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A custom Home Assistant component for declaring and setting generic variable entities dynamically.
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README.md

home-assistant-variables

The var component is a Home Assistant integration for declaring and setting generic variable entities. Variables can be set manually using the var.set service or they can be set using templates or SQL queries which will be run automatically whenever a specified event fires. The var component depends on the recorder component for up-to-date SQL queries and uses the same database setting.

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Table of Contents

Installation

MANUAL INSTALLATION

  1. Download the latest release.
  2. Unpack the release and copy the custom_components/var directory into the custom_components directory of your Home Assistant installation.
  3. Add a var entry to your configuration.yaml.
  4. Restart Home Assistant.

INSTALLATION VIA HACS

  1. Ensure that HACS is installed.
  2. Search for and install the "Variable" integration.
  3. Add a var entry to your configuration.yaml.
  4. Restart Home Assistant.

Configuration

To add a variable, include it under the var component in your configuration.yaml. The following example adds two variable entities, x and y:

# Example configuration.yaml entry
var:
  x:
    friendly_name: 'X'
    initial_value: 0
    icon: mdi:bug
  y:
    friendly_name: 'Y'
    initial_value: 'Sleeping'
    entity_picture: '/local/sleep.png'

CONFIGURATION VARIABLES

var (map) (Required)

  • friendly_name (string)(Optional) Name to use in the frontend.

  • friendly_name_template (template)(Optional) Defines a template for the name to be used in the frontend (this overrides friendly_name).

    Note: friendly_name_template is evaluated every time an update is triggered for the variable (i.e., via tracked_entity_id, tracked_event_type, or var.update). To pass a template to be evaluated once by var.set, use the friendly_name parameter in a data_template.

  • initial_value (match_all)(Optional) Initial value when Home Assistant starts.

  • value_template (template)(Optional) Defines a template for the value (this overrides initial_value).

    Note: value_template is evaluated every time an update is triggered for the variable (i.e., via tracked_entity_id, tracked_event_type, or var.update). To pass a template to be evaluated once by var.set, use the value parameter in a data_template.

  • tracked_entity_id (string | list)(Optional) A list of entity IDs so the variable reacts to state changes of these entities.

  • tracked_event_type (string | list)(Optional) A list of event types so the variable reacts to these events firing.

  • query (string)(Optional) An SQL QUERY string, should return 1 result at most.

  • column (string)(Optional) The SQL COLUMN to select from the result of the SQL QUERY.

  • restore (boolean)(Optional) Restores the value of the variable whenever Home Assistant is restarted.

    Default value: true

  • force_update (boolean)(Optional) Trigger a state change event every time the value of the variable is updated, even if the value hasn't changed. If false, state change events will only be triggered by distinct changes in value.

    Default value: false

  • unit_of_measurement (string)(Optional) Defines the units of measurement of the variable, if any. This will also influence the graphical presentation in the history visualization as a continuous value. Variables with missing unit_of_measurement are shown as discrete values.

    Default value: None

  • icon (string)(Optional) Icon to display for the component.

  • icon_template (template)(Optional) Defines a template for the icon to be used in the frontend (this overrides icon).

    Note: icon_template is evaluated every time an update is triggered for the variable (i.e., via tracked_entity_id, tracked_event_type, or var.update). To pass a template to be evaluated once by var.set, use the icon parameter in a data_template.

  • entity_picture (string)(Optional) Picture to display for the component.

  • entity_picture_template (template)(Optional) Defines a template for the entity_picture to be used in the frontend (this overrides entity_picture).

    Note: entity_picture_template is evaluated every time an update is triggered for the variable (i.e., via tracked_entity_id, tracked_event_type, or var.update). To pass a template to be evaluated once by var.set, use the entity_picture parameter in a data_template.

Services

var.set

The set service can be used to set the state or attributes of the variable entity from an automation or a script. All config parameters can also be set using var.set.

