gistfile1.go

package main

import (
	"flag"
	"fmt"
	"io"
	"log"
	"net/http"
)

var host = flag.String("host", "127.0.0.1", "the host to listen on")
var port = flag.Int("port", 8000, "the port to listen on")

func oneHandler(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "text/html;charset=UTF-8")
	io.WriteString(w, "Don't Panic!")
}

func twoHandler(w http.ResponseWriter, r *http.Request) {
	panic("boom!")
}

func main() {
	flag.Parse()
	http.HandleFunc("/one", oneHandler)
	http.HandleFunc("/two", twoHandler)

	addr := fmt.Sprintf("%s:%d", *host, *port)
	log.Printf("Listening on http://%s\n", addr)
	listenErr := http.ListenAndServe(addr, nil)

	if listenErr != nil {
		panic(listenErr)
	}
}