Code:play 

package main

import (
	"fmt"
	"io"
	"log"
	"net"
	"net/http"
	"net/rpc"
	"strings"

	"golang.org/x/net/context"
	"golang.org/x/net/websocket"
	"google.golang.org/grpc"
	"google.golang.org/grpc/examples/helloworld/helloworld"

	"github.com/cockroachdb/cmux"
)

type exampleHTTPHandler struct{}

func (h *exampleHTTPHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintf(w, "example http response")
}

func serveHTTP(l net.Listener) {
	s := &http.Server{
		Handler: &exampleHTTPHandler{},
	}
	if err := s.Serve(l); err != cmux.ErrListenerClosed {
		panic(err)
	}
}

func EchoServer(ws *websocket.Conn) {
	if _, err := io.Copy(ws, ws); err != nil {
		panic(err)
	}
}

func serveWS(l net.Listener) {
	s := &http.Server{
		Handler: websocket.Handler(EchoServer),
	}
	if err := s.Serve(l); err != cmux.ErrListenerClosed {
		panic(err)
	}
}

type ExampleRPCRcvr struct{}

func (r *ExampleRPCRcvr) Cube(i int, j *int) error {
	*j = i * i
	return nil
}

func serveRPC(l net.Listener) {
	s := rpc.NewServer()
	if err := s.Register(&ExampleRPCRcvr{}); err != nil {
		panic(err)
	}
	for {
		conn, err := l.Accept()
		if err != nil {
			if err != cmux.ErrListenerClosed {
				panic(err)
			}
			return
		}
		go s.ServeConn(conn)
	}
}

type grpcServer struct{}

func (s *grpcServer) SayHello(ctx context.Context, in *helloworld.HelloRequest) (
	*helloworld.HelloReply, error) {

	return &helloworld.HelloReply{Message: "Hello " + in.Name + " from cmux"}, nil
}

func serveGRPC(l net.Listener) {
	grpcs := grpc.NewServer()
	helloworld.RegisterGreeterServer(grpcs, &grpcServer{})
	if err := grpcs.Serve(l); err != cmux.ErrListenerClosed {
		panic(err)
	}
}

func main() {
	l, err := net.Listen("tcp", "127.0.0.1:50051")
	if err != nil {
		log.Panic(err)
	}

	m := cmux.New(l)

	// We first match the connection against HTTP2 fields. If matched, the
	// connection will be sent through the "grpcl" listener.
	grpcl := m.Match(cmux.HTTP2HeaderField("content-type", "application/grpc"))
	//Otherwise, we match it againts a websocket upgrade request.
	wsl := m.Match(cmux.HTTP1HeaderField("Upgrade", "websocket"))

	// Otherwise, we match it againts HTTP1 methods. If matched,
	// it is sent through the "httpl" listener.
	httpl := m.Match(cmux.HTTP1Fast())
	// If not matched by HTTP, we assume it is an RPC connection.
	rpcl := m.Match(cmux.Any())

	// Then we used the muxed listeners.
	go serveGRPC(grpcl)
	go serveWS(wsl)
	go serveHTTP(httpl)
	go serveRPC(rpcl)

	if err := m.Serve(); !strings.Contains(err.Error(), "use of closed network connection") {
		panic(err)
	}
}

This is an example for serving HTTP and HTTPS on the same port.

Code:play 

package main

import (
	"crypto/rand"
	"crypto/tls"
	"fmt"
	"log"
	"net"
	"net/http"
	"strings"

	"github.com/cockroachdb/cmux"
)

type anotherHTTPHandler struct{}

func (h *anotherHTTPHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintf(w, "example http response")
}

func serveHTTP1(l net.Listener) {
	s := &http.Server{
		Handler: &anotherHTTPHandler{},
	}
	if err := s.Serve(l); err != cmux.ErrListenerClosed {
		panic(err)
	}
}

func serveHTTPS(l net.Listener) {
	// Load certificates.
	certificate, err := tls.LoadX509KeyPair("cert.pem", "key.pem")
	if err != nil {
		log.Panic(err)
	}

	config := &tls.Config{
		Certificates: []tls.Certificate{certificate},
		Rand:         rand.Reader,
	}

