diff options
Diffstat (limited to 'vendor/k8s.io/client-go/tools/cache/reflector.go')
-rw-r--r-- | vendor/k8s.io/client-go/tools/cache/reflector.go | 421 |
1 files changed, 421 insertions, 0 deletions
diff --git a/vendor/k8s.io/client-go/tools/cache/reflector.go b/vendor/k8s.io/client-go/tools/cache/reflector.go new file mode 100644 index 000000000..9a730610c --- /dev/null +++ b/vendor/k8s.io/client-go/tools/cache/reflector.go @@ -0,0 +1,421 @@ +/* +Copyright 2014 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 ( + "errors" + "fmt" + "io" + "math/rand" + "net" + "net/url" + "reflect" + "regexp" + goruntime "runtime" + "runtime/debug" + "strconv" + "strings" + "sync" + "syscall" + "time" + + "github.com/golang/glog" + apierrs "k8s.io/apimachinery/pkg/api/errors" + "k8s.io/apimachinery/pkg/api/meta" + metav1 "k8s.io/apimachinery/pkg/apis/meta/v1" + "k8s.io/apimachinery/pkg/runtime" + "k8s.io/apimachinery/pkg/util/clock" + utilruntime "k8s.io/apimachinery/pkg/util/runtime" + "k8s.io/apimachinery/pkg/util/wait" + "k8s.io/apimachinery/pkg/watch" +) + +// Reflector watches a specified resource and causes all changes to be reflected in the given store. +type Reflector struct { + // name identifies this reflector. By default it will be a file:line if possible. + name string + + // The type of object we expect to place in the store. + expectedType reflect.Type + // The destination to sync up with the watch source + store Store + // listerWatcher is used to perform lists and watches. + listerWatcher ListerWatcher + // period controls timing between one watch ending and + // the beginning of the next one. + period time.Duration + resyncPeriod time.Duration + ShouldResync func() bool + // clock allows tests to manipulate time + clock clock.Clock + // lastSyncResourceVersion is the resource version token last + // observed when doing a sync with the underlying store + // it is thread safe, but not synchronized with the underlying store + lastSyncResourceVersion string + // lastSyncResourceVersionMutex guards read/write access to lastSyncResourceVersion + lastSyncResourceVersionMutex sync.RWMutex +} + +var ( + // We try to spread the load on apiserver by setting timeouts for + // watch requests - it is random in [minWatchTimeout, 2*minWatchTimeout]. + // However, it can be modified to avoid periodic resync to break the + // TCP connection. + minWatchTimeout = 5 * time.Minute +) + +// NewNamespaceKeyedIndexerAndReflector creates an Indexer and a Reflector +// The indexer is configured to key on namespace +func NewNamespaceKeyedIndexerAndReflector(lw ListerWatcher, expectedType interface{}, resyncPeriod time.Duration) (indexer Indexer, reflector *Reflector) { + indexer = NewIndexer(MetaNamespaceKeyFunc, Indexers{"namespace": MetaNamespaceIndexFunc}) + reflector = NewReflector(lw, expectedType, indexer, resyncPeriod) + return indexer, reflector +} + +// NewReflector creates a new Reflector object which will keep the given store up to +// date with the server's contents for the given resource. Reflector promises to +// only put things in the store that have the type of expectedType, unless expectedType +// is nil. If resyncPeriod is non-zero, then lists will be executed after every +// resyncPeriod, so that you can use reflectors to periodically process everything as +// well as incrementally processing the things that change. +func NewReflector(lw ListerWatcher, expectedType interface{}, store Store, resyncPeriod time.Duration) *Reflector { + return NewNamedReflector(getDefaultReflectorName(internalPackages...), lw, expectedType, store, resyncPeriod) +} + +// NewNamedReflector same as NewReflector, but with a specified name for logging +func NewNamedReflector(name string, lw ListerWatcher, expectedType interface{}, store Store, resyncPeriod time.Duration) *Reflector { + r := &Reflector{ + name: name, + listerWatcher: lw, + store: store, + expectedType: reflect.TypeOf(expectedType), + period: time.Second, + resyncPeriod: resyncPeriod, + clock: &clock.RealClock{}, + } + return r +} + +// internalPackages are packages that ignored when creating a default reflector name. These packages are in the common +// call chains to NewReflector, so they'd be low entropy names for reflectors +var internalPackages = []string{"client-go/tools/cache/", "/runtime/asm_"} + +// getDefaultReflectorName walks back through the call stack until we find a caller from outside of the ignoredPackages +// it returns back a shortpath/filename:line to aid in identification of this reflector when it starts logging +func getDefaultReflectorName(ignoredPackages ...string) string { + name := "????" + const maxStack = 10 + for i := 1; i < maxStack; i++ { + _, file, line, ok := goruntime.Caller(i) + if !ok { + file, line, ok = extractStackCreator() + if !ok { + break + } + i += maxStack + } + if hasPackage(file, ignoredPackages) { + continue + } + + file = trimPackagePrefix(file) + name = fmt.Sprintf("%s:%d", file, line) + break + } + return name +} + +// hasPackage returns true if the file is in one of the ignored packages. +func hasPackage(file string, ignoredPackages []string) bool { + for _, ignoredPackage := range ignoredPackages { + if strings.Contains(file, ignoredPackage) { + return true + } + } + return false +} + +// trimPackagePrefix reduces duplicate values off the front of a package name. +func trimPackagePrefix(file string) string { + if l := strings.LastIndex(file, "k8s.io/client-go/pkg/"); l >= 0 { + return file[l+len("k8s.io/client-go/"):] + } + if l := strings.LastIndex(file, "/src/"); l >= 0 { + return file[l+5:] + } + if l := strings.LastIndex(file, "/pkg/"); l >= 0 { + return file[l+1:] + } + return file +} + +var stackCreator = regexp.MustCompile(`(?m)^created by (.*)\n\s+(.*):(\d+) \+0x[[:xdigit:]]+$`) + +// extractStackCreator retrieves the goroutine file and line that launched this stack. Returns false +// if the creator cannot be located. +// TODO: Go does not expose this via runtime https://github.com/golang/go/issues/11440 +func extractStackCreator() (string, int, bool) { + stack := debug.Stack() + matches := stackCreator.FindStringSubmatch(string(stack)) + if matches == nil || len(matches) != 4 { + return "", 0, false + } + line, err := strconv.Atoi(matches[3]) + if err != nil { + return "", 0, false + } + return matches[2], line, true +} + +// Run starts a watch and handles watch events. Will restart the watch if it is closed. +// Run starts a goroutine and returns immediately. +func (r *Reflector) Run() { + glog.V(3).Infof("Starting reflector %v (%s) from %s", r.expectedType, r.resyncPeriod, r.name) + go wait.Until(func() { + if err := r.ListAndWatch(wait.NeverStop); err != nil { + utilruntime.HandleError(err) + } + }, r.period, wait.NeverStop) +} + +// RunUntil starts a watch and handles watch events. Will restart the watch if it is closed. +// RunUntil starts a goroutine and returns immediately. It will exit when stopCh is closed. +func (r *Reflector) RunUntil(stopCh <-chan struct{}) { + glog.V(3).Infof("Starting reflector %v (%s) from %s", r.expectedType, r.resyncPeriod, r.name) + go wait.Until(func() { + if err := r.ListAndWatch(stopCh); err != nil { + utilruntime.HandleError(err) + } + }, r.period, stopCh) +} + +var ( + // nothing will ever be sent down this channel + neverExitWatch <-chan time.Time = make(chan time.Time) + + // Used to indicate that watching stopped so that a resync could happen. + errorResyncRequested = errors.New("resync channel fired") + + // Used to indicate that watching stopped because of a signal from the stop + // channel passed in from a client of the reflector. + errorStopRequested = errors.New("Stop requested") +) + +// resyncChan returns a channel which will receive something when a resync is +// required, and a cleanup function. +func (r *Reflector) resyncChan() (<-chan time.Time, func() bool) { + if r.resyncPeriod == 0 { + return neverExitWatch, func() bool { return false } + } + // The cleanup function is required: imagine the scenario where watches + // always fail so we end up listing frequently. Then, if we don't + // manually stop the timer, we could end up with many timers active + // concurrently. + t := r.clock.NewTimer(r.resyncPeriod) + return t.C(), t.Stop +} + +// ListAndWatch first lists all items and get the resource version at the moment of call, +// and then use the resource version to watch. +// It returns error if ListAndWatch didn't even try to initialize watch. +func (r *Reflector) ListAndWatch(stopCh <-chan struct{}) error { + glog.V(3).Infof("Listing and watching %v from %s", r.expectedType, r.name) + var resourceVersion string + resyncCh, cleanup := r.resyncChan() + defer cleanup() + + // Explicitly set "0" as resource version - it's fine for the List() + // to be served from cache and potentially be delayed relative to + // etcd contents. Reflector framework will catch up via Watch() eventually. + options := metav1.ListOptions{ResourceVersion: "0"} + list, err := r.listerWatcher.List(options) + if err != nil { + return fmt.Errorf("%s: Failed to list %v: %v", r.name, r.expectedType, err) + } + listMetaInterface, err := meta.ListAccessor(list) + if err != nil { + return fmt.Errorf("%s: Unable to understand list result %#v: %v", r.name, list, err) + } + resourceVersion = listMetaInterface.GetResourceVersion() + items, err := meta.ExtractList(list) + if err != nil { + return fmt.Errorf("%s: Unable to understand list result %#v (%v)", r.name, list, err) + } + if err := r.syncWith(items, resourceVersion); err != nil { + return fmt.Errorf("%s: Unable to sync list result: %v", r.name, err) + } + r.setLastSyncResourceVersion(resourceVersion) + + resyncerrc := make(chan error, 1) + cancelCh := make(chan struct{}) + defer close(cancelCh) + go func() { + for { + select { + case <-resyncCh: + case <-stopCh: + return + case <-cancelCh: + return + } + if r.ShouldResync == nil || r.ShouldResync() { + glog.V(4).Infof("%s: forcing