Simple Go TLS server with Let's Encrypt automatic certificates

server.go

package main

import (
	"crypto/tls"
	"fmt"
	"net/http"
	
	"golang.org/x/crypto/acme/autocert"
)

func handler(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintf(w, "Hello")
}

func main() {
	m := autocert.Manager{
		Prompt:     autocert.AcceptTOS,
		HostPolicy: autocert.HostWhitelist("example.com"),
		Cache:      autocert.DirCache("./certs"),
	}
	http.HandleFunc("/", handler)
	s := &http.Server{
		Addr:      ":https",
		TLSConfig: &tls.Config{GetCertificate: m.GetCertificate},
	}
	s.ListenAndServeTLS("", "")
}

server_with_all_suites.go

package main

import (
	"crypto/tls"
	"fmt"
	"net/http"
	
	"golang.org/x/crypto/acme/autocert"
)

func handler(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintf(w, "Hello")
}

func main() {
	m := autocert.Manager{
		Prompt:     autocert.AcceptTOS,
		HostPolicy: autocert.HostWhitelist("example.com"),
		Cache:      autocert.DirCache("./certs"),
	}
	http.HandleFunc("/", handler)
	s := &http.Server{
		Addr: ":https",
		TLSConfig: &tls.Config{
			GetCertificate:           m.GetCertificate,
			PreferServerCipherSuites: true,
			CipherSuites: []uint16{
				tls.TLS_FALLBACK_SCSV,
				tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
				tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
				tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
				tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
				tls.TLS_ECDHE_RSA_WITH_RC4_128_SHA,
				tls.TLS_ECDHE_ECDSA_WITH_RC4_128_SHA,
				tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
				tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
				tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
				tls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
				tls.TLS_RSA_WITH_AES_128_GCM_SHA256,
				tls.TLS_RSA_WITH_AES_256_GCM_SHA384,
				tls.TLS_RSA_WITH_RC4_128_SHA,
				tls.TLS_RSA_WITH_AES_128_CBC_SHA,
				tls.TLS_RSA_WITH_AES_256_CBC_SHA,
				tls.TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
				tls.TLS_RSA_WITH_3DES_EDE_CBC_SHA,
			},
		},
	}
	s.ListenAndServeTLS("", "")
}