Add support for MQTTS certificates

[naimo84]

Hey @coldfire84,

I'd like to share my small feature "Add support for MQTTS certificates" with you. Background, why I implemented this: I'm hosting your great Alexa Home Skill on my own server within kubernetes. As I don't wanna transfer my mqtt message via unencrypted mqtt, I decided to setup the MQTT Server with a TLS config :) Therefore the new properties are needed. Also because of k8s, I needed an opportunity to use an different port than 1883 or 8883. Of course I could use my LoadBalancer Config to bind to 1883, but out of simplicity I'm gonna use a NodePort :D

TL;DR
I hope it's ok for you, that I coded this on my own ;) It was an interesting journey on how k8s, mqtt and alexa smart home skill works 👍

Greets,
Benjamin

[coldfire84]

Thanks for the PR.

As I don't wanna transfer my mqtt message via unencrypted mqtt, I decided to setup the MQTT Server with a TLS config :)

To be clear - the public service using MQTT w/ TLS: the server presents a certificate that must be trusted by clients and enables a secure connection between the server and client. Communication via unencrypted MQTT/ TCP 1883 is blocked.

If I have understood correctly, the objective here is to enable Mutual TLS (mTLS)?