fix: 경매방 하나라도 퇴장 시 세션 만료되는 문제 수정

src/main/java/devut/buzzerbidder/domain/chat/service/ChatRoomService.java

@@ -127,9 +127,6 @@ public void enterChatRoom(User user, ChatRoom chatRoom) {
     }
 
     public void exitAuctionChatRoom(Long auctionId, User user) {
-
-        walletRedisService.flushBalanceAndClearSession(user.getId(), null);
-
         ChatRoom chatRoom = chatRoomRepository.findByAuctionId(auctionId)
                 .orElseThrow(() -> new BusinessException(ErrorCode.CHATROOM_NOT_FOUND));
 

src/main/java/devut/buzzerbidder/domain/liveBid/service/HeartbeatService.java

@@ -14,6 +14,7 @@ public class HeartbeatService {
 
     private final StringRedisTemplate redis;
 
+    private static final String SESSION_EXP_ZSET = "auction:sessions:exp";
     private static final Duration SESSION_TTL = Duration.ofSeconds(35);
     private static final Duration BALANCE_TTL = Duration.ofMinutes(10);
 
@@ -29,5 +30,7 @@ public void heartbeat(Long userId) {
 
         redis.expire(balKey, BALANCE_TTL);
         redis.expire(verKey, BALANCE_TTL);
+        long expireAtMs = System.currentTimeMillis() + SESSION_TTL.toMillis();
+        redis.opsForZSet().add(SESSION_EXP_ZSET, userId.toString(), expireAtMs);
     }
 }

src/main/java/devut/buzzerbidder/domain/liveBid/service/SessionExpireScheduler.java

@@ -0,0 +1,109 @@
+package devut.buzzerbidder.domain.liveBid.service;
+
+import devut.buzzerbidder.domain.wallet.service.WalletRedisService;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.data.redis.core.StringRedisTemplate;
+import org.springframework.data.redis.core.script.DefaultRedisScript;
+import org.springframework.scheduling.annotation.Scheduled;
+import org.springframework.stereotype.Component;
+
+import java.util.List;
+import java.util.Objects;
+import java.util.concurrent.TimeUnit;
+
+@Component
+@RequiredArgsConstructor
+@Slf4j
+public class SessionExpireScheduler {
+
+    private final StringRedisTemplate redis;
+    private final WalletRedisService walletRedisService;
+
+    private static final String SESSION_PREFIX = "auction:session:";
+    private static final String SESSION_EXP_ZSET = "auction:sessions:exp";
+
+    // 한 번에 처리할 최대 개수(배치 제한)
+    private static final int BATCH_SIZE = 100;
+
+    /**
+     * score <= nowMs 인 멤버를 최대 limit개 꺼내고, 같은 스크립트 안에서 제거까지 수행
+     */
+    private static final String POP_DUE_MEMBERS_SCRIPT = """
+        local zkey = KEYS[1]
+        local nowMs = tonumber(ARGV[1])
+        local limit = tonumber(ARGV[2])
+
+        if (not limit) or limit <= 0 then
+          return {}
+        end
+
+        local members = redis.call('ZRANGEBYSCORE', zkey, '-inf', nowMs, 'LIMIT', 0, limit)
+        if (not members) or (#members == 0) then
+          return {}
+        end
+
+        redis.call('ZREM', zkey, unpack(members))
+        return members
+    """;
+
+    private final DefaultRedisScript<List<String>> popDueMembersScript = buildPopDueMembersScript();
+
+    @Scheduled(fixedDelay = 500)
+    public void processExpiredSessions() {
+        long nowMs = System.currentTimeMillis();
+
+        // 원자적으로 due userId들을 꺼냄(다른 서버와 경합해도 중복 감소)
+        List<String> userIds = executeStringList(
+                popDueMembersScript,
+                List.of(SESSION_EXP_ZSET),
+                String.valueOf(nowMs),
+                String.valueOf(BATCH_SIZE)
+        );
+
+        if (userIds.isEmpty()) return;
+
+        for (String userIdStr : userIds) {
+            String sessionKey = SESSION_PREFIX + userIdStr;
+
+            try {
+                // 1) 진짜 만료됐는지 최종 확인
+                Boolean exists = redis.hasKey(sessionKey);
+                if (Boolean.TRUE.equals(exists)) {
+                    // 아직 살아있으면(heartbeat가 늦게 갱신) TTL로 다시 스케줄
+                    Long ttlSec = redis.getExpire(sessionKey, TimeUnit.SECONDS);
+                    if (ttlSec != null && ttlSec > 0) {
+                        long expireAtMs = System.currentTimeMillis() + ttlSec * 1000L;
+                        redis.opsForZSet().add(SESSION_EXP_ZSET, userIdStr, expireAtMs);
+                    }
+                    continue;
+                }
+
+                // 2) 만료 확정이면 flush
+                walletRedisService.flushBalanceAndClearSession(Long.parseLong(userIdStr), null);
+
+            } catch (Exception e) {
+                // 실패 시 로그
+                log.error("SessionExpireScheduler failed. userId={}", userIdStr, e);
+            }
+        }
+    }
+
+    /* ==================== Lua Script 빌더/실행 헬퍼 ==================== */
+
+    private DefaultRedisScript<List<String>> buildPopDueMembersScript() {
+        DefaultRedisScript<List<String>> script = new DefaultRedisScript<>();
+
+        @SuppressWarnings({"rawtypes", "unchecked"})
+        Class<List<String>> listClass = (Class) List.class;
+        script.setResultType(listClass);
+
+        script.setScriptText(POP_DUE_MEMBERS_SCRIPT);
+        return script;
+    }
+
+    private List<String> executeStringList(DefaultRedisScript<List<String>> script, List<String> keys, String... args) {
+        List<String> result = redis.execute(script, keys, (Object[]) args);
+        return Objects.requireNonNullElse(result, List.of());
+    }
+}