Configure the host address for rasa run

[bastbnl]

I've been playing around with rasa open source edition on a classic vm, using a virtualenv for installation. I'm impressed.

I tried to figure out how to start rasa on a specific address instead of just localhost -- which appears to be every network interface and I was unable to find a way to configure the interface for rasa open source edition other than listing a port number at startup. I didn't find anything for the address. Inspecting the code learned me that starting rasa using rasa run -p 1531 will make the Sanic webserver listen on every interface using that specific port number.

The reason why I want to start RASA on a specific address is that I can limit access to the service by making rasa listen on a VPN interface, thus making it available to every machine on the VPN. I could probably archieve the same using a firewall and I may add one later on, but I figured being able to limit the netwerk interfaces would be a quick win.

A not-so-quick google search showed multiple questions surrounding this feature, so I'm adding a PR including just that.

[sara-tagger]

Thanks for submitting this feature request 🚀 @samsucik will get back to you about it soon! ✨

[samsucik]

I'll let @degiz deal with this one (if there's anything to be said), since he's assigned as a reviewer on the actual PR 🙂

[degiz]

Hey @bastbnl
If you need a "production" version of Rasa Open Source, then you probably want to deploy it with docker, and then use a reverse proxy to do the networking for you, for example nginx.

[bastbnl]

Thanks for the advice, @degiz. It's probably better to run it in a docker container, but I'm currently running from a virtualenv and I guess this change would benefit others too.

Is there a link to the recommended production install btw?