diff options
Diffstat (limited to 'vendor/k8s.io/apimachinery/pkg/util/wait/wait.go')
| -rw-r--r-- | vendor/k8s.io/apimachinery/pkg/util/wait/wait.go | 504 |
1 files changed, 0 insertions, 504 deletions
diff --git a/vendor/k8s.io/apimachinery/pkg/util/wait/wait.go b/vendor/k8s.io/apimachinery/pkg/util/wait/wait.go deleted file mode 100644 index bc6b18d2b..000000000 --- a/vendor/k8s.io/apimachinery/pkg/util/wait/wait.go +++ /dev/null @@ -1,504 +0,0 @@ -/* -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) -} - -// UntilWithContext loops until context is done, running f every period. -// -// UntilWithContext is syntactic sugar on top of JitterUntilWithContext -// with zero jitter factor and with sliding = true (which means the timer -// for period starts after the f completes). -func UntilWithContext(ctx context.Context, f func(context.Context), period time.Duration) { - JitterUntilWithContext(ctx, f, period, 0.0, true) -} - -// 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) -} - -// NonSlidingUntilWithContext loops until context is done, running f every -// period. -// -// NonSlidingUntilWithContext is syntactic sugar on top of JitterUntilWithContext -// with zero jitter factor, with sliding = false (meaning the timer for period -// starts at the same time as the function starts). -func NonSlidingUntilWithContext(ctx context.Context, f func(context.Context), period time.Duration) { - JitterUntilWithContext(ctx, f, period, 0.0, false) -} - -// 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 - } - } -} - -// JitterUntilWithContext loops until context is done, 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. -// -// Cancel context to stop. f may not be invoked if context is already expired. -func JitterUntilWithContext(ctx context.Context, f func(context.Context), period time.Duration, jitterFactor float64, sliding bool) { - JitterUntil(func() { f(ctx) }, period, jitterFactor, sliding, ctx.Done()) -} - -// 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 { - // The initial duration. - Duration time.Duration - // Duration is multiplied by factor each iteration. Must be greater - // than or equal to zero. - Factor float64 - // The amount of jitter applied each iteration. Jitter is applied after - // cap. - Jitter float64 - // The number of steps before duration stops changing. If zero, initial - // duration is always used. Used for exponential backoff in combination - // with Factor. - Steps int - // The returned duration will never be greater than cap *before* jitter - // is applied. The actual maximum cap is `cap * (1.0 + jitter)`. - Cap time.Duration -} - -// Step returns the next interval in the exponential backoff. This method -// will mutate the provided backoff. -func (b *Backoff) Step() time.Duration { - if b.Steps < 1 { - if b.Jitter > 0 { - return Jitter(b.Duration, b.Jitter) - } - return b.Duration - } - b.Steps-- - - duration := b.Duration - - // calculate the next step - if b.Factor != 0 { - b.Duration = time.Duration(float64(b.Duration) * b.Factor) - if b.Cap > 0 && b.Duration > b.Cap { - b.Duration = b.Cap - b.Steps = 0 - } - } - - if b.Jitter > 0 { - duration = Jitter(duration, b.Jitter) - } - return duration -} - -// contextForChannel derives a child context from a parent channel. -// -// The derived context's Done channel is closed when the returned cancel function -// is called or when the parent channel is closed, whichever happens first. -// -// Note the caller must *always* call the CancelFunc, otherwise resources may be leaked. -func contextForChannel(parentCh <-chan struct{}) (context.Context, context.CancelFunc) { - ctx, cancel := context.WithCancel(context.Background()) - - go func() { - select { - case <-parentCh: - cancel() - case <-ctx.Done(): - } - }() - return ctx, cancel -} - -// 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 { - for backoff.Steps > 0 { - if ok, err := condition(); err != nil || ok { - return err - } - if backoff.Steps == 1 { - break - } - time.Sleep(backoff.Step()) - } - 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. -// -// PollImmediate 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 immediately Poll something forever, see PollImmediateInfinite. -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. -// -// PollUntil 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 { - ctx, cancel := contextForChannel(stopCh) - defer cancel() - return WaitFor(poller(interval, 0), condition, ctx.Done()) -} - -// PollImmediateUntil tries a condition func until it returns true, an error or stopCh is closed. -// -// PollImmediateUntil runs the 'condition' before waiting for the interval. -// 'condition' will always be invoked at least once. -func PollImmediateUntil(interval time.Duration, condition ConditionFunc, stopCh <-chan struct{}) error { - done, err := condition() - if err != nil { - return err - } - if done { - return nil - } - select { - case <-stopCh: - return ErrWaitTimeout - default: - return PollUntil(interval, 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 the channel is closed -// and 'fn' returns false without error, WaitFor returns ErrWaitTimeout. -// -// If 'fn' returns an error the loop ends and that error is returned. If -// 'fn' returns true the loop ends and nil is returned. -// -// ErrWaitTimeout will be returned if the 'done' channel is closed without fn ever -// returning true. -// -// When the done channel is closed, because the golang `select` statement is -// "uniform pseudo-random", the `fn` might still run one or multiple time, -// though eventually `WaitFor` will return. -func WaitFor(wait WaitFunc, fn ConditionFunc, done <-chan struct{}) error { - stopCh := make(chan struct{}) - defer close(stopCh) - c := wait(stopCh) - for { - select { - case _, open := <-c: - ok, err := fn() - if err != nil { - return err - } - if ok { - return nil - } - if !open { - return ErrWaitTimeout - } - case <-done: - 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, and in such a case -// it would be the caller's responsibility to close the done channel. -// Failure to do so would result in a leaked goroutine. -// -// 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 -} |