refactor: SalesCountEvent 제거 및 캐시 삭제 작업을 위한ProductStockEvent 기반 재고 관리 로직 개선

- SalesCountEvent를 제거하고 관련 로직을 ProductStockEvent로 전면 대체
- MetricsEventConsumer에서 ProductStockEvent를 처리하도록 수정
- ProductMetricsService를 확장하여 재고 기반 지표 관리 및 재고 소진 시 Redis 캐시 삭제 로직 추가
- ProductRepository에 findStockById 메서드, ProductService에 getStock 메서드 추가
- Redis 캐시에서 페이징 응답을 감싸기 위한 PageWrapper 도입
- 패턴 기반 캐시 삭제를 지원하도록 RedisCacheHandler 이동 및 기능 확장

Author: yeonjiyeon

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

@@ -1,7 +1,8 @@
 package com.loopers.application.order.event;
 
 import com.loopers.domain.event.OutboxService;
-import com.loopers.event.SalesCountEvent;
+import com.loopers.domain.product.ProductService;
+import com.loopers.event.ProductStockEvent;
 import lombok.RequiredArgsConstructor;
 import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.scheduling.annotation.Async;
@@ -13,6 +14,7 @@
 @RequiredArgsConstructor
 public class OrderSalesAggregateListener {
 
+  private final ProductService productService;
   private final OutboxService outboxService;
   private final ApplicationEventPublisher eventPublisher;
 
@@ -22,12 +24,14 @@ public void handleOrderCreated(OrderCreatedEvent event) {
 
     event.items().forEach(item -> {
 
-      SalesCountEvent kafkaEvent = SalesCountEvent.of(
+      int currentStock = productService.getStock(item.productId());
+      ProductStockEvent kafkaEvent = ProductStockEvent.of(
           item.productId(),
-          item.quantity()
+          item.quantity(),
+          currentStock
       );
 
-      outboxService.saveEvent("SALES_METRICS", String.valueOf(item.productId()), kafkaEvent);
+      outboxService.saveEvent("STOCKS_METRICS", String.valueOf(item.productId()), kafkaEvent);
       eventPublisher.publishEvent(kafkaEvent);
     });
   }

apps/commerce-api/src/main/java/com/loopers/domain/product/ProductRepository.java

@@ -13,4 +13,6 @@ public interface ProductRepository {
   Optional<Product> findById(Long id);
 
   Page<Product> findByBrandId(Long brandId, Pageable pageable);
+
+  int findStockById(Long id);
 }

apps/commerce-api/src/main/java/com/loopers/domain/product/ProductService.java

@@ -1,7 +1,7 @@
 package com.loopers.domain.product;
 
 import com.loopers.domain.order.OrderItem;
-import com.loopers.support.cache.RedisCacheHandler;
+import com.loopers.core.cache.RedisCacheHandler;
 import com.loopers.support.error.CoreException;
 import com.loopers.support.error.ErrorType;
 import java.time.Duration;
@@ -104,4 +104,8 @@ private String makeCacheKey(String prefix, Pageable pageable) {
     }
     return sb.toString();
   }
+
+  public int getStock(Long id) {
+    return productRepository.findStockById(id);
+  }
 }

apps/commerce-streamer/src/main/java/com/loopers/domain/metrics/ProductMetricsService.java

@@ -1,9 +1,10 @@
 package com.loopers.domain.metrics;
 
+import com.loopers.core.cache.RedisCacheHandler;
 import com.loopers.domain.event.EventHandled;
 import com.loopers.event.LikeCountEvent;
+import com.loopers.event.ProductStockEvent;
 import com.loopers.event.ProductViewEvent;
-import com.loopers.event.SalesCountEvent;
 import com.loopers.infrastructure.EventHandledRepository;
 import com.loopers.infrastructure.ProductMetricsRepository;
 import java.time.LocalDateTime;
@@ -17,6 +18,7 @@ public class ProductMetricsService {
 
   private final ProductMetricsRepository metricsRepository;
   private final EventHandledRepository eventHandledRepository;
+  private final RedisCacheHandler redisCacheHandler;
 
   @Transactional
   public void processLikeCountEvent(LikeCountEvent event) {
@@ -41,12 +43,18 @@ public void processProductViewEvent(ProductViewEvent event) {
   }
 
   @Transactional
-  public void processSalesCountEvent(SalesCountEvent event) {
+  public void processSalesCountEvent(ProductStockEvent event) {
     if (isAlreadyHandled(event.eventId())) return;
 
     ProductMetrics metrics = getOrCreateMetrics(event.productId());
 
-    metrics.addSalesCount(event.quantity());
+    metrics.addSalesCount(event.sellQuantity());
+
+    if (event.currentStock() <= 0) {
+      redisCacheHandler.delete("product:detail:" + event.productId());
+      redisCacheHandler.deleteByPattern("product:list");
+
+    }
 
     completeProcess(event.eventId(), metrics);
   }

apps/commerce-streamer/src/main/java/com/loopers/interfaces/consumer/MetricsEventConsumer.java

