fix(rate-limit): make 429 fallback cooldown configurable

backend/internal/service/ratelimit_service.go

@@ -55,6 +55,11 @@ type geminiUsageTotalsBatchProvider interface {
 
 const geminiPrecheckCacheTTL = time.Minute
 
+const (
+	defaultRateLimit429CooldownSeconds = 5
+	maxRateLimit429CooldownSeconds     = 7200
+)
+
 const (
 	openAI403CooldownMinutesDefault = 10
 	openAI403DisableThreshold       = 3
@@ -891,12 +896,8 @@ func (s *RateLimitService) handle429(ctx context.Context, account *Account, head
 			return
 		}
 
-		// 其他平台：没有重置时间，使用默认5分钟
-		resetAt := time.Now().Add(5 * time.Minute)
-		slog.Warn("rate_limit_no_reset_time", "account_id", account.ID, "platform", account.Platform, "using_default", "5m")
-		if err := s.accountRepo.SetRateLimited(ctx, account.ID, resetAt); err != nil {
-			slog.Warn("rate_limit_set_failed", "account_id", account.ID, "error", err)
-		}
+		// 其他平台：没有重置时间，使用可配置的秒级默认回避，避免误伤长时间不可调度。
+		s.apply429FallbackRateLimit(ctx, account, "no_reset_time")
 		return
 	}
 
@@ -904,10 +905,7 @@ func (s *RateLimitService) handle429(ctx context.Context, account *Account, head
 	ts, err := strconv.ParseInt(resetTimestamp, 10, 64)
 	if err != nil {
 		slog.Warn("rate_limit_reset_parse_failed", "reset_timestamp", resetTimestamp, "error", err)
-		resetAt := time.Now().Add(5 * time.Minute)
-		if err := s.accountRepo.SetRateLimited(ctx, account.ID, resetAt); err != nil {
-			slog.Warn("rate_limit_set_failed", "account_id", account.ID, "error", err)
-		}
+		s.apply429FallbackRateLimit(ctx, account, "reset_parse_failed")
 		return
 	}
 
@@ -929,6 +927,51 @@ func (s *RateLimitService) handle429(ctx context.Context, account *Account, head
 	slog.Info("account_rate_limited", "account_id", account.ID, "reset_at", resetAt)
 }
 
+func (s *RateLimitService) apply429FallbackRateLimit(ctx context.Context, account *Account, reason string) {
+	cooldown, enabled := s.get429FallbackCooldown(ctx, account)
+	if !enabled {
+		slog.Info("rate_limit_429_fallback_ignored", "account_id", account.ID, "platform", account.Platform, "reason", reason)
+		return
+	}
+
+	resetAt := time.Now().Add(cooldown)
+	slog.Warn("rate_limit_429_fallback_used", "account_id", account.ID, "platform", account.Platform, "reason", reason, "using_default", cooldown.String())
+	if err := s.accountRepo.SetRateLimited(ctx, account.ID, resetAt); err != nil {
+		slog.Warn("rate_limit_set_failed", "account_id", account.ID, "error", err)
+	}
+}
+
+func (s *RateLimitService) get429FallbackCooldown(ctx context.Context, account *Account) (time.Duration, bool) {
+	if s.settingService != nil {
+		settings, err := s.settingService.GetRateLimit429CooldownSettings(ctx)
+		if err == nil && settings != nil {
+			if !settings.Enabled {
+				return 0, false
+			}
+			seconds := clampRateLimit429CooldownSeconds(settings.CooldownSeconds)
+			return time.Duration(seconds) * time.Second, true
+		}
+		slog.Warn("rate_limit_429_settings_read_failed", "account_id", account.ID, "error", err)
+	}
+
+	seconds := defaultRateLimit429CooldownSeconds
+	if s.cfg != nil && s.cfg.RateLimit.RateLimit429CooldownSeconds > 0 {
+		seconds = s.cfg.RateLimit.RateLimit429CooldownSeconds
+	}
+	seconds = clampRateLimit429CooldownSeconds(seconds)
+	return time.Duration(seconds) * time.Second, true
+}
+
+func clampRateLimit429CooldownSeconds(seconds int) int {
+	if seconds < 1 {
+		return 1
+	}
+	if seconds > maxRateLimit429CooldownSeconds {
+		return maxRateLimit429CooldownSeconds
+	}
+	return seconds
+}
+
 // calculateOpenAI429ResetTime 从 OpenAI 429 响应头计算正确的重置时间
 // 返回 nil 表示无法从响应头中确定重置时间
 func calculateOpenAI429ResetTime(headers http.Header) *time.Time {