simple golagn echo server

echo_server.go

package main

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

const (  
    CONN_HOST = ""
    CONN_PORT = "8020"
    CONN_TYPE = "tcp"
)

func main() {  
    // Listen for incoming connections.
    l, err := net.Listen(CONN_TYPE, ":"+CONN_PORT)
    if err != nil {
        fmt.Println("Error listening:", err.Error())
        os.Exit(1)
    }
    // Close the listener when the application closes.
    defer l.Close()
    fmt.Println("Listening on " + CONN_HOST + ":" + CONN_PORT)
    for {
        // Listen for an incoming connection.
        conn, err := l.Accept()
        if err != nil {
            fmt.Println("Error accepting: ", err.Error())
            os.Exit(1)
        }

        //logs an incoming message
        fmt.Printf("Received message %s -> %s \n", conn.RemoteAddr(), conn.LocalAddr())

        // Handle connections in a new goroutine.
        go handleRequest(conn)
    }
}

// Handles incoming requests.
func handleRequest(conn net.Conn) {  
  // Make a buffer to hold incoming data.
  defer conn.Close()
  defer fmt.Println("conn closed")
  for{ 
  buf := make([]byte, 1024)
  // Read the incoming connection into the buffer.
  rn, err := conn.Read(buf)
  fmt.Printf("read %d\n",rn)
  if err != nil {
    fmt.Println("Error reading:", err.Error())
    //break;
    return
  }
  // Builds the message.
  message := ""
  n := bytes.Index(buf, []byte{0})
  message += string(buf[:n])
  
  fmt.Printf("recv message: %s\n", message);

  // Write the message in the connection channel.
  wn, err := conn.Write([]byte(message));
  if err != nil {
    fmt.Println("write err\n");
    fmt.Println(err)
    continue
    //return
  }
  fmt.Printf("wirte %d\n", wn)
  // Close the connection when you're done with it.
  }
}