README.md

Kafka Streams Count

This module demonstrates the following:

• The usage of the Kafka Streams DSL, including count(), groupBy(), toStream() and peek().
• Unit testing using Topology Test Driver.

In this module, records of type <String, KafkaPerson> are streamed from a topic named PERSON_TOPIC. The following tasks are performed:

1. Group the stream by nationality using the groupBy() operation.
2. Apply the count() operation to count the number of KafkaPerson records for each nationality.
3. Write the resulting counts to a new topic named PERSON_COUNT_TOPIC.

Requirements

To compile and run this demo, you will need the following:

• Java 21
• Maven
• Docker

Running the Application

To run the application manually, please follow the steps below:

• Start a Confluent Platform in a Docker environment.
• Produce records of type <String, KafkaPerson> to a topic named PERSON_TOPIC. You can use the producer person to do this.
• Start the Kafka Streams.

To run the application in Docker, please use the following command:

docker-compose up -d

This command will start the following services in Docker:

• 1 Kafka broker KRaft
• 1 Schema registry
• 1 Control Center
• 1 producer Person
• 1 Kafka Streams Count