chore: sliding window rate limiter

redispattern/slidingwindowratelimiter/sliding_window_rate_limiter.go

@@ -30,13 +30,6 @@ return limit - count
 `
 )
 
-var errLimitHit = errors.New("limit hit")
-
-// IsLimitHit detects a limit condition.
-func IsLimitHit(err error) bool {
-	return errors.Is(err, errLimitHit)
-}
-
 func scriptDigest() (string, error) {
 	s := sha1.New()
 	_, err := io.WriteString(s, script)
@@ -87,10 +80,10 @@ func (sl *SlidingWindowRateLimiter) Allow() (bool, error) {
 	}
 	switch v := ret.(type) {
 	case int64:
-		if v == 0 {
-			return false, errLimitHit
+		if v <= 0 {
+			return false, errors.New("limit reached")
 		}
-		return v > 0, nil
+		return true, nil
 	default:
 		return false, fmt.Errorf("sliding window rate limiter err: %#v, key = %s, window = %s, limit = %d", ret, sl.key, sl.window, sl.limit)
 	}