faet: 이벤트 기반 주문 트랜잭션과 쿠폰 사용 처리 분리

Author: Kimjipang

apps/commerce-api/src/main/java/com/loopers/application/event/coupon/CouponEventHandler.java

@@ -0,0 +1,30 @@
+package com.loopers.application.event.coupon;
+
+import com.loopers.application.order.OrderCreatedEvent;
+import com.loopers.domain.coupon.Coupon;
+import com.loopers.domain.coupon.CouponRepository;
+import com.loopers.support.error.CoreException;
+import com.loopers.support.error.ErrorType;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Component;
+import org.springframework.transaction.annotation.Propagation;
+import org.springframework.transaction.annotation.Transactional;
+import org.springframework.transaction.event.TransactionPhase;
+import org.springframework.transaction.event.TransactionalEventListener;
+
+@Component
+@RequiredArgsConstructor
+public class CouponEventHandler {
+    private final CouponRepository couponRepository;
+
+    @Transactional(propagation = Propagation.REQUIRES_NEW)
+    @TransactionalEventListener(phase = TransactionPhase.AFTER_COMMIT)
+    public void onOrderCreated(OrderCreatedEvent event) {
+        Long couponId = event.couponId();
+        Coupon coupon = couponRepository.findById(couponId).orElseThrow(
+                () -> new CoreException(ErrorType.NOT_FOUND, "존재하지 않는 쿠폰입니다.")
+        );
+
+        coupon.useCoupon();
+    }
+}

apps/commerce-api/src/main/java/com/loopers/application/order/OrderCreatedEvent.java

@@ -0,0 +1,4 @@
+package com.loopers.application.order;
+
+public record OrderCreatedEvent(Long couponId) {
+}

apps/commerce-api/src/main/java/com/loopers/application/order/OrderFacade.java

@@ -3,7 +3,6 @@
 import com.loopers.application.orderitem.OrderItemInfo;
 import com.loopers.domain.coupon.Coupon;
 import com.loopers.domain.coupon.CouponRepository;
-import com.loopers.domain.coupon.CouponType;
 import com.loopers.domain.order.Order;
 import com.loopers.domain.order.OrderRepository;
 import com.loopers.domain.orderitem.OrderItem;
@@ -15,6 +14,7 @@
 import com.loopers.support.error.CoreException;
 import com.loopers.support.error.ErrorType;
 import lombok.RequiredArgsConstructor;
+import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.stereotype.Component;
 import org.springframework.transaction.annotation.Transactional;
 
@@ -29,6 +29,7 @@ public class OrderFacade {
     private final UserRepository userRepository;
     private final ProductRepository productRepository;
     private final CouponRepository couponRepository;
+    private final ApplicationEventPublisher publisher;
 
     @Transactional
     public OrderResultInfo createOrder(OrderV1Dto.OrderRequest request) {
@@ -55,7 +56,7 @@ public OrderResultInfo createOrder(OrderV1Dto.OrderRequest request) {
                             );
 
                             if (product.getStock() < item.quantity()) {
-                                throw new CoreException(ErrorType.BAD_REQUEST, product.getName() + "상품의 재고가 부족합니다.");
+                                throw new CoreException(ErrorType.BAD_REQUEST, product.getName() + " 상품의 재고가 부족합니다.");
                             }
 
                             product.decreaseStock(item.quantity());
@@ -85,10 +86,10 @@ public OrderResultInfo createOrder(OrderV1Dto.OrderRequest request) {
             totalPrice = totalPrice
                     .multiply(BigDecimal.valueOf(100 - rate))
                     .divide(BigDecimal.valueOf(100));
-
-            coupon.useCoupon();
         }
 
+        publisher.publishEvent(new OrderCreatedEvent(couponId));
+
         Order order = request.toEntity(totalPrice);
         Order saved = orderRepository.save(order);