Spring - Resilience4j circuit breaker example

Resilience4j는 내결함성(fault tolerance) 라이브러리다.

 

Netflix Hystrix는 더이상 개발되지 않아 Resilience4j 사용을 권장하고 있습니다. 

 

 

Resilience4j는 다음과 같은 모듈을 제공합니다.

 

- circuitbreaker

- ratelimiter

- bulkhead

- retry

- timelimiter

- cache

 

 

 

CircuitBreaker Config

import io.github.resilience4j.circuitbreaker.CircuitBreaker;
import io.github.resilience4j.circuitbreaker.CircuitBreakerConfig;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import java.time.Duration;

@Configuration
public class CircuitBreakerConfig {

    @Bean
    public CircuitBreaker circuitBreaker() {
        CircuitBreakerConfig circuitBreakerConfig = CircuitBreakerConfig.custom()
            .failureRateThreshold(50) // Threshold for opening the circuit
            .waitDurationInOpenState(Duration.ofMillis(1000)) // Time the circuit will stay open before resetting
			.build();

        return CircuitBreaker.of("myCircuitBreaker", circuitBreakerConfig);
    }
}

 

 

- failureRateThreshold: 실패율 임계값(백분율)

- waitDurationInOpenState: circuitbreaker가 OPEN에서 HALF_OPEN으로 전환하기 전 대기 시간

 

 

 

호출 예제

import org.springframework.stereotype.Service;
import io.github.resilience4j.circuitbreaker.annotation.CircuitBreaker;

@Service
public class MyService {

    @CircuitBreaker(name = "customCircuitBreaker", fallbackMethod = "callFallback")
    public String riskyServiceCall() {
        // Code that might fail or take too long
        // For example, an external API call
        return "Service Response";
    }

    public String callFallback(Throwable t) {
        // This method is called if riskyServiceCall fails
        return "Fallback Response";
    }
}

 

 

build.gradle 파일

plugins {
    id 'org.springframework.boot' version '2.6.3' // Replace with your Spring Boot version
    id 'io.spring.dependency-management' version '1.0.11.RELEASE'
    id 'java'
}

group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '11' // Replace with your Java version

repositories {
    mavenCentral()
}

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-web'

    // Resilience4j dependency for Spring Boot
    implementation 'io.github.resilience4j:resilience4j-spring-boot2:1.7.1' // Replace with the latest version

    // If you need additional Resilience4j modules, add them here. For example:
    // implementation 'io.github.resilience4j:resilience4j-circuitbreaker:1.7.1'
    // implementation 'io.github.resilience4j:resilience4j-ratelimiter:1.7.1'
    // implementation 'io.github.resilience4j:resilience4j-bulkhead:1.7.1'
    // implementation 'io.github.resilience4j:resilience4j-retry:1.7.1'

    testImplementation 'org.springframework.boot:spring-boot-starter-test'
}

test {
    useJUnitPlatform()
}