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Merge pull request #66971 from tnozicka/informer-watcher

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Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

#50102 Task 2: Add UntilWithSync

**What this PR does / why we need it**:
This is a split off from https://github.com/kubernetes/kubernetes/pull/50102 to go in smaller pieces.

Introduces UntilWithSync based on informer.

**Needs https://github.com/kubernetes/kubernetes/pull/66906 first**
/hold

**Release note**:
```release-note
NONE
```

/priority important-soon
/kind bug
(bug after the main PR which is this split from)

Kubernetes-commit: c4f355a2ad9692f5459541d4e4d94fcbc5f7d946
This commit is contained in:
Kubernetes Publisher
2018-08-23 07:26:25 -07:00
parent 301c6f6aca 811147bdcf
commit d51645b4a2
9 changed files with 419 additions and 473 deletions
Download Patch File Download Diff File Expand all files Collapse all files
vendor/k8s.io/client-go/tools/cache/listwatch.go
Generated Vendored
-78
View File
@@ -20,15 +20,12 @@ import (
"context"
"time"
"k8s.io/apimachinery/pkg/api/meta"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/fields"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/util/wait"
"k8s.io/apimachinery/pkg/watch"
restclient "k8s.io/client-go/rest"
"k8s.io/client-go/tools/pager"
watchtools "k8s.io/client-go/tools/watch"
)
// ListerWatcher is any object that knows how to perform an initial list and start a watch on a resource.
@@ -113,78 +110,3 @@ func (lw *ListWatch) List(options metav1.ListOptions) (runtime.Object, error) {
func (lw *ListWatch) Watch(options metav1.ListOptions) (watch.Interface, error) {
return lw.WatchFunc(options)
}
// ListWatchUntil checks the provided conditions against the items returned by the list watcher, returning wait.ErrWaitTimeout
// if timeout is exceeded without all conditions returning true, or an error if an error occurs.
// TODO: check for watch expired error and retry watch from latest point? Same issue exists for Until.
func ListWatchUntil(timeout time.Duration, lw ListerWatcher, conditions ...watchtools.ConditionFunc) (*watch.Event, error) {
if len(conditions) == 0 {
return nil, nil
}
list, err := lw.List(metav1.ListOptions{})
if err != nil {
return nil, err
}
initialItems, err := meta.ExtractList(list)
if err != nil {
return nil, err
}
// use the initial items as simulated "adds"
var lastEvent *watch.Event
currIndex := 0
passedConditions := 0
for _, condition := range conditions {
// check the next condition against the previous event and short circuit waiting for the next watch
if lastEvent != nil {
done, err := condition(*lastEvent)
if err != nil {
return lastEvent, err
}
if done {
passedConditions = passedConditions + 1
continue
}
}
ConditionSucceeded:
for currIndex < len(initialItems) {
lastEvent = &watch.Event{Type: watch.Added, Object: initialItems[currIndex]}
currIndex++
done, err := condition(*lastEvent)
if err != nil {
return lastEvent, err
}
if done {
passedConditions = passedConditions + 1
break ConditionSucceeded
}
}
}
if passedConditions == len(conditions) {
return lastEvent, nil
}
remainingConditions := conditions[passedConditions:]
metaObj, err := meta.ListAccessor(list)
if err != nil {
return nil, err
}
currResourceVersion := metaObj.GetResourceVersion()
watchInterface, err := lw.Watch(metav1.ListOptions{ResourceVersion: currResourceVersion})
if err != nil {
return nil, err
}
ctx, cancel := watchtools.ContextWithOptionalTimeout(context.Background(), timeout)
defer cancel()
evt, err := watchtools.UntilWithoutRetry(ctx, watchInterface, remainingConditions...)
if err == watchtools.ErrWatchClosed {
// present a consistent error interface to callers
err = wait.ErrWaitTimeout
}
return evt, err
}
vendor/k8s.io/client-go/tools/watch/until.go
Generated Vendored
-102
View File
@@ -1,102 +0,0 @@
/*
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 watch
import (
"context"
"errors"
"time"
"github.com/golang/glog"
"k8s.io/apimachinery/pkg/util/wait"
"k8s.io/apimachinery/pkg/watch"
)
// ConditionFunc returns true if the condition has been reached, false if it has not been reached yet,
// or an error if the condition cannot be checked and should terminate. In general, it is better to define
// level driven conditions over edge driven conditions (pod has ready=true, vs pod modified and ready changed
// from false to true).
type ConditionFunc func(event watch.Event) (bool, error)
// ErrWatchClosed is returned when the watch channel is closed before timeout in UntilWithoutRetry.
var ErrWatchClosed = errors.New("watch closed before UntilWithoutRetry timeout")
// UntilWithoutRetry reads items from the watch until each provided condition succeeds, and then returns the last watch
// encountered. The first condition that returns an error terminates the watch (and the event is also returned).
// If no event has been received, the returned event will be nil.
// Conditions are satisfied sequentially so as to provide a useful primitive for higher level composition.
// Waits until context deadline or until context is canceled.
//
// Warning: Unless you have a very specific use case (probably a special Watcher) don't use this function!!!
// Warning: This will fail e.g. on API timeouts and/or 'too old resource version' error.
// Warning: You are most probably looking for a function *Until* or *UntilWithSync* below,
// Warning: solving such issues.
// TODO: Consider making this function private to prevent misuse when the other occurrences in our codebase are gone.
func UntilWithoutRetry(ctx context.Context, watcher watch.Interface, conditions ...ConditionFunc) (*watch.Event, error) {
ch := watcher.ResultChan()
defer watcher.Stop()
var lastEvent *watch.Event
for _, condition := range conditions {
// check the next condition against the previous event and short circuit waiting for the next watch
if lastEvent != nil {
done, err := condition(*lastEvent)
if err != nil {
return lastEvent, err
}
if done {
continue
}
}
ConditionSucceeded:
for {
select {
case event, ok := <-ch:
if !ok {
return lastEvent, ErrWatchClosed
}
lastEvent = &event
done, err := condition(event)
if err != nil {
return lastEvent, err
}
if done {
break ConditionSucceeded
}
case <-ctx.Done():
return lastEvent, wait.ErrWaitTimeout
}
}
}
return lastEvent, nil
}
// ContextWithOptionalTimeout wraps context.WithTimeout and handles infinite timeouts expressed as 0 duration.
func ContextWithOptionalTimeout(parent context.Context, timeout time.Duration) (context.Context, context.CancelFunc) {
if timeout < 0 {
// This should be handled in validation
glog.Errorf("Timeout for context shall not be negative!")
timeout = 0
}
if timeout == 0 {
return context.WithCancel(parent)
}
return context.WithTimeout(parent, timeout)
}