135 lines
3.4 KiB
Go
135 lines
3.4 KiB
Go
/*
|
|
Copyright 2016 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"
|
|
"os"
|
|
"reflect"
|
|
"strconv"
|
|
"sync"
|
|
"time"
|
|
|
|
"k8s.io/apimachinery/pkg/runtime"
|
|
"k8s.io/apimachinery/pkg/util/diff"
|
|
"k8s.io/client-go/pkg/api"
|
|
)
|
|
|
|
var mutationDetectionEnabled = false
|
|
|
|
func init() {
|
|
mutationDetectionEnabled, _ = strconv.ParseBool(os.Getenv("KUBE_CACHE_MUTATION_DETECTOR"))
|
|
}
|
|
|
|
type CacheMutationDetector interface {
|
|
AddObject(obj interface{})
|
|
Run(stopCh <-chan struct{})
|
|
}
|
|
|
|
func NewCacheMutationDetector(name string) CacheMutationDetector {
|
|
if !mutationDetectionEnabled {
|
|
return dummyMutationDetector{}
|
|
}
|
|
return &defaultCacheMutationDetector{name: name, period: 1 * time.Second}
|
|
}
|
|
|
|
type dummyMutationDetector struct{}
|
|
|
|
func (dummyMutationDetector) Run(stopCh <-chan struct{}) {
|
|
}
|
|
func (dummyMutationDetector) AddObject(obj interface{}) {
|
|
}
|
|
|
|
// defaultCacheMutationDetector gives a way to detect if a cached object has been mutated
|
|
// It has a list of cached objects and their copies. I haven't thought of a way
|
|
// to see WHO is mutating it, just that it's getting mutated.
|
|
type defaultCacheMutationDetector struct {
|
|
name string
|
|
period time.Duration
|
|
|
|
lock sync.Mutex
|
|
cachedObjs []cacheObj
|
|
|
|
// failureFunc is injectable for unit testing. If you don't have it, the process will panic.
|
|
// This panic is intentional, since turning on this detection indicates you want a strong
|
|
// failure signal. This failure is effectively a p0 bug and you can't trust process results
|
|
// after a mutation anyway.
|
|
failureFunc func(message string)
|
|
}
|
|
|
|
// cacheObj holds the actual object and a copy
|
|
type cacheObj struct {
|
|
cached interface{}
|
|
copied interface{}
|
|
}
|
|
|
|
func (d *defaultCacheMutationDetector) Run(stopCh <-chan struct{}) {
|
|
// we DON'T want protection from panics. If we're running this code, we want to die
|
|
go func() {
|
|
for {
|
|
d.CompareObjects()
|
|
|
|
select {
|
|
case <-stopCh:
|
|
return
|
|
case <-time.After(d.period):
|
|
}
|
|
}
|
|
}()
|
|
}
|
|
|
|
// AddObject makes a deep copy of the object for later comparison. It only works on runtime.Object
|
|
// but that covers the vast majority of our cached objects
|
|
func (d *defaultCacheMutationDetector) AddObject(obj interface{}) {
|
|
if _, ok := obj.(DeletedFinalStateUnknown); ok {
|
|
return
|
|
}
|
|
if _, ok := obj.(runtime.Object); !ok {
|
|
return
|
|
}
|
|
|
|
copiedObj, err := api.Scheme.Copy(obj.(runtime.Object))
|
|
if err != nil {
|
|
return
|
|
}
|
|
|
|
d.lock.Lock()
|
|
defer d.lock.Unlock()
|
|
d.cachedObjs = append(d.cachedObjs, cacheObj{cached: obj, copied: copiedObj})
|
|
}
|
|
|
|
func (d *defaultCacheMutationDetector) CompareObjects() {
|
|
d.lock.Lock()
|
|
defer d.lock.Unlock()
|
|
|
|
altered := false
|
|
for i, obj := range d.cachedObjs {
|
|
if !reflect.DeepEqual(obj.cached, obj.copied) {
|
|
fmt.Printf("CACHE %s[%d] ALTERED!\n%v\n", d.name, i, diff.ObjectDiff(obj.cached, obj.copied))
|
|
altered = true
|
|
}
|
|
}
|
|
|
|
if altered {
|
|
msg := fmt.Sprintf("cache %s modified", d.name)
|
|
if d.failureFunc != nil {
|
|
d.failureFunc(msg)
|
|
return
|
|
}
|
|
panic(msg)
|
|
}
|
|
}
|