golang之tcp自動重連

操作系統： CentOS 6.9_x64

go語言版本： 1.8.3

問題描述

現有一個tcp客戶端程式，需定期從伺服器取數據，但由於種種原因（網路不穩定等）需要自動重連。

測試伺服器示例代碼：

/*
tcp server for test
E-Mail : [email protected]
*/


package main

import (
    "fmt"
    "net"
    "os"
    "strings"
    "time"
)

func checkError(err error) {
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }
}

func handleClient(conn net.Conn) {
    conn.SetReadDeadline(time.Now().Add(3 * time.Minute))
    request := make([]byte,1024)
    defer conn.Close()

    for {
        recv_len,err := conn.Read(request)
        if err != nil {
            fmt.Println(err)
            break
        }
        if recv_len == 0 {
            break
        }
        recvData := strings.TrimSpace(string(request[:recv_len]))
        fmt.Println("recv_len : ",recv_len)
        fmt.Println("recv_data : " + recvData)
        daytime := time.Now().String()
        conn.Write([]byte(daytime + "\n"))
        request = make([]byte,1024)
    }
}

func main() {
    bindInfo := ":12345"
    tcpAddr,err := net.ResolveTCPAddr("tcp4",bindInfo)
    checkError(err)
    listener,err := net.ListenTCP("tcp",tcpAddr)
    checkError(err)
    for {
        cc,err := listener.Accept()
        if err != nil {
            continue
        }
        go handleClient(cc)
    }
}

解決方案

/*
tcp client with reconnect
E-Mail : [email protected]
*/

package main

import (
    "net"
    "fmt"
    "bufio"
    "time"
)

func doTask(conn net.Conn) {
    for {
        fmt.Fprintf(conn,"test msg\n")
        msg,err := bufio.NewReader(conn).ReadString('\n')
        if err != nil {
            fmt.Println("recv data error")
            break
        }else{
            fmt.Println("recv msg : ",msg)
        }
        time.Sleep(1 * time.Second)
    }

}

func main() {
    hostInfo := "127.0.0.1:12345"

    for {
        conn,err := net.Dial("tcp",hostInfo)
        fmt.Print("connect (",hostInfo)
        if err != nil {
            fmt.Println(") fail")
        }else{
            fmt.Println(") ok")
            defer conn.Close()
            doTask(conn)
        }
        time.Sleep(3 * time.Second)
    }
}

運行效果：

[root@local t1]# ./tcpClient1
connect (127.0.0.1:12345) ok
recv msg :  2017-06-12 21:10:32.110977137 +0800 CST

recv msg :  2017-06-12 21:10:33.111868746 +0800 CST

recv data error
connect (127.0.0.1:12345) fail
connect (127.0.0.1:12345) fail
connect (127.0.0.1:12345) ok
recv msg :  2017-06-12 21:10:43.117203432 +0800 CST

recv msg :  2017-06-12 21:10:44.11853427 +0800 CST

討論

這裡只是個簡單的示例代碼，實現了tcp自動重連。

好，就這些了，希望對你有幫助。

本文github地址：

https://github.com/mike-zhang/mikeBlogEssays/blob/master/2017/20170613_golang之tcp自動重連.rst

歡迎補充