문제 상황

현재 시스템은 컨슈머가 이벤트를 처리할 때 에러가 발생하면, 쿠폰 발급 count는 증가하지만 실제 쿠폰은 발급되지 않는 문제가 있다.

@Component
public class CouponCreatedConsumer {

    private final CouponRepository couponRepository;

    public CouponCreatedConsumer(CouponRepository couponRepository) {
        this.couponRepository = couponRepository;
    }

    @KafkaListener(topics = "coupon_create", groupId = "group_1")
    public void listener(Long userId) {
        couponRepository.save(new Coupon(userId));
    }

}

문제 해결

• 백업 데이터 만들기 → 배치로 다시 저장
• 로그 남기기

@Entity
public class FailedEvent {
    @Id @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private Long userId;

    public FailedEvent() {}

    public FailedEvent(Long userId) {
        this.userId = userId;
    }
}

public interface FailedEventRepository extends JpaRepository<FailedEvent, Long> {
}

@Component
public class CouponCreatedConsumer {

    private final CouponRepository couponRepository;
    private final FailedEventRepository failedEventRepository;
    private final Logger logger = LoggerFactory.getLogger(CouponCreatedConsumer.class);

    public CouponCreatedConsumer(CouponRepository couponRepository, FailedEventRepository failedEventRepository) {
        this.couponRepository = couponRepository;
        this.failedEventRepository = failedEventRepository;
    }

    @KafkaListener(topics = "coupon_create", groupId = "group_1")
    public void listener(Long userId) {
        try {
            couponRepository.save(new Coupon(userId));
        } catch (Exception e) {
            logger.error("failed to create coupon::"+userId);
            failedEventRepository.save(new FailedEvent(userId));
        }
    }

}