第一次使用etcd为什么这个API这样使用是错误的

func main() {

SetLogConfToEtcd()
//EtcdExmaple()

}

func EtcdExmaple() { cli, err := clientv3.New(clientv3.Config{ Endpoints: []string{"localhost:2379", "localhost:22379", "localhost:32379"}, DialTimeout: 5 * time.Second, }) if err != nil { fmt.Println("connect failed, err:", err) return }

fmt.Println("connect succ")
defer cli.Close()

ctx, cancel := context.WithTimeout(context.Background(), time.Second)
_, err = cli.Put(ctx, "/logagent/conf/", "sample_value")
cancel()
if err != nil {
    fmt.Println("put failed, err:", err)
    return
}

ctx, cancel = context.WithTimeout(context.Background(), time.Second)
resp, err := cli.Get(ctx, "/logagent/conf/")
cancel()
if err != nil {
    fmt.Println("get failed, err:", err)
    return
}
for _, ev := range resp.Kvs {
    fmt.Printf("%s : %s\n", ev.Key, ev.Value)
}

}