mirror of
https://github.com/ceph/ceph-csi.git
synced 2024-12-05 04:30:23 +00:00
386 lines
11 KiB
Go
386 lines
11 KiB
Go
|
/*
|
||
|
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 wait
|
||
|
|
||
|
import (
|
||
|
"context"
|
||
|
"errors"
|
||
|
"math/rand"
|
||
|
"sync"
|
||
|
"time"
|
||
|
|
||
|
"k8s.io/apimachinery/pkg/util/runtime"
|
||
|
)
|
||
|
|
||
|
// For any test of the style:
|
||
|
// ...
|
||
|
// <- time.After(timeout):
|
||
|
// t.Errorf("Timed out")
|
||
|
// The value for timeout should effectively be "forever." Obviously we don't want our tests to truly lock up forever, but 30s
|
||
|
// is long enough that it is effectively forever for the things that can slow down a run on a heavily contended machine
|
||
|
// (GC, seeks, etc), but not so long as to make a developer ctrl-c a test run if they do happen to break that test.
|
||
|
var ForeverTestTimeout = time.Second * 30
|
||
|
|
||
|
// NeverStop may be passed to Until to make it never stop.
|
||
|
var NeverStop <-chan struct{} = make(chan struct{})
|
||
|
|
||
|
// Group allows to start a group of goroutines and wait for their completion.
|
||
|
type Group struct {
|
||
|
wg sync.WaitGroup
|
||
|
}
|
||
|
|
||
|
func (g *Group) Wait() {
|
||
|
g.wg.Wait()
|
||
|
}
|
||
|
|
||
|
// StartWithChannel starts f in a new goroutine in the group.
|
||
|
// stopCh is passed to f as an argument. f should stop when stopCh is available.
|
||
|
func (g *Group) StartWithChannel(stopCh <-chan struct{}, f func(stopCh <-chan struct{})) {
|
||
|
g.Start(func() {
|
||
|
f(stopCh)
|
||
|
})
|
||
|
}
|
||
|
|
||
|
// StartWithContext starts f in a new goroutine in the group.
|
||
|
// ctx is passed to f as an argument. f should stop when ctx.Done() is available.
|
||
|
func (g *Group) StartWithContext(ctx context.Context, f func(context.Context)) {
|
||
|
g.Start(func() {
|
||
|
f(ctx)
|
||
|
})
|
||
|
}
|
||
|
|
||
|
// Start starts f in a new goroutine in the group.
|
||
|
func (g *Group) Start(f func()) {
|
||
|
g.wg.Add(1)
|
||
|
go func() {
|
||
|
defer g.wg.Done()
|
||
|
f()
|
||
|
}()
|
||
|
}
|
||
|
|
||
|
// Forever calls f every period for ever.
|
||
|
//
|
||
|
// Forever is syntactic sugar on top of Until.
|
||
|
func Forever(f func(), period time.Duration) {
|
||
|
Until(f, period, NeverStop)
|
||
|
}
|
||
|
|
||
|
// Until loops until stop channel is closed, running f every period.
|
||
|
//
|
||
|
// Until is syntactic sugar on top of JitterUntil with zero jitter factor and
|
||
|
// with sliding = true (which means the timer for period starts after the f
|
||
|
// completes).
|
||
|
func Until(f func(), period time.Duration, stopCh <-chan struct{}) {
|
||
|
JitterUntil(f, period, 0.0, true, stopCh)
|
||
|
}
|
||
|
|
||
|
// NonSlidingUntil loops until stop channel is closed, running f every
|
||
|
// period.
|
||
|
//
|
||
|
// NonSlidingUntil is syntactic sugar on top of JitterUntil with zero jitter
|
||
|
// factor, with sliding = false (meaning the timer for period starts at the same
|
||
|
// time as the function starts).
|
||
|
func NonSlidingUntil(f func(), period time.Duration, stopCh <-chan struct{}) {
|
||
|
JitterUntil(f, period, 0.0, false, stopCh)
|
||
|
}
|
||
|
|
||
|
// JitterUntil loops until stop channel is closed, running f every period.
