git subrepo clone (merge) https://github.com/kubernetes-incubator/metrics-server.git metrics-server
subrepo:
subdir: "metrics-server"
merged: "92d8412"
upstream:
origin: "https://github.com/kubernetes-incubator/metrics-server.git"
branch: "master"
commit: "92d8412"
git-subrepo:
version: "0.4.0"
origin: "???"
commit: "???"
diff --git a/metrics-server/vendor/k8s.io/apimachinery/pkg/util/wait/wait.go b/metrics-server/vendor/k8s.io/apimachinery/pkg/util/wait/wait.go
new file mode 100644
index 0000000..a25e924
--- /dev/null
+++ b/metrics-server/vendor/k8s.io/apimachinery/pkg/util/wait/wait.go
@@ -0,0 +1,405 @@
+/*
+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.
+//
+// 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 {
+ return WaitFor(poller(interval, 0), condition, stopCh)
+}
+
+// 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 '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
+}