feat: 서킷브레이커가 열려있다면 fallback 메서드를 실행한다.

build.gradle

@@ -27,25 +27,29 @@ repositories {
 }
 
 dependencies {
+	implementation("org.springframework.boot:spring-boot-starter")
+	implementation("org.springframework.boot:spring-boot-starter-web")
 	implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
 	implementation 'org.springframework.boot:spring-boot-starter-validation'
-	implementation 'org.springframework.boot:spring-boot-starter-web'
-	annotationProcessor "org.springframework.boot:spring-boot-configuration-processor"
 	implementation 'org.mindrot:jbcrypt:0.4'
 
 	// Resilience4j-CircuitBreaker
-	implementation 'io.github.resilience4j:resilience4j-spring-boot3'
+	implementation "org.springframework.boot:spring-boot-starter-aop"
+	implementation group: 'io.github.resilience4j', name: 'resilience4j-spring-boot3', version: '2.1.0'
+
 
 	// WebClient
 	implementation 'org.springframework.boot:spring-boot-starter-webflux'
 
 	//redis
 	implementation 'org.springframework.boot:spring-boot-starter-data-redis'
-	implementation("it.ozimov:embedded-redis:0.7.2")
+	implementation "it.ozimov:embedded-redis:0.7.2"
 
 	compileOnly 'org.projectlombok:lombok'
 	runtimeOnly 'com.h2database:h2'
 	runtimeOnly 'com.mysql:mysql-connector-j'
+
+	annotationProcessor "org.springframework.boot:spring-boot-configuration-processor"
 	annotationProcessor 'org.projectlombok:lombok'
 
 	// JWT

src/main/java/com/integrated/techhub/auth/application/client/WebClientGithubClient.java

@@ -5,7 +5,10 @@
 import com.integrated.techhub.auth.application.client.dto.response.GithubPrInfoResponse;
 import com.integrated.techhub.auth.application.client.dto.response.OAuthGithubUsernameResponse;
 import com.integrated.techhub.auth.application.client.dto.response.OAuthTokensResponse;
+import com.integrated.techhub.resilience4j.circuitbreaker.exception.CircuitBreakerInvalidException;
+import io.github.resilience4j.circuitbreaker.annotation.CircuitBreaker;
 import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
 import org.springframework.http.HttpHeaders;
 import org.springframework.stereotype.Component;
 import org.springframework.web.reactive.function.BodyInserters;
@@ -19,6 +22,7 @@
 
 @Component
 @RequiredArgsConstructor
+@Slf4j
 public class WebClientGithubClient implements GithubClient {
 
     private static final int LAST_PAGE = 40;
@@ -28,6 +32,7 @@ public class WebClientGithubClient implements GithubClient {
     private final GithubClientProperties githubClientProperties;
 
     @Override
+    @CircuitBreaker(name = "webClientGithubClient", fallbackMethod = "throwBadGateway")
     public OAuthTokensResponse getGithubTokens(final String code) {
         final String clientId = githubClientProperties.clientId();
         final String clientSecret = githubClientProperties.clientSecret();
@@ -40,6 +45,7 @@ public OAuthTokensResponse getGithubTokens(final String code) {
     }
 
     @Override
+    @CircuitBreaker(name = "webClientGithubClient", fallbackMethod = "throwBadGateway")
     public OAuthTokensResponse getNewAccessToken(final String refreshToken) {
         final String clientId = githubClientProperties.clientId();
         final String clientSecret = githubClientProperties.clientSecret();
@@ -53,6 +59,7 @@ public OAuthTokensResponse getNewAccessToken(final String refreshToken) {
 
     @Override
     @Deprecated
+    @CircuitBreaker(name = "webClientGithubClient", fallbackMethod = "throwBadGateway")
     public OAuthGithubUsernameResponse getGithubUsername(final String accessToken) {
         final HttpHeaders headers = new HttpHeaders();
         headers.setBearerAuth(accessToken);
@@ -69,11 +76,12 @@ public OAuthGithubUsernameResponse getGithubUsername(final String accessToken) {
      * 인증된 유저 기준 시간당 5,000회
      * using: 사용자가 직접 요청하는 동기화 API
      * */
+
     @Override
+    @CircuitBreaker(name = "webClientGithubClient", fallbackMethod = "fallback")
     public List<GithubPrInfoResponse> getPrsByRepoName(final String accessToken, final String repo) {
         final List<GithubPrInfoResponse> responses = new ArrayList<>();
         final List<String> prRequestUrls = createPrApiRequestUrls(repo, LAST_PAGE);
-
         Flux.fromIterable(prRequestUrls)
                 .flatMap(url -> fetchPrs(accessToken, url))
                 .collectList()
@@ -100,4 +108,8 @@ private Flux<List<GithubPrInfoResponse>> fetchPrs(final String accessToken, fina
                 .flux();
     }
 
