fix: Outbox 최종 실패 상태 변경을 단일 트랜잭션으로 처리

src/main/java/com/backendsystemdesignlab/notification/outbox/OutboxFailureService.java

@@ -0,0 +1,73 @@
+package com.backendsystemdesignlab.notification.outbox;
+
+import com.backendsystemdesignlab.notification.notification.domain.DeliveryStatus;
+import com.backendsystemdesignlab.notification.notification.domain.Notification;
+import com.backendsystemdesignlab.notification.notification.domain.NotificationDelivery;
+import com.backendsystemdesignlab.notification.notification.repository.NotificationDeliveryRepository;
+import com.backendsystemdesignlab.notification.notification.repository.NotificationRepository;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+@Service
+@RequiredArgsConstructor
+public class OutboxFailureService {
+
+    private static final int MAX_PUBLISH_ATTEMPTS = 5;
+
+    private final OutboxEventRepository outboxEventRepository;
+    private final NotificationRepository notificationRepository;
+    private final NotificationDeliveryRepository deliveryRepository;
+
+    @Transactional
+    public boolean recordFailure(Long outboxEventId, String error) {
+
+        OutboxEvent event = outboxEventRepository.findById(outboxEventId)
+                .orElseThrow(() -> new IllegalArgumentException("Outbox event not found: " + outboxEventId));
+
+        if (event.getStatus() != OutboxStatus.PENDING) {
+            return false;
+        }
+
+        event.recordFailure(error);
+
+        if (event.getAttemptCount() < MAX_PUBLISH_ATTEMPTS) {
+            return false;
+        }
+
+        event.markFailed();
+
+        Notification notification = notificationRepository.findByIdForUpdate(event.getNotificationId())
+                .orElseThrow(() -> new IllegalArgumentException("알림을 찾을 수 없습니다."));
+
+        NotificationDelivery delivery = deliveryRepository.findById(event.getDeliveryId())
+                .orElseThrow(() -> new IllegalArgumentException("전송 정보를 찾을 수 없습니다."));
+
+        if (delivery.getStatus() == DeliveryStatus.PENDING) {
+            delivery.markFailed();
+        }
+
+        updateNotificationStatus(notification);
+
+        return true;
+    }
+
+    private void updateNotificationStatus(Notification notification) {
+        deliveryRepository.flush();
+
+        long total = deliveryRepository.countByNotificationId(notification.getId());
+        long sent = deliveryRepository.countByNotificationIdAndStatus(notification.getId(), DeliveryStatus.SENT);
+        long failed = deliveryRepository.countByNotificationIdAndStatus(notification.getId(), DeliveryStatus.FAILED);
+
+        // 아직 처리 중인 Delivery 존재
+        if (sent + failed < total) {
+            return;
+        }
+
+        if (failed > 0) {
+            notification.fail();
+        } else {
+            notification.complete();
+        }
+    }
+}

src/main/java/com/backendsystemdesignlab/notification/outbox/OutboxPublisher.java

@@ -22,6 +22,7 @@ public class OutboxPublisher {
     private final OutboxTransactionService transactionService;
     private final RabbitTemplate rabbitTemplate;
     private final NotificationTransactionService notificationTransactionService;
+    private final OutboxFailureService failureService;
 
     // DB Connection 없음 (RabbitMQ가 DB를 잡고 있지 않게)
     @Scheduled(
@@ -95,14 +96,9 @@ private String routingKey(OutboxEvent event) {
 
     private void handleFailure(OutboxEvent event, String reason) {
 
-        boolean finalFailure = transactionService.recordPublishFailure(event.getId(), reason);
+        boolean finalFailure = failureService.recordFailure(event.getId(), reason);
 
         if (finalFailure) {
-            notificationTransactionService.recordPublishFinalFailure(
-                    event.getNotificationId(),
-                    event.getDeliveryId()
-            );
-
             log.error("Outbox 마지막 시도 실패. outboxId={}, reason={}", event.getId(), reason);
         } else {
             log.warn("Outbox publish 실패.  outboxId={}, reason={}", event.getId(), reason);

src/main/java/com/backendsystemdesignlab/notification/outbox/OutboxTransactionService.java

@@ -11,7 +11,6 @@
 public class OutboxTransactionService {
 
     private final OutboxEventRepository outboxEventRepository;
-    private static final int MAX_PUBLISH_ATTEMPTS = 5;
 
     @Transactional(readOnly = true)
     public List<OutboxEvent> findPendingEvents() {
@@ -28,23 +27,4 @@ public void markPublished(Long outboxEventId) {
         }
         event.markPublished();
     }
-
-    @Transactional
-    public boolean recordPublishFailure(Long outboxEventId, String error) {
-        OutboxEvent event = outboxEventRepository.findById(outboxEventId)
-                .orElseThrow(() -> new IllegalArgumentException("Outbox event not found: " + outboxEventId));
-
-        if (event.getStatus() != OutboxStatus.PENDING) {
-            return false;
-        }
-
-        event.recordFailure(error);
-
-        if (event.getAttemptCount() >= MAX_PUBLISH_ATTEMPTS) {
-            event.markFailed();
-            return true;
-        }
-
-        return false;
-    }
 }