refactor: 많이 조회한 게시글 키워드 구조 변경

src/main/java/in/koreatech/koin/domain/community/article/model/ArticleSearchKeyword.java

@@ -62,4 +62,8 @@ public void resetWeight() {
     public void incrementTotalSearch() {
         this.totalSearch++;
     }
+
+    public void updateLastSearchedAt(LocalDateTime now) {
+        this.lastSearchedAt = now;
+    }
 }

src/main/java/in/koreatech/koin/domain/community/article/model/ArticleSearchKeywordIpMap.java

@@ -51,6 +51,13 @@ public void incrementSearchCount() {
         this.searchCount++;
     }
 
+    public void incrementSearchCountBy(Integer additionalCount) {
+        if (additionalCount == null || additionalCount <= 0) {
+            return;
+        }
+        this.searchCount += additionalCount;
+    }
+
     public void resetSearchCount() {
         this.searchCount = 0;
     }

src/main/java/in/koreatech/koin/domain/community/article/model/redis/RedisKeywordTracker.java

@@ -0,0 +1,65 @@
+package in.koreatech.koin.domain.community.article.model.redis;
+
+import lombok.RequiredArgsConstructor;
+import org.springframework.data.redis.core.RedisTemplate;
+import org.springframework.stereotype.Component;
+
+import org.springframework.data.redis.core.ZSetOperations.TypedTuple;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+
+@Component
+@RequiredArgsConstructor
+public class RedisKeywordTracker {
+
+    private static final double FIXED_WEIGHT_AFTER_FIVE_SEARCHES = 0.0625;
+    private static final int MAX_SEARCH_COUNT_FOR_WEIGHT = 10;
+
+    private final RedisTemplate<String, Object> redisTemplate;
+
+    private static final String KEYWORD_SET = "popular_keywords";
+    private static final String IP_SEARCH_COUNT_PREFIX = "search:count:ip:";
+
+    public void updateKeywordWeight(String ipAddress, String keyword) {
+        if (keyword == null || keyword.isBlank() || ipAddress == null || ipAddress.isBlank()) {
+            return;
+        }
+
+        String ipSearchCountKey = IP_SEARCH_COUNT_PREFIX + ipAddress;
+
+        Long currentIpCount = redisTemplate.opsForHash().increment(ipSearchCountKey, keyword, 1);
+        if (currentIpCount == null) currentIpCount = 1L;
+
+        double additionalWeight = calculateWeight(currentIpCount);
+        if (additionalWeight > 0) {
+            redisTemplate.opsForZSet().incrementScore(KEYWORD_SET, keyword, additionalWeight);
+        }
+    }
+
+    private double calculateWeight(Long currentCount) {
+        if (currentCount <= 5) {
+            return 1.0 / Math.pow(2, currentCount - 1);
+        } else if (currentCount <= MAX_SEARCH_COUNT_FOR_WEIGHT) {
+            return FIXED_WEIGHT_AFTER_FIVE_SEARCHES;
+        }
+        return 0.0;
+    }
+
+    public Set<String> getTopKeywords(int limit) {
+        Set<TypedTuple<Object>> keywordTuples = redisTemplate.opsForZSet()
+            .reverseRangeWithScores(KEYWORD_SET, 0, limit - 1);
+
+        if (keywordTuples == null || keywordTuples.isEmpty()) {
+            return Set.of();
+        }
+
+        return keywordTuples.stream()
+            .map(TypedTuple::getValue)
+            .map(String::valueOf)
+            .collect(Collectors.toSet());
+    }
+}

src/main/java/in/koreatech/koin/domain/community/article/model/strategy/FallbackKeywordStrategy.java

@@ -0,0 +1,32 @@
+package in.koreatech.koin.domain.community.article.model.strategy;
+
+import in.koreatech.koin.domain.community.article.repository.ArticleSearchKeywordRepository;
+import lombok.RequiredArgsConstructor;
+
+import org.springframework.data.domain.PageRequest;
+import org.springframework.data.domain.Pageable;
+import org.springframework.stereotype.Component;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+@Component
+@RequiredArgsConstructor
+public class FallbackKeywordStrategy implements KeywordRetrievalStrategy {
+
+    private final ArticleSearchKeywordRepository keywordRepository;
+
+    @Override
+    public List<String> getTopKeywords(int count) {
+        LocalDateTime fromDate = LocalDateTime.now().minusWeeks(1);
+        Pageable pageable = PageRequest.of(0, count);
+
+        List<String> topKeywords = keywordRepository.findTopKeywords(fromDate, pageable);
+
+        if (topKeywords.isEmpty()) {
+            topKeywords = keywordRepository.findTopKeywordsByLatest(pageable);
+        }
+
+        return topKeywords;
+    }
+}

src/main/java/in/koreatech/koin/domain/community/article/model/strategy/KeywordRetrievalContext.java

