tcp_echo_client.go

package main

import (
	"bufio"
	"log"
	"net"
	"strings"
)

const RemoteAddress = "localhost"
const RemotePort = "4545"

const Message = "Hi!\n"

func main() {
	conn, err := net.Dial("tcp", net.JoinHostPort(RemoteAddress, RemotePort))
	if err != nil {
		log.Fatalln(err)
	}
	defer conn.Close()
	log.Printf("Connected to %v\n", conn.RemoteAddr())

	_, err = conn.Write([]byte(Message))
	if err != nil {
		log.Fatalln(err)
	}
	log.Printf("Sent a message '%s' to %v", strings.TrimRight(Message, "\n"), conn.RemoteAddr())

	response, err := bufio.NewReader(conn).ReadString('\n')
	if err != nil {
		log.Fatalln(err)
	}
	log.Printf("Recieved a response '%s' from %v\n",
		strings.TrimRight(response, "\n"), conn.RemoteAddr())
}

tcp_echo_server.go

package main

import (
	"bufio"
	"log"
	"net"
	"strings"
)

const Address = "localhost"
const Port = "4545"

func handleTCPClient(conn net.Conn) {
	defer conn.Close()

	message, err := bufio.NewReader(conn).ReadString('\n')
	if err != nil {
		log.Fatalln(err)
	}
	log.Printf("Recieved a message '%s' from %v\n",
		strings.TrimRight(message, "\n"), conn.RemoteAddr())

	response := message + " " + conn.RemoteAddr().String()
	_, err = conn.Write([]byte(response))
	if err != nil {
		log.Fatalln(err)
	}
	log.Printf("Echo a message '%s' to %v", strings.TrimRight(message, "\n"), conn.RemoteAddr())
}

func main() {

	listener, err := net.Listen("tcp", net.JoinHostPort(Address, Port))
	if err != nil {
		log.Fatalln(err)
	}
	defer listener.Close()

	log.Printf("Listening on %v\n", listener.Addr())

	for {
		conn, err := listener.Accept()
		if err != nil {
			log.Println(err)
			continue
		}

		log.Printf("Handling Client %v\n", conn.RemoteAddr())

		go handleTCPClient(conn)
	}
}