WTH Templates not evaluated everywhere

Archive Month of "What the heck?!" 2022
1

I’m fighting with templates not usable everywhere. To be honest not sure if this is pure HA issue, or the custom cards I’m using (mushroom)

just as an example: I’d like to have a single button with different action based on a entity state - if room lights are off, swith on the main light. If any light in the room is on, switch off everything (light group)

In developer tools this is working fine

data: {}
target:
  entity_id: '{{ "light.room_main" if states("light.grp_room") == "off" else "light.grp_room"}}'

(where light.room_main is the main light and light.grp_room is the group of all lights in the room.)

But trying to incorporate that to the UI with mushroom cards is a pain. The same goes to custom icon colors… (with an workaround by the mushroom template card).

Why the hell can’t the templates be used and evaluated simply anywhere?

2

Mushroom cards is a third party frontend module. You need to take this up with the developer.

3

Using the inbuilt button card I’ve got the same experience. Template is not evaluated.

- type: button
  entity: sensor.room_temperature
  name: Room
  show_name: true
  show_icon: true
  icon: mdi:desktop-classic
  show_state: true
  tap_action:
    action: call-service
    service: light.toggle
    data: {}
    target:
  	entity_id: >-
	    {{ "light.room_main" if states("light.grp_room") == "off" else "light.grp_room"}}
  hold_action:
    action: navigate
    navigation_path: room/

What am I doing wrong? Or is the original question valid? Why can’t the templates be used and evaluated simply anywhere?

4

Home Assistant’s standard cards don’t support templates (except for the Markdown card).

5

So the templates are just for scripts and automations? (and some custom cards, somewhere… but out of the pure HA scope). Pitty. It’s quite powerful.

6

Except for a few special cases templates can only be used under the following:

service:

data:

target:

service in dashboard card tap actions is not included (it used to be service_data).