etcd使用笔记1

1、启动服务端

2、设置版本set ETCDCTL_API=3

3、使用客户端命令操作：

etcdctl put key1 value1 成功返回OK

4、代码操作

1、向etcd中put,set

package main

import (
	"context"
	"encoding/json"
	"fmt"
	"time"

	"github.com/coreos/etcd/clientv3"
)

const (
	EtcdKey = "/tcy/backend/logAgent/config/192.168.238.1"
)

type LogConf struct {
	Path  string `json:"path"`
	Topic string `json:"topic"`      //写到哪个topic下面
}

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

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

	var logConfArr []LogConf
	logConfArr = append(
		logConfArr,
		LogConf{
			Path:  "./day12/etcd_example/logs/access.log",
			Topic: "topic01",
		},
	)
	logConfArr = append(
		logConfArr,
		LogConf{
			Path:  "./day12/etcd_example/logs/error.log",
			Topic: "topic01",
		},
	)

	data, err := json.Marshal(logConfArr)
	if err != nil {
		fmt.Println("json failed, ", err)
		return
	}

	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	_, err = cli.Put(ctx, EtcdKey, string(data))
	cancel()
	if err != nil {
		fmt.Println("put failed, err:", err)
		return
	}

	ctx, cancel = context.WithTimeout(context.Background(), time.Second)
	resp, err := cli.Get(ctx, EtcdKey)
	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)
	}
}

func main() {

	SetLogConfToEtcd()
	//EtcdExmaple()
}

func EtcdExmaple() {
	cli, err := clientv3.New(clientv3.Config{
		Endpoints:   []string{"localhost:2379"},
		DialTimeout: 100 * 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(), 10*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)
	}
}

connect succ
/tcy/backend/logAgent/config/192.168.238.1 : [{"path":"./day12/etcd_example/logs/access.log","topic":"topic01"},{"path":"./day12/etcd_example/logs/error.log","topic":"topic01"}

2、watch监听

func main() {

	cli, err := clientv3.New(clientv3.Config{
		Endpoints:   []string{"localhost:2379"},
		DialTimeout: 10 * time.Second,
	})
	if err != nil {
		fmt.Println("connect failed, err:", err)
		return
	}

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

	cli.Put(context.Background(), "/logagent/conf/", "2222222222")
	for {
		rch := cli.Watch(context.Background(), "/logagent/conf/")    //到这里就会停下，一直监听。
		for wresp := range rch {
			for _, ev := range wresp.Events {
				fmt.Printf("%s %q : %q\n", ev.Type, ev.Kv.Key, ev.Kv.Value)
			}
		}
	}
}

结果：

1、处于监听状态：

2、修改etcd中的key值，etcd可以监听到了。

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