[feat] SSE 하트비트 추가

backend/src/main/java/io/f1/backend/domain/game/app/GameService.java

@@ -59,7 +59,7 @@ public class GameService {
     private final RoomRepository roomRepository;
     private final ApplicationEventPublisher eventPublisher;
 
-    @DistributedLock(prefix = "room", key = "#roomId", waitTime = 0)
+    @DistributedLock(prefix = "room", key = "#roomId")
     public void gameStart(Long roomId, UserPrincipal principal) {
 
         String destination = getDestination(roomId);

backend/src/main/java/io/f1/backend/domain/game/sse/app/SseService.java

@@ -9,28 +9,30 @@
 import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;
 
 import java.io.IOException;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
 
 @Service
 @RequiredArgsConstructor
 public class SseService {
 
     private final SseEmitterRepository emitterRepository;
+    private final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
 
     public SseEmitter subscribe() {
         SseEmitter emitter = new SseEmitter(1_800_000L);
         emitterRepository.save(emitter);
 
         try {
-            // emitter 정상 전송확인 메시지
             emitter.send(SseEmitter.event().name("connect").data("connected"));
+            startHeartBeat(emitter);
         } catch (IOException e) {
-            // emitter send() 호출 시 예외 처리
-            emitterRepository.remove(emitter);
+            emitter.completeWithError(e);
         }
         return emitter;
     }
 
-    // 로비로 SSE 메시지를 쏘기위한 메서드
     public <T> void notifyLobbyUpdate(LobbySseEvent<T> event) {
         for (SseEmitter emitter : emitterRepository.getAll()) {
             try {
@@ -40,4 +42,18 @@ public <T> void notifyLobbyUpdate(LobbySseEvent<T> event) {
             }
         }
     }
+
+    private void startHeartBeat(SseEmitter emitter) {
+        scheduler.scheduleAtFixedRate(
+                () -> {
+                    try {
+                        emitter.send(SseEmitter.event().name("heartbeat").data("sse-alive"));
+                    } catch (IOException e) {
+                        emitterRepository.remove(emitter);
+                    }
+                },
+                5,
+                60,
+                TimeUnit.SECONDS);
+    }
 }

backend/src/main/java/io/f1/backend/domain/game/sse/store/SseEmitterRepository.java

@@ -13,18 +13,16 @@ public class SseEmitterRepository {
 
     public void save(SseEmitter emitter) {
         emitters.add(emitter);
-        // 연결종료 객체정리
+
         emitter.onCompletion(() -> emitters.remove(emitter));
         emitter.onTimeout(() -> emitters.remove(emitter));
         emitter.onError(error -> emitters.remove(emitter));
     }
 
-    // 연결 종료 객체 정리
     public void remove(SseEmitter emitter) {
         emitters.remove(emitter);
     }
 
-    // 브로드캐스팅
     public List<SseEmitter> getAll() {
         return emitters;
     }