Routing Based On Route Metadata Tags Not Working Properly

[FWinkler79]

I am using ...
Spring Boot: 2.2.0.RELEASE
Spring Cloud: Hoxton.BUILD-SNAPSHOT
Spring Cloud RSocket: 0.2.0.BUILD-SNAPSHOT
Sample project: here

In my setup reservation-service-client communicates with reservation-service via RSocket and the service-gateway.

reservation-service registers with the following route metadata tags (see reservation-service/src/main/resources/application.yml):

spring:
  cloud:
    gateway:
      rsocket:
        client:
          service-name: reservation-service
          route-id: 400
          tags: 
            instance_name: reservation-service-1
            version: 1.0-RELEASE  # <-- I want to route based on that version.
          broker: 
            host: localhost
            port: 7002     

reservation-service-client declares forwarding information like that(see reservation-service-client/src/main/resources/application.yml):

spring:
  cloud:
    gateway:
      rsocket:
        client:
          service-name: reservation-service-client
          route-id: 500
          forwarding:       # Routing / forwarding hints to the Gateway broker.
            "[create.reservation.{vrsn}]":
              service_name: reservation-service
              version:      "{vrsn}-RELEASE"

... where {vrsn} is resolved to 2.0 as coded in reservation-service-client's ReservationServiceClient like so:

public Mono<ReservationConfirmation> createReservation(CreateReservationRequest request) {
    String version = "2.0";
    return rsocketRequester.route("create.reservation.{vrsn}", version) 
                    .data(request)
                    .retrieveMono(ReservationConfirmation.class)
                    .log();
  }

Thus, the client should be forwarded to a reservation-service instance of version 2.0-RELEASE (which is not available). However, that is not the case, and client is getting forwarded to a service instance of version 1.0-RELEASE.

When the client sends the request via the gateway to the service, you can see output in the gateway logs, that the forwarding metadata is properly available and {vrsn} was resolved properly as well, yet the gateway simply forwards to the reservation-service instance of version 1.0-RELEASE although the client routing metadata states otherwise.

Expected behaviour in this case (imo) would be to respond with max backpressure from the gateway since the service is not (yet) available.

To reproduce:

1. start service-gateway
2. start reservation-service
3. start reservation-service-client
4. send a POST request to http://localhost:9999/reservation/create/ReservationName (Web endpoint of client that will send the RSocket request)