Add option to trigger template triggers when the template updates

[Petro31]

Proposed change

Currently, template triggers only trigger when the template previously renders false and then renders true. This limits template triggers and forces users to create template entities.

Adding the ability to optionally trigger off any template change opens up functionality for automations and template entities.

e.g. A user would now be able to create a trigger based template sensor where there's shared templates across states and attributes.

template:
- trigger:
  - platform: template
    value_template: "{{ label_entities('living_room') | select('is_state', 'on') | list }}"
    render: True
  sensor:
  - name: Living Room On Entities
    state: "{{ trigger.value | count }}"
    attributes:
      entity_id: "{{ trigger.value }}"

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Deprecation (breaking change to happen in the future)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request: Add option to trigger when a template trigger renders any result. home-assistant.io#33614

Checklist

• The code change is tested and works locally.
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• There is no commented out code in this PR.
• I have followed the development checklist
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• Tests have been added to verify that the new code works.

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[home-assistant]

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[Mariusthvdb]

sounds very useful indeed.
Would the trigger.value keep the datetime type if datetime would be used in the trigger.
(and not return a string, as happens when using trigger variables)

template:
- trigger:
  - platform: template
    value_template: "{{'2024-07-08'|as_datetime|as_local}}"
    render: True
  sensor:
  - name: Value is datetime
    state: "{{ trigger.value is datetime}}"

if yes, consider my +1 to be +10

[Petro31]

sounds very useful indeed. Would the trigger.value keep the datetime type if datetime would be used in the trigger. (and not return a string, as happens when using trigger variables)

template:
- trigger:
  - platform: template
    value_template: "{{'2024-07-08'|as_datetime|as_local}}"
    render: True
  sensor:
  - name: Value is datetime
    state: "{{ trigger.value is datetime}}"

if yes, consider my +1 to be +10

It should, lucky for you too... template triggers by default resolve once a minute if the template never updates.

[gjohansson-ST]

LGTM 👍