262 lines
8.2 KiB
Go
262 lines
8.2 KiB
Go
|
/*
|
||
|
|
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 cache
|
||
|
|
|
||
|
|
import (
|
||
|
|
"fmt"
|
||
|
|
"strconv"
|
||
|
|
"sync"
|
||
|
|
"time"
|
||
|
|
|
||
|
|
"k8s.io/klog"
|
||
|
|
|
||
|
|
"k8s.io/apimachinery/pkg/api/meta"
|
||
|
|
"k8s.io/apimachinery/pkg/runtime"
|
||
|
|
utilcache "k8s.io/apimachinery/pkg/util/cache"
|
||
|
|
utilruntime "k8s.io/apimachinery/pkg/util/runtime"
|
||
|
|
"k8s.io/apimachinery/pkg/util/sets"
|
||
|
|
)
|
||
|
|
|
||
|
|
// MutationCache is able to take the result of update operations and stores them in an LRU
|
||
|
|
// that can be used to provide a more current view of a requested object. It requires interpreting
|
||
|
|
// resourceVersions for comparisons.
|
||
|
|
// Implementations must be thread-safe.
|
||
|
|
// TODO find a way to layer this into an informer/lister
|
||
|
|
type MutationCache interface {
|
||
|
|
GetByKey(key string) (interface{}, bool, error)
|
||
|
|
ByIndex(indexName, indexKey string) ([]interface{}, error)
|
||
|
|
Mutation(interface{})
|
||
|
|
}
|
||
|
|
|
||
|
|
type ResourceVersionComparator interface {
|
||
|
|
CompareResourceVersion(lhs, rhs runtime.Object) int
|
||
|
|
}
|
||
|
|
|
||
|
|
// NewIntegerResourceVersionMutationCache returns a MutationCache that understands how to
|
||
|
|
// deal with objects that have a resource version that:
|
||
|
|
//
|
||
|
|
// - is an integer
|
||
|
|
// - increases when updated
|
||
|
|
// - is comparable across the same resource in a namespace
|
||
|
|
//
|
||
|
|
// Most backends will have these semantics. Indexer may be nil. ttl controls how long an item
|
||
|
|
// remains in the mutation cache before it is removed.
|
||
|
|
//
|
||
|
|
// If includeAdds is true, objects in the mutation cache will be returned even if they don't exist
|
||
|
|
// in the underlying store. This is only safe if your use of the cache can handle mutation entries
|
||
|
|
// remaining in the cache for up to ttl when mutations and deletes occur very closely in time.
|
||
|
|
func NewIntegerResourceVersionMutationCache(backingCache Store, indexer Indexer, ttl time.Duration, includeAdds bool) MutationCache {
|
||
|
|
return &mutationCache{
|
||
|
|
backingCache: backingCache,
|
||
|
|
indexer: indexer,
|
||
|
|
mutationCache: utilcache.NewLRUExpireCache(100),
|
||
|
|
comparator: etcdObjectVersioner{},
|
||
|
|
ttl: ttl,
|
||
|
|
includeAdds: includeAdds,
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// mutationCache doesn't guarantee that it returns values added via Mutation since they can page out and
|
||
|
|
// since you can't distinguish between, "didn't observe create" and "was deleted after create",
|
||
|
|
// if the key is missing from the backing cache, we always return it as missing
|
||
|
|
type mutationCache struct {
|
||
|
|
lock sync.Mutex
|
||
|
|
backingCache Store
|
||
|
|
indexer Indexer
|
||
|
|
mutationCache *utilcache.LRUExpireCache
|
||
|
|
includeAdds bool
|
||
|
|
ttl time.Duration
|
||
|
|
|
||
|
|
comparator ResourceVersionComparator
|
||
|
|
}
|
||
|
|
|
||
|
|
// GetByKey is never guaranteed to return back the value set in Mutation. It could be paged out, it could
|
||
|
|
// be older than another copy, the backingCache may be more recent or, you might have written twice into the same key.
