HandlerFunc Generator

main.go

package main

import (
	"errors"
	"fmt"
	"log"
	"math/rand"
	"net/http"
)

type Scope struct {
	id int64
}

func (s *Scope) Log(format string, args ...interface{}) {
	argsWithPrefix := make([]interface{}, 0, len(args)+1)
	argsWithPrefix = append(argsWithPrefix, s.id)
	argsWithPrefix = append(argsWithPrefix, args...)
	log.Printf("%x "+format, argsWithPrefix...)
}

func (s *Scope) Hello(w http.ResponseWriter, r *http.Request) {
	s.Log("%v %v %v", "in Hello function", "second argument", 1000)
	s.Bye()
	fmt.Fprintln(w, s.id, "hello world")
}

func (s *Scope) Bye() {
	s.Log("in Bye funcion")
	s.Log("%#v %#v", errors.New("some error"), s)
}

func HandlerFuncGenerator() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		s := Scope{
			id: rand.Int63(),
		}
		s.Hello(w, r)
	}
}

func main() {
	http.HandleFunc("/", HandlerFuncGenerator())
	log.Println("listening ...")
	http.ListenAndServe(":8080", nil)
}