Fault tolerance is a crucial aspect of microservices system design. In this project, I built the circuit breaker pattern using Resilience4j for services written in Java/Spring Boot, with Redis as a fallback caching mechanism.
The circuit breaker pattern enables us to have resilient, fault-tolerant microservices by gracefully handling service failures and preventing system overloads. In microservices architecture, a circuit breaker acts as a safeguard against the failure of a service or an external dependency. It constantly monitors for failures and upon reaching a threshold, it "trips" to prevent further strain on the failing service. This helps in maintaining the system's stability and performance, as well as preventing failure chains.
In distributed systems, services depend on each other. If one service fails, it can cascade and impact other services, leading to system-wide failures. Implementing a circuit breaker helps in isolating problems and ensuring system reliability.
This project comprises two microservices: Publication and Comments. The Comments service is wrapped with a Resilience4J circuit breaker. Normal Operation: Under normal conditions, requests to the Comments service are processed as usual. Circuit Breaker Activation: When the Comments service fails or becomes unresponsive, the circuit breaker trips after a predefined threshold. Redis as Fallback Cache: Once the circuit breaker is open, the system falls back to the last cached results from Redis, ensuring continued availability of data. System Recovery: The circuit breaker periodically allows a limited number of requests to pass through to check if the underlying service is back to normal. If the service is healthy, the circuit breaker closes, and normal operation resumes.
This project further enhanced my competence in building fault-tolerant microservices in Java/Spring by using advanced patterns. Here, I also demonstrated the effective use of Redis for fallback caching, ensuring data availability even when parts of the system fail. The core idea I implemented here can be supported with further improvements.
- Event-Driven CQRS & SAGA Choreography with Hexagonal Architecture
- Distributed transactions, event-driven microservices, Apache Kafka, Java, Spring Boot, ports & adapters pattern
- Implementing Distributed Microservices Communication with Spring Eureka & RabbitMQ
- Java, Spring Cloud Gateway, Spring Security, RabbitMQ, Eureka Discovery Server, distributed tracing