feat: SSE 서비스 운영 상태 정의 로직 구현

src/main/java/kr/allcll/backend/admin/preseat/AdminPreSeatService.java

@@ -3,6 +3,8 @@
 import java.time.LocalDate;
 import java.util.List;
 import kr.allcll.backend.admin.preseat.dto.PreSeatResponse;
+import kr.allcll.backend.support.sse.SseService;
+import kr.allcll.backend.support.sse.SseStatus;
 import kr.allcll.crawler.client.SeatClient;
 import kr.allcll.crawler.client.model.SeatResponse;
 import kr.allcll.crawler.client.payload.SeatPayload;
@@ -22,13 +24,14 @@
 @RequiredArgsConstructor
 public class AdminPreSeatService {
 
+    private final SseService sseService;
     private final SeatClient seatClient;
     private final Credentials credentials;
     private final AllPreSeatBuffer allPreSeatBuffer;
     private final CrawlerSubjectRepository crawlerSubjectRepository;
 
-
     public void getAllPreSeat(String userId) {
+        sseService.updateStatus(SseStatus.PRESEAT);
         Credential credential = credentials.findByUserId(userId);
         List<CrawlerSubject> crawlerSubjects = crawlerSubjectRepository.findAllBySemesterAt(CrawlerSemester.now());
         for (CrawlerSubject crawlerSubject : crawlerSubjects) {
@@ -52,6 +55,7 @@ private void sendExternalPreSeatsRequest(CrawlerSubject crawlerSubject, Credenti
         } catch (CrawlerAllcllException e) {
             log.error(
                 "[여석] 외부 API 호출에 실패했습니다. PreSeat: " + crawlerSubject.getCuriNo() + "-" + crawlerSubject.getClassName());
+            sseService.updateStatus(SseStatus.ERROR);
         }
     }
 

src/main/java/kr/allcll/backend/admin/seat/AdminSeatService.java

@@ -6,6 +6,8 @@
 import java.util.concurrent.atomic.AtomicLong;
 import kr.allcll.backend.admin.seat.dto.ChangeSubjectsResponse;
 import kr.allcll.backend.admin.seat.dto.SeatStatusResponse;
+import kr.allcll.backend.support.sse.SseService;
+import kr.allcll.backend.support.sse.SseStatus;
 import kr.allcll.crawler.client.SeatClient;
 import kr.allcll.crawler.client.model.SeatResponse;
 import kr.allcll.crawler.client.payload.SeatPayload;
@@ -25,7 +27,9 @@
 @RequiredArgsConstructor
 public class AdminSeatService {
 
+    private final AtomicLong lastSuccessCrawlingTime = new AtomicLong(0);
     private static final long RECENT_CRAWLING_SUCCESS_THRESHOLD_MS = 3_000;
+
     private final SeatClient seatClient;
     private final Credentials credentials;
     private final TargetSubjectStorage targetSubjectStorage;
@@ -34,22 +38,25 @@ public class AdminSeatService {
     private final SjptProperties sjptProperties;
     private final ChangeDetector changeDetector;
     private final AllSeatBuffer allSeatBuffer;
-    private final AtomicLong lastSuccessCrawlingTime = new AtomicLong(0);
+    private final SseService sseService;
 
     public void getAllSeatPeriodically(String userId) {
+        sseService.updateStatus(SseStatus.LIVE);
         Credential credential = credentials.findByUserId(userId);
         fetchPinSeat(credential);
         fetchGeneralSeat(credential);
     }
 
     public void getSeasonSeatPeriodically(String userId) {
+        sseService.updateStatus(SseStatus.LIVE);
         Credential credential = credentials.findByUserId(userId);
         fetchPinSeat(credential);
         fetchGeneralSeat(credential);
     }
 
     public void cancelSeatScheduling() {
         seatScheduler.cancelAll();
+        sseService.updateStatus(SseStatus.IDLE);
     }
 
     public SeatStatusResponse getSeatCrawlerStatus() {
@@ -125,6 +132,7 @@ private void sendExternalRequestWithOutDetect(CrawlerSubject crawlerSubject, Cre
         } catch (CrawlerAllcllException e) {
             log.error(
                 "[여석] 외부 API 호출에 실패했습니다. 과목: " + crawlerSubject.getCuriNo() + "-" + crawlerSubject.getClassName());
+            sseService.updateStatus(SseStatus.ERROR);
         }
     }
 

src/main/java/kr/allcll/backend/support/sse/SseService.java

@@ -15,12 +15,14 @@
 public class SseService {
 
     private final SseEmitterStorage sseEmitterStorage;
+    private volatile SseStatus currentStatus = SseStatus.IDLE;
 
     public SseEmitter connect(String token) {
         SseEmitter sseEmitter = createSseEmitter();
         sseEmitterStorage.add(token, sseEmitter);
         SseEventBuilder initialEvent = SseEventBuilderFactory.createInitialEvent();
         sendEvent(sseEmitter, initialEvent);
+        sendStatusEvent(sseEmitter);
         return sseEmitter;
     }
 
