feat: Added FoodRepositoryFacade

- added FoodRepositoryFacade that handles RETRY logic on the food locks

src/main/java/com/f_lab/la_planete/facade/FoodRepositoryFacade.java

@@ -0,0 +1,47 @@
+package com.f_lab.la_planete.facade;
+
+import com.f_lab.la_planete.domain.Food;
+import com.f_lab.la_planete.repository.FoodRepository;
+import jakarta.persistence.LockTimeoutException;
+import jakarta.persistence.PessimisticLockException;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+
+import org.springframework.stereotype.Component;
+
+@Slf4j
+@Component
+@RequiredArgsConstructor
+public class FoodRepositoryFacade {
+
+  private static final int MAX_RETRY = 3;
+
+  private final FoodRepository foodRepository;
+
+  public void save(Food food) {
+    foodRepository.save(food);
+  }
+
+  public Food findFoodWithLockAndRetry(Long foodId) {
+    int attempts = 0;
+
+    while (attempts < MAX_RETRY) {
+      try {
+        Food food = foodRepository.findFoodByFoodIdWithPessimisticLock(foodId);
+
+        if (food != null)
+          return food;
+
+      } catch (PessimisticLockException | LockTimeoutException e) {
+        log.warn("시도 횟수={}, 다시 id={} 에 해당되는 food의 락을 얻기를 시도합니다", attempts, foodId);
+      } catch (Exception e) {
+        log.error("Error Occurred at FoodLockFacade.findFoodWithLockAndRetry", e);
+        throw e;
+      }
+
+      attempts++;
+    }
+
+    throw new RuntimeException("현재 너무 많은 요청을 처리하고 있습니다. 다시 시도해주세요");
+  }
+}

src/main/java/com/f_lab/la_planete/service/OrderService.java

@@ -5,7 +5,7 @@
 import com.f_lab.la_planete.domain.Payment;
 import com.f_lab.la_planete.dto.request.OrderCreateRequestDTO;
 import com.f_lab.la_planete.dto.response.OrderCreateResponseDTO;
-import com.f_lab.la_planete.repository.FoodRepository;
+import com.f_lab.la_planete.facade.FoodRepositoryFacade;
 import com.f_lab.la_planete.repository.OrderRepository;
 import com.f_lab.la_planete.repository.PaymentRepository;
 import lombok.RequiredArgsConstructor;
@@ -23,16 +23,16 @@
 public class OrderService {
 
   private final OrderRepository orderRepository;
-  private final FoodRepository foodRepository;
+  private final FoodRepositoryFacade foodRepositoryFacade;
   private final PaymentRepository paymentRepository;
 
   @Transactional
   public OrderCreateResponseDTO createFoodOrder(OrderCreateRequestDTO request) {
 
     // 음식을 조회 후 요청한 수 만큼 빼기
-    Food food = findFoodWithLock(request.getFoodId());
+    Food food = foodRepositoryFacade.findFoodWithLockAndRetry(request.getFoodId());
     food.minusQuantity(request.getQuantity());
-    foodRepository.save(food);
+    foodRepositoryFacade.save(food);
 
     // 주문 생성 후 총 금액 계산
     Order order = request.toEntity(food);
@@ -51,9 +51,5 @@ public OrderCreateResponseDTO createFoodOrder(OrderCreateRequestDTO request) {
 
     return new OrderCreateResponseDTO("CREATED");
   }
-
-  private Food findFoodWithLock(Long foodId) {
-     return foodRepository.findFoodByFoodIdWithPessimisticLock(foodId);
-  }
 }
 

src/test/java/com/f_lab/la_planete/facade/FoodRepositoryFacadeTest.java

@@ -0,0 +1,82 @@
+package com.f_lab.la_planete.facade;
+
+import com.f_lab.la_planete.domain.Food;
+import com.f_lab.la_planete.repository.FoodRepository;
+import jakarta.persistence.LockTimeoutException;
+import jakarta.persistence.PessimisticLockException;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.springframework.boot.test.context.SpringBootTest;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.mockito.ArgumentMatchers.anyLong;
+import static org.mockito.Mockito.when;
+
+@SpringBootTest
+class FoodRepositoryFacadeTest {
+
+  @InjectMocks
+  FoodRepositoryFacade foodRepositoryFacade;
+  @Mock
+  FoodRepository foodRepository;
+
+  @Test
+  @DisplayName("락 없이 첫 시도에 성공")
+  void test_find_food_lock_and_retry_success() {
+    // given
+    Long foodId = 1L;
+    Food expectedFood = createFood(foodId);
+
+    // when
+    when(foodRepository.findFoodByFoodIdWithPessimisticLock(anyLong())).thenReturn(expectedFood);
+    Food foundFood = foodRepositoryFacade.findFoodWithLockAndRetry(foodId);
+
+    // then
+    assertThat(foundFood.getId()).isEqualTo(foodId);
+  }
+
+  @Test
+  @DisplayName("첫 번째 시도는 실패하고 두 번째 시도에 성공")
+  void test_find_food_lock_and_retry_fail_on_first_then_success() {
+    // given
+    Long foodId = 1L;
+    Food expectedFood = createFood(foodId);
+
+    // when
+    when(foodRepository.findFoodByFoodIdWithPessimisticLock(anyLong()))
+        .thenThrow(new PessimisticLockException())
+        .thenReturn(expectedFood);
+
+    Food foundFood = foodRepositoryFacade.findFoodWithLockAndRetry(foodId);
+
+    // then
+    assertThat(foundFood.getId()).isEqualTo(foodId);
+  }
+
+  @Test
+  @DisplayName("락 타임아웃으로 최대 재시도 후 실패")
+  void test_find_food_lock_and_retry_fail() {
+    // given
+    Long foodId = 1L;
+
+    // when
+    when(foodRepository.findFoodByFoodIdWithPessimisticLock(anyLong()))
+        .thenThrow(new PessimisticLockException())
+        .thenThrow(new LockTimeoutException())
+        .thenThrow(new LockTimeoutException());
+
+    assertThatThrownBy(() -> foodRepositoryFacade.findFoodWithLockAndRetry(foodId))
+        .isInstanceOf(RuntimeException.class)
+        .hasMessage("현재 너무 많은 요청을 처리하고 있습니다. 다시 시도해주세요");
+  }
+
+
+  private Food createFood(Long foodId) {
+    return Food.builder()
+        .id(foodId)
+        .build();
+  }
+}