mirror of
https://github.com/kubernetes/client-go.git
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Move Until from apimachinery to client-go
Kubernetes-commit: ccb92f6ef867c9e2ede91b7877a492a161986623
This commit is contained in:
Tomas Nozicka
Kubernetes Publisher
parent
791991630f
commit
5764fa1b79
87
tools/watch/until.go
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87
tools/watch/until.go
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@ -0,0 +1,87 @@
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/*
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Copyright 2016 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package watch
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import (
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"errors"
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"time"
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"k8s.io/apimachinery/pkg/util/wait"
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)
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// ConditionFunc returns true if the condition has been reached, false if it has not been reached yet,
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// or an error if the condition cannot be checked and should terminate. In general, it is better to define
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// level driven conditions over edge driven conditions (pod has ready=true, vs pod modified and ready changed
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// from false to true).
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type ConditionFunc func(event Event) (bool, error)
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// ErrWatchClosed is returned when the watch channel is closed before timeout in Until.
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var ErrWatchClosed = errors.New("watch closed before Until timeout")
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// Until reads items from the watch until each provided condition succeeds, and then returns the last watch
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// encountered. The first condition that returns an error terminates the watch (and the event is also returned).
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// If no event has been received, the returned event will be nil.
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// Conditions are satisfied sequentially so as to provide a useful primitive for higher level composition.
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// A zero timeout means to wait forever.
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func Until(timeout time.Duration, watcher Interface, conditions ...ConditionFunc) (*Event, error) {
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ch := watcher.ResultChan()
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defer watcher.Stop()
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var after <-chan time.Time
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if timeout > 0 {
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after = time.After(timeout)
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} else {
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ch := make(chan time.Time)
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defer close(ch)
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after = ch
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}
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var lastEvent *Event
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for _, condition := range conditions {
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// check the next condition against the previous event and short circuit waiting for the next watch
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if lastEvent != nil {
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done, err := condition(*lastEvent)
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if err != nil {
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return lastEvent, err
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}
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if done {
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continue
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}
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}
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ConditionSucceeded:
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for {
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select {
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case event, ok := <-ch:
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if !ok {
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return lastEvent, ErrWatchClosed
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}
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lastEvent = &event
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// TODO: check for watch expired error and retry watch from latest point?
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done, err := condition(event)
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if err != nil {
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return lastEvent, err
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}
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if done {
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break ConditionSucceeded
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}
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case <-after:
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return lastEvent, wait.ErrWaitTimeout
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}
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}
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}
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return lastEvent, nil
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}
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172
tools/watch/until_test.go
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172
tools/watch/until_test.go
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@ -0,0 +1,172 @@
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/*
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Copyright 2016 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package watch
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import (
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"errors"
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"strings"
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"testing"
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"time"
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"k8s.io/apimachinery/pkg/runtime"
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"k8s.io/apimachinery/pkg/runtime/schema"
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"k8s.io/apimachinery/pkg/util/wait"
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)
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type fakePod struct {
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name string
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}
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func (obj *fakePod) GetObjectKind() schema.ObjectKind { return schema.EmptyObjectKind }
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func (obj *fakePod) DeepCopyObject() runtime.Object { panic("DeepCopyObject not supported by fakePod") }
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func TestUntil(t *testing.T) {
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fw := NewFake()
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go func() {
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var obj *fakePod
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fw.Add(obj)
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fw.Modify(obj)
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}()
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conditions := []ConditionFunc{
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func(event Event) (bool, error) { return event.Type == Added, nil },
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func(event Event) (bool, error) { return event.Type == Modified, nil },
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}
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timeout := time.Minute
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lastEvent, err := Until(timeout, fw, conditions...)
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if err != nil {
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t.Fatalf("expected nil error, got %#v", err)
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}
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if lastEvent == nil {
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t.Fatal("expected an event")
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}
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if lastEvent.Type != Modified {
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t.Fatalf("expected MODIFIED event type, got %v", lastEvent.Type)
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}
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if got, isPod := lastEvent.Object.(*fakePod); !isPod {
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t.Fatalf("expected a pod event, got %#v", got)
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}
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}
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func TestUntilMultipleConditions(t *testing.T) {
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fw := NewFake()
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go func() {
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var obj *fakePod
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fw.Add(obj)
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}()
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conditions := []ConditionFunc{
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func(event Event) (bool, error) { return event.Type == Added, nil },
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func(event Event) (bool, error) { return event.Type == Added, nil },
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}
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timeout := time.Minute
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lastEvent, err := Until(timeout, fw, conditions...)
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if err != nil {
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t.Fatalf("expected nil error, got %#v", err)
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}
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if lastEvent == nil {
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t.Fatal("expected an event")
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}
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if lastEvent.Type != Added {
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t.Fatalf("expected MODIFIED event type, got %v", lastEvent.Type)
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}
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if got, isPod := lastEvent.Object.(*fakePod); !isPod {
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t.Fatalf("expected a pod event, got %#v", got)
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}
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}
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func TestUntilMultipleConditionsFail(t *testing.T) {
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fw := NewFake()
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go func() {
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var obj *fakePod
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fw.Add(obj)
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}()
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conditions := []ConditionFunc{
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func(event Event) (bool, error) { return event.Type == Added, nil },
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func(event Event) (bool, error) { return event.Type == Added, nil },
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func(event Event) (bool, error) { return event.Type == Deleted, nil },
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}
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timeout := 10 * time.Second
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lastEvent, err := Until(timeout, fw, conditions...)
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if err != wait.ErrWaitTimeout {
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t.Fatalf("expected ErrWaitTimeout error, got %#v", err)
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}
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if lastEvent == nil {
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t.Fatal("expected an event")
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}
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if lastEvent.Type != Added {
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t.Fatalf("expected ADDED event type, got %v", lastEvent.Type)
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}
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if got, isPod := lastEvent.Object.(*fakePod); !isPod {
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t.Fatalf("expected a pod event, got %#v", got)
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}
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}
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func TestUntilTimeout(t *testing.T) {
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fw := NewFake()
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go func() {
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var obj *fakePod
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fw.Add(obj)
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fw.Modify(obj)
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}()
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conditions := []ConditionFunc{
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func(event Event) (bool, error) {
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return event.Type == Added, nil
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},
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func(event Event) (bool, error) {
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return event.Type == Modified, nil
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},
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}
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timeout := time.Duration(0)
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lastEvent, err := Until(timeout, fw, conditions...)
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if err != nil {
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t.Fatalf("expected nil error, got %#v", err)
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}
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if lastEvent == nil {
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t.Fatal("expected an event")
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}
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if lastEvent.Type != Modified {
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t.Fatalf("expected MODIFIED event type, got %v", lastEvent.Type)
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}
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if got, isPod := lastEvent.Object.(*fakePod); !isPod {
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t.Fatalf("expected a pod event, got %#v", got)
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}
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}
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func TestUntilErrorCondition(t *testing.T) {
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fw := NewFake()
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go func() {
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var obj *fakePod
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fw.Add(obj)
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}()
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expected := "something bad"
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conditions := []ConditionFunc{
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func(event Event) (bool, error) { return event.Type == Added, nil },
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func(event Event) (bool, error) { return false, errors.New(expected) },
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}
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timeout := time.Minute
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_, err := Until(timeout, fw, conditions...)
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if err == nil {
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t.Fatal("expected an error")
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}
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if !strings.Contains(err.Error(), expected) {
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t.Fatalf("expected %q in error string, got %q", expected, err.Error())
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}
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}
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