That's interesting. I'm looking to do something similar, but need wire compatibility with postgresql. This allows any postgres client to talk to our service. Didn't have a lot of luck finding a good "middleware"
you could consider hosting an empty postgresql database, compile your code as a postgresql foreign data wrapper and expose it as a view. Nothing is more compatible with the postgres wire protocol than postgresql itself ;)
That's a good idea and we considered FDW (for this and more stuff), but having a middleware makes it more flexible - FDW has limitations around pushdown with subselects, we are still constrained to a single postgresql instance for execution, when in theory we could parallelize (certain) queries across nodes.