How to get a notification when tomorrow's prices are available?

[tvwerkhoven]

I'd like to know when tomorrow's prices are available, instead of waiting for the usual 17:00. I'm trying to make an automation that uses <> to check tomorrow's price, and make a boolean sensor out of the availability. However it's always listed as 'on'. Any idea how to fix this?

template:
  - triggers:
      - trigger: time_pattern
        minutes: /5
    action:
      - service: epex_spot.get_lowest_price_interval
        data:
          earliest_start: "00:00:00"
          earliest_start_post: 1
          duration:
            hours: 1
        response_variable: resp
    binary_sensor:
      - name: EPEX tomorrow available
        state: "{{ resp.start is defined }}"

I'm now changing the state to "{{ resp.start is defined and is_number(resp.price_per_kwh) }}" and adding a debug sensor with state "{{ resp }}" to see what's going on, but ideas are welcome (I can't debug this easily as I can't control the availability of tomorrow's prices :)).

[tvwerkhoven]

I found two bugs:

1. latest_end needs to be explicitly defined, the default gives an error with the given earliest_start.
2. {{ resp.start is defined }} always triggers, but instead I should check for null.

I'm now testing the following:

template:
  - triggers:
      - trigger: time_pattern
        minutes: /5
    action:
      - service: epex_spot.get_lowest_price_interval
        data:
          earliest_start: "00:00:00"
          earliest_start_post: 1
          latest_end: "00:00:00"
          latest_end_post: 2
          duration:
            hours: 1
        response_variable: resp
    binary_sensor:
      - name: EPEX tomorrow available
        state: "{{ resp.price_per_kwh is defined and is_number(resp.price_per_kwh) }}"