MQTT Enhancements for Home Assistant

[LorenKeagle]

Description

I've recently attempted to integrate Diun into my Home Assistant installation for reporting docker image updates using the Home Assistant MQTT Update provider.

From the documentation:

state_topic string (optional)
The MQTT topic subscribed to receive state updates. The state update may be either JSON or a simple string with installed_version value. When a JSON payload is detected, the state value of the JSON payload should supply the installed_version and can optional supply: latest_version, title, release_summary, release_url or an entity_picture URL.

The issue with the data provided from Diun is that it only contains information about the detected update. Ideally, the JSON payload could provide the "installed_version" and "latest_version" entries, as well as the container name and other attributes supported by this Home Assistant provider.

In addition, sending all updates through a single topic is not ideal, as this provider will only generate a single entity. A dynamic topic such as docker/diun/<container_name> would make things much easier.

Of course, a dedicate Home Assistant integration would be ideal from a user perspective, but this seems like the most direct way to integrate multiple container update entities with minimal configuration and state tracking.

[linuxdaemon]

Supporting templated topics like telegraf or similar tools do would work, allowing things like topic: docker/diun/{{ .Container.Name }} to allow for more control. I suppose a payload template as well would allow for a nice generic solution to this, allowing a user to set the payload structure as needed.