cmux: Connection Mux

cmux is a generic Go library to multiplex connections based on their content. Using cmux, one can serve gRPC, HTTP, and Go RPC on the same TCP listener to avoid having to use one port per protocol.

How-To

Simply create your main listener, create a cmux for that listener, and then match connections:

// Create the main listener.
l, err := net.Listen("tcp", ":23456")
if err != nil {
	log.Fatal(err)
}

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

// Match connections in order.
grpcl := m.Match(cmux.HTTP2HeaderField("content-type", "application/grpc"))
httpl := m.Match(cmux.Any()) // Any means anything that is not yet matched.

// Create your protocol servers.
grpcS := grpc.NewServer()
pb.RegisterGreeterServer(grpcs, &server{})

httpS := &http.Server{
	Handler: &testHTTP1Handler{},
}

// Use the muxed listeners for your servers.
go grpcS.Serve(grpcl)
go httpS.Serve(httpl)

// Start serving!
m.Serve()

Take a look at other examples in the GoDoc.

Docs

• GoDocs

Performance

There is a huge room for improvment but since we are only matching the very first bytes of a connection, the performance overheads on long-lived connections (i.e., RPCs and pipelined HTTP streams) is negligible.

TODO(soheil): Add benchmarks.

Limitations

TLS: Since cmux sits in between the actual listener and the mux'ed listeners, TLS handshake is not handled inside the actual servers. Because of that, when you handle HTTPS using cmux http.Request.TLS would not be set.