[feat] 주문 시점에 Cart에 낙관락을 추가한 버전

build.gradle

@@ -51,6 +51,10 @@ dependencies {
     annotationProcessor "jakarta.annotation:jakarta.annotation-api"
     annotationProcessor "jakarta.persistence:jakarta.persistence-api"
 
+    // Retryable
+    implementation 'org.springframework.retry:spring-retry'
+    implementation 'org.springframework:spring-aspects'
+
     // actuator
     implementation 'org.springframework.boot:spring-boot-starter-actuator'
     implementation 'io.micrometer:micrometer-registry-prometheus'

src/main/java/camp/woowak/lab/LabApplication.java

@@ -3,9 +3,11 @@
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.data.jpa.repository.config.EnableJpaAuditing;
+import org.springframework.retry.annotation.EnableRetry;
 
 @SpringBootApplication
 @EnableJpaAuditing
+@EnableRetry
 public class LabApplication {
 
 	public static void main(String[] args) {

src/main/java/camp/woowak/lab/cart/exception/CartErrorCode.java

@@ -8,7 +8,8 @@ public enum CartErrorCode implements ErrorCode {
 	MENU_NOT_FOUND(HttpStatus.NOT_FOUND, "ca_1_1", "해당 메뉴가 존재하지 않습니다."),
 	OTHER_STORE_MENU(HttpStatus.BAD_REQUEST, "ca_1_2", "다른 매장의 메뉴는 등록할 수 없습니다."),
 	STORE_NOT_OPEN(HttpStatus.BAD_REQUEST, "ca_1_3", "주문 가능한 시간이 아닙니다."),
-	NOT_FOUND(HttpStatus.BAD_REQUEST, "ca_2_1", "카트에 담긴 상품이 없습니다.");
+	NOT_FOUND(HttpStatus.BAD_REQUEST, "ca_2_1", "카트에 담긴 상품이 없습니다."),
+	RAPID_ADD_MENU(HttpStatus.BAD_REQUEST, "ca_3_1", "잠시 후 다시 요청해주세요.");
 
 	private final int status;
 	private final String errorCode;

src/main/java/camp/woowak/lab/cart/exception/RapidAddCartException.java

@@ -0,0 +1,9 @@
+package camp.woowak.lab.cart.exception;
+
+import camp.woowak.lab.common.exception.BadRequestException;
+
+public class RapidAddCartException extends BadRequestException {
+	public RapidAddCartException(String message) {
+		super(CartErrorCode.RAPID_ADD_MENU, message);
+	}
+}

src/main/java/camp/woowak/lab/cart/persistence/jpa/entity/CartEntity.java

@@ -13,6 +13,7 @@
 import jakarta.persistence.GenerationType;
 import jakarta.persistence.Id;
 import jakarta.persistence.OneToMany;
+import jakarta.persistence.Version;
 import lombok.AccessLevel;
 import lombok.NoArgsConstructor;
 
@@ -26,6 +27,8 @@ public class CartEntity {
 	private UUID customerId;
 	@OneToMany(mappedBy = "cart", cascade = CascadeType.ALL, orphanRemoval = true)
 	private List<CartItemEntity> cartItems;
+	@Version
+	private long version;
 
 	public Cart toDomain() {
 		List<CartItem> cartItems = this.cartItems.stream().map(CartItemEntity::toDomain).collect(Collectors.toList());

src/main/java/camp/woowak/lab/cart/persistence/jpa/repository/CartEntityRepository.java

@@ -4,9 +4,12 @@
 import java.util.UUID;
 
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Lock;
 
 import camp.woowak.lab.cart.persistence.jpa.entity.CartEntity;
+import jakarta.persistence.LockModeType;
 
 public interface CartEntityRepository extends JpaRepository<CartEntity, Long> {
+	@Lock(LockModeType.OPTIMISTIC)
 	Optional<CartEntity> findByCustomerId(UUID customerId);
 }

src/main/java/camp/woowak/lab/cart/service/CartService.java

@@ -2,6 +2,9 @@
 
 import java.util.List;
 