@@ -0,0 +1,30 @@
+package in.koreatech.koin.domain.community.article.model.strategy;
+
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Component;
+
+import java.util.ArrayList;
+import java.util.List;
+
+@Component
+@RequiredArgsConstructor
+public class KeywordRetrievalContext {
+
+    private final RedisKeywordStrategy redisKeywordStrategy;
+    private final FallbackKeywordStrategy fallbackKeywordStrategy;
+
+    public List<String> retrieveTopKeywords(int count) {
+        List<String> primaryKeywords = redisKeywordStrategy.getTopKeywords(count);
+        List<String> finalKeywords = new ArrayList<>(primaryKeywords);
+
+        if (primaryKeywords.size() < count) {
+            int remainingCount = count - primaryKeywords.size();
+            List<String> secondaryKeywords = fallbackKeywordStrategy.getTopKeywords(remainingCount);
+            secondaryKeywords.stream()
+                .filter(keyword -> !finalKeywords.contains(keyword))
+                .forEach(finalKeywords::add);
+        }
+
+        return finalKeywords;
+    }
+}

src/main/java/in/koreatech/koin/domain/community/article/model/strategy/KeywordRetrievalStrategy.java

@@ -0,0 +1,7 @@
+package in.koreatech.koin.domain.community.article.model.strategy;
+
+import java.util.List;
+
+public interface KeywordRetrievalStrategy {
+    List<String> getTopKeywords(int count);
+}

src/main/java/in/koreatech/koin/domain/community/article/model/strategy/RedisKeywordStrategy.java

@@ -0,0 +1,26 @@
+package in.koreatech.koin.domain.community.article.model.strategy;
+
+import in.koreatech.koin.domain.community.article.model.redis.RedisKeywordTracker;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Component;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+@Component
+@RequiredArgsConstructor
+public class RedisKeywordStrategy implements KeywordRetrievalStrategy {
+
+    private final RedisKeywordTracker redisKeywordTracker;
+
+    @Override
+    public List<String> getTopKeywords(int count) {
+        Set<String> redisKeywords = redisKeywordTracker.getTopKeywords(count);
+        return new ArrayList<>(redisKeywords);
+    }
+}

src/main/java/in/koreatech/koin/domain/community/article/repository/ArticleSearchKeywordRepository.java

@@ -12,17 +12,17 @@
 
 public interface ArticleSearchKeywordRepository extends Repository<ArticleSearchKeyword, Integer> {
 
-    void save(ArticleSearchKeyword keyword);
+    ArticleSearchKeyword save(ArticleSearchKeyword keyword);
 
     Optional<ArticleSearchKeyword> findByKeyword(String keywordStr);
 
     @Query("""
         SELECT k.keyword
         FROM ArticleSearchKeyword k
-        WHERE k.lastSearchedAt >= :oneWeekAgo
+        WHERE k.lastSearchedAt >= :fromDate
         ORDER BY k.weight DESC, k.lastSearchedAt DESC
         """)
-    List<String> findTopKeywords(LocalDateTime oneWeekAgo, Pageable pageable);
+    List<String> findTopKeywords(LocalDateTime fromDate, Pageable pageable);
 
     @Query("""
         SELECT k.keyword

src/main/java/in/koreatech/koin/domain/community/article/scheduler/ArticleScheduler.java

@@ -3,7 +3,7 @@
 import org.springframework.scheduling.annotation.Scheduled;
 import org.springframework.stereotype.Component;
 
-import in.koreatech.koin.domain.community.article.service.ArticleService;
+import in.koreatech.koin.domain.community.article.service.ArticleSyncService;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 
@@ -12,30 +12,30 @@
 @RequiredArgsConstructor
 public class ArticleScheduler {
 
-    private final ArticleService articleService;
+    private final ArticleSyncService articleSyncService;
 
     @Scheduled(cron = "0 0 6 * * *")
     public void updateHotArticles() {
         try {
-            articleService.updateHotArticles();
+            articleSyncService.updateHotArticles();
         } catch (Exception e) {
             log.error("인기 게시글 업데이트 중에 오류가 발생했습니다.", e);
         }
     }
 
-    @Scheduled(cron = "0 0 0/6 * * *")
-    public void resetOldKeywordsAndIpMaps() {
+    @Scheduled(cron = "0 */5 * * * *")
+    public void syncKeywordsToDatabase() {
         try {
-            articleService.resetWeightsAndCounts();
+            articleSyncService.synchronizeSearchKeywords();
         } catch (Exception e) {
-            log.error("많이 검색한 키워드 초기화 중에 오류가 발생했습니다.", e);
+            log.error("Redis에서 MySQL로 키워드 동기화 중 오류가 발생했습니다.", e);
         }
     }
 
     @Scheduled(cron = "0 0 * * * *")
     public void getBusNoticeArticle() {
         try {
-            articleService.updateBusNoticeArticle();
+            articleSyncService.updateBusNoticeArticle();
         } catch (Exception e) {
             log.error("버스 공지 게시글 조회 중에 오류가 발생했습니다.", e);
         }