[UPDATE][BE] 퍼즐 업로드 동시성 처리

backend/frazzle/.gitignore

@@ -37,4 +37,4 @@ out/
 ### VS Code ###
 .vscode/
 
-application-*.properties
+application-*.yml

backend/frazzle/src/main/java/com/frazzle/main/domain/piece/entity/Piece.java

@@ -30,6 +30,10 @@ public class Piece {
     @JoinColumn(name = "user_id")
     private User user;
 
+    @Version
+    @Column(name = "version")
+    private Integer version;
+
     @UpdateTimestamp
     @Column(name = "modified_at", columnDefinition = "TIMESTAMP")
     private LocalDateTime modifiedAt;

backend/frazzle/src/main/java/com/frazzle/main/global/exception/ErrorCode.java

@@ -35,7 +35,8 @@ public enum ErrorCode {
     IMAGE_NOT_FOUND("이미지가 존재하지 않습니다.", HttpStatus.NOT_FOUND),
     VOTE_NOT_FOUND("투표가 비활성화 되었습니다.", HttpStatus.NOT_FOUND),
     NOTIFICATION_NOT_FOUND("존재하지 않는 초대 요청입니다.", HttpStatus.NOT_FOUND),
-    NOT_COMPLETE_GAME("게임을 클리어하지 않았습니다.", HttpStatus.NOT_FOUND)
+    NOT_COMPLETE_GAME("게임을 클리어하지 않았습니다.", HttpStatus.NOT_FOUND),
+    CONCURRENT_UPDATE_PIECE("다른 사용자가 먼저 퍼즐 조각을 업로드하였습니다.", HttpStatus.CONFLICT)
     ;
 
     private final String message;

backend/frazzle/src/main/java/com/frazzle/main/global/exception/GlobalExceptionHandler.java

@@ -5,6 +5,7 @@
 import org.slf4j.LoggerFactory;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
+import org.springframework.orm.ObjectOptimisticLockingFailureException;
 import org.springframework.web.bind.annotation.ControllerAdvice;
 import org.springframework.web.bind.annotation.ExceptionHandler;
 
@@ -25,6 +26,18 @@ public ResponseEntity<ResultDto<Object>> handleCustomException(CustomException e
         return new ResponseEntity<>(response, ex.getErrorCode().getHttpStatus());
     }
 
+    @ExceptionHandler(ObjectOptimisticLockingFailureException.class)
+    public ResponseEntity<ResultDto<Object>> handleOptimisticLockingException(Exception ex) {
+        logger.error("[OptimisticException] message: " + ex.getMessage());
+
+        ResultDto<Object> response = ResultDto.res(
+                ErrorCode.CONCURRENT_UPDATE_PIECE.getHttpStatus().value(),
+                ErrorCode.CONCURRENT_UPDATE_PIECE.getMessage()
+        );
+
+        return new ResponseEntity<>(response, HttpStatus.CONFLICT);
+    }
+
     @ExceptionHandler(RuntimeException.class)
     public ResponseEntity<ResultDto<Object>> handleRuntimeException(RuntimeException ex) {
         logger.error("[RuntimeException] message: " + ex.getMessage());

backend/frazzle/src/main/resources/application.yml

@@ -0,0 +1,38 @@
+spring:
+  application:
+    name: frazzle
+
+  servlet:
+    context-path: /api/v1
+    multipart:
+      enabled: true
+      max-file-size: 10MB
+      max-request-size: 10MB
+
+  profiles:
+    include: secret
+
+  jpa:
+    hibernate:
+      ddl-auto: update
+    show-sql: true
+    properties:
+      hibernate:
+        dialect: org.hibernate.dialect.MySQL8Dialect
+        format_sql: true
+        jdbc:
+          batch_size: 20
+
+  datasource:
+    hikari:
+      connection-timeout: 30000
+      maximum-pool-size: 10
+      minimum-idle: 5
+      idle-timeout: 600000
+      max-lifetime: 1800000
+
+springdoc:
+  api-docs:
+    path: /v3/api-docs
+  swagger-ui:
+    path: /swagger-ui.html