Simple UDP Client/Server in golang

Being a new language, the example codes are not easily available for Golang. For other languages like Java and C, just put a keyword in Google, you will find a lot examples for it. Same is not true for golang.

I faced the same issue for UDP Client and Server code. Finally I managed to code with help of few available examples.

First set the PATH for go by using following command.

export PATH=/path/to/go/bin:$PATH

Here is the code for the same.

Server: server.go

package main

import (
    "fmt"
    "net"
    "os"
)

/* A Simple function to verify error */
func CheckError(err error) {
    if err  != nil {
        fmt.Println("Error: " , err)
        os.Exit(0)
    }
}

func main() {
    /* Lets prepare a address at any address at port 10001*/    
    ServerAddr,err := net.ResolveUDPAddr("udp",":10001")
    CheckError(err)

    /* Now listen at selected port */
    ServerConn, err := net.ListenUDP("udp", ServerAddr)
    CheckError(err)
    defer ServerConn.Close()

    buf := make([]byte, 1024)

    for {
        n,addr,err := ServerConn.ReadFromUDP(buf)
        fmt.Println("Received ",string(buf[0:n]), " from ",addr)

        if err != nil {
            fmt.Println("Error: ",err)
        } 
    }
}

Run this file with following command

go run server.go

Client: client.go

package main

import (
	"fmt"
	"net"
	"time"
	"strconv"
)

func CheckError(err error) {
	if err  != nil {
		fmt.Println("Error: " , err)
	}
}

func main() {
	ServerAddr,err := net.ResolveUDPAddr("udp","127.0.0.1:10001")
	CheckError(err)

	LocalAddr, err := net.ResolveUDPAddr("udp", "127.0.0.1:0")
	CheckError(err)

	Conn, err := net.DialUDP("udp", LocalAddr, ServerAddr)
	CheckError(err)

	defer Conn.Close()
	i := 0
	for {
		msg := strconv.Itoa(i)
		i++
		buf := []byte(msg)
		_,err := Conn.Write(buf)
		if err != nil {
			fmt.Println(msg, err)
		}
		time.Sleep(time.Second * 1)
	}
}

Run this file with following command in another terminal

go run client.go