@@ -2,8 +2,8 @@
 
 import com.loopers.domain.metrics.ProductMetricsService;
 import com.loopers.event.LikeCountEvent;
+import com.loopers.event.ProductStockEvent;
 import com.loopers.event.ProductViewEvent;
-import com.loopers.event.SalesCountEvent;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.kafka.clients.consumer.ConsumerRecord;
@@ -48,7 +48,7 @@ public void consumeProductView(ProductViewEvent event, Acknowledgment ack) {
       topics = "catalog-events",
       groupId = "metrics-group"
   )
-  public void consumeSalesCount(SalesCountEvent event, Acknowledgment ack) {
+  public void consumeSalesCount(ProductStockEvent event, Acknowledgment ack) {
     try {
       metricsService.processSalesCountEvent(event);
       ack.acknowledge();

apps/commerce-streamer/src/test/java/com/loopers/domain/metrics/IdempotencyIntegrationTest.java

@@ -2,16 +2,21 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 
-import com.loopers.event.SalesCountEvent;
+import com.loopers.config.redis.RedisConfig;
+import com.loopers.core.cache.RedisCacheHandler;
+import com.loopers.event.ProductStockEvent;
 import com.loopers.infrastructure.ProductMetricsRepository;
 import com.loopers.utils.DatabaseCleanUp;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.context.annotation.Import;
+import org.springframework.test.context.bean.override.mockito.MockitoBean;
 
 @SpringBootTest
+@Import(RedisConfig.class)
 class IdempotencyIntegrationTest {
 
   @Autowired
@@ -20,6 +25,9 @@ class IdempotencyIntegrationTest {
   @Autowired
   private ProductMetricsRepository metricsRepository;
 
+  @MockitoBean
+  private RedisCacheHandler redisCacheHandler;
+
   @Autowired
   private DatabaseCleanUp databaseCleanUp;
 
@@ -35,8 +43,9 @@ void shouldHandleDuplicateEventIdempotently() {
     // Given: 동일한 ID를 가진 이벤트 준비
     Long productId = 99L;
     int salesQuantity = 2;
+    int currentStock = 10;
 
-    SalesCountEvent firstEvent = SalesCountEvent.of(productId, salesQuantity);
+    ProductStockEvent firstEvent = ProductStockEvent.of(productId, salesQuantity, currentStock);
 
     // When: 첫 번째 전송
     metricsService.processSalesCountEvent(firstEvent);

modules/kafka/src/main/java/com/loopers/event/ProductStockEvent.java

@@ -0,0 +1,21 @@
+package com.loopers.event;
+
+import java.util.UUID;
+
+public record ProductStockEvent(
+    String eventId,
+    Long productId,
+    int sellQuantity,
+    int currentStock,
+    long timestamp
+) {
+  public static ProductStockEvent of(Long productId, int sellQuantity, int currentStock) {
+    return new ProductStockEvent(
+        UUID.randomUUID().toString(),
+        productId,
+        sellQuantity,
+        currentStock,
+        System.currentTimeMillis()
+    );
+  }
+}

modules/kafka/src/main/java/com/loopers/event/SalesCountEvent.java

@@ -1,7 +1,8 @@
-package com.loopers.support.cache;
+package com.loopers.core.cache;
 
-import com.loopers.support.page.PageWrapper;
+import com.loopers.core.cache.page.PageWrapper;
 import java.time.Duration;
+import java.util.Set;
 import java.util.function.Supplier;
 import lombok.RequiredArgsConstructor;
 import org.springframework.data.domain.Page;
@@ -49,4 +50,15 @@ public <T> T getOrLoad(String key, Duration ttl, Class<T> type, Supplier<T> dbFe
 
     return result;
   }
+
+  public void delete(String key) {
+    redisTemplate.delete(key);
+  }
+
+  public void deleteByPattern(String pattern) {
+    Set<String> keys = redisTemplate.keys(pattern + "*");
+    if (keys != null && !keys.isEmpty()) {
+      redisTemplate.delete(keys);
+    }
+  }
 }

…ers/support/cache/RedisCacheHandler.java …oopers/core/cache/RedisCacheHandler.javaapps/commerce-api/src/main/java/com/loopers/support/cache/RedisCacheHandler.java renamed to modules/redis/src/main/java/com/loopers/core/cache/RedisCacheHandler.java apps/commerce-api/src/main/java/com/loopers/support/cache/RedisCacheHandler.java renamed to modules/redis/src/main/java/com/loopers/core/cache/RedisCacheHandler.java

@@ -0,0 +1,31 @@
+package com.loopers.core.cache.page;
+
+import java.util.List;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.PageImpl;
+import org.springframework.data.domain.PageRequest;
+
+public class PageWrapper<T> {
+  private List<T> content;
+  private long totalElements;
+  private int pageNumber;
+  private int pageSize;
+
+  public PageWrapper() {}
+
+  public PageWrapper(Page<T> page) {
+    this.content = page.getContent();
+    this.totalElements = page.getTotalElements();
+    this.pageNumber = page.getNumber();
+    this.pageSize = page.getSize();
+  }
+
+  public Page<T> toPage() {
+    return new PageImpl<>(content, PageRequest.of(pageNumber, pageSize), totalElements);
+  }
+
+  public List<T> getContent() { return content; }
+  public long getTotalElements() { return totalElements; }
+  public int getPageNumber() { return pageNumber; }
+  public int getPageSize() { return pageSize; }
+}