Java Microservices Skill

Build production microservices with Spring Cloud and distributed system patterns.

Overview

This skill covers microservices architecture with Spring Cloud including service discovery, API gateway, circuit breakers, event-driven communication, and distributed tracing.

When to Use This Skill

Use when you need to:

Design microservices architecture Implement service-to-service communication Configure resilience patterns Set up event-driven messaging Add distributed tracing Topics Covered Spring Cloud Components Config Server (centralized config) Service Discovery (Eureka, Consul) API Gateway (Spring Cloud Gateway) Load Balancing (Spring Cloud LoadBalancer) Resilience Patterns Circuit Breaker (Resilience4j) Retry with backoff Bulkhead isolation Rate limiting Event-Driven Architecture Apache Kafka integration Spring Cloud Stream Saga pattern Event sourcing basics Observability Distributed tracing (Micrometer) Metrics (Prometheus) Log correlation Quick Reference // Saga with Choreography @Component public class OrderSagaListener {

@KafkaListener(topics = "order.created")
public void handleOrderCreated(OrderCreatedEvent event) {
    inventoryService.reserve(event.getItems());
}

@KafkaListener(topics = "payment.failed")
public void handlePaymentFailed(PaymentFailedEvent event) {
    // Compensating transaction
    inventoryService.release(event.getOrderId());
    orderService.cancel(event.getOrderId());
}

}

// Circuit Breaker Configuration @Configuration public class ResilienceConfig {

@Bean
public Customizer<Resilience4JCircuitBreakerFactory> cbCustomizer() {
    return factory -> factory.configureDefault(id ->
        new Resilience4JConfigBuilder(id)
            .circuitBreakerConfig(CircuitBreakerConfig.custom()
                .failureRateThreshold(50)
                .waitDurationInOpenState(Duration.ofSeconds(30))
                .slidingWindowSize(10)
                .build())
            .build());
}

}

// API Gateway Routes @Configuration public class GatewayConfig {

@Bean
public RouteLocator routes(RouteLocatorBuilder builder) {
    return builder.routes()
        .route("orders", r -> r
            .path("/api/orders/**")
            .filters(f -> f
                .stripPrefix(1)
                .circuitBreaker(c -> c.setName("order-cb"))
                .retry(retry -> retry.setRetries(3)))
            .uri("lb://order-service"))
        .build();
}

}

Observability Configuration management: tracing: sampling: probability: 1.0 endpoints: web: exposure: include: health,info,metrics,prometheus

logging: pattern: level: "%5p [${spring.application.name:},%X{traceId:-},%X{spanId:-}]"

Common Patterns Saga Pattern Order → Inventory → Payment → (Success | Compensate)

Circuit Breaker States CLOSED → (failures exceed threshold) → OPEN OPEN → (wait duration) → HALF_OPEN HALF_OPEN → (success) → CLOSED HALF_OPEN → (failure) → OPEN

Troubleshooting Common Issues Problem Cause Solution Cascade failure No circuit breaker Add Resilience4j Message lost No ack Enable manual ack Inconsistent data No compensation Implement saga Service not found Discovery delay Tune heartbeat Debug Checklist □ Trace request (traceId) □ Check circuit breaker state □ Verify Kafka consumer lag □ Review gateway routes □ Monitor retry counts

Usage Skill("java-microservices")

Related Skills java-spring-boot - Spring Cloud java-docker - Containerization

安装