I had added reactive-feign to one of our most important micro-services in here, and we are using Eureka for Service Discovery.
All of our services register itself as only secure ports being enabled... and feign-reactive picks the 443 ports right away. However, it is still making calls using http scheme when using Ribbon (Cloud module).

We are unable to bump this microservice to Spring Boot 2.2, so we are still using Spring Boot 2.1 and cannot use Cloud 2 implementation that takes schema into account.

The current implementation for Ribbon in the cloud module is

  protected ReactiveHttpRequest loadBalanceRequest(ReactiveHttpRequest request, Server server) {
    URI lbUrl =
        UriComponentsBuilder.fromUri(request.uri())
            .host(server.getHost())
            .port(server.getPort())
            .build(true)
            .toUri();
    return new ReactiveHttpRequest(request, lbUrl);

So it uses the schema received from the ReactiveFeignClientFactoryBean that is hardcoded to use http only.

I can provide a PR that will take Eureka data into consideration and use it as the schema for this code.