Simplify cache item expiration check.

Author: Baliedge

algorithms.go

@@ -146,18 +146,18 @@ func tokenBucket(ctx context.Context, s Store, c Cache, r *RateLimitReq, reqStat
 			rl.ResetTime = expire
 		}
 
-		if s != nil && reqState.IsOwner {
-			defer func() {
-				s.OnChange(ctx, r, item)
-			}()
-		}
-
 		// Client is only interested in retrieving the current status or
 		// updating the rate limit config.
 		if r.Hits == 0 {
 			return rl, nil
 		}
 
+		if s != nil && reqState.IsOwner {
+			defer func() {
+				s.OnChange(ctx, r, item)
+			}()
+		}
+
 		// If we are already at the limit.
 		if rl.Remaining == 0 && r.Hits > 0 {
 			trace.SpanFromContext(ctx).AddEvent("Already over the limit")

cache.go

@@ -39,3 +39,19 @@ type CacheItem struct {
 	// for the latest rate limit data.
 	InvalidAt int64
 }
+
+func (item *CacheItem) IsExpired() bool {
+	now := MillisecondNow()
+
+	// If the entry is invalidated
+	if item.InvalidAt != 0 && item.InvalidAt < now {
+		return true
+	}
+
+	// If the entry has expired, remove it from the cache
+	if item.ExpireAt < now {
+		return true
+	}
+
+	return false
+}

gubernator.go

@@ -318,7 +318,7 @@ func (s *V1Instance) asyncRequest(ctx context.Context, req *AsyncReq) {
 	funcTimer := prometheus.NewTimer(metricFuncTimeDuration.WithLabelValues("V1Instance.asyncRequest"))
 	defer funcTimer.ObserveDuration()
 
-	reqState := RateLimitReqState{IsOwner: false}
+	reqState := RateLimitReqState{IsOwner: req.Peer.Info().IsOwner}
 	resp := AsyncResp{
 		Idx: req.Idx,
 	}
@@ -337,7 +337,7 @@ func (s *V1Instance) asyncRequest(ctx context.Context, req *AsyncReq) {
 
 		// If we are attempting again, the owner of this rate limit might have changed to us!
 		if attempts != 0 {
-			if req.Peer.Info().IsOwner {
+			if reqState.IsOwner {
 				resp.Resp, err = s.getLocalRateLimit(ctx, req.Req, reqState)
 				if err != nil {
 					s.log.WithContext(ctx).

lrucache.go

@@ -112,16 +112,7 @@ func (c *LRUCache) GetItem(key string) (item *CacheItem, ok bool) {
 	if ele, hit := c.cache[key]; hit {
 		entry := ele.Value.(*CacheItem)
 
-		now := MillisecondNow()
-		// If the entry is invalidated
-		if entry.InvalidAt != 0 && entry.InvalidAt < now {
-			c.removeElement(ele)
-			metricCacheAccess.WithLabelValues("miss").Add(1)
-			return
-		}
-
-		// If the entry has expired, remove it from the cache
-		if entry.ExpireAt < now {
+		if entry.IsExpired() {
 			c.removeElement(ele)
 			metricCacheAccess.WithLabelValues("miss").Add(1)
 			return