etcd租约及监听key

etcd中kv存储已经租约和监听的基本使.都说源码之下了无秘密，就不打字了.

package main

import (
    "context"
    "log"
    "time"

    "go.etcd.io/etcd/clientv3"
)

func main() {
    var conf = clientv3.Config{
        Endpoints:   []string{"127.0.0.1:2380"},
        DialTimeout: 5 * time.Second,
    }

    //创建clinetv3
    client, err := clientv3.New(conf)
    defer client.Close()

    if err != nil {
        log.Fatal(err.Error())
    }

    //创建租约
    lease := clientv3.NewLease(client)

    //设置租约时间
    leaseResp, err := lease.Grant(context.TODO(), 30)
    if err != nil {
        log.Fatal(err.Error())
    }

    //设置续租
    leaseID := leaseResp.ID
    ctx, _ := context.WithCancel(context.TODO())
    leaseRespChan, err := lease.KeepAlive(ctx, leaseID)
    if err != nil {
        log.Fatal(err.Error()) //设置续租失败 续期之后向leaseRespChan通知
    }

    //监听租约
    go func() {
        for {
            select {
            case resp := <-leaseRespChan:
                if resp == nil {
                    log.Println("租约已经到期关闭")
                    goto LEASE_OVER
                } else {
                    log.Println("续租成功")
                    goto END
                }
            }
        LEASE_OVER:
            log.Println("lease 监听结束")
            break
        END:
            time.Sleep(500 * time.Millisecond)
        }
    }()

    //监听某个key的变化
    //ctx1, _ := context.WithTimeout(context.TODO(),20)
    go func() {
        wc := client.Watch(context.TODO(), "/job/v3/1", clientv3.WithPrevKV()) //创建监听
        for v := range wc {                                                    //range 监听事件
            for _, e := range v.Events {
                log.Printf("type:%v kv:%v  prevKey:%v \n ", e.Type, string(e.Kv.Key), e.PrevKv)
            }
        }
    }()

    //key授权租约
    kv := clientv3.NewKV(client)

    //通过租约put
    putResp, err := kv.Put(context.TODO(), "/job/v3/1", "koock", clientv3.WithLease(leaseID))
    if err != nil {
        log.Printf("put 失败：%s", err.Error())
    }
    log.Printf("%v\n", putResp.Header)

    time.Sleep(10 * time.Second)

    //撤销租约
    _, err = lease.Revoke(context.TODO(), leaseID)
    if err != nil {
        log.Fatalf("撤销租约失败:%s\n", err.Error())
    }
    log.Println("撤销租约成功")
    //cancelFunc()

    //查询key
    getResp, err := kv.Get(context.TODO(), "/job/v3/1")
    if err != nil {
        log.Fatalf("get 失败：%s", err.Error())
    }
    log.Printf("%v", getResp.Kvs)
    time.Sleep(20 * time.Second)
}