从零开始学习etcd的使用

etcd做注册服务使用 类似java生态的zookeeper，最近在学学习

1、下载etcd包

//直接下载即可（因为包比较大有翻墙，可以直接去 https://golangtc.com/download/package 下载）
go get  go.etcd.io/etcd/clientv3

2、使用记录

packge main

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

func main() {
  var (
        config clientv3.Config
        client *clientv3.Client
        err error
        kv clientv3.KV
        putResp *clientv3.PutResponse
        getResp *clientv3.GetResponse
        delResp *clientv3.DeleteResponse
        keepResp *clientv3.LeaseKeepAliveResponse
        keepRespChan <-chan *clientv3.LeaseKeepAliveResponse
    )
}
//客户端配置
config = clientv3.Config{
    Endpoints:[]string{"127.0.0.1:2379"},
    DialTimeout:5 * time.Second,
}
    //建立连接
if client,err = clientv3.New(config);err != nil {
    fmt.Println(err)
    return
}
//得到操作etcd键值对的kv
kv = clientv3.NewKV(client)

//写入etcd
if putResp,err = kv.Put(context.TODO(),"/cron/jobs/job2","....",clientv3.WithPrevKV()/*可选参数，得到上次操作的值*/);err != nil {
    fmt.Println(err)
} else {
    fmt.Println(putResp.Header.Revision)

    if putResp.PrevKv != nil {
        fmt.Println(string(putResp.PrevKv.Value))
    }
}
//读取某个key的value值
getResp,err = kv.Get(context.TODO(),"/cron/jobs/job1"/*,clientv3.WithCountOnly()可选参数，得到数量*/)
    if err != nil {
        fmt.Println(err)
        return
    } else {
        fmt.Println(getResp.Kvs[0].Value/*得到的是一个切片*/)
    }
//读取前缀为XXX的所有的key的value(需要加上参数clientv3.WithPrefix())
if getResp,err = kv.Get(context.TODO(),"/cron/jobs/",clientv3.WithPrefix());err != nil {
        fmt.Println(err)
        return
    } else {
        fmt.Println(getResp.Kvs)
    }
//删除操作
if delResp,err = kv.Delete(context.TODO(),"/cron/jobs/job2",clientv3.WithPrevKV()/*得到删除之前的值*/);err != nil {
        fmt.Println(err)
        return
    } else {
        if len(delResp.PrevKvs) != 0 {
            fmt.Println(delResp.PrevKvs)
        }
    }