Need help with autocert package

[geosoft1 (George Calianu)]

I’m experimenting with autocert. I found something on internet:

package main

import (
	"crypto/tls"
	"net/http"

	"golang.org/x/crypto/acme/autocert"
)

func main() {
	m := autocert.Manager{
		Prompt:     autocert.AcceptTOS,
		HostPolicy: autocert.HostWhitelist("localhost"),
		Cache:      autocert.DirCache("certs"),
	}

	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		w.Write([]byte("Hello world"))
	})

	s := &http.Server{
		Addr: ":https",
		TLSConfig: &tls.Config{
			GetCertificate: m.GetCertificate,
		},
	}

	s.ListenAndServeTLS("", "")
}

After running as root on Linux (Ubuntu 14.04) i get this error when i access from browser https://:localhost:

http: TLS handshake error from 127.0.0.1:43018: acme/autocert: server name component count invalid

Any suggestions?
Thanks!

[christophberger]

Does your machine have a valid domain name? If so, whitelist this instead of localhost. Letsencrypt cannot issue certificates for localhost.

[geosoft1 (George Calianu)]

Now i understand, indeed the machine don’t have a valid domain name. I was playing on my laptop.

[geosoft1 (George Calianu)]

How i resolved, some providers offer DDNS services (mine too ) so i just activated some name on my internet connection and by forwarding 443 port to my laptop ip i was able to run and obtain valid cerificates from Let’s Encrypt. I also replaced autocert.HostWhitelist("localhost") with autocert.HostWhitelist("mydomainname.com"). Can be useful when you don’t have a real payed domain name.