| /* |
| Copyright 2017 The Kubernetes Authors. |
| |
| Licensed under the Apache License, Version 2.0 (the "License"); |
| you may not use this file except in compliance with the License. |
| You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, software |
| distributed under the License is distributed on an "AS IS" BASIS, |
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| See the License for the specific language governing permissions and |
| limitations under the License. |
| */ |
| |
| package eventratelimit |
| |
| import ( |
| "github.com/hashicorp/golang-lru" |
| |
| "k8s.io/client-go/util/flowcontrol" |
| ) |
| |
| // cache is an interface for caching the limits of a particular type |
| type cache interface { |
| // get the rate limiter associated with the specified key |
| get(key interface{}) flowcontrol.RateLimiter |
| } |
| |
| // singleCache is a cache that only stores a single, constant item |
| type singleCache struct { |
| // the single rate limiter held by the cache |
| rateLimiter flowcontrol.RateLimiter |
| } |
| |
| func (c *singleCache) get(key interface{}) flowcontrol.RateLimiter { |
| return c.rateLimiter |
| } |
| |
| // lruCache is a least-recently-used cache |
| type lruCache struct { |
| // factory to use to create new rate limiters |
| rateLimiterFactory func() flowcontrol.RateLimiter |
| // the actual LRU cache |
| cache *lru.Cache |
| } |
| |
| func (c *lruCache) get(key interface{}) flowcontrol.RateLimiter { |
| value, found := c.cache.Get(key) |
| if !found { |
| rateLimter := c.rateLimiterFactory() |
| c.cache.Add(key, rateLimter) |
| return rateLimter |
| } |
| return value.(flowcontrol.RateLimiter) |
| } |