Core Concepts

Spring Microservices are built on key concepts:

1. Service Discovery: Services register themselves with a discovery server (like Eureka). Other services locate them dynamically rather than using hardcoded URLs.
2. API Gateway: Single entry point that routes requests to appropriate microservices, handles authentication, and load balancing. Spring Cloud Gateway is commonly used.
3. Load Balancing: Distributes traffic across service instances using client-side (Ribbon) or server-side balancing.
4. Circuit Breaker: Prevents cascade failures by monitoring service health and providing fallbacks (using Resilience4j or Hystrix).
5. Configuration Management: Externalized configuration using Spring Cloud Config Server for centralized management across services.
6. Service Communication:
   • Synchronous: REST/HTTP using RestTemplate or WebClient
   • Asynchronous: Message queues like RabbitMQ/Kafka
7. Distributed Tracing: Tracks requests across services using tools like Spring Cloud Sleuth and Zipkin.