Update dependency go modules in client for k8s v1.26.0-rc.0

client/vendor/k8s.io/client-go/util/flowcontrol/backoff.go

@@ -0,0 +1,181 @@
+/*
+Copyright 2015 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 flowcontrol
+
+import (
+	"math/rand"
+	"sync"
+	"time"
+
+	"k8s.io/utils/clock"
+	testingclock "k8s.io/utils/clock/testing"
+	"k8s.io/utils/integer"
+)
+
+type backoffEntry struct {
+	backoff    time.Duration
+	lastUpdate time.Time
+}
+
+type Backoff struct {
+	sync.RWMutex
+	Clock           clock.Clock
+	defaultDuration time.Duration
+	maxDuration     time.Duration
+	perItemBackoff  map[string]*backoffEntry
+	rand            *rand.Rand
+
+	// maxJitterFactor adds jitter to the exponentially backed off delay.
+	// if maxJitterFactor is zero, no jitter is added to the delay in
+	// order to maintain current behavior.
+	maxJitterFactor float64
+}
+
+func NewFakeBackOff(initial, max time.Duration, tc *testingclock.FakeClock) *Backoff {
+	return newBackoff(tc, initial, max, 0.0)
+}
+
+func NewBackOff(initial, max time.Duration) *Backoff {
+	return NewBackOffWithJitter(initial, max, 0.0)
+}
+
+func NewFakeBackOffWithJitter(initial, max time.Duration, tc *testingclock.FakeClock, maxJitterFactor float64) *Backoff {
+	return newBackoff(tc, initial, max, maxJitterFactor)
+}
+
+func NewBackOffWithJitter(initial, max time.Duration, maxJitterFactor float64) *Backoff {
+	clock := clock.RealClock{}
+	return newBackoff(clock, initial, max, maxJitterFactor)
+}
+
+func newBackoff(clock clock.Clock, initial, max time.Duration, maxJitterFactor float64) *Backoff {
+	var random *rand.Rand
+	if maxJitterFactor > 0 {
+		random = rand.New(rand.NewSource(clock.Now().UnixNano()))
+	}
+	return &Backoff{
+		perItemBackoff:  map[string]*backoffEntry{},
+		Clock:           clock,
+		defaultDuration: initial,
+		maxDuration:     max,
+		maxJitterFactor: maxJitterFactor,
+		rand:            random,
+	}
+}
+
+// Get the current backoff Duration
+func (p *Backoff) Get(id string) time.Duration {
+	p.RLock()
+	defer p.RUnlock()
+	var delay time.Duration
+	entry, ok := p.perItemBackoff[id]
+	if ok {
+		delay = entry.backoff
+	}
+	return delay
+}
+
+// move backoff to the next mark, capping at maxDuration
+func (p *Backoff) Next(id string, eventTime time.Time) {
+	p.Lock()
+	defer p.Unlock()
+	entry, ok := p.perItemBackoff[id]
+	if !ok || hasExpired(eventTime, entry.lastUpdate, p.maxDuration) {
+		entry = p.initEntryUnsafe(id)
+		entry.backoff += p.jitter(entry.backoff)
+	} else {
+		delay := entry.backoff * 2       // exponential
+		delay += p.jitter(entry.backoff) // add some jitter to the delay
+		entry.backoff = time.Duration(integer.Int64Min(int64(delay), int64(p.maxDuration)))
+	}
+	entry.lastUpdate = p.Clock.Now()
+}
+
+// Reset forces clearing of all backoff data for a given key.
+func (p *Backoff) Reset(id string) {
+	p.Lock()
+	defer p.Unlock()
+	delete(p.perItemBackoff, id)
+}
+
+// Returns True if the elapsed time since eventTime is smaller than the current backoff window
+func (p *Backoff) IsInBackOffSince(id string, eventTime time.Time) bool {
+	p.RLock()
+	defer p.RUnlock()
+	entry, ok := p.perItemBackoff[id]
+	if !ok {
+		return false
+	}
+	if hasExpired(eventTime, entry.lastUpdate, p.maxDuration) {
+		return false
+	}
+	return p.Clock.Since(eventTime) < entry.backoff
+}
+
+// Returns True if time since lastupdate is less than the current backoff window.
+func (p *Backoff) IsInBackOffSinceUpdate(id string, eventTime time.Time) bool {
+	p.RLock()
+	defer p.RUnlock()
+	entry, ok := p.perItemBackoff[id]
+	if !ok {
+		return false
+	}
+	if hasExpired(eventTime, entry.lastUpdate, p.maxDuration) {
+		return false
+	}
+	return eventTime.Sub(entry.lastUpdate) < entry.backoff
+}
+
+// Garbage collect records that have aged past maxDuration. Backoff users are expected
+// to invoke this periodically.
+func (p *Backoff) GC() {
+	p.Lock()
+	defer p.Unlock()
+	now := p.Clock.Now()
+	for id, entry := range p.perItemBackoff {
+		if now.Sub(entry.lastUpdate) > p.maxDuration*2 {
+			// GC when entry has not been updated for 2*maxDuration
+			delete(p.perItemBackoff, id)
+		}
+	}
+}
+
+func (p *Backoff) DeleteEntry(id string) {
+	p.Lock()
+	defer p.Unlock()
+	delete(p.perItemBackoff, id)
+}
+
+// Take a lock on *Backoff, before calling initEntryUnsafe
+func (p *Backoff) initEntryUnsafe(id string) *backoffEntry {
+	entry := &backoffEntry{backoff: p.defaultDuration}
+	p.perItemBackoff[id] = entry
+	return entry
+}
+
+func (p *Backoff) jitter(delay time.Duration) time.Duration {
+	if p.rand == nil {
+		return 0
+	}
+
+	return time.Duration(p.rand.Float64() * p.maxJitterFactor * float64(delay))
+}
+
+// After 2*maxDuration we restart the backoff factor to the beginning
+func hasExpired(eventTime time.Time, lastUpdate time.Time, maxDuration time.Duration) bool {
+	return eventTime.Sub(lastUpdate) > maxDuration*2 // consider stable if it's ok for twice the maxDuration
+}