|
||
|
//
|
||
|
// If jitterFactor is positive, the period is jittered before every run of f.
|
||
|
// If jitterFactor is not positive, the period is unchanged and not jittered.
|
||
|
//
|
||
|
// If sliding is true, the period is computed after f runs. If it is false then
|
||
|
// period includes the runtime for f.
|
||
|
//
|
||
|
// Close stopCh to stop. f may not be invoked if stop channel is already
|
||
|
// closed. Pass NeverStop to if you don't want it stop.
|
||
|
func JitterUntil(f func(), period time.Duration, jitterFactor float64, sliding bool, stopCh <-chan struct{}) {
|
||
|
var t *time.Timer
|
||
|
var sawTimeout bool
|
||
|
|
||
|
for {
|
||
|
select {
|
||
|
case <-stopCh:
|
||
|
return
|
||
|
default:
|
||
|
}
|
||
|
|
||
|
jitteredPeriod := period
|
||
|
if jitterFactor > 0.0 {
|
||
|
jitteredPeriod = Jitter(period, jitterFactor)
|
||
|
}
|
||
|
|
||
|
if !sliding {
|
||
|
t = resetOrReuseTimer(t, jitteredPeriod, sawTimeout)
|
||
|
}
|
||
|
|
||
|
func() {
|
||
|
defer runtime.HandleCrash()
|
||
|
f()
|
||
|
}()
|
||
|
|
||
|
if sliding {
|
||
|
t = resetOrReuseTimer(t, jitteredPeriod, sawTimeout)
|
||
|
}
|
||
|
|
||
|
// NOTE: b/c there is no priority selection in golang
|
||
|
// it is possible for this to race, meaning we could
|
||
|
// trigger t.C and stopCh, and t.C select falls through.
|
||
|
// In order to mitigate we re-check stopCh at the beginning
|
||
|
// of every loop to prevent extra executions of f().
|
||
|
select {
|
||
|
case <-stopCh:
|
||
|
return
|
||
|
case <-t.C:
|
||
|
sawTimeout = true
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// Jitter returns a time.Duration between duration and duration + maxFactor *
|
||
|
// duration.
|
||
|
//
|
||
|
// This allows clients to avoid converging on periodic behavior. If maxFactor
|
||
|
// is 0.0, a suggested default value will be chosen.
|
||
|
func Jitter(duration time.Duration, maxFactor float64) time.Duration {
|
||
|
if maxFactor <= 0.0 {
|
||
|
maxFactor = 1.0
|
||
|
}
|
||
|
wait := duration + time.Duration(rand.Float64()*maxFactor*float64(duration))
|
||
|
return wait
|
||
|
}
|
||
|
|
||
|
// ErrWaitTimeout is returned when the condition exited without success.
|
||
|
var ErrWaitTimeout = errors.New("timed out waiting for the condition")
|
||
|
|
||
|
// ConditionFunc returns true if the condition is satisfied, or an error
|
||
|
// if the loop should be aborted.
|
||
|
type ConditionFunc func() (done bool, err error)
|
||
|
|
||
|
// Backoff holds parameters applied to a Backoff function.
|
||
|
type Backoff struct {
|
||
|
Duration time.Duration // the base duration
|
||
|
Factor float64 // Duration is multiplied by factor each iteration
|
||
|
Jitter float64 // The amount of jitter applied each iteration
|
||
|
Steps int // Exit with error after this many steps
|
||
|
}
|
||
|
|
||
|
// ExponentialBackoff repeats a condition check with exponential backoff.
|
||
|
//
|
||
|
// It checks the condition up to Steps times, increasing the wait by multiplying
|
||
|
// the previous duration by Factor.
|
||
|
//
|
||
|
// If Jitter is greater than zero, a random amount of each duration is added
|
||
|
// (between duration and duration*(1+jitter)).
|
||
|
//
|
||
|
// If the condition never returns true, ErrWaitTimeout is returned. All other
|
||
|
// errors terminate immediately.
