定期续租

package util

import (
    "context"
    "fmt"
    "go.etcd.io/etcd/clientv3"
    "time"
)

type Service struct {
    client *clientv3.Client
}

func NewService() *Service {
    config := clientv3.Config{
        Endpoints:   []string{"106.12.72.181:23791", "106.12.72.181:23792"},
        DialTimeout: 10 * time.Second,
    }
    client, _ := clientv3.New(config)
    return &Service{client: client}
}

//注册服务
func (this *Service) RegService(id string, name string, address string) error {
    kv := clientv3.NewKV(this.client)
    key_prefix := "/services/"
    ctx := context.Background()
    lease := clientv3.NewLease(this.client)
    leaseRes, err := clientv3.NewLease(this.client).Grant(ctx, 20) //设置租约过期时间为20秒
    if err != nil {
        return err
    }
    _, err = kv.Put(context.Background(), key_prefix+id+"/"+name, address, clientv3.WithLease(leaseRes.ID)) //把服务的key绑定到租约下面
    if err != nil {
        return err
    }
    keepaliveRes, err := lease.KeepAlive(context.TODO(), leaseRes.ID) //续租时间大概自动为租约的三分之一时间，context.TODO官方定义为是你不知道要传什么context的时候就用这个
    if err != nil {
        return err
    }
    go lisKeepAlive(keepaliveRes)
    return err
}

func lisKeepAlive(keepaliveRes <-chan *clientv3.LeaseKeepAliveResponse) {
    for {
        select {
        case ret := <-keepaliveRes:
            if ret != nil {
                fmt.Println("续租成功", time.Now())
            }
        }
    }
}

//反注册服务
func (this *Service) UnregService(id string) error {
    kv := clientv3.NewKV(this.client)
    key_prefix := "/services/" + id
    _, err := kv.Delete(context.Background(), key_prefix, clientv3.WithPrefix())
    fmt.Println(err)
    return err
}