Protecting against poison pills in Apache Kafka applications (demo)

This sample project demonstrates how to protect Apache Kafka applications against poison pills (Deserialization exceptions).

Kafka Consumer and KStream configuration included.

Getting Started

Prerequisites

• Java 11
• Docker

Usage

• Start docker-compose.

  docker compose -f docker/docker-compose.yml up -d

• Start application.

  ./gradlew bootRun

• Produce valid json messages to Consumer and KStreams.

  # Send message to `events` topic (Kafka Consumer)
  (cd docker && docker-compose exec broker bash -c "echo '{\"message\": \"Hello from Kafka Consumer\"}' | kafka-console-producer --broker-list localhost:9092 --topic events")
  
  # Send message to `kstream.events` topic (Kafka Streams)
  (cd docker && docker-compose exec broker bash -c "echo '{\"message\": \"Hello from Kafka Streams\"}' | kafka-console-producer --broker-list localhost:9092 --topic kstream.events")

• Verify that messages were successfully handled.

  # 2021-06-17 12:32:36.521  INFO 2947 --- [ntainer#0-0-C-1] c.r.kafka.app.events.EventListener       : Event(message=Hello from Kafka Consumer) received
  # [KSTREAM-SOURCE-0000000000]: null, Event(message=Hello from Kafka Streams)

• Produce poison pills.

  # Send poison pill to 'events' topic (Kafka Consumer)
  (cd docker && docker-compose exec broker bash -c "echo 'poison pill' | kafka-console-producer --broker-list localhost:9092 --topic events")
   
  # Send poison pill to 'kstream.events' topic (Kafka Streams)
  (cd docker && docker-compose exec broker bash -c "echo 'poison pill' | kafka-console-producer --broker-list localhost:9092 --topic kstream.events")

• Open your web browser and go to Kowl Web UI topic page.

• Confirm that poison pills were successfully handled by checking the content of dead letter topics (events.DLT and kstream.events.DLT).

References

• Streaming Apps and Poison Pills: handle the unexpected with Kafka Streams

License

Distributed under the MIT License. See LICENSE for more information.