|
||
|
func ExponentialBackoff(backoff Backoff, condition ConditionFunc) error {
|
||
|
duration := backoff.Duration
|
||
|
for i := 0; i < backoff.Steps; i++ {
|
||
|
if i != 0 {
|
||
|
adjusted := duration
|
||
|
if backoff.Jitter > 0.0 {
|
||
|
adjusted = Jitter(duration, backoff.Jitter)
|
||
|
}
|
||
|
time.Sleep(adjusted)
|
||
|
duration = time.Duration(float64(duration) * backoff.Factor)
|
||
|
}
|
||
|
if ok, err := condition(); err != nil || ok {
|
||
|
return err
|
||
|
}
|
||
|
}
|
||
|
return ErrWaitTimeout
|
||
|
}
|
||
|
|
||
|
// Poll tries a condition func until it returns true, an error, or the timeout
|
||
|
// is reached.
|
||
|
//
|
||
|
// Poll always waits the interval before the run of 'condition'.
|
||
|
// 'condition' will always be invoked at least once.
|
||
|
//
|
||
|
// Some intervals may be missed if the condition takes too long or the time
|
||
|
// window is too short.
|
||
|
//
|
||
|
// If you want to Poll something forever, see PollInfinite.
|
||
|
func Poll(interval, timeout time.Duration, condition ConditionFunc) error {
|
||
|
return pollInternal(poller(interval, timeout), condition)
|
||
|
}
|
||
|
|
||
|
func pollInternal(wait WaitFunc, condition ConditionFunc) error {
|
||
|
done := make(chan struct{})
|
||
|
defer close(done)
|
||
|
return WaitFor(wait, condition, done)
|
||
|
}
|
||
|
|
||
|
// PollImmediate tries a condition func until it returns true, an error, or the timeout
|
||
|
// is reached.
|
||
|
//
|
||
|
// Poll always checks 'condition' before waiting for the interval. 'condition'
|
||
|
// will always be invoked at least once.
|
||
|
//
|
||
|
// Some intervals may be missed if the condition takes too long or the time
|
||
|
// window is too short.
|
||
|
//
|
||
|
// If you want to Poll something forever, see PollInfinite.
|
||
|
func PollImmediate(interval, timeout time.Duration, condition ConditionFunc) error {
|
||
|
return pollImmediateInternal(poller(interval, timeout), condition)
|
||
|
}
|
||
|
|
||
|
func pollImmediateInternal(wait WaitFunc, condition ConditionFunc) error {
|
||
|
done, err := condition()
|
||
|
if err != nil {
|
||
|
return err
|
||
|
}
|
||
|
if done {
|
||
|
return nil
|
||
|
}
|
||
|
return pollInternal(wait, condition)
|
||
|
}
|
||
|
|
||
|
// PollInfinite tries a condition func until it returns true or an error
|
||
|
//
|
||
|
// PollInfinite always waits the interval before the run of 'condition'.
|
||
|
//
|
||
|
// Some intervals may be missed if the condition takes too long or the time
|
||
|
// window is too short.
|
||
|
func PollInfinite(interval time.Duration, condition ConditionFunc) error {
|
||
|
done := make(chan struct{})
|
||
|
defer close(done)
|
||
|
return PollUntil(interval, condition, done)
|
||
|
}
|
||
|
|
||
|
// PollImmediateInfinite tries a condition func until it returns true or an error
|
||
|
//
|
||
|
// PollImmediateInfinite runs the 'condition' before waiting for the interval.
|
||
|
//
|
||
|
// Some intervals may be missed if the condition takes too long or the time
|
||
|
// window is too short.
|
||
|
func PollImmediateInfinite(interval time.Duration, condition ConditionFunc) error {
|
||
|
done, err := condition()
|
||
|
if err != nil {
|
||
|
return err
|
||
|
}
|
||
|
if done {
|
||
|
return nil
|
||
|
}
|
||
|
return PollInfinite(interval, condition)
|
||
|
}
|
||
|
|
||
|
// PollUntil tries a condition func until it returns true, an error or stopCh is
|
||
|
// closed.
|
||
|
//
|
||
|
// PolUntil always waits interval before the first run of 'condition'.