|
||
|
|
// You get a value that was valid at some snapshot of time and will always return the newer of backingCache and mutationCache.
|
||
|
|
func (c *mutationCache) GetByKey(key string) (interface{}, bool, error) {
|
||
|
|
c.lock.Lock()
|
||
|
|
defer c.lock.Unlock()
|
||
|
|
|
||
|
|
obj, exists, err := c.backingCache.GetByKey(key)
|
||
|
|
if err != nil {
|
||
|
|
return nil, false, err
|
||
|
|
}
|
||
|
|
if !exists {
|
||
|
|
if !c.includeAdds {
|
||
|
|
// we can't distinguish between, "didn't observe create" and "was deleted after create", so
|
||
|
|
// if the key is missing, we always return it as missing
|
||
|
|
return nil, false, nil
|
||
|
|
}
|
||
|
|
obj, exists = c.mutationCache.Get(key)
|
||
|
|
if !exists {
|
||
|
|
return nil, false, nil
|
||
|
|
}
|
||
|
|
}
|
||
|
|
objRuntime, ok := obj.(runtime.Object)
|
||
|
|
if !ok {
|
||
|
|
return obj, true, nil
|
||
|
|
}
|
||
|
|
return c.newerObject(key, objRuntime), true, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// ByIndex returns the newer objects that match the provided index and indexer key.
|
||
|
|
// Will return an error if no indexer was provided.
|
||
|
|
func (c *mutationCache) ByIndex(name string, indexKey string) ([]interface{}, error) {
|
||
|
|
c.lock.Lock()
|
||
|
|
defer c.lock.Unlock()
|
||
|
|
if c.indexer == nil {
|
||
|
|
return nil, fmt.Errorf("no indexer has been provided to the mutation cache")
|
||
|
|
}
|
||
|
|
keys, err := c.indexer.IndexKeys(name, indexKey)
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
var items []interface{}
|
||
|
|
keySet := sets.NewString()
|
||
|
|
for _, key := range keys {
|
||
|
|
keySet.Insert(key)
|
||
|
|
obj, exists, err := c.indexer.GetByKey(key)
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
if !exists {
|
||
|
|
continue
|
||
|
|
}
|
||
|
|
if objRuntime, ok := obj.(runtime.Object); ok {
|
||
|
|
items = append(items, c.newerObject(key, objRuntime))
|
||
|
|
} else {
|
||
|
|
items = append(items, obj)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
if c.includeAdds {
|
||
|
|
fn := c.indexer.GetIndexers()[name]
|
||
|
|
// Keys() is returned oldest to newest, so full traversal does not alter the LRU behavior
|
||
|
|
for _, key := range c.mutationCache.Keys() {
|
||
|
|
updated, ok := c.mutationCache.Get(key)
|
||
|
|
if !ok {
|
||
|
|
continue
|
||
|
|
}
|
||
|
|
if keySet.Has(key.(string)) {
|
||
|
|
continue
|
||
|
|
}
|
||
|
|
elements, err := fn(updated)
|
||
|
|
if err != nil {
|
||
|
|
klog.V(4).Infof("Unable to calculate an index entry for mutation cache entry %s: %v", key, err)
|
||
|
|
continue
|
||
|
|
}
|
||
|
|
for _, inIndex := range elements {
|
||
|
|
if inIndex != indexKey {
|
||
|
|
continue
|
||
|
|
}
|
||
|
|
items = append(items, updated)
|
||
|
|
break
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
return items, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// newerObject checks the mutation cache for a newer object and returns one if found. If the
|
||
|
|
// mutated object is older than the backing object, it is removed from the Must be
|
||
|
|
// called while the lock is held.
