You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
73 lines
2.6 KiB
73 lines
2.6 KiB
# cmux: Connection Mux [](https://travis-ci.org/cockroachdb/cmux) [](https://godoc.org/github.com/cockroachdb/cmux)
|
|
|
|
cmux is a generic Go library to multiplex connections based on their payload.
|
|
Using cmux, you can serve gRPC, SSH, HTTPS, HTTP, Go RPC, and pretty much any
|
|
other protocol on the same TCP listener.
|
|
|
|
## How-To
|
|
Simply create your main listener, create a cmux for that listener,
|
|
and then match connections:
|
|
```go
|
|
// 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:
|
|
// First grpc, then HTTP, and otherwise Go RPC/TCP.
|
|
grpcL := m.Match(cmux.HTTP2HeaderField("content-type", "application/grpc"))
|
|
httpL := m.Match(cmux.HTTP1Fast())
|
|
trpcL := m.Match(cmux.Any()) // Any means anything that is not yet matched.
|
|
|
|
// Create your protocol servers.
|
|
grpcS := grpc.NewServer()
|
|
grpchello.RegisterGreeterServer(grpcs, &server{})
|
|
|
|
httpS := &http.Server{
|
|
Handler: &helloHTTP1Handler{},
|
|
}
|
|
|
|
trpcS := rpc.NewServer()
|
|
s.Register(&ExampleRPCRcvr{})
|
|
|
|
// Use the muxed listeners for your servers.
|
|
go grpcS.Serve(grpcL)
|
|
go httpS.Serve(httpL)
|
|
go trpcS.Accept(trpcL)
|
|
|
|
// Start serving!
|
|
m.Serve()
|
|
```
|
|
|
|
There are [more examples on GoDoc](https://godoc.org/github.com/cockroachdb/cmux#pkg-examples).
|
|
|
|
## Performance
|
|
Since we are only matching the very first bytes of a connection, the
|
|
performance overhead on long-lived connections (i.e., RPCs and pipelined HTTP
|
|
streams) is negligible.
|
|
|
|
## Limitations
|
|
* *TLS*: `net/http` uses a [type assertion](https://github.com/golang/go/issues/14221)
|
|
to identify TLS connections; since cmux's lookahead-implementing connection
|
|
wraps the underlying TLS connection, this type assertion fails. This means you
|
|
can serve HTTPS using cmux but `http.Request.TLS` will not be set in your
|
|
handlers. If you are able to wrap TLS around cmux, you can work around this
|
|
limitation. See https://github.com/cockroachdb/cockroach/commit/83caba2 for an
|
|
example of this approach.
|
|
|
|
* *Different Protocols on The Same Connection*: `cmux` matches the connection
|
|
when it's accepted. For example, one connection can be either gRPC or REST, but
|
|
not both. That is, we assume that a client connection is either used for gRPC
|
|
or REST.
|
|
|
|
# Copyright and License
|
|
Copyright 2016 The CMux Authors. All rights reserved.
|
|
|
|
See [CONTRIBUTORS](https://github.com/cockroachdb/cmux/blob/master/CONTRIBUTORS)
|
|
for the CMux Authors. Code is released under
|
|
[the Apache 2 license](https://github.com/cockroachdb/cmux/blob/master/LICENSE).
|