cookie := http.Cookie{"test", "tcookie", "/", "www.dummy.com", expire, expire.Format(time.UnixDate), 86400, true, true, "test=tcookie", []string{"test=tcookie"}}
should be something like this:
cookie := &http.Cookie{Name:"test", Value:"tcookie", Expires:time.Now().Add(356*24*time.Hour), HttpOnly:true}
after this
change
req.AddCookie(&cookie)
to
http.SetCookie(w, cookie)
and finally because your application is running on Google App Engine change:
func main()
to
func init()