@@ -42,6 +44,13 @@ public void propagate(String token, String eventName, Object data) {
         });
     }
 
+    public void updateStatus(SseStatus newStatus) {
+        if (this.currentStatus != newStatus) {
+            this.currentStatus = newStatus;
+            propagateStatus();
+        }
+    }
+
     private void sendEvent(SseEmitter sseEmitter, SseEventBuilder eventBuilder) {
         try {
             sseEmitter.send(eventBuilder);
@@ -51,12 +60,25 @@ private void sendEvent(SseEmitter sseEmitter, SseEventBuilder eventBuilder) {
         }
     }
 
-    public List<String> getConnectedTokens() {
-        return sseEmitterStorage.getUserTokens().stream().toList();
+    private void sendStatusEvent(SseEmitter sseEmitter) {
+        SseStatusResponse sseStatusResponse = SseStatusResponse.of(currentStatus.name().toLowerCase(),
+            currentStatus.getMessage());
+
+        SseEventBuilder eventBuilder = SseEventBuilderFactory.create("status", sseStatusResponse);
+        sendEvent(sseEmitter, eventBuilder);
+    }
+
+    private void propagateStatus() {
+        SseStatusResponse statusResponse = SseStatusResponse.of(currentStatus.name().toLowerCase(),
+            currentStatus.getMessage());
+
+        sseEmitterStorage.getEmitters().forEach(emitter -> {
+            SseEventBuilder eventBuilder = SseEventBuilderFactory.create("status", statusResponse);
+            sendEvent(emitter, eventBuilder);
+        });
     }
 
-    public SseStatusResponse isConnected(String token) {
-        boolean isConnected = sseEmitterStorage.getEmitter(token).isPresent();
-        return SseStatusResponse.of(isConnected);
+    public List<String> getConnectedTokens() {
+        return sseEmitterStorage.getUserTokens().stream().toList();
     }
 }

src/main/java/kr/allcll/backend/support/sse/SseStatus.java

@@ -0,0 +1,18 @@
+package kr.allcll.backend.support.sse;
+
+public enum SseStatus {
+    LIVE("실시간 여석을 제공중이에요"),
+    PRESEAT("preseat 여석을 이용해주세요"),
+    IDLE("실시간 여석 제공 전이에요. 서비스가 시작되면 알림을 드릴게요."),
+    ERROR("2025-09-02 까지 서비스 점검 중이에요");
+
+    private final String message;
+
+    SseStatus(String message) {
+        this.message = message;
+    }
+
+    public String getMessage() {
+        return message;
+    }
+}

src/main/java/kr/allcll/backend/support/sse/dto/SseStatusResponse.java

@@ -1,9 +1,11 @@
 package kr.allcll.backend.support.sse.dto;
 
 public record SseStatusResponse(
-    boolean isConnected
+    String status,
+    String message
 ) {
-    public static SseStatusResponse of(boolean isConnected) {
-        return new SseStatusResponse(isConnected);
+
+    public static SseStatusResponse of(String status, String message) {
+        return new SseStatusResponse(status, message);
     }
 }

src/test/java/kr/allcll/backend/support/sse/SseServiceTest.java

@@ -53,6 +53,7 @@ void sseConnectionTest() {
 
         // then
         SseTestHelper.assertResponseContainsMessage(response, "success");
+        SseTestHelper.assertResponseContainsMessage(response, "idle");
     }
 
     @DisplayName("동시에 여러 클라이언트와 SSE 연결을 유지하고, 모두에게 메시지를 전달한다.")
@@ -86,6 +87,10 @@ void ssePropagationTest() {
             + "data:success\n"
             + "\n"
             + "retry:1000\n"
+            + "event:status\n"
+            + "data:{\"status\":\"idle\",\"message\":\"실시간 여석 제공 전이에요. 서비스가 시작되면 알림을 드릴게요.\"}\n"
+            + "\n"
+            + "retry:1000\n"
             + "event:message\n"
             + "data:\"Hello, SSE!\"\n"
             + "\n";