Merge pull request #366 from GTable/fix#365-cancel-bug

refactor:  ReservationNotFoundException 터지는 경우 멱등키 롤백 로직 추가

Author: Jjiggu

nowait-app-user-api/src/main/java/com/nowait/applicationuser/waiting/redis/WaitingIdempotencyRepository.java

@@ -85,4 +85,8 @@ public void saveIdempotencyInProgress(String key) {
 			throw new IllegalArgumentException("Failed to serialize value for Redis", e);
 		}
 	}
+
+	public void deleteByRegisterKey(String key) {
+		redisTemplate.delete(key);
+	}
 }

nowait-app-user-api/src/main/java/com/nowait/applicationuser/waiting/service/IdempotencyService.java

@@ -48,4 +48,11 @@ public void saveIdempotencyKeyInProgress(String idempotentKey) {
 		}
 	}
 
+	public void rollbackIdempotencyKey(String idempotentKey) {
+		if (idempotentKey != null && !idempotentKey.isBlank()) {
+			log.info("Rolling back idempotency key: {}", idempotentKey);
+			waitingIdempotencyRepository.deleteByRegisterKey(idempotentKey);
+		}
+	}
+
 }

nowait-app-user-api/src/main/java/com/nowait/applicationuser/waiting/service/WaitingService.java

@@ -142,13 +142,20 @@ public CancelWaitingResponse cancelWaiting(CustomOAuth2User oAuth2User, String p
 			.orElseThrow(UserNotFoundException::new);
 
 		// DB 웨이팅 상태 취소 처리
-		Reservation reservation = reservationRepository.findReservationByReservationNumber(request.getWaitingNumber())
-			.orElseThrow(ReservationNotFoundException::new);
-
-		reservation.markAsCancelled(LocalDateTime.now());
-
-		// Redis 대기열 취소 이벤트 발행
-		waitingRedisRepository.removeWaiting(storeId, user.getId());
+		Reservation reservation;
+		try {
+			reservation = reservationRepository.findReservationByReservationNumber(request.getWaitingNumber())
+				.orElseThrow(ReservationNotFoundException::new);
+
+			reservation.markAsCancelled(LocalDateTime.now());
+
+			// Redis 대기열 취소 이벤트 발행
+			waitingRedisRepository.removeWaiting(storeId, user.getId());
+		} catch (RuntimeException e) {
+			// 롤백 처리
+			idempotencyService.rollbackIdempotencyKey(httpServletRequest.getHeader("Idempotency-Key"));
+			throw e;
+		}
 
 		CancelWaitingResponse response = CancelWaitingResponse.builder()
 			.waitingNumber(reservation.getReservationNumber())