumeMessages(topic: String) {
    subscribe(listOf(topic))
    while (true) {
      val messages: ConsumerRecords<String, String> = poll(Duration.ofMillis(5000))
      for (message in messages) {
        println("Consumer reading message: ${message.value()}")
      }
      commitAsync()
    }
  }

• ← Public val with a private backing field
• Kafka producer and consumer written with Kotlin →