What listeners should be considered when filtering hostnames in routes?

[randmonkey]

Currently, HTTPRoute, TLSRoute, GRPCRoute includes hostnames in their specifications. As described in API specifiations, their hostnames should be filtered to include only the intersection of hostnames in its attached listeners. So what listeners should be taken into consideration if the route has not specified a listener attached to it? I have came out of the following options:

• The implementation MUST attach exactly one listener to route if there are at least one listener can be attach to it, so that we only consider the attached listener.
• Only listeners with compatible protocol with the route are considered:
  • HTTP and HTTPS (TLS?) listeners for HTTPRoute
  • TLS listeners for TLSRoute
  • HTTPS (HTTP? TLS?) listeners for GRPCRoute .
• ALL listeners that are possible to set a hostname are considered. This includes all listeners with HTTP, HTTPS, orTLS protocol.

[youngnick]

For the route to be useful, it has to attach to a Gateway; if a specific listener is not selected, the Route should attach to all compatible listeners in that Gateway.

Then, implementations should use "no requested hostname == match any hostname" for both sides of the Gateway and Route match.

This could probably use a small spec update to clarify though.

Also, we probably haven't done enough to give specific requirements about what Protocol matches what Route types though.

[randmonkey]

Thank you. I also think option 2: attach to ALL compatible listeners is the most reasonable answer. But It was not specified that what protocols of listeners could be compatible with which type of route.

[youngnick]

I think that for protocol support it's kind of left as an exercise for implementations for now, but I don't think that's enough to ensure compatibility for the future. I'll make a note.