feat: ES 장애 시 약 검색 MySQL 자동 폴백

src/main/java/com/piuda/callcare/domain/druginfo/service/query/DrugSearchQueryService.java

@@ -8,12 +8,15 @@
 import com.piuda.callcare.global.exception.CallCareException;
 import com.piuda.callcare.global.exception.ErrorCode;
 import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.dao.DataAccessException;
 import org.springframework.data.domain.PageRequest;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
 import java.util.List;
 
+@Slf4j
 @Service
 @Transactional(readOnly = true)
 @RequiredArgsConstructor
@@ -23,15 +26,27 @@ public class DrugSearchQueryService {
     private final DrugInfoQueryService drugInfoQueryService;
     private final DrugInfoConverter drugInfoConverter;
 
-    // Elasticsearch 약품명 검색 (자동완성·오타·중간 단어·초성 통합, 관련도 순, 최대 20건)
+    /**
+     * Elasticsearch 약품명 검색 (자동완성·오타·중간 단어·초성 통합, 관련도 순, 최대 20건).
+     * <p>
+     * ES 연결 실패·타임아웃 등 저장소 접근 예외({@link DataAccessException})가 나면
+     * MySQL {@code LIKE} 검색(폴백)으로 자동 전환한다. 파라미터 검증 실패({@link CallCareException})는
+     * 이 catch 대상이 아니므로 그대로 400으로 전파된다.
+     */
     public List<DrugSearchResponse> search(String keyword) {
         if (keyword == null || keyword.isBlank()) {
             throw new CallCareException(ErrorCode.INVALID_PARAMETER);
         }
-        return drugSearchRepository.searchByItemName(keyword.trim(), PageRequest.of(0, 20))
-                .stream()
-                .map(drugInfoConverter::toSearchResponse)
-                .toList();
+        String trimmed = keyword.trim();
+        try {
+            return drugSearchRepository.searchByItemName(trimmed, PageRequest.of(0, 20))
+                    .stream()
+                    .map(drugInfoConverter::toSearchResponse)
+                    .toList();
+        } catch (DataAccessException e) {
+            log.warn("ES 약품 검색 실패 - MySQL 폴백으로 전환. keyword={}", trimmed, e);
+            return drugInfoQueryService.searchByKeyword(trimmed);
+        }
     }
 
     // 선택한 약의 자동 입력 데이터 반환 (drugName, drugType, memo 자동 생성)

src/test/java/com/piuda/callcare/domain/druginfo/service/query/DrugSearchQueryServiceTest.java

@@ -0,0 +1,90 @@
+package com.piuda.callcare.domain.druginfo.service.query;
+
+import com.piuda.callcare.domain.druginfo.converter.DrugInfoConverter;
+import com.piuda.callcare.domain.druginfo.document.DrugDocument;
+import com.piuda.callcare.domain.druginfo.dto.response.DrugSearchResponse;
+import com.piuda.callcare.domain.druginfo.repository.DrugSearchRepository;
+import com.piuda.callcare.global.exception.CallCareException;
+import com.piuda.callcare.global.exception.ErrorCode;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import org.springframework.dao.DataAccessResourceFailureException;
+import org.springframework.data.domain.PageRequest;
+
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.BDDMockito.then;
+import static org.mockito.Mockito.never;
+
+@ExtendWith(MockitoExtension.class)
+@DisplayName("DrugSearchQueryService 단위 테스트 — ES 장애 시 MySQL 자동 폴백")
+class DrugSearchQueryServiceTest {
+
+    @InjectMocks
+    private DrugSearchQueryService drugSearchQueryService;
+
+    @Mock private DrugSearchRepository drugSearchRepository;
+    @Mock private DrugInfoQueryService drugInfoQueryService;
+    @Mock private DrugInfoConverter drugInfoConverter;
+
+    @Test
+    @DisplayName("정상 케이스: ES가 정상이면 MySQL 폴백을 타지 않는다")
+    void search_uses_es_when_healthy() {
+        DrugDocument document = DrugDocument.builder().itemSeq("1").itemName("타이레놀").build();
+        DrugSearchResponse response = new DrugSearchResponse("1", "타이레놀", null, null, null, null);
+        given(drugSearchRepository.searchByItemName(anyString(), any())).willReturn(List.of(document));
+        given(drugInfoConverter.toSearchResponse(document)).willReturn(response);
+
+        List<DrugSearchResponse> result = drugSearchQueryService.search("타이레놀");
+
+        assertThat(result).containsExactly(response);
+        then(drugInfoQueryService).should(never()).searchByKeyword(anyString());
+    }
+
+    @Test
+    @DisplayName("장애 케이스: ES 접근 예외가 나면 MySQL LIKE 검색으로 폴백한다")
+    void search_falls_back_to_mysql_when_es_fails() {
+        DrugSearchResponse fallbackResponse = new DrugSearchResponse("1", "타이레놀", null, null, null, null);
+        given(drugSearchRepository.searchByItemName(anyString(), any()))
+                .willThrow(new DataAccessResourceFailureException("ES 연결 실패"));
+        given(drugInfoQueryService.searchByKeyword("타이레놀")).willReturn(List.of(fallbackResponse));
+
+        List<DrugSearchResponse> result = drugSearchQueryService.search("타이레놀");
+
+        assertThat(result).containsExactly(fallbackResponse);
+        then(drugInfoQueryService).should().searchByKeyword("타이레놀");
+    }
+
+    @Test
+    @DisplayName("예외 케이스: 빈 키워드는 폴백 없이 즉시 INVALID_PARAMETER")
+    void search_throws_on_blank_keyword_without_fallback() {
+        assertThatThrownBy(() -> drugSearchQueryService.search("  "))
+                .isInstanceOf(CallCareException.class)
+                .hasFieldOrPropertyWithValue("errorCode", ErrorCode.INVALID_PARAMETER);
+
+        then(drugSearchRepository).should(never()).searchByItemName(anyString(), any());
+        then(drugInfoQueryService).should(never()).searchByKeyword(anyString());
+    }
+
+    @Test
+    @DisplayName("경계: 검색어 앞뒤 공백은 잘라서 폴백 서비스에도 그대로 전달된다")
+    void search_trims_keyword_before_fallback() {
+        given(drugSearchRepository.searchByItemName(anyString(), any()))
+                .willThrow(new DataAccessResourceFailureException("ES 연결 실패"));
+        given(drugInfoQueryService.searchByKeyword("타이레놀")).willReturn(List.of());
+
+        drugSearchQueryService.search("  타이레놀  ");
+
+        then(drugSearchRepository).should().searchByItemName("타이레놀", PageRequest.of(0, 20));
+        then(drugInfoQueryService).should().searchByKeyword("타이레놀");
+    }
+}