	// Create TLS listener.
	tlsl := tls.NewListener(l, config)

	// Serve HTTP over TLS.
	serveHTTP1(tlsl)
}

// This is an example for serving HTTP and HTTPS on the same port.
func main() {
	// Create the TCP listener.
	l, err := net.Listen("tcp", "127.0.0.1:50051")
	if err != nil {
		log.Panic(err)
	}

	// Create a mux.
	m := cmux.New(l)

	// We first match on HTTP 1.1 methods.
	httpl := m.Match(cmux.HTTP1Fast())

	// If not matched, we assume that its TLS.
	//
	// Note that you can take this listener, do TLS handshake and
	// create another mux to multiplex the connections over TLS.
	tlsl := m.Match(cmux.Any())

	go serveHTTP1(httpl)
	go serveHTTPS(tlsl)

	if err := m.Serve(); !strings.Contains(err.Error(), "use of closed network connection") {
		panic(err)
	}
}

This is an example for serving HTTP, HTTPS, and GoRPC/TLS on the same port.

Code:play 

package main

import (
	"crypto/rand"
	"crypto/tls"
	"fmt"
	"log"
	"net"
	"net/http"
	"net/rpc"
	"strings"

	"github.com/cockroachdb/cmux"
)

type recursiveHTTPHandler struct{}

func (h *recursiveHTTPHandler) ServeHTTP(w http.ResponseWriter,
	r *http.Request) {

	fmt.Fprintf(w, "example http response")
}

func recursiveServeHTTP(l net.Listener) {
	s := &http.Server{
		Handler: &recursiveHTTPHandler{},
	}
	if err := s.Serve(l); err != cmux.ErrListenerClosed {
		panic(err)
	}
}

func tlsListener(l net.Listener) net.Listener {
	// Load certificates.
	certificate, err := tls.LoadX509KeyPair("cert.pem", "key.pem")
	if err != nil {
		log.Panic(err)
	}

	config := &tls.Config{
		Certificates: []tls.Certificate{certificate},
		Rand:         rand.Reader,
	}

	// Create TLS listener.
	tlsl := tls.NewListener(l, config)
	return tlsl
}

type RecursiveRPCRcvr struct{}

func (r *RecursiveRPCRcvr) Cube(i int, j *int) error {
	*j = i * i
	return nil
}

func recursiveServeRPC(l net.Listener) {
	s := rpc.NewServer()
	if err := s.Register(&RecursiveRPCRcvr{}); err != nil {
		panic(err)
	}
	for {
		conn, err := l.Accept()
		if err != nil {
			if err != cmux.ErrListenerClosed {
				panic(err)
			}
			return
		}
		go s.ServeConn(conn)
	}
}

// This is an example for serving HTTP, HTTPS, and GoRPC/TLS on the same port.
func main() {
	// Create the TCP listener.
	l, err := net.Listen("tcp", "127.0.0.1:50051")
	if err != nil {
		log.Panic(err)
	}

	// Create a mux.
	tcpm := cmux.New(l)

	// We first match on HTTP 1.1 methods.
	httpl := tcpm.Match(cmux.HTTP1Fast())

	// If not matched, we assume that its TLS.
	tlsl := tcpm.Match(cmux.Any())
	tlsl = tlsListener(tlsl)

	// Now, we build another mux recursively to match HTTPS and GoRPC.
	// You can use the same trick for SSH.
	tlsm := cmux.New(tlsl)
	httpsl := tlsm.Match(cmux.HTTP1Fast())
	gorpcl := tlsm.Match(cmux.Any())
	go recursiveServeHTTP(httpl)
	go recursiveServeHTTP(httpsl)
	go recursiveServeRPC(gorpcl)

	go func() {
		if err := tlsm.Serve(); err != cmux.ErrListenerClosed {
			panic(err)
		}
	}()
	if err := tcpm.Serve(); !strings.Contains(err.Error(), "use of closed network connection") {
		panic(err)
	}
}