|
||
|
|
func (c *mutationCache) newerObject(key string, backing runtime.Object) runtime.Object {
|
||
|
|
mutatedObj, exists := c.mutationCache.Get(key)
|
||
|
|
if !exists {
|
||
|
|
return backing
|
||
|
|
}
|
||
|
|
mutatedObjRuntime, ok := mutatedObj.(runtime.Object)
|
||
|
|
if !ok {
|
||
|
|
return backing
|
||
|
|
}
|
||
|
|
if c.comparator.CompareResourceVersion(backing, mutatedObjRuntime) >= 0 {
|
||
|
|
c.mutationCache.Remove(key)
|
||
|
|
return backing
|
||
|
|
}
|
||
|
|
return mutatedObjRuntime
|
||
|
|
}
|
||
|
|
|
||
|
|
// Mutation adds a change to the cache that can be returned in GetByKey if it is newer than the backingCache
|
||
|
|
// copy. If you call Mutation twice with the same object on different threads, one will win, but its not defined
|
||
|
|
// which one. This doesn't affect correctness, since the GetByKey guaranteed of "later of these two caches" is
|
||
|
|
// preserved, but you may not get the version of the object you want. The object you get is only guaranteed to
|
||
|
|
// "one that was valid at some point in time", not "the one that I want".
|
||
|
|
func (c *mutationCache) Mutation(obj interface{}) {
|
||
|
|
c.lock.Lock()
|
||
|
|
defer c.lock.Unlock()
|
||
|
|
|
||
|
|
key, err := DeletionHandlingMetaNamespaceKeyFunc(obj)
|
||
|
|
if err != nil {
|
||
|
|
// this is a "nice to have", so failures shouldn't do anything weird
|
||
|
|
utilruntime.HandleError(err)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
if objRuntime, ok := obj.(runtime.Object); ok {
|
||
|
|
if mutatedObj, exists := c.mutationCache.Get(key); exists {
|
||
|
|
if mutatedObjRuntime, ok := mutatedObj.(runtime.Object); ok {
|
||
|
|
if c.comparator.CompareResourceVersion(objRuntime, mutatedObjRuntime) < 0 {
|
||
|
|
return
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
c.mutationCache.Add(key, obj, c.ttl)
|
||
|
|
}
|
||
|
|
|
||
|
|
// etcdObjectVersioner implements versioning and extracting etcd node information
|
||
|
|
// for objects that have an embedded ObjectMeta or ListMeta field.
|
||
|
|
type etcdObjectVersioner struct{}
|
||
|
|
|
||
|
|
// ObjectResourceVersion implements Versioner
|
||
|
|
func (a etcdObjectVersioner) ObjectResourceVersion(obj runtime.Object) (uint64, error) {
|
||
|
|
accessor, err := meta.Accessor(obj)
|
||
|
|
if err != nil {
|
||
|
|
return 0, err
|
||
|
|
}
|
||
|
|
version := accessor.GetResourceVersion()
|
||
|
|
if len(version) == 0 {
|
||
|
|
return 0, nil
|
||
|
|
}
|
||
|
|
return strconv.ParseUint(version, 10, 64)
|
||
|
|
}
|
||
|
|
|
||
|
|
// CompareResourceVersion compares etcd resource versions. Outside this API they are all strings,
|
||
|
|
// but etcd resource versions are special, they're actually ints, so we can easily compare them.
|
||
|
|
func (a etcdObjectVersioner) CompareResourceVersion(lhs, rhs runtime.Object) int {
|
||
|
|
lhsVersion, err := a.ObjectResourceVersion(lhs)
|
||
|
|
if err != nil {
|
||
|
|
// coder error
|
||
|
|
panic(err)
|
||
|
|
}
|
||
|
|
rhsVersion, err := a.ObjectResourceVersion(rhs)
|
||
|
|
if err != nil {
|
||
|
|
// coder error
|
||
|
|
panic(err)
|
||
|
|
}
|
||
|
|
|
||
|
|
if lhsVersion == rhsVersion {
|
||
|
|
return 0
|
||
|
|
}
|
||
|
|
if lhsVersion < rhsVersion {
|
||
|
|
return -1
|
||
|
|
}
|
||
|
|
|
||
|
|
return 1
|
||
|
|
}
|