+import org.springframework.orm.ObjectOptimisticLockingFailureException;
+import org.springframework.retry.annotation.Backoff;
+import org.springframework.retry.annotation.Retryable;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
@@ -30,6 +33,11 @@ public CartService(CartRepository cartRepository, MenuRepository menuRepository)
 	 * @throws camp.woowak.lab.cart.exception.OtherStoreMenuException 다른 가게의 메뉴를 담은 경우 도메인에서 발생
 	 * @throws camp.woowak.lab.cart.exception.StoreNotOpenException   해당 가게가 열려있지 않은 경우 발생
 	 */
+	@Retryable(
+		retryFor = ObjectOptimisticLockingFailureException.class,
+		maxAttempts = 3,
+		backoff = @Backoff(delay = 1000, multiplier = 2, random = true)
+	)
 	public void addMenu(AddCartCommand command) {
 		Cart customerCart = getCart(command.customerId());
 

src/main/java/camp/woowak/lab/common/aop/CartTransactionAop.java

@@ -0,0 +1,31 @@
+package camp.woowak.lab.common.aop;
+
+import org.aspectj.lang.annotation.AfterThrowing;
+import org.aspectj.lang.annotation.Aspect;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.core.annotation.Order;
+import org.springframework.orm.ObjectOptimisticLockingFailureException;
+import org.springframework.stereotype.Component;
+
+import camp.woowak.lab.cart.exception.RapidAddCartException;
+import camp.woowak.lab.order.exception.DuplicatedOrderException;
+
+@Aspect
+@Component
+@Order(1)
+public class CartTransactionAop {
+	private static final Logger log = LoggerFactory.getLogger(CartTransactionAop.class);
+
+	@AfterThrowing(pointcut = "execution(* camp.woowak.lab.cart.service.CartService..*(..))", throwing = "ex")
+	public void afterThrowingCart(ObjectOptimisticLockingFailureException ex) {
+		log.info("카트에 상품을 담기 위한 낙관적 락을 획득하지 못했습니다.", ex);
+		throw new RapidAddCartException("카트에 상품을 담기 위한 낙관적 락 획득에 실패했습니다.");
+	}
+
+	@AfterThrowing(pointcut = "execution(* camp.woowak.lab.order.service.OrderCreationService..*(..))", throwing = "ex")
+	public void afterThrowingOrder(ObjectOptimisticLockingFailureException ex) {
+		log.info("주문/결제를 하기 위한 낙관적 락을 획득하지 못했습니다.", ex);
+		throw new DuplicatedOrderException("결제를 위한 낙관적 락 획득에 실패했습니다.");
+	}
+}

src/test/java/camp/woowak/lab/cart/persistence/jpa/repository/JpaCartRepositoryTest.java

@@ -16,14 +16,15 @@
 import org.springframework.boot.test.context.TestConfiguration;
 import org.springframework.context.annotation.Bean;
 import org.springframework.dao.DataIntegrityViolationException;
-import org.springframework.transaction.annotation.Transactional;
+import org.springframework.transaction.support.TransactionTemplate;
 
 import camp.woowak.lab.cart.domain.Cart;
 import camp.woowak.lab.cart.repository.CartRepository;
 
 @DataJpaTest
-@Transactional
 class JpaCartRepositoryTest {
+	@Autowired
+	private TransactionTemplate transactionTemplate;
 	@Autowired
 	private CartRepository cartRepository;
 	@Autowired
@@ -51,7 +52,8 @@ class FindByCustomerIdIs {
 		@Test
 		@DisplayName("저장된 CartEntity가 있는 경우")
 		void returnOptionalWhenCartEntityIsFound() {
-			Optional<Cart> findCart = cartRepository.findByCustomerId(fakeCustomerId.toString());
+			Optional<Cart> findCart = transactionTemplate.execute(
+				(status) -> cartRepository.findByCustomerId(fakeCustomerId.toString()));
 			assertThat(findCart.isPresent()).isTrue();
 			assertThat(findCart.get().getCustomerId()).isEqualTo(fakeCustomerId.toString());
 		}
@@ -60,7 +62,8 @@ void returnOptionalWhenCartEntityIsFound() {
 		@DisplayName("저장된 CartEntity가 없는 경우")
 		void returnEmptyOptionalWhenCartEntityIsNotFound() {
 			cartEntityRepository.deleteAll();
-			Optional<Cart> findCart = cartRepository.findByCustomerId(fakeCustomerId.toString());
+			Optional<Cart> findCart = transactionTemplate.execute(
+				(status) -> cartRepository.findByCustomerId(fakeCustomerId.toString()));
 			assertThat(findCart.isPresent()).isFalse();
 		}
 	}
@@ -80,8 +83,7 @@ void duplicateCustomerId() {
 		void success() {
 			UUID newFakeCustomerId = UUID.randomUUID();
 			Cart save = cartRepository.save(new Cart(newFakeCustomerId.toString()));
-
 			assertThat(save.getCustomerId()).isEqualTo(newFakeCustomerId.toString());
 		}
 	}
-}
+}