Tag entity

[gjohansson-ST]

Context

Currently tags is implemented in a manner to use them in automation as scanning is triggering an event in the system.

mobile_app, mqtt and esphome is today capable of triggering a scanned tag by calling tag.async_scan_tag(hass, tag_id, device_id)

Current use in an automation:

trigger:
    platform: event
    event_type: tag_scanned

Proposal

Implement a tag entity / expand the tag integration to also create a tag entity for each tag registered in it's store.

The tag integration will itself create the necessary entities from it's store instead of making an entity component and other integrations (as mentioned above) is creating the entities.

Implementation

• Implement a new tag entity: TagEntity which derives from EventEntity.
• Create / update / delete tag entities by it's events in the tag store.
  • Current UI to create/update/delete tags are kept as is.
• The new tag entity listens to EVENT_TAG_SCANNED for updating it's state (triggered time).
  • As event remains there is nothing breaking with current user implementations.
  • One listener managed from setup, not one per tag.
• Add tag_id and device_id as additional attributes.

Alternatives considered

Make TagEntity an entity component instead and allow other integrations to implement tag entities

Why not alternative

Tags (cards, stickers, QR codes etc.) can be consumed by multiple integrations and there needs to be central location for managing tags so therefore the tag integration is not suitable as an entity component but instead as a self contained integrations as central location for managing all tags and integrations should only be allowed to scan tags (tag.async_scan_tag) and the tag integration will be responsible for triggering events, manage entities and update it's central store.

[balloob]

This would mean if we have 100 tags, we add 100 entities and 100 event listeners. This is a burden when we startup the UI and it is something that we will probably render.

What would be the benefit of this change?

[balloob]

@gjohansson-ST sounds good. Let's do it 👍

[edenhaus]

Implement with home-assistant/core#115048