| /* |
| 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/klog" |
| |
| "k8s.io/apimachinery/pkg/runtime" |
| "k8s.io/apimachinery/pkg/util/diff" |
| ) |
| |
| 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{} |
| } |
| klog.Warningln("Mutation detector is enabled, this will result in memory leakage.") |
| 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 |
| 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 obj, ok := obj.(runtime.Object); ok { |
| copiedObj := obj.DeepCopyObject() |
| |
| 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) |
| } |
| } |