KNX Group Monitorn History Data

[chrisch80]

Is it possible to have a longer history in the KNX group monitor view?
Is this data stored in a DB and can bei accessed somehow?

[farmio]

Hi 👋!
Yes, it is possible to adjust that in the integration configurations "communication settings" menu.

The data is stored in memory.
Since 2023.8 it's also written to a file, but only when the integration unloads - to be able to restore history data after eg. a restart.

[chrisch80]

Cool, thanks
Do you have some proposal how to store it in a db or could this be added as feature in the future?

[farmio]

There are no plans to do so currently. What would be the usecase for that?

It was initially built to only write to disk on shutdown - with RaspberryPi SD-Card installations in mind. This feature should not stress these cards more than necessary.

[chrisch80]

I would like to montior the KNX-BUS with own scripts, but maybe it is better to fully integrate it in HomeAssistant.

[farmio]

Aha. Tbh this sounds a little bit out of scope for the HA KNX integration.

But anyway, I don't think you'd need a database for that. You can just use the same websocket endpoint we use for the group monitor to get live data and process it in your script. See https://github.com/home-assistant/core/blob/f0abea48a6aef5c8f35770f36df5a47488ed3df6/homeassistant/components/knx/websocket.py#L163
Be aware, that this is not considered a public API currently and may be subject of change in future releases.

You could of course also just use an xknx instance in your script and have a separate connection providing callbacks to your logic.

From Home Assistant it may be doable using HA Events (knx_event) - depending on what you actually want to monitor.

[chrisch80]

cool thx

[rvk]

+1 for this feature, and I'll provide a standard use case.

Many visualization products for KNX have the data logging feature. It's used to diagnose intermittent problems that can't be reproduced while integrator is on-site.

For this, data survivability is critical, but timing of the writes is not. I think good solution for both considerations would be to have default behaviour as it is, but to add disk writing frequency as configurable option. Could you consider adding this?