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author | Matthew Heon <matthew.heon@gmail.com> | 2017-11-01 11:24:59 -0400 |
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committer | Matthew Heon <matthew.heon@gmail.com> | 2017-11-01 11:24:59 -0400 |
commit | a031b83a09a8628435317a03f199cdc18b78262f (patch) | |
tree | bc017a96769ce6de33745b8b0b1304ccf38e9df0 /vendor/k8s.io/apimachinery/pkg/util/wait | |
parent | 2b74391cd5281f6fdf391ff8ad50fd1490f6bf89 (diff) | |
download | podman-a031b83a09a8628435317a03f199cdc18b78262f.tar.gz podman-a031b83a09a8628435317a03f199cdc18b78262f.tar.bz2 podman-a031b83a09a8628435317a03f199cdc18b78262f.zip |
Initial checkin from CRI-O repo
Signed-off-by: Matthew Heon <matthew.heon@gmail.com>
Diffstat (limited to 'vendor/k8s.io/apimachinery/pkg/util/wait')
-rw-r--r-- | vendor/k8s.io/apimachinery/pkg/util/wait/doc.go | 19 | ||||
-rw-r--r-- | vendor/k8s.io/apimachinery/pkg/util/wait/wait.go | 349 |
2 files changed, 368 insertions, 0 deletions
diff --git a/vendor/k8s.io/apimachinery/pkg/util/wait/doc.go b/vendor/k8s.io/apimachinery/pkg/util/wait/doc.go new file mode 100644 index 000000000..3f0c968ec --- /dev/null +++ b/vendor/k8s.io/apimachinery/pkg/util/wait/doc.go @@ -0,0 +1,19 @@ +/* +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 provides tools for polling or listening for changes +// to a condition. +package wait // import "k8s.io/apimachinery/pkg/util/wait" diff --git a/vendor/k8s.io/apimachinery/pkg/util/wait/wait.go b/vendor/k8s.io/apimachinery/pkg/util/wait/wait.go new file mode 100644 index 000000000..badaa2159 --- /dev/null +++ b/vendor/k8s.io/apimachinery/pkg/util/wait/wait.go @@ -0,0 +1,349 @@ +/* +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 ( + "errors" + "math/rand" + "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{}) + +// 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 +} |