Adding extra_attributes to Weather forecast

[kamiyo]

I would like to propose allowing extra attributes back into the weather forecast, this time as a dict on extra_attributes attribute. Right now, the weather template limits the attributes forecasts can return, but many services return useful and interesting data (for example, it is possible from NWS to get chance of thunderstorm, wet bulb temperature, etc.).

I am also unsure about the reason for the strict attribute list in the forecasts. Was this because of worries about the size of the state?

There have been some users discussing a bit here: #114799

[elupus]

Just add additional entities?

[joostlek]

Right, but then you're still creating a place for non standardized data, but then in standardized data. I would rather see it as a separate service because then people know it's actually specific to this integration and not to expect this at every service.

[MatthewFlamm]

It would be ideal from a code owners perspective if the weather integration provides the skeleton for integrations to use, i.e. weather provides the service for the non standard data and integrations provide the data. But I'm not sure what the exact proposal is yet, so maybe it needs to evolve separately before coalescing if the services overlap significantly.

[MatthewFlamm]

It would be good to have some guidance on this topic, even if not an architecture decision, as other integrations are already down the road of the 'thousand entity' approach. See. home-assistant/core#115847

[gjohansson-ST]

Like @joostlek says if NWS has some custom things in its forecasts it should setup its own service to provide it to the users.

It would be kinda weird to allow suddenly unstructured data in the structure which is in place and nothing stopping integrations to provide this on their own either by entities or by a service with return value.

[joostlek]

I also want to mention that I dislike the thousand entity approach. It could also just be a service call with response imo

[kamiyo]

I'm not quite getting what you mean. Do you mean to add additional sensors to specific weather integration?

[elupus]

Yes

[kamiyo]

@MatthewFlamm Do you have any thoughts on this? I really want to try to get those extra bits of forecast in from NWS (from detailed_forecast).

Unless I'm misunderstanding how this would work, for one, that seems to me creating a whole lot of sensors - not to mention to fit in with the forecast model of hourly/daily/twice_daily, you would have to create three separate sensors of each attribute for each type of forecast.

Unless we add a special service to call to get these extra forecast attributes depending on the forecast type. But then I feel like we're just duplicating the get_forecasts code, except to get the "unsanctioned" attributes. In which case, it would just be better to use get_forecasts. Maybe even putting in the data param for the service call the extra attributes you want to fetch, so it's an opt-in rather than opt-out thing, keeping clutter to a minimum.

Thanks for humoring my thoughts.