Apache Kafka for Developers using Spring Boot[LatestEdition]

📚 WebMVC Annotation and MockMVC

• Understand how to use @RestController and @GetMapping, @PostMapping, etc., for defining RESTful endpoints.
• Use MockMvc for testing the REST controllers by simulating HTTP requests.
• Add validations to your request payloads using constraints like @NotBlank, @Min, @Max, etc.
• Write custom error handlers to return different response codes and messages for various scenarios.

📧 Kafka Producer - Sending Message With Key

• Learn how to send records to a Kafka topic with a key for partitioning and consistent group management.

🔗 Kafka Producer - Important Configurations

• Understand configurations like key.serializer, value.serializer, partitioner, and their impact on message delivery.
• Learn about the importance of acks setting and its role in ensuring data durability.
• Explore producer interceptors for logging or pre/post-processing messages.

🧐 Build SpringBoot Kafka Consumer

• Set up a project with the necessary dependencies for a Kafka consumer.
• Learn about @KafkaListener, @KafkaEventHandler, and how to consume messages from topics.
• Understand the auto-configuration properties in Spring Boot for Kafka consumers.

👨‍🚀 Consumer Groups and Offset Management

• Explain how consumer groups work and why they are essential for scalability and fault tolerance.
• Manually manage offsets to ensure messages are consumed exactly once and not skipped or duplicated after a failure.
• Demonstrate how to scale message consumption by configuring the concurrency level.

🗂️ Persisting Library Events in DB - Using H2 InMemory DataBase

• Configure an H2 in-memory database and integrate it with your application.
• Define entities like LibraryEvent and Book and use Spring Data JPA to interact with the database.
• Create service methods to handle library events for ADDing and MODIFYing records.

🔄 Integration Testing using Embedded Kafka - Kafka Consumer

• Configure an embedded Kafka instance within your test environment.
• Write unit and integration tests to validate the consumer logic and message processing.
• Use TestContainers for real database integration tests.

🛠️ Error Handling, Retry and Recovery - Kafka Consumers

• Implement custom error handling strategies for consumer failures.
• Configure retry mechanisms to handle transient errors.
• Set up a recovery process to handle more critical issues that prevent the consumer from functioning correctly.

🚫 Error Handling, Retry/Recovery - Kafka Producer

• Handle producer errors using error callbacks.
• Implement retry logic for scenarios like broker unavailability or when the required number of replicas are not in sync.
• Learn how to recover and retain failed records until they can be successfully produced.

🎉 Conclusion

By completing this journey, you will have a solid understanding of building robust Kafka consumers and producers with Spring Boot, along with comprehensive unit and integration testing strategies using EmbeddedKafka. You'll be equipped to handle real-world scenarios involving message production, consumption, validation, error handling, retry mechanisms, and recovery processes. Your applications will be resilient, scalable, and maintainable.