[AutoDiscovery] Develop auto-discovery for OctoPrint printers

[davidzwa]

Implement a method to auto-discover printers.

Possible solutions

• MQTT
• SSDP
• ZeroConf

Possible installations

• OctoPrint
• Moonraker (Fluidd / Mainsail)

[davidzwa]

Currently leaning towards installing https://plugins.octoprint.org/plugins/mqtt/ for autodiscovery

Also looking at:
Requires HA and Mosquitto https://plugins.octoprint.org/plugins/homeassistant/

Alternative codebases (as example):
Requires Mosquitto but is easy to break https://plugins.octoprint.org/plugins/mqttpublish/
Bridges the API to MQTT https://github.com/jneilliii/OctoPrint-MQTTSubscribe

[davidzwa]

https://cedalo.com/blog/nodejs-mqtt-usage-with-mosquitto-example/
https://iot-blogger.com/mqtt-node-js/

NodeJS MQTT broker
https://github.com/moscajs/aedes

[mkevenaar]

Help wanted
I have implemented SSDP before, but I experienced issues where it was slow or inconsistent (mostly docker). Another doubt I had with it, when I was working on this for OctoFarm, was that I did not know how to complete the authentication triangle (asymmetric crypto / key sharing).

Why SSDP
It's a protocol that is supported by most networks/routers and which does not require separate brokers or applications (compared to MQTT). Furthermore, OctoPrint itself already has it built in, where as MQTT would require two plugins or a newly written plugin with the downside of having to depend on a plugin (instead of a built-in/pre-packaged feature). This does not mean I do not see the benefits of MQTT and a dedicated broker, it's just that I realize SSDP is a nice method to discover OctoPrints out of the box.

[davidzwa]

At this moment FDM Monster will not implement auto-discovery using MQTT, SSDP and similar host-installed services. If this changes in the future a new issue should be created as a feature request.