mirror of
https://github.com/ceph/ceph-csi.git
synced 2024-11-18 12:20:24 +00:00
96 lines
2.8 KiB
Go
96 lines
2.8 KiB
Go
/*
|
|
Copyright 2023 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 wait
|
|
|
|
import (
|
|
"context"
|
|
"time"
|
|
|
|
"k8s.io/apimachinery/pkg/util/runtime"
|
|
)
|
|
|
|
// loopConditionUntilContext executes the provided condition at intervals defined by
|
|
// the provided timer until the provided context is cancelled, the condition returns
|
|
// true, or the condition returns an error. If sliding is true, the period is computed
|
|
// after condition runs. If it is false then period includes the runtime for condition.
|
|
// If immediate is false the first delay happens before any call to condition, if
|
|
// immediate is true the condition will be invoked before waiting and guarantees that
|
|
// the condition is invoked at least once, regardless of whether the context has been
|
|
// cancelled. The returned error is the error returned by the last condition or the
|
|
// context error if the context was terminated.
|
|
//
|
|
// This is the common loop construct for all polling in the wait package.
|
|
func loopConditionUntilContext(ctx context.Context, t Timer, immediate, sliding bool, condition ConditionWithContextFunc) error {
|
|
defer t.Stop()
|
|
|
|
var timeCh <-chan time.Time
|
|
doneCh := ctx.Done()
|
|
|
|
if !sliding {
|
|
timeCh = t.C()
|
|
}
|
|
|
|
// if immediate is true the condition is
|
|
// guaranteed to be executed at least once,
|
|
// if we haven't requested immediate execution, delay once
|
|
if immediate {
|
|
if ok, err := func() (bool, error) {
|
|
defer runtime.HandleCrash()
|
|
return condition(ctx)
|
|
}(); err != nil || ok {
|
|
return err
|
|
}
|
|
}
|
|
|
|
if sliding {
|
|
timeCh = t.C()
|
|
}
|
|
|
|
for {
|
|
|
|
// Wait for either the context to be cancelled or the next invocation be called
|
|
select {
|
|
case <-doneCh:
|
|
return ctx.Err()
|
|
case <-timeCh:
|
|
}
|
|
|
|
// IMPORTANT: Because there is no channel priority selection in golang
|
|
// it is possible for very short timers to "win" the race in the previous select
|
|
// repeatedly even when the context has been canceled. We therefore must
|
|
// explicitly check for context cancellation on every loop and exit if true to
|
|
// guarantee that we don't invoke condition more than once after context has
|
|
// been cancelled.
|
|
if err := ctx.Err(); err != nil {
|
|
return err
|
|
}
|
|
|
|
if !sliding {
|
|
t.Next()
|
|
}
|
|
if ok, err := func() (bool, error) {
|
|
defer runtime.HandleCrash()
|
|
return condition(ctx)
|
|
}(); err != nil || ok {
|
|
return err
|
|
}
|
|
if sliding {
|
|
t.Next()
|
|
}
|
|
}
|
|
}
|