Add config reloaded events for automation and scene

[frenck]

Proposed change

This PR is adding events when automations or scenes might have been reloaded (and thus might have been changed).

Reasoning and use case:

Automations (and others) can be changed on the fly. Either via UI editing, UI reloading or by reloading YAML configuration via, e.g., the automation.reload service.

Triggers fire, conditions are checked and actions follow. The beautify of this is that automations can be used to bring your home into a state automatically.

Consider this automation:

alias: garden_lights_on
trigger:
  - platform: homeassistant
    event: start
  - platform: state
    entity_id:
      - alarm_control_panel.home_alarm
      - sun.sun
condition:
  - condition: state
    entity_id: alarm_control_panel.home_alarm
    state: disarmed
  - condition: numeric_state
    entity_id: sun.sun
    value_template: >-
      {{ state_attr('sun.sun', 'elevation') }}
    below: 1.0
action:
  - service: light.turn_on
    data:
      entity_id:
        - light.garden_wall
      transition: 5

The Home Assistant start is used here to ensure the state of the light is correct if Home Assistant starts (nb: Due to recent changes, that is not as viable anymore... but not the point 😉).

This is nice and all, but if automation gets changed, we need a manual trigger or re-apply manually, instead of it just happing (if automation is set up that way).

The same can be done for e.g., a scene. If a scene changes, the automation can re-trigger applying the changed/updated scene.

trigger:
  - platform: event
    event: automation_reloaded

With the change in the PR, is becomes possible for an automation to listen for the updated event, after which it can trigger and re-evaluate conditions and/or re-apply changes in the automation automatically.

This PR only applies to scenes and automations. In all other cases, it will cause entities to fire a change on entity level, which will just work as we are used to.

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)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Example entry for configuration.yaml:

# Example configuration.yaml

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request: Add config reloaded events for automation and scene home-assistant.io#13644

Checklist

• The code change is tested and works locally.
• Local tests pass. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist
• The code has been formatted using Black (black --fast homeassistant tests)
• Tests have been added to verify that the new code works.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io

If the code communicates with devices, web services, or third-party tools:

• The manifest file has all fields filled out correctly.
  Updated and included derived files by running: python3 -m script.hassfest.
• New or updated dependencies have been added to requirements_all.txt.
  Updated by running python3 -m script.gen_requirements_all.
• Untested files have been added to .coveragerc.

The integration reached or maintains the following Integration Quality Scale:

• No score or internal
• 🥈 Silver
• 🥇 Gold
• 🏆 Platinum

[probot-home-assistant]

Hey there @home-assistant/core, mind taking a look at this pull request as its been labeled with a integration (automation) you are listed as a codeowner for? Thanks!

[frenck]

Stripped down this PR to its bare basics, limiting its scope, rebased it, and added documentation.

[frenck]

It looks like an unrelated test failure to me.

[balloob]

That's unrelated indeed. That's flakiness caused by the background PR.

[balloob]

Fix for the flaky test #36358