admin-entrance/server/package/graveserver/leafstalk/covenant/etcd/lease.go

package etcd

import (
	"context"
	"fmt"
	"time"
)

// 创建租约，需要维持租约
func (sd *EtcdService) CreateLease() (*LeaseItem, error) {
	cli := sd.EtcdCli
	if cli == nil {
		return nil, fmt.Errorf("no client")
	}

	ctx2, cancel2 := context.WithTimeout(sd.coreCtx, time.Second*5)
	l, err := cli.Grant(ctx2, int64(sd.ttl))
	cancel2()
	if err != nil {
		return nil, err
	}
	fmt.Println("new lease:", l.ID)

	//一次调用一直保持，直到通道关闭或出错为止
	ctx, cancel3 := context.WithCancel(sd.coreCtx)
	kac, err := cli.KeepAlive(ctx, l.ID)
	if err != nil || kac == nil {
		cancel3()
		return nil, err
	}

	li := new(LeaseItem)
	li.LeaseID = l.ID
	li.CancelKeep = cancel3
	li.ChanKeepAliveResponse = kac
	return li, nil

	// // go func(kac <-chan *clientv3.LeaseKeepAliveResponse) {
	// // 	defer close(donec)
	// // 	//for resp := range kac {
	// // 	for range kac {
	// // 		// eat messages until keep alive channel closes
	// // 		//log.Infoln(resp.ID)
	// // 	}
	// // 	// log.Infoln("keepalive donec")
	// // }(kac)

	// if _, ok := <-kac; !ok {
	// 	return errors.New("lease chan shutdown")
	// }

	// // sd.chLease <- kac

	// return nil
}

// 取消租约
func (sd *EtcdService) revokeLease(l *LeaseItem) error {
	ctx, cancel := context.WithTimeout(sd.coreCtx, time.Duration(sd.ttl)*time.Second)
	_, err := sd.EtcdCli.Revoke(ctx, l.LeaseID)
	cancel()
	return err
}