func (le *LeaderElector) release() bool {
	if !le.IsLeader() {
		return true
	}
	leaderElectionRecord := rl.LeaderElectionRecord{
		LeaderTransitions: le.observedRecord.LeaderTransitions,
	}
	if err := le.config.Lock.Update(leaderElectionRecord); err != nil {
		klog.Errorf("Failed to release lock: %v", err)
		return false
	}
	le.observedRecord = leaderElectionRecord
	le.observedTime = le.clock.Now()
	return true
}
release attempts to release the leader lease if we have acquired it.
package leaderelection
import (
	"bytes"
	"context"
	"fmt"
	"time"
	"k8s.io/apimachinery/pkg/api/errors"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/util/clock"
	"k8s.io/apimachinery/pkg/util/runtime"
	"k8s.io/apimachinery/pkg/util/wait"
	rl "k8s.io/client-go/tools/leaderelection/resourcelock"
	"k8s.io/klog"
)
const (
	JitterFactor = 1.2
)
func NewLeaderElector(lec LeaderElectionConfig) (*LeaderElector, error) {
	if lec.LeaseDuration <= lec.RenewDeadline {
		return nil, fmt.Errorf("leaseDuration must be greater than renewDeadline")
	}
	if lec.RenewDeadline <= time.Duration(JitterFactor*float64(lec.RetryPeriod)) {
		return nil, fmt.Errorf("renewDeadline must be greater than retryPeriod*JitterFactor")
	}
	if lec.LeaseDuration < 1 {
		return nil, fmt.Errorf("leaseDuration must be greater than zero")
	}
	if lec.RenewDeadline < 1 {
		return nil, fmt.Errorf("renewDeadline must be greater than zero")
	}
	if lec.RetryPeriod < 1 {
		return nil, fmt.Errorf("retryPeriod must be greater than zero")
	}
	if lec.Callbacks.OnStartedLeading == nil {
		return nil, fmt.Errorf("OnStartedLeading callback must not be nil")
	}
	if lec.Callbacks.OnStoppedLeading == nil {
		return nil, fmt.Errorf("OnStoppedLeading callback must not be nil")
	}
	if lec.Lock == nil {
		return nil, fmt.Errorf("Lock must not be nil.")
	}
	le := LeaderElector{
		config:  lec,
		clock:   clock.RealClock{},
		metrics: globalMetricsFactory.newLeaderMetrics(),
	}
	le.metrics.leaderOff(le.config.Name)
	return &le, nil
}
type LeaderElectionConfig struct {
	Lock rl.Interface
	LeaseDuration time.Duration
	RenewDeadline time.Duration
	RetryPeriod time.Duration
	Callbacks LeaderCallbacks
	WatchDog *HealthzAdaptor
	ReleaseOnCancel bool
	Name string
}
type LeaderCallbacks struct {
	OnStartedLeading func(context.Context)
	OnStoppedLeading func()
	OnNewLeader func(identity string)
}
type LeaderElector struct {
	config LeaderElectionConfig
	observedRecord    rl.LeaderElectionRecord
	observedRawRecord []byte
	observedTime      time.Time
	reportedLeader string
	clock clock.Clock
	metrics leaderMetricsAdapter
	name string
}
func (le *LeaderElector) Run(ctx context.Context) {
	defer func() {
		runtime.HandleCrash()
		le.config.Callbacks.OnStoppedLeading()
	}()
	if !le.acquire(ctx) {
		return  
	}
	ctx, cancel := context.WithCancel(ctx)
	defer cancel()
	go le.config.Callbacks.OnStartedLeading(ctx)
	le.renew(ctx)
}
func RunOrDie(ctx context.Context, lec LeaderElectionConfig) {
	le, err := NewLeaderElector(lec)
	if err != nil {
		panic(err)
	}
	if lec.WatchDog != nil {
		lec.WatchDog.SetLeaderElection(le)
	}
	le.Run(ctx)
}
func (le *LeaderElector) GetLeader() string {
	return le.observedRecord.HolderIdentity
}
func (le *LeaderElector) IsLeader() bool {
	return le.observedRecord.HolderIdentity == le.config.Lock.Identity()
}
func (le *LeaderElector) acquire(ctx context.Context) bool {
	ctx, cancel := context.WithCancel(ctx)
	defer cancel()
	succeeded := false
	desc := le.config.Lock.Describe()
	klog.Infof("attempting to acquire leader lease  %v...", desc)
	wait.JitterUntil(func() {
		succeeded = le.tryAcquireOrRenew()
		le.maybeReportTransition()
		if !succeeded {
			klog.V(4).Infof("failed to acquire lease %v", desc)
			return
		}
		le.config.Lock.RecordEvent("became leader")
		le.metrics.leaderOn(le.config.Name)
		klog.Infof("successfully acquired lease %v", desc)
		cancel()
	}, le.config.RetryPeriod, JitterFactor, true, ctx.Done())
	return succeeded
}
func (le *LeaderElector) renew(ctx context.Context) {
	ctx, cancel := context.WithCancel(ctx)
	defer cancel()
	wait.Until(func() {
		timeoutCtx, timeoutCancel := context.WithTimeout(ctx, le.config.RenewDeadline)
		defer timeoutCancel()
		err := wait.PollImmediateUntil(le.config.RetryPeriod, func() (bool, error) {
			done := make(chan bool, 1)
			go func() {
				defer close(done)
				done <- le.tryAcquireOrRenew()
			}()
			select {
			case <-timeoutCtx.Done():
				return false, fmt.Errorf("failed to tryAcquireOrRenew %s", timeoutCtx.Err())
			case result := <-done:
				return result, nil
			}
		}, timeoutCtx.Done())
		le.maybeReportTransition()
		desc := le.config.Lock.Describe()
		if err == nil {
			klog.V(5).Infof("successfully renewed lease %v", desc)
			return
		}
		le.config.Lock.RecordEvent("stopped leading")
		le.metrics.leaderOff(le.config.Name)
		klog.Infof("failed to renew lease %v: %v", desc, err)
		cancel()
	}, le.config.RetryPeriod, ctx.Done())
	if le.config.ReleaseOnCancel {
		le.release()
	}
}