[erdii]

It is even easier: https://github.com/mholt/certmagic

Edit: Taken from certmagic docs

Instead of:

// plaintext HTTP, gross

http.ListenAndServe(":80", mux)

Use CertMagic:

// encrypted HTTPS with HTTP->HTTPS redirects - yay!

certmagic.HTTPS([]string{"example.com"}, mux)