|
||
|
// 'condition' will always be invoked at least once.
|
||
|
func PollUntil(interval time.Duration, condition ConditionFunc, stopCh <-chan struct{}) error {
|
||
|
return WaitFor(poller(interval, 0), condition, stopCh)
|
||
|
}
|
||
|
|
||
|
// WaitFunc creates a channel that receives an item every time a test
|
||
|
// should be executed and is closed when the last test should be invoked.
|
||
|
type WaitFunc func(done <-chan struct{}) <-chan struct{}
|
||
|
|
||
|
// WaitFor continually checks 'fn' as driven by 'wait'.
|
||
|
//
|
||
|
// WaitFor gets a channel from 'wait()'', and then invokes 'fn' once for every value
|
||
|
// placed on the channel and once more when the channel is closed.
|
||
|
//
|
||
|
// If 'fn' returns an error the loop ends and that error is returned, and if
|
||
|
// 'fn' returns true the loop ends and nil is returned.
|
||
|
//
|
||
|
// ErrWaitTimeout will be returned if the channel is closed without fn ever
|
||
|
// returning true.
|
||
|
func WaitFor(wait WaitFunc, fn ConditionFunc, done <-chan struct{}) error {
|
||
|
c := wait(done)
|
||
|
for {
|
||
|
_, open := <-c
|
||
|
ok, err := fn()
|
||
|
if err != nil {
|
||
|
return err
|
||
|
}
|
||
|
if ok {
|
||
|
return nil
|
||
|
}
|
||
|
if !open {
|
||
|
break
|
||
|
}
|
||
|
}
|
||
|
return ErrWaitTimeout
|
||
|
}
|
||
|
|
||
|
// poller returns a WaitFunc that will send to the channel every interval until
|
||
|
// timeout has elapsed and then closes the channel.
|
||
|
//
|
||
|
// Over very short intervals you may receive no ticks before the channel is
|
||
|
// closed. A timeout of 0 is interpreted as an infinity.
|
||
|
//
|
||
|
// Output ticks are not buffered. If the channel is not ready to receive an
|
||
|
// item, the tick is skipped.
|
||
|
func poller(interval, timeout time.Duration) WaitFunc {
|
||
|
return WaitFunc(func(done <-chan struct{}) <-chan struct{} {
|
||
|
ch := make(chan struct{})
|
||
|
|
||
|
go func() {
|
||
|
defer close(ch)
|
||
|
|
||
|
tick := time.NewTicker(interval)
|
||
|
defer tick.Stop()
|
||
|
|
||
|
var after <-chan time.Time
|
||
|
if timeout != 0 {
|
||
|
// time.After is more convenient, but it
|
||
|
// potentially leaves timers around much longer
|
||
|
// than necessary if we exit early.
|
||
|
timer := time.NewTimer(timeout)
|
||
|
after = timer.C
|
||
|
defer timer.Stop()
|
||
|
}
|
||
|
|
||
|
for {
|
||
|
select {
|
||
|
case <-tick.C:
|
||
|
// If the consumer isn't ready for this signal drop it and
|
||
|
// check the other channels.
|
||
|
select {
|
||
|
case ch <- struct{}{}:
|
||
|
default:
|
||
|
}
|
||
|
case <-after:
|
||
|
return
|
||
|
case <-done:
|
||
|
return
|
||
|
}
|
||
|
}
|
||
|
}()
|
||
|
|
||
|
return ch
|
||
|
})
|
||
|
}
|
||
|
|
||
|
// resetOrReuseTimer avoids allocating a new timer if one is already in use.
|
||
|
// Not safe for multiple threads.
|
||
|
func resetOrReuseTimer(t *time.Timer, d time.Duration, sawTimeout bool) *time.Timer {
|
||
|
if t == nil {
|
||
|
return time.NewTimer(d)
|
||
|
}
|
||
|
if !t.Stop() && !sawTimeout {
|
||
|
<-t.C
|
||
|
}
|
||
|
t.Reset(d)
|
||
|
return t
|
||
|
}
|