✨ Feature - WebClient에 Fallback과 CircuitBreaker를 추가한다

✨ Feature - WebClient에 Fallback과 CircuitBreaker를 추가한다

Author: oOccasio

build.gradle

@@ -95,6 +95,10 @@ dependencies {
     implementation 'org.springframework.boot:spring-boot-starter-webflux'
 
     implementation 'io.micrometer:context-propagation:1.1.1'
+
+    //resilience4j
+    implementation 'io.github.resilience4j:resilience4j-spring-boot3'
+    implementation 'io.github.resilience4j:resilience4j-reactor'
 }
 
 tasks.named('test') {

src/main/java/sopt/comfit/auth/kakao/service/KakaoAuthService.java

@@ -29,9 +29,6 @@ public class KakaoAuthService {
     @Value("${kakao.client-id}") String clientId;
     @Value("${kakao.client-secret}") String clientSecret;
     @Value("${kakao.redirect-uri}") String redirectUri;
-    private final JwtUtil jwtUtil;
-    private final UserRepository userRepository;
-    private final UniversityRepository universityRepository;
     private final AuthService authService;
 
     public LoginQueryDto getKakaoUserInfoByCode(String code) {

src/main/java/sopt/comfit/experience/domain/Experience.java

@@ -12,6 +12,7 @@
 import sopt.comfit.user.domain.User;
 
 import java.time.LocalDate;
+import java.time.ZoneId;
 
 @Slf4j
 @Entity
@@ -114,12 +115,14 @@ public void activateDefault() {
 
     //validate 메서드
     public static void validateDate(LocalDate startAt, LocalDate endAt) {
+        LocalDate today = LocalDate.now(ZoneId.of("Asia/Seoul"));
+
         if (endAt.isBefore(startAt)) {
             log.warn("종료일시가 시작일시보다 빠를 수 없습니다. startAt: {}, endAt: {}", startAt, endAt);
             throw BaseException.type(ExperienceErrorCode.END_DATE_BEFORE_START_DATE);
         }
 
-        if (startAt.isAfter(LocalDate.now()) || endAt.isAfter(LocalDate.now())) {
+        if (startAt.isAfter(today) || endAt.isAfter(today)) {
             log.warn("종료일시 및 시작일시는 미래 날짜가 될 수 없습니다. startAt: {}, endAt: {}", startAt, endAt);
             throw BaseException.type(ExperienceErrorCode.NOT_ALLOWED_FUTURE_DATE);
         }

src/main/java/sopt/comfit/report/exception/AIReportErrorCode.java

@@ -11,9 +11,14 @@ public enum AIReportErrorCode implements ErrorCode {
 
     AI_RESPONSE_EMPTY(HttpStatus.BAD_GATEWAY, "AI_502_001", "AI 응답이 비어있습니다"),
     AI_RESPONSE_PARSE_FAILED(HttpStatus.INTERNAL_SERVER_ERROR, "AI_500_001", "AI 응답 파싱에 실패했습니다"),
-    AI_REPORT_NOT_FOUND(HttpStatus.NOT_FOUND, "AI_404_001", "AI 리포트를 찾을 수 없습니다");
-
+    AI_REPORT_NOT_FOUND(HttpStatus.NOT_FOUND, "AI_404_001", "AI 리포트를 찾을 수 없습니다"),
+    AI_SERVICE_UNAVAILABLE(HttpStatus.SERVICE_UNAVAILABLE, "AI_503_001", "AI 서비스를 현재 이용할 수 없습니다."),
+    AI_CIRCUIT_OPEN(HttpStatus.SERVICE_UNAVAILABLE, "AI_503_002", "AI 서비스 일시 중단됨"),
+    AI_AUTH_FAILED(HttpStatus.INTERNAL_SERVER_ERROR, "AI_500_002", "AI 서비스 인증 실패"),
+    AI_RATE_LIMITED(HttpStatus.TOO_MANY_REQUESTS, "AI_429_001", "AI 요청 한도 초과"),
+    AI_SERVER_ERROR(HttpStatus.BAD_GATEWAY, "AI_502_002", "AI 서버 오류"),
 
+    ;
     private final HttpStatus status;
     private final String prefix;
     private final String message;

src/main/java/sopt/comfit/report/infra/webclient/AiWebClient.java

@@ -1,10 +1,16 @@
 package sopt.comfit.report.infra.webclient;
 
+import io.github.resilience4j.circuitbreaker.CircuitBreaker;
+import io.github.resilience4j.circuitbreaker.CircuitBreakerRegistry;
+import io.github.resilience4j.retry.annotation.Retry;
+import io.github.resilience4j.timelimiter.annotation.TimeLimiter;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.stereotype.Component;
 import org.springframework.web.reactive.function.client.WebClient;
 import reactor.core.publisher.Mono;
+import sopt.comfit.global.exception.BaseException;
+import sopt.comfit.report.exception.AIReportErrorCode;
 import sopt.comfit.report.infra.dto.CreateReportAiRequestDto;
 import sopt.comfit.report.infra.dto.CreateReportAiResponseDto;
 
@@ -14,21 +20,49 @@
 public class AiWebClient {
 
     private final WebClient webClient;
+    private final CircuitBreakerRegistry circuitBreakerRegistry;
 
+    @io.github.resilience4j.circuitbreaker.annotation.CircuitBreaker(name = "openai", fallbackMethod = "createReportFallback")
+    @Retry(name = "openai")
+    @TimeLimiter(name = "openai")
     public Mono<CreateReportAiResponseDto> createReport(CreateReportAiRequestDto request){
         long startTIme = System.currentTimeMillis();
 
         return webClient.post()
                 .uri("/v1/chat/completions")
                 .bodyValue(request)
                 .retrieve()
+                .onStatus(status -> status.value() == 401,
+                        response -> Mono.error(BaseException.type(AIReportErrorCode.AI_AUTH_FAILED)))
+                .onStatus(status -> status.value() == 429,
+                        response -> Mono.error(BaseException.type(AIReportErrorCode.AI_RATE_LIMITED)))
+                .onStatus(status -> status.value() >= 500,
+                        response -> Mono.error(BaseException.type(AIReportErrorCode.AI_SERVER_ERROR)))
                 .bodyToMono(CreateReportAiResponseDto.class)
                 .doOnSubscribe(subscription ->
-                        log.info("OpenAI API 호출 시작 (WebClient)"))
+                        log.info("OpenAI API 호출 시작"))
                 .doOnSuccess(response ->
-                        log.info("OpenAI API 호출 완료(WebClient) - duration : {} ms",
+                        log.info("OpenAI API 호출 완료 - duration: {}ms",
                                 System.currentTimeMillis() - startTIme))
                 .doOnError(error ->
-                        log.error("OpenAI API 호출 실패 (WebClient)", error));
+                        log.error("OpenAI API 호출 실패", error));
+    }
+
+
+    private Mono<CreateReportAiResponseDto> createReportFallback(
+            CreateReportAiRequestDto request, Throwable t) {
+
+        CircuitBreaker cb = circuitBreakerRegistry.circuitBreaker("openai");
+
+        if (cb.getState() == CircuitBreaker.State.OPEN) {
+            return Mono.error(BaseException.type(AIReportErrorCode.AI_SERVICE_UNAVAILABLE));
+        }
+
+        if (t instanceof BaseException) {
+            return Mono.error(t);  // 401, 429 등 그대로
+        }
+
+        log.warn("OpenAI fallback 실행 - 원인: {}", t.getMessage());
+        return Mono.error(BaseException.type(AIReportErrorCode.AI_SERVICE_UNAVAILABLE));
     }
 }