Help with running ld-relay as part of an application

[simonkotwicz]

Describe the bug
Could you please tell me what I'm doing wrong? I'm trying to build ld-relay within an application.

To reproduce

func main() {
	r, err := relay.NewRelay(createRelayConfig(), ldlog.NewDefaultLoggers(), nil)
	if err != nil {
		log.Fatal(fmt.Sprintf("Error creating relay: %s", err))
	}

	router := mux.NewRouter()
	// router.HandleFunc("/test", handleFunc)
	router.PathPrefix("/relay").Handler(r)

	srv := &http.Server{
		Handler: router,
		Addr:    "127.0.0.1:8030",
	}
	srv.ListenAndServe()
}

func createRelayConfig() config.Config {
	var cfg config.Config
	cfg.Main.Port, _ = configtypes.NewOptIntGreaterThanZero(8030)
	cfg.Environment = map[string]*config.EnvConfig{
		"test": {
			SDKKey: config.SDKKey("-redacted-"),
		},
	}
	return cfg
}

Expected behavior
Expect curl http://localhost:8030/relay/status not to return a 404

[eli-darkly]

I believe the problem has to do with how routers work in gorilla/mux. When you put your router with a path prefix in front of the Relay handler r in this way, router doesn't strip the prefix off of the path before passing it to r. So the Relay handler receives a request for /relay/status, rather than for /status which is what it expects the path to be.

I'm not sure if gorilla/mux has a way to say "pass this request on to another router while stripping the path prefix" when the other router (in this case r) was not created using .Subrouter(); it looks to me like their API kind of assumes that you know what all the router relationships will be ahead of time when you're creating them, which isn't the case here.

But Go does have a helper for this kind of thing: http.StripPrefix. Try this:

    router.PathPrefix("/relay").Handler(http.StripPrefix("/relay", r))

[simonkotwicz]

thanks! I made a PR to update the README in case someone else has the same problem.