Template project for Spring Boot and Kafka Streams with Reactive REST API (WebFlux)
- Lombok (Java annotation library which helps to reduce boilerplate code)
- Spring for Apache Kafka (Publish, subscribe, store, and process streams of records)
- Spring for Apache Kafka Streams (Building stream processing applications with Apache Kafka Streams)
- Spring Web (Build web applications with Spring MVC)
- Spring Boot Actuator (Supports built in (or custom) endpoints that let you monitor and manage your application - such as application health, metrics, sessions, etc.)
- Testcontainers (Provide lightweight, throwaway instances of common databases, Selenium web browsers, or anything else that can run in a Docker container)
Our sample application reads streaming events from an input Kafka topic. Once the records are read, it processes them to split the text and counts the individual words. Subsequently, it sends the updated word count to the Kafka output. In addition to the output topic, we’ll also create a simple REST service to expose this count over an HTTP endpoint.
Overall, the output topic will be continuously updated with the words extracted from the input events and their updated counts.
Based on https://www.baeldung.com/spring-boot-kafka-streams.
We used Spring Initializr (https://start.spring.io/) for creating stub for this project. After generation, several improvements were made, to make it more production-ready and in order to improve developer experience:
- Maven build replaced with Gradle on Kotlin DSL
- Dependency on Lombok replaced with Lombok Gradle Plugin
@SpringBootTestreplaced with@WebFluxTestfor integration test (which disables full auto-configuration and only applies configuration relevant to WebFlux tests) which improves performanceconfluentinc/cp-kafkaupgraded to7.6.1(to supportaarch64)io.spring.dependency-managementplugin replaced with Gradleplatformplugin- Test Pyramid with explicit separation of component, integration and functional tests
- Gradle parallel build turned on (
gradle.properties)
