Merge pull request #10 from Kimjipang/round04

feat: 좋아요 등록 API 비관적락으로 동시성 제어

Author: Kimjipang

apps/commerce-api/src/main/java/com/loopers/application/like/LikeFacade.java

@@ -36,7 +36,7 @@ public LikeInfo doLike(LikeV1Dto.LikeRequest request) {
                 () -> new CoreException(ErrorType.NOT_FOUND, "존재하지 않는 상품입니다.")
         );
 
-        return likeRepository.findByUserIdAndProductId(userId, productId)
+        return likeRepository.findByUserIdAndProductIdForUpdate(userId, productId)
                 .map(LikeInfo::from)
                 .orElseGet(() -> {
                     Like newLike = request.toEntity();

apps/commerce-api/src/main/java/com/loopers/domain/like/Like.java

@@ -4,13 +4,22 @@
 import jakarta.persistence.Column;
 import jakarta.persistence.Entity;
 import jakarta.persistence.Table;
+import jakarta.persistence.UniqueConstraint;
 import lombok.AccessLevel;
 import lombok.Getter;
 import lombok.NoArgsConstructor;
 
 @Getter
 @Entity
-@Table(name = "product_like")
+@Table(
+        name = "product_like",
+        uniqueConstraints = {
+                @UniqueConstraint(
+                        name = "uk_like_user_product",
+                        columnNames = {"ref_user_id", "ref_product_id"}
+                )
+        }
+)
 @NoArgsConstructor(access = AccessLevel.PROTECTED)
 public class Like extends BaseEntity {
     @Column(name = "ref_user_id", nullable = false)

apps/commerce-api/src/main/java/com/loopers/domain/like/LikeRepository.java

@@ -3,6 +3,8 @@
 import java.util.Optional;
 
 public interface LikeRepository {
+    Optional<Like> findByUserIdAndProductIdForUpdate(Long userId, Long productId);
+
     Optional<Like> findByUserIdAndProductId(Long userId, Long productId);
 
     Like save(Like like);

apps/commerce-api/src/main/java/com/loopers/infrastructure/like/LikeJpaRepository.java

@@ -1,7 +1,10 @@
 package com.loopers.infrastructure.like;
 
 import com.loopers.domain.like.Like;
+import jakarta.persistence.LockModeType;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Lock;
+import org.springframework.data.jpa.repository.Query;
 
 import java.util.Optional;
 
@@ -11,4 +14,8 @@ public interface LikeJpaRepository extends JpaRepository<Like, Long> {
     int countByProductId(Long productId);
 
     int countByUserIdAndProductId(Long userId, Long productId);
+
+    @Lock(LockModeType.PESSIMISTIC_WRITE)
+    @Query("SELECT l FROM Like l WHERE l.userId = :userId AND l.productId = :productId")
+    Optional<Like> findByUserIdAndProductIdForUpdate(Long userId, Long productId);
 }

apps/commerce-api/src/main/java/com/loopers/infrastructure/like/LikeRepositoryImpl.java

@@ -12,6 +12,11 @@
 public class LikeRepositoryImpl implements LikeRepository {
     private final LikeJpaRepository likeJpaRepository;
 
+    @Override
+    public Optional<Like> findByUserIdAndProductIdForUpdate(Long userId, Long productId) {
+        return likeJpaRepository.findByUserIdAndProductIdForUpdate(userId, productId);
+    }
+
     @Override
     public Optional<Like> findByUserIdAndProductId(Long userId, Long productId) {
         return likeJpaRepository.findByUserIdAndProductId(userId, productId);

apps/commerce-api/src/test/java/com/loopers/domain/like/LikeConcurrencyIntegrationTest.java

@@ -1,20 +1,24 @@
 package com.loopers.domain.like;
 
 import com.loopers.application.like.LikeFacade;
+import com.loopers.domain.product.Product;
+import com.loopers.domain.product.ProductRepository;
+import com.loopers.domain.user.Gender;
+import com.loopers.domain.user.UserEntity;
+import com.loopers.domain.user.UserRepository;
 import com.loopers.interfaces.api.like.LikeV1Dto;
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;
-import org.springframework.transaction.annotation.Transactional;
 
+import java.math.BigDecimal;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
 @SpringBootTest
-@Transactional
 public class LikeConcurrencyIntegrationTest {
 
     @Autowired
@@ -23,29 +27,63 @@ public class LikeConcurrencyIntegrationTest {
     @Autowired
     private LikeRepository likeRepository;
 
+    @Autowired
+    private UserRepository userRepository;
+
+    @Autowired
+    private ProductRepository productRepository;
+
     @Test
     void 동시에_100개의_좋아요요청이_들어오면_좋아요는_1개만_생성된다() throws Exception {
-        Long userId = 1L;
-        Long productId = 1L;
 
+        // 1. 유저/상품 테스트 데이터 생성
+        UserEntity user = userRepository.save(
+                new UserEntity(
+                        "happy97",
+                        "test@test.com",
+                        Gender.MALE,
+                        "1997-09-23",
+                        "test1234!"
+                )
+        );
+
+        Product product = productRepository.save(
+                new Product(
+                        1L,
+                        "테스트 상품",
+                        BigDecimal.valueOf(10000),
+                        100
+                )
+        );
+
+        Long userId = user.getId();
+        Long productId = product.getId();
+
+        // 2. 동시 실행 환경 설정
         int threadCount = 100;
         ExecutorService executor = Executors.newFixedThreadPool(threadCount);
         CountDownLatch latch = new CountDownLatch(threadCount);
 
+        // 3. 동시에 doLike() 실행
         for (int i = 0; i < threadCount; i++) {
             executor.submit(() -> {
                 try {
                     likeFacade.doLike(new LikeV1Dto.LikeRequest(userId, productId));
+                } catch (Exception e) {
+                    // 스레드 예외 출력 (중요)
+                    e.printStackTrace();
                 } finally {
                     latch.countDown();
                 }
             });
         }
 
-        // 모든 스레드 작업이 종료될 때까지 대기
+        // 4. 모든 요청이 끝날 때까지 대기
         latch.await();
 
+        // 5. 좋아요 개수 확인
         long count = likeRepository.countByUserIdAndProductId(userId, productId);
+
         assertThat(count).isEqualTo(1);
     }
 }