mirror of
https://github.com/ceph/ceph-csi.git
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93 lines
2.8 KiB
Go
93 lines
2.8 KiB
Go
/*
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Copyright 2016 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package controller
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import (
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"hash/fnv"
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"sync"
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"github.com/golang/groupcache/lru"
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metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
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hashutil "k8s.io/kubernetes/pkg/util/hash"
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)
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type objectWithMeta interface {
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metav1.Object
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}
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// keyFunc returns the key of an object, which is used to look up in the cache for it's matching object.
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// Since we match objects by namespace and Labels/Selector, so if two objects have the same namespace and labels,
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// they will have the same key.
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func keyFunc(obj objectWithMeta) uint64 {
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hash := fnv.New32a()
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hashutil.DeepHashObject(hash, &equivalenceLabelObj{
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namespace: obj.GetNamespace(),
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labels: obj.GetLabels(),
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})
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return uint64(hash.Sum32())
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}
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type equivalenceLabelObj struct {
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namespace string
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labels map[string]string
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}
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// MatchingCache save label and selector matching relationship
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type MatchingCache struct {
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mutex sync.RWMutex
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cache *lru.Cache
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}
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// NewMatchingCache return a NewMatchingCache, which save label and selector matching relationship.
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func NewMatchingCache(maxCacheEntries int) *MatchingCache {
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return &MatchingCache{
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cache: lru.New(maxCacheEntries),
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}
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}
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// Add will add matching information to the cache.
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func (c *MatchingCache) Add(labelObj objectWithMeta, selectorObj objectWithMeta) {
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key := keyFunc(labelObj)
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c.mutex.Lock()
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defer c.mutex.Unlock()
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c.cache.Add(key, selectorObj)
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}
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// GetMatchingObject lookup the matching object for a given object.
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// Note: the cache information may be invalid since the controller may be deleted or updated,
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// we need check in the external request to ensure the cache data is not dirty.
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func (c *MatchingCache) GetMatchingObject(labelObj objectWithMeta) (controller interface{}, exists bool) {
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key := keyFunc(labelObj)
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// NOTE: we use Lock() instead of RLock() here because lru's Get() method also modifies state(
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// it need update the least recently usage information). So we can not call it concurrently.
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c.mutex.Lock()
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defer c.mutex.Unlock()
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return c.cache.Get(key)
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}
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// Update update the cached matching information.
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func (c *MatchingCache) Update(labelObj objectWithMeta, selectorObj objectWithMeta) {
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c.Add(labelObj, selectorObj)
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}
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// InvalidateAll invalidate the whole cache.
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func (c *MatchingCache) InvalidateAll() {
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c.mutex.Lock()
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defer c.mutex.Unlock()
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c.cache = lru.New(c.cache.MaxEntries)
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}
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