TCP Dynamic Proxy route without specifying exact IP?

[evandam]

I'm using tcp-dynamic proxy with proxy.addr = :9999,0.0.0.0:0;proto=tcp-dynamic;refresh=5s but wondering if there's a way to use routes without hardcoding an IP address if I understand correctly?

For example, I have a service with the following tags:

fabio-0.0.0.0:6379 proto=tcp
fabio-:6379 proto=tcp
fabio-mydnsrecord:6379 proto=tcp

The routes get added successfully, but they all result in "No route found" logs.

Oct 30 18:07:52 default-ubuntu-1804 fabio[19887]: 2020/10/30 18:07:52 [WARN] No route for 192.168.33.33:6379

Is it possible to be able to resolve a hostname instead of use an IP address, or route based on port-only instead of ip:port?

Thanks in advance!

[nathanejohnson]

This is not currently possible because currently routes are matched based on the host, and no wildcards are currently supported. It might be feasible to come up with a custom lookup function just for tcp dynamic, but I'm not sure there is a general enough use case to support it. Also, since with tcp fabio has no idea which dns name may have been used to connect there really isn't a clean way to match it on hostname either. With http or https we have other ways of determining that, but not with TCP.

How are you spinning up your environment?

[nathanejohnson]

So after digging in it's not a terribly difficult change to make (~ 4 lines), but I'm not really sure how generally useful this is. The change involved doing a lookup on the existing full local address with port, and then falling back to a route based on a target name which just used the local port that was connected to. I'll have to think this over, I may put together a small PR to get some eyes on it. I don't personally use the tcp dynamic feature.