[GO] go使用etcd和watch方法進行實時的配置變更

監控代碼

package main

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

func main() {
    cli, err := clientv3.New(clientv3.Config{
        Endpoints:[]string{"localhost:2379", "localhost:23279", "localhost:33279"},//etcd集群三個實例的端口
        DialTimeout:2*time.Second,
    })

    if err != nil {
        fmt.Println("connect failed, err:", err)
        return
    }

    fmt.Println("connect succ")

    defer cli.Close()

    for true {
        rch := cli.Watch(context.Background(), "/logagent/conf/")//阻塞在這里，如果沒有key里沒有變化，就一直停留在這里
        for wresp := range rch{
            for _, ev := range wresp.Events{
                fmt.Printf("%s %q:%q\n", ev.Type, ev.Kv.Key, ev.Kv.Value)
            }
        }
    }
}

配置變更代碼

package main

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

func main() {
    cli, err := clientv3.New(clientv3.Config{
        Endpoints:[]string{"localhost:2379", "localhost:23279", "localhost:33279"}, //etcd的集群的三個實例端口

        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(), 2*time.Second)
    _, err = cli.Put(ctx, "/logagent/conf/", "samplevalue")
    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)
    }
}

執行后， 監控代碼的執行結果為