@@ -17,38 +17,39 @@ limitations under the License.
1717package watch
1818
1919import (
20+ "context"
2021 "errors"
2122 "time"
2223
24+ "github.com/golang/glog"
2325 "k8s.io/apimachinery/pkg/util/wait"
26+ "k8s.io/apimachinery/pkg/watch"
2427)
2528
2629// ConditionFunc returns true if the condition has been reached, false if it has not been reached yet,
2730// or an error if the condition cannot be checked and should terminate. In general, it is better to define
2831// level driven conditions over edge driven conditions (pod has ready=true, vs pod modified and ready changed
2932// from false to true).
30- type ConditionFunc func (event Event ) (bool , error )
33+ type ConditionFunc func (event watch. Event ) (bool , error )
3134
32- // ErrWatchClosed is returned when the watch channel is closed before timeout in Until .
33- var ErrWatchClosed = errors .New ("watch closed before Until timeout" )
35+ // ErrWatchClosed is returned when the watch channel is closed before timeout in UntilWithoutRetry .
36+ var ErrWatchClosed = errors .New ("watch closed before UntilWithoutRetry timeout" )
3437
35- // Until reads items from the watch until each provided condition succeeds, and then returns the last watch
38+ // UntilWithoutRetry reads items from the watch until each provided condition succeeds, and then returns the last watch
3639// encountered. The first condition that returns an error terminates the watch (and the event is also returned).
3740// If no event has been received, the returned event will be nil.
3841// Conditions are satisfied sequentially so as to provide a useful primitive for higher level composition.
39- // A zero timeout means to wait forever.
40- func Until (timeout time.Duration , watcher Interface , conditions ... ConditionFunc ) (* Event , error ) {
42+ // Waits until context deadline or until context is canceled.
43+ //
44+ // Warning: Unless you have a very specific use case (probably a special Watcher) don't use this function!!!
45+ // Warning: This will fail e.g. on API timeouts and/or 'too old resource version' error.
46+ // Warning: You are most probably looking for a function *Until* or *UntilWithSync* below,
47+ // Warning: solving such issues.
48+ // TODO: Consider making this function private to prevent misuse when the other occurrences in our codebase are gone.
49+ func UntilWithoutRetry (ctx context.Context , watcher watch.Interface , conditions ... ConditionFunc ) (* watch.Event , error ) {
4150 ch := watcher .ResultChan ()
4251 defer watcher .Stop ()
43- var after <- chan time.Time
44- if timeout > 0 {
45- after = time .After (timeout )
46- } else {
47- ch := make (chan time.Time )
48- defer close (ch )
49- after = ch
50- }
51- var lastEvent * Event
52+ var lastEvent * watch.Event
5253 for _ , condition := range conditions {
5354 // check the next condition against the previous event and short circuit waiting for the next watch
5455 if lastEvent != nil {
@@ -69,7 +70,6 @@ func Until(timeout time.Duration, watcher Interface, conditions ...ConditionFunc
6970 }
7071 lastEvent = & event
7172
72- // TODO: check for watch expired error and retry watch from latest point?
7373 done , err := condition (event )
7474 if err != nil {
7575 return lastEvent , err
@@ -78,10 +78,25 @@ func Until(timeout time.Duration, watcher Interface, conditions ...ConditionFunc
7878 break ConditionSucceeded
7979 }
8080
81- case <- after :
81+ case <- ctx . Done () :
8282 return lastEvent , wait .ErrWaitTimeout
8383 }
8484 }
8585 }
8686 return lastEvent , nil
8787}
88+
89+ // ContextWithOptionalTimeout wraps context.WithTimeout and handles infinite timeouts expressed as 0 duration.
90+ func ContextWithOptionalTimeout (parent context.Context , timeout time.Duration ) (context.Context , context.CancelFunc ) {
91+ if timeout < 0 {
92+ // This should be handled in validation
93+ glog .Errorf ("Timeout for context shall not be negative!" )
94+ timeout = 0
95+ }
96+
97+ if timeout == 0 {
98+ return context .WithCancel (parent )
99+ }
100+
101+ return context .WithTimeout (parent , timeout )
102+ }
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