There's no wsgi transport built-in, we haven't found any golang libraries that let us do this yet. For now, until we find a solution, we recommend using something like gunicorn and use the `reverse_proxy` directive in Caddy to proxy to it.
I'm no *SGI expert, but ASGI might be easier to bridge with the Golang-style concurrency-model than WSGI. Not sure if there are any libraries for go<->ASGI yet though.