feat: Redis 설정 및 캐시 기본 구조 구축

성능 최적화를 위한 Redis 캐시 레이어 기본 인프라 구축
- CacheConfig: Redis 캐시 설정 및 CacheManager 구성
- CacheKeyGenerator: 일관된 캐시 키 생성 유틸리티
- CacheInvalidationService: 캐시 무효화 로직 중앙화

Author: sylee6529

apps/commerce-api/src/main/java/com/loopers/infrastructure/cache/CacheConfig.java

@@ -0,0 +1,37 @@
+package com.loopers.infrastructure.cache;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
+import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory;
+import org.springframework.data.redis.core.RedisTemplate;
+import org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer;
+import org.springframework.data.redis.serializer.StringRedisSerializer;
+
+@Configuration
+public class CacheConfig {
+
+    @Bean
+    public RedisTemplate<String, Object> cacheRedisTemplate(LettuceConnectionFactory connectionFactory) {
+        RedisTemplate<String, Object> template = new RedisTemplate<>();
+        template.setConnectionFactory(connectionFactory);
+
+        // Key serializer
+        template.setKeySerializer(new StringRedisSerializer());
+        template.setHashKeySerializer(new StringRedisSerializer());
+
+        // Value serializer - JSON
+        ObjectMapper objectMapper = new ObjectMapper();
+        objectMapper.registerModule(new JavaTimeModule());
+        objectMapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
+
+        GenericJackson2JsonRedisSerializer jsonSerializer = new GenericJackson2JsonRedisSerializer(objectMapper);
+        template.setValueSerializer(jsonSerializer);
+        template.setHashValueSerializer(jsonSerializer);
+
+        template.afterPropertiesSet();
+        return template;
+    }
+}

apps/commerce-api/src/main/java/com/loopers/infrastructure/cache/CacheInvalidationService.java

@@ -0,0 +1,38 @@
+package com.loopers.infrastructure.cache;
+
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.stereotype.Component;
+
+@Slf4j
+@RequiredArgsConstructor
+@Component
+public class CacheInvalidationService {
+
+    private final ProductDetailCache productDetailCache;
+
+    /**
+     * Invalidate caches when a product is liked or unliked
+     *
+     * @param productId The product that was liked/unliked
+     * @param brandId The brand of the product
+     */
+    public void invalidateOnLikeChange(Long productId, Long brandId) {
+        log.info("[CacheInvalidation] Invalidating caches for productId={}, brandId={}", productId, brandId);
+
+        // Invalidate product detail cache
+        productDetailCache.delete(productId);
+
+        // Note: Product list cache는 TTL(60초)에 의존하여 자동 무효화
+
+        log.info("[CacheInvalidation] Cache invalidation completed for productId={}, brandId={}", productId, brandId);
+    }
+
+    /**
+     * Invalidate cache when product info is updated (name, price, description, etc.)
+     */
+    public void invalidateOnProductUpdate(Long productId) {
+        log.info("[CacheInvalidation] Invalidating cache for product update, productId={}", productId);
+        productDetailCache.delete(productId);
+    }
+}

apps/commerce-api/src/main/java/com/loopers/infrastructure/cache/CacheKeyGenerator.java

@@ -0,0 +1,53 @@
+package com.loopers.infrastructure.cache;
+
+import com.loopers.domain.product.enums.ProductSortCondition;
+
+public class CacheKeyGenerator {
+
+    private static final String VERSION = "v1";
+
+    // Product detail cache key
+    public static String productDetailKey(Long productId) {
+        return String.format("product:detail:%s:%d", VERSION, productId);
+    }
+
+    // Top liked products (global) cache key
+    public static String topLikedProductsKey() {
+        return String.format("products:top-liked:global:%s", VERSION);
+    }
+
+    // Brand top products cache key
+    public static String brandTopProductsKey(Long brandId, int limit) {
+        return String.format("products:top-liked:brand:%s:%d:%d", VERSION, brandId, limit);
+    }
+
+    // Brand top products pattern for deletion
+    public static String brandTopProductsPattern(Long brandId) {
+        return String.format("products:top-liked:brand:%s:%d:*", VERSION, brandId);
+    }
+
+    // Product list cache key
+    public static String productListKey(Long brandId, ProductSortCondition sort, int page, int size) {
+        String brandParam = brandId != null ? String.valueOf(brandId) : "all";
+        String sortParam = sort != null ? sort.name() : "DEFAULT";
+        return String.format("products:list:%s:brand=%s:sort=%s:page=%d:size=%d",
+                VERSION, brandParam, sortParam, page, size);
+    }
+
+    // Member likes cache key
+    public static String memberLikesKey(Long memberId) {
+        return String.format("likes:member:%s:%d", VERSION, memberId);
+        // 예: "likes:member:v1:123"
+    }
+
+    // Product like count cache key
+    public static String productLikeCountKey(Long productId) {
+        return String.format("product:like:count:%s:%d", VERSION, productId);
+        // 예: "product:like:count:v1:456"
+    }
+
+    // Product like count cache key pattern (for scanning)
+    public static String productLikeCountKeyPattern() {
+        return String.format("product:like:count:%s:*", VERSION);
+    }
+}