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authorMatthew Heon <matthew.heon@gmail.com>2017-11-01 11:24:59 -0400
committerMatthew Heon <matthew.heon@gmail.com>2017-11-01 11:24:59 -0400
commita031b83a09a8628435317a03f199cdc18b78262f (patch)
treebc017a96769ce6de33745b8b0b1304ccf38e9df0 /vendor/k8s.io/client-go/tools/cache/reflector.go
parent2b74391cd5281f6fdf391ff8ad50fd1490f6bf89 (diff)
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Initial checkin from CRI-O repo
Signed-off-by: Matthew Heon <matthew.heon@gmail.com>
Diffstat (limited to 'vendor/k8s.io/client-go/tools/cache/reflector.go')
-rw-r--r--vendor/k8s.io/client-go/tools/cache/reflector.go421
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
+}