Detect remote connection closing

_running.txt

% go run main.go
2013/07/24 13:47:30 accepted
2013/07/24 13:47:31 closing
2013/07/24 13:47:31 watcher read error EOF
2013/07/24 13:47:31 write error write tcp 127.0.0.1:5000: broken pipe

main.go

package main

import (
	"log"
	"net"
	"time"
)

var serverPort = "5000"

func serve(conn net.Conn) {
	defer conn.Close()
	time.Sleep(1 * time.Second)
	log.Println("closing")
}

func server(port string, readyCh chan bool) {
	ln, err := net.Listen("tcp", ":"+port)
	if err != nil {
		log.Fatalln("listen error", err)
	}
	readyCh <- true

	for {
		conn, err := ln.Accept()
		if err != nil {
			log.Println("accept error", err)
			continue
		}
		log.Println("accepted")
		go serve(conn)
	}
}

func closeWatch(conn net.Conn) {
	b := make([]byte, 1)
	for {
		_, err := conn.Read(b)
		if err != nil {
			log.Println("watcher read error", err)
			break
		}
	}
}

func client(port string) {
	conn, err := net.Dial("tcp", "localhost:"+port)
	if err != nil {
		log.Fatalln("dial error", err)
	}
	go closeWatch(conn)

	for {
		_, err := conn.Write([]byte("hello"))
		if err != nil {
			log.Fatalln("write error", err)
		}
	}
}

func main() {
	readyCh := make(chan bool)
	go server(serverPort, readyCh)
	<-readyCh

	go client(serverPort)

	select {}
}