[feat #4] 입찰 동시성 제어

api/src/main/java/dev/handsup/bidding/controller/BiddingApiController.java

@@ -41,7 +41,7 @@ public ResponseEntity<BiddingResponse> registerBidding(
 		@Valid @RequestBody RegisterBiddingRequest request,
 		@Parameter(hidden = true) @JwtAuthorization User bidder
 	) {
-		BiddingResponse response = biddingService.registerBidding(request, auctionId, bidder);
+		BiddingResponse response = biddingService.registerBiddingWithPessimisticLock(request, auctionId, bidder);
 		return ResponseEntity.ok(response);
 	}
 

core/src/main/java/dev/handsup/auction/repository/auction/AuctionRepository.java

@@ -1,14 +1,18 @@
 package dev.handsup.auction.repository.auction;
 
+import java.util.Optional;
+
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Slice;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Lock;
 import org.springframework.data.jpa.repository.Query;
 import org.springframework.data.repository.query.Param;
 
 import dev.handsup.auction.domain.Auction;
 import dev.handsup.auction.domain.auction_field.AuctionStatus;
 import dev.handsup.user.domain.User;
+import jakarta.persistence.LockModeType;
 
 public interface AuctionRepository extends JpaRepository<Auction, Long>, AuctionQueryRepository {
 
@@ -20,4 +24,12 @@ public interface AuctionRepository extends JpaRepository<Auction, Long>, Auction
 
 	Slice<Auction> findBySeller_IdAndStatusOrderByCreatedAtDesc(
 		Long sellerId, AuctionStatus auctionStatus, Pageable pageable);
+
+	@Lock(LockModeType.PESSIMISTIC_WRITE)
+	@Query("select a from Auction a where a.id = :id")
+	Optional<Auction> findByIdWithPessimisticLock(Long id);
+
+	@Lock(LockModeType.OPTIMISTIC)
+	@Query("select a from Auction a where a.id = :id")
+	Optional<Auction> findByIdWithOptimisticLock(Long id);
 }

core/src/main/java/dev/handsup/bidding/repository/BiddingRepository.java

@@ -38,4 +38,5 @@ public interface BiddingRepository extends JpaRepository<Bidding, Long> {
 	Slice<Bidding> findByBidderAndAuction_StatusOrderByAuction_CreatedAtDesc(
 		User bidder, AuctionStatus auctionStatus, Pageable pageable);
 
+	Long countByAuctionId(Long auctionId);
 }

core/src/main/java/dev/handsup/bidding/service/BiddingService.java

@@ -36,18 +36,49 @@ public class BiddingService {
 
 	@Transactional
 	@DistributeLock(key = "'auction_' + #auctionId") // auctionId 값을 추출하여 락 키로 사용
-	public BiddingResponse registerBidding(RegisterBiddingRequest request, Long auctionId, User bidder) {
+	public BiddingResponse registerBiddingWithDistributedLock(RegisterBiddingRequest request, Long auctionId, User bidder) {
 		Auction auction = getAuctionById(auctionId);
 
-		validateBiddingPrice(request.biddingPrice(), auction); // 경매 입찰 최고가보다 입찰가 높은지 확인
-		auction.updateCurrentBiddingPrice(request.biddingPrice()); // 경매 입찰 최고가 갱신
-		auction.increaseBiddingCount(); // 경매 입찰 수 + 1
+		validateBiddingPrice(request.biddingPrice(), auction);
+		updateAuctionOnNewBidding(request, auction);
 		Bidding bidding = BiddingMapper.toBidding(request.biddingPrice(), auction, bidder);
-		sendBiddingNotification(bidder, auction); //알림 전송
+
+		sendBiddingNotification(bidder, auction);
 
 		return BiddingMapper.toBiddingResponse(biddingRepository.save(bidding));
 	}
 
+	@Transactional
+	public BiddingResponse registerBiddingWithPessimisticLock(RegisterBiddingRequest request, Long auctionId, User bidder) {
+		Auction auction = auctionRepository
+				.findByIdWithPessimisticLock(auctionId)
+				.orElseThrow(() -> new NotFoundException(AuctionErrorCode.NOT_FOUND_AUCTION));
+
+		validateBiddingPrice(request.biddingPrice(), auction);
+		updateAuctionOnNewBidding(request, auction);
+		Bidding bidding = BiddingMapper.toBidding(request.biddingPrice(), auction, bidder);
+
+		sendBiddingNotification(bidder, auction);
+
+		return BiddingMapper.toBiddingResponse(biddingRepository.save(bidding));
+	}
+
+	@Transactional
+	public BiddingResponse registerBiddingWithOptimisticLock(RegisterBiddingRequest request, Long auctionId, User bidder) {
+		Auction auction = auctionRepository
+			.findByIdWithOptimisticLock(auctionId)
+			.orElseThrow(() -> new NotFoundException(AuctionErrorCode.NOT_FOUND_AUCTION));
+
+		validateBiddingPrice(request.biddingPrice(), auction);
+		updateAuctionOnNewBidding(request, auction);
+		Bidding bidding = BiddingMapper.toBidding(request.biddingPrice(), auction, bidder);
+
+		sendBiddingNotification(bidder, auction);
+
+		return BiddingMapper.toBiddingResponse(biddingRepository.save(bidding));
+	}
+
+
 	@Transactional(readOnly = true)
 	public PageResponse<BiddingResponse> getBidsOfAuction(Long auctionId, Pageable pageable) {
 		Slice<BiddingResponse> biddingResponsePage = biddingRepository
@@ -116,4 +147,9 @@ private void sendBiddingNotification(User bidder, Auction auction) {
 			NotificationType.BIDDING_CREATED
 		);
 	}
+
+	private void updateAuctionOnNewBidding(RegisterBiddingRequest request, Auction auction) {
+		auction.updateCurrentBiddingPrice(request.biddingPrice()); // 경매 입찰 최고가 갱신
+		auction.increaseBiddingCount(); // 경매 입찰 수 + 1
+	}
 }

core/src/main/java/dev/handsup/bidding/service/OptimisticLockAuctionFacade.java

@@ -0,0 +1,39 @@
+package dev.handsup.bidding.service;
+
+import org.springframework.orm.ObjectOptimisticLockingFailureException;
+import org.springframework.stereotype.Service;
+
+import dev.handsup.bidding.dto.request.RegisterBiddingRequest;
+import dev.handsup.bidding.dto.response.BiddingResponse;
+import dev.handsup.user.domain.User;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+
+@Service
+@RequiredArgsConstructor
+@Slf4j
+public class OptimisticLockAuctionFacade {
+	private final BiddingService biddingService;
+	private static final long RETRY_DELAY_MS = 50;
+
+	public BiddingResponse registerBidding(
+		RegisterBiddingRequest request, Long auctionId, User bidder
+	) throws InterruptedException {
+		int retryCount = 0;
+		while (true) {
+			try {
+				BiddingResponse response = biddingService.registerBiddingWithOptimisticLock(request, auctionId,
+					bidder);
+				log.info("경매 입찰 성공 - auctionId: {}, bidderId: {}, 총 시도횟수: {}",
+					auctionId, bidder.getId(), retryCount++);
+				return response;
+			} catch (ObjectOptimisticLockingFailureException e) {
+				{
+					log.info("경매 입찰 실패 - auctionId: {}, bidderId: {}, 총 시도횟수: {}",
+						auctionId, bidder.getId(), retryCount);
+					Thread.sleep(RETRY_DELAY_MS);
+				}
+			}
+		}
+	}
+}