Adding an SSL cert to Lita bot using Docker

Question

I've connected my Lita bot to a Diaglogflow agent via the lita-api-ai plugin and (currently) a Firebase-enabled fulfillment script edited inline on the Dialogflow site.

I'd like to convert that webhook into ruby and host it as a handler in Lita itself, but Dialogflow requires SSL on the webhook endpoint.

I'm using the standard docker setup for Lita on CoreOS, and I'd like to use a Let's Encrypt cert. How can I do this? I'm not experienced with the innards of Docker or a ruby app like Lita (as opposed to a full-blown nginx/Apache setup) -- can I put something around Docker to handle the SSL? Do I need to modify the Docker image itself?

Answer 1

The best way to go about this is to install a web server (nginx, caddy, etc.) to handle SSL termination. It should then proxy requests to the Docker instance. You can use nginx-proxy with the LetsEncrypt companion as the basic setup, although you'll need to alter the Lita systemd script to include config and environment variables (e.g., VIRTUAL_HOST, expose).

nginx-proxy listens for container changes to dynamically update its proxying, but I created systemd services for both nginx-proxy and the LetsEncrypt companion so that they would start on boot.