resync", r.name) + if err := r.store.Resync(); err != nil { + resyncerrc <- err + return + } + } + cleanup() + resyncCh, cleanup = r.resyncChan() + } + }() + + for { + timemoutseconds := int64(minWatchTimeout.Seconds() * (rand.Float64() + 1.0)) + options = metav1.ListOptions{ + ResourceVersion: resourceVersion, + // We want to avoid situations of hanging watchers. Stop any wachers that do not + // receive any events within the timeout window. + TimeoutSeconds: &timemoutseconds, + } + + w, err := r.listerWatcher.Watch(options) + if err != nil { + switch err { + case io.EOF: + // watch closed normally + case io.ErrUnexpectedEOF: + glog.V(1).Infof("%s: Watch for %v closed with unexpected EOF: %v", r.name, r.expectedType, err) + default: + utilruntime.HandleError(fmt.Errorf("%s: Failed to watch %v: %v", r.name, r.expectedType, err)) + } + // If this is "connection refused" error, it means that most likely apiserver is not responsive. + // It doesn't make sense to re-list all objects because most likely we will be able to restart + // watch where we ended. + // If that's the case wait and resend watch request. + if urlError, ok := err.(*url.Error); ok { + if opError, ok := urlError.Err.(*net.OpError); ok { + if errno, ok := opError.Err.(syscall.Errno); ok && errno == syscall.ECONNREFUSED { + time.Sleep(time.Second) + continue + } + } + } + return nil + } + + if err := r.watchHandler(w, &resourceVersion, resyncerrc, stopCh); err != nil { + if err != errorStopRequested { + glog.Warningf("%s: watch of %v ended with: %v", r.name, r.expectedType, err) + } + return nil + } + } +} + +// syncWith replaces the store's items with the given list. +func (r *Reflector) syncWith(items []runtime.Object, resourceVersion string) error { + found := make([]interface{}, 0, len(items)) + for _, item := range items { + found = append(found, item) + } + return r.store.Replace(found, resourceVersion) +} + +// watchHandler watches w and keeps *resourceVersion up to date. +func (r *Reflector) watchHandler(w watch.Interface, resourceVersion *string, errc chan error, stopCh <-chan struct{}) error { + start := r.clock.Now() + eventCount := 0 + + // Stopping the watcher should be idempotent and if we return from this function there's no way + // we're coming back in with the same watch interface. + defer w.Stop() + +loop: + for { + select { + case <-stopCh: + return errorStopRequested + case err := <-errc: + return err + case event, ok := <-w.ResultChan(): + if !ok { + break loop + } + if event.Type == watch.Error { + return apierrs.FromObject(event.Object) + } + if e, a := r.expectedType, reflect.TypeOf(event.Object); e != nil && e != a { + utilruntime.HandleError(fmt.Errorf("%s: expected type %v, but watch event object had type %v", r.name, e, a)) + continue + } + meta, err := meta.Accessor(event.Object) + if err != nil { + utilruntime.HandleError(fmt.Errorf("%s: unable to understand watch event %#v", r.name, event)) + continue + } + newResourceVersion := meta.GetResourceVersion() + switch event.Type { + case watch.Added: + err := r.store.Add(event.Object) + if err != nil { + utilruntime.HandleError(fmt.Errorf("%s: unable to add watch event object (%#v) to store: %v", r.name, event.Object, err)) + } + case watch.Modified: + err := r.store.Update(event.Object) + if err != nil { + utilruntime.HandleError(fmt.Errorf("%s: unable to update watch event object (%#v) to store: %v", r.name, event.Object, err)) + } + case watch.Deleted: + // TODO: Will any consumers need access to the "last known + // state", which is passed in event.Object? If so, may need + // to change this. + err := r.store.Delete(event.Object) + if err != nil { + utilruntime.HandleError(fmt.Errorf("%s: unable to delete watch event object (%#v) from store: %v", r.name, event.Object, err)) + } + default: + utilruntime.HandleError(fmt.Errorf("%s: unable to understand watch event %#v", r.name, event)) + } + *resourceVersion = newResourceVersion + r.setLastSyncResourceVersion(newResourceVersion) + eventCount++ + } + } + + watchDuration := r.clock.Now().Sub(start) + if watchDuration < 1*time.Second && eventCount == 0 { + glog.V(4).Infof("%s: Unexpected watch close - watch lasted less than a second and no items received", r.name) + return errors.New("very short watch") + } + glog.V(4).Infof("%s: Watch close - %v total %v items received", r.name, r.expectedType, eventCount) + return nil +} + +// LastSyncResourceVersion is the resource version observed when last sync with the underlying store +// The value returned is not synchronized with access to the underlying store and is not thread-safe +func (r *Reflector) LastSyncResourceVersion() string { + r.lastSyncResourceVersionMutex.RLock() + defer r.lastSyncResourceVersionMutex.RUnlock() + return r.lastSyncResourceVersion +} + +func (r *Reflector) setLastSyncResourceVersion(v string) { + r.lastSyncResourceVersionMutex.Lock() + defer r.lastSyncResourceVersionMutex.Unlock() + r.lastSyncResourceVersion = v +} |