Spring Kafka micrometer

Example project to play around with Spring Kafka Micrometer.

Versions used in this project:

• Spring Boot: 2.1.0
• Spring Kafka: 2.2.0.RELEASE
• Micrometer: 1.1.0

How to build the project

./mvnw clean package

How to run this project

Make sure to set the environment variable DOCKER_HOST_IP to the ip of the host running the Docker containers using docker-compose.

On Linux you can get the correct IP from docker0 interface by executing: ifconfig In my case DOCKER_HOST_IP=172.17.0.1

If you are using Docker for Mac <= 1.11, or Docker Toolbox for Windows (your docker machine IP is usually 192.168.99.100)

docker-compose up -d

Start the producer:

cd spring-kafka-producer
mvn spring-boot:run

The producer will publish a Hello World message to topic: hello-world-messages

Start the consumer:

cd
mvn spring-boot:run

How the consumer metrics:

http://localhost:8081/metrics/

Kafka metrics are visible.

See specific Kafka metrics:

http://localhost:8081/actuator/metrics/kafka.consumer.records.consumed.total

{
  name: "kafka.consumer.records.consumed.total",
  description: "The total number of records consumed.",
  baseUnit: "records",
  measurements: [
    {
      statistic: "COUNT",
      value: "NaN"
    }
  ],
  availableTags: [
    {
      tag: 'client.id',
      values: [
        "spring-kafka-consumer-hello-world-app"
      ]
    }
  ]
}

My Question why is the value of COUNT NaN?

{
  measurements: [
    {
      statistic: "COUNT",
      value: "NaN"
    }
  ]
}

This issue has been fixed in Micrometer version 1.1.1 see commit

Kafka manager

Part of the docker-compose setup is the Kafka Manager. To get more insight in the broker, topics and more you can use this tool.

• Open http://localhost:9000
• Create a Kafka cluster view http://localhost:9000/addCluster