golang open a udp server

package mainimport (
        "fmt"
        "net"
        "os"
        "strconv"
        "strings"
)const(
        SERVER_IP = "127.0.0.1"
        PORT = 8080
)func main() {
        fmt.Println("upd test")
        address := SERVER_IP + ":" + strconv.Itoa(PORT)
        addr, err := net.ResolveUDPAddr("udp", address)
        if err != nil {
                fmt.Println(err)
                os.Exit(1)
        }
        conn, err := net.ListenUDP("udp", addr)
        if err != nil {
                fmt.Println(err)
                os.Exit(1)
        }
        defer conn.Close()
        for {
                data := make([]byte, 1024)
                _, rAddr, err := conn.ReadFromUDP(data)
                if err != nil {
                        fmt.Println("Read From Udp err =",err)
                        continue
                }
                strData := string(data)
                fmt.Println("Received:", strData)
                upper := strings.ToUpper(strData)
                _, err = conn.WriteToUDP([]byte(strData), rAddr)
                if err != nil {
                        fmt.Println("Write Udp err =",err)
                        continue
                }
                fmt.Println("Send:", upper)
        }
}