Fabio currently uses specially crafted Consul tags (urlprefix-host/path opt opt ...) to generate route commands which build the fabio routing table. There is a certain impedance mismatch between the syntax of the urlprefix- tags and the route add commands they generate, e.g.

urlprefix-/
route add <svcname> / http://<svcaddr>/

urlprefix-/ strip=/foo
route add <svcname> / http://<svcaddr>/ opts "strip=/foo"

urlprefix-:1234 proto=tcp
route add <svcname> :1234 tcp://<svcaddr>/

urlprefix-/ proto=https
route add <svcname> / https://<svcaddr>/

It would be useful if the urlprefix- tags are just a convenient shorthand notation for common more complex route commands but users could choose to express the same thing as a route command as well. This would limit the syntax of the urlprefix- commands to what is necessary for the most common uses cases.

For this to work, the code would need to distinguish between two types of tags: short and raw

raw tags are added verbatim (without the tag prefix) to the routing table whereas the short tags provide a special shorthand notation syntax which needs to be parsed and transformed.

Additionally, the raw tags need pseudo-variables to inject the service name and service address which are currently generated from the urlprefix- tags to be fully equivalent.

urlprefix-/ could then also be written as fabio route add $service / http://$addr/ assuming that fabio is the raw prefix tag.

The open questions are whether there should be a different prefix for the raw tags or whether this should be rolled into the urlprefix- syntax. Since the urlprefix- syntax is already used for defining TCP services I think we shouldn't overload it even further.

I'd like to gather some ideas on the syntax of a fabio tag for defining routes and allowing raw route commands and then we start with the route commands.

Note

There is an open issue/pr somewhere which has these ideas but I can't find it right now. Will update when I do.

Note2

Part of the discussion is in #87 (comment)