+    private List<GithubPrInfoResponse> fallback(Throwable t) {
+        throw new CircuitBreakerInvalidException();
+    }
+
 }

src/main/java/com/integrated/techhub/resilience4j/circuitbreaker/aspect/WebClientCircuitBreakerAspect.java

@@ -0,0 +1,37 @@
+package com.integrated.techhub.resilience4j.circuitbreaker.aspect;
+
+import io.github.resilience4j.circuitbreaker.CircuitBreakerRegistry;
+import lombok.RequiredArgsConstructor;
+import org.aspectj.lang.ProceedingJoinPoint;
+import org.aspectj.lang.annotation.Around;
+import org.aspectj.lang.annotation.Aspect;
+import org.springframework.stereotype.Component;
+
+import java.net.URI;
+import java.util.Optional;
+
+@Aspect
+@Component
+@RequiredArgsConstructor
+public class WebClientCircuitBreakerAspect {
+
+    private final CircuitBreakerRegistry registry;
+
+    @Around("execution(* org.springframework.web.reactive.function.client.WebClient.*(..)) && args(url,..)")
+    public Object aspect(ProceedingJoinPoint pjp, String url) throws Throwable {
+        return aspect(pjp, new URI(url));
+    }
+
+    @Around("execution(* org.springframework.web.reactive.function.client.WebClient.*(..)) && args(uri,..)")
+    public Object aspect(ProceedingJoinPoint pjp, URI uri) throws Throwable {
+        return registry.circuitBreaker(findHost(uri))
+                .executeCheckedSupplier(pjp::proceed);
+    }
+
+    private String findHost(URI uri) {
+        return Optional.ofNullable(uri)
+                .map(URI::getHost)
+                .orElse("default");
+    }
+
+}

src/main/java/com/integrated/techhub/resilience4j/circuitbreaker/config/CircuitRecordFailurePredicate.java

@@ -0,0 +1,16 @@
+package com.integrated.techhub.resilience4j.circuitbreaker.config;
+
+import com.integrated.techhub.common.exception.TechHubException;
+
+import java.util.function.Predicate;
+
+public class CircuitRecordFailurePredicate implements Predicate<Throwable> {
+
+    @Override
+    public boolean test(Throwable throwable) {
+        if (throwable instanceof TechHubException) {
+            return false;
+        }
+        return true;
+    }
+}

src/main/java/com/integrated/techhub/resilience4j/circuitbreaker/exception/CircuitBreakerInvalidException.java

@@ -0,0 +1,14 @@
+package com.integrated.techhub.resilience4j.circuitbreaker.exception;
+
+import com.integrated.techhub.common.exception.ErrorCode;
+import com.integrated.techhub.common.exception.TechHubException;
+
+import static org.springframework.http.HttpStatus.*;
+
+public class CircuitBreakerInvalidException extends TechHubException {
+
+    public CircuitBreakerInvalidException() {
+        super(new ErrorCode(NOT_FOUND, "깃허브 서버가 불안정합니다. 다른 API를 사용해주세요"));
+    }
+
+}

src/main/resources/application-local.yml

@@ -20,7 +20,7 @@ spring:
     database-platform: org.hibernate.dialect.MySQL57Dialect
     generate-ddl: true
     hibernate:
-      ddl-auto: update
+      ddl-auto: none
     properties:
       hibernate:
         format_sql: true

src/main/resources/application.yml

@@ -60,16 +60,18 @@ resilience4j:
   circuitbreaker:
     configs:
       default:
+        sliding-window-type: COUNT_BASED
         registerHealthIndicator: true
-        slidingWindowSize: 10
-        minimumNumberOfCalls: 5
+        slidingWindowSize: 3
+        minimumNumberOfCalls: 1
         permittedNumberOfCallsInHalfOpenState: 3
         automaticTransitionFromOpenToHalfOpenEnabled: true
         waitDurationInOpenState: 5s
         failureRateThreshold: 50
         eventConsumerBufferSize: 10
+        recordFailurePredicate: com.integrated.techhub.resilience4j.circuitbreaker.config.CircuitRecordFailurePredicate
   instances:
-    orderService:
+    webClientGithubClient:
       baseConfig: default
   timelimiter:
     configs: