[BE] feat: 동시 요청 시 발생할 수 있는 중복 회원 생성 문제 해결 (#443) (#445)

* feat: member unique 제약조건 추가

* feat: admin unique 제약조건 추가

* feat: 회원 탈퇴시 로깅

* refactor: 회원 탈퇴시 social_id만 Null로 설정

* refactor: UNIQUE 제약조건 이름 수정

* feat: flyway 스크립트 추가

* test: Unique제약조건으로 깨지는 테스트 수정

backend/src/main/java/com/festago/admin/domain/Admin.java

@@ -5,8 +5,18 @@
 import jakarta.persistence.GeneratedValue;
 import jakarta.persistence.GenerationType;
 import jakarta.persistence.Id;
+import jakarta.persistence.Table;
+import jakarta.persistence.UniqueConstraint;
 
 @Entity
+@Table(
+    uniqueConstraints = {
+        @UniqueConstraint(
+            name = "UNIQUE_USERNAME",
+            columnNames = {"username"}
+        )
+    }
+)
 public class Admin extends BaseTimeEntity {
 
     @Id

backend/src/main/java/com/festago/auth/application/AuthService.java

@@ -6,13 +6,17 @@
 import com.festago.common.exception.NotFoundException;
 import com.festago.member.domain.Member;
 import com.festago.member.repository.MemberRepository;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
 @Service
 @Transactional
 public class AuthService {
 
+    private static final Logger log = LoggerFactory.getLogger(AuthService.class);
+
     private final MemberRepository memberRepository;
 
     public AuthService(MemberRepository memberRepository) {
@@ -35,6 +39,12 @@ private Member signUp(UserInfo userInfo) {
     public void deleteMember(Long memberId) {
         Member member = memberRepository.findById(memberId)
             .orElseThrow(() -> new NotFoundException(ErrorCode.MEMBER_NOT_FOUND));
+        logDeleteMember(member);
         memberRepository.delete(member);
     }
+
+    private void logDeleteMember(Member member) {
+        log.info("[DELETE MEMBER] memberId: {} / socialType: {} / socialId: {}",
+            member.getId(), member.getSocialType(), member.getSocialId());
+    }
 }

backend/src/main/java/com/festago/member/domain/Member.java

@@ -8,15 +8,28 @@
 import jakarta.persistence.GeneratedValue;
 import jakarta.persistence.GenerationType;
 import jakarta.persistence.Id;
+import jakarta.persistence.Table;
+import jakarta.persistence.UniqueConstraint;
 import jakarta.validation.constraints.NotNull;
 import jakarta.validation.constraints.Size;
 import java.time.LocalDateTime;
 import org.hibernate.annotations.SQLDelete;
 import org.hibernate.annotations.Where;
 
 @Entity
-@SQLDelete(sql = "UPDATE member SET deleted_at = now(), nickname = '탈퇴한 회원', profile_image = '' WHERE id=?")
+@SQLDelete(sql = "UPDATE member SET deleted_at = now(), nickname = '탈퇴한 회원', profile_image = '', social_id = null WHERE id=?")
 @Where(clause = "deleted_at is null")
+@Table(
+    uniqueConstraints = {
+        @UniqueConstraint(
+            name = "SOCIAL_UNIQUE",
+            columnNames = {
+                "socialId",
+                "socialType"
+            }
+        )
+    }
+)
 public class Member extends BaseTimeEntity {
 
     private static final String DEFAULT_IMAGE_URL = "https://festa-go.site/images/default-profile.png";
@@ -25,7 +38,6 @@ public class Member extends BaseTimeEntity {
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Long id;
 
-    @NotNull
     @Size(max = 255)
     private String socialId;
 

backend/src/main/resources/db/migration/V3__unique_admin_social.sql

@@ -0,0 +1,5 @@
+alter table admin
+    add constraint UNIQUE_USERNAME unique (username);
+
+alter table member
+    add constraint UNIQUE_SOCIAL unique (social_id, social_type);

backend/src/test/java/com/festago/domain/MemberTicketRepositoryTest.java

@@ -58,8 +58,8 @@ class 회원의_ID로_에매한_티켓을_모두_조회 {
         @Test
         void 성공() {
             // given
-            Member member1 = memberRepository.save(MemberFixture.member().build());
-            Member member2 = memberRepository.save(MemberFixture.member().build());
+            Member member1 = memberRepository.save(MemberFixture.member().socialId("abc").build());
+            Member member2 = memberRepository.save(MemberFixture.member().socialId("def").build());
 
             Festival festival = festivalRepository.save(FestivalFixture.festival().build());
             Stage stage1 = stageRepository.save(StageFixture.stage().festival(festival).build());