PARAMETERS

  • entity_id (string | list)(Required) A list of var entity IDs to be set by the service.
  • friendly_name (string)(Optional)
  • friendly_name_template (template)(Optional)
  • value (match_all)(Optional)
  • value_template (template)(Optional)
  • tracked_entity_id (string | list)(Optional)
  • tracked_event_type (string | list)(Optional)
  • query (string)(Optional)
  • column (string)(Optional)
  • restore (boolean)(Optional)
  • force_update (boolean)(Optional)
  • unit_of_measurement (string)(Optional)
  • icon (string)(Optional)
  • icon_template (template)(Optional)
  • entity_picture (string)(Optional)
  • entity_picture_template (template)(Optional)

EXAMPLE

This example sets up an automation that resets the values of the variables at midnight.

var:
  daily_diaper_count:
    friendly_name: "Daily Diaper Count"
    initial_value: 0
    icon: mdi:toilet
  daily_bottle_feed_volume_formula:
    friendly_name: "Daily Formula Intake"
    initial_value: 0
    unit_of_measurement: 'ounces'
    icon: mdi:baby-bottle-outline

automation:
  - alias: "Reset Baby Counters"
    trigger:
      - platform: time
        at: '00:00:00'
    action:
      - service: var.set
        data:
          entity_id:
            - var.daily_diaper_count
            - var.daily_bottle_feed_volume_formula
          value: 0
          icon: mdi:null

var.update

The update service can be used to force the variable entity to update from an automation or a script.

PARAMETERS

  • entity_id (string | list)(Required) A list of var entity IDs to be updated by the service.

EXAMPLE

This example sets up an automation that updates the variable every 5 minutes.

var:
  temp_sensor_battery:
    friendly_name: "Temp Sensor Battery"
    value_template: "{{ state.attr('sensor.temperature', 'battery') }}"

automation:
  - alias: "Update Temp Sensor Battery Var Every 5 Minutes"
    trigger:
      - platform: time_pattern
        minutes: '/5'
    action:
      - service: var.update
        data:
          entity_id: var.temp_sensor_battery

Note: The homeassistant.update_entity service can be used more generally to update any entity, including var entities.

Automatic Updates

UPDATING USING TRACKED ENTITIES

A variable can be set to update whenever the state of an entity changes. This example counts the number of times the state changes for input_boolean.foo and input_boolean.bar.

var:
  toggle_count:
    friendly_name: "Toggle Count"
    initial_value: 0
    value_template: "{{ (states('var.toggle_count') | int) + 1 }}"
    tracked_entity_id:
      - input_boolean.foo
      - input_boolean.bar

UPDATING USING TRACKED EVENT TYPES

A variable can be set to update whenever an event fires. This example multiplies variables y and z whenever my_custom_event fires.

var:
  x:
    friendly_name: 'yz'
    value_template: "{{ (states('var.y') | int) * ( states('var.z') | int) }}"
    tracked_event_type: my_custom_event

Templates

The var component shares features with the template sensor. Many of a variable's attributes can be set using templates.

SELECTING ENTITY/VALUE USING TEMPLATES

Templates can be used with the variable set service to select the entity_id and to set any of the attributes of a variable entity. This example shows entity_id and value being selected via template.

automation:
  - alias: "Handle Bottle Feed Event"
    trigger:
      platform: event
      event_type: bottle_feed_event
    action:
      service: var.set
      data_template:
        entity_id: >-
          {% if trigger.event.data.contents == 'milk' %}
            var.daily_bottle_feed_volume_milk
          {% elif trigger.event.data.contents == 'formula' %}
            var.daily_bottle_feed_volume_formula
          {% endif %}
        value: >-
          {% if trigger.event.data.contents == 'milk' %}
            {{ (states('var.daily_bottle_feed_volume_milk') | int) + (trigger.event.data.volume | int) }}
          {% elif trigger.event.data.contents == 'formula' %}
            {{ (states('var.daily_bottle_feed_volume_formula') | int) + (trigger.event.data.volume | int) }}
          {% endif %}

DYNAMIC VARIABLE UPDATES USING TEMPLATES

This example shows how the value, and other attributes of the variable, can be set to update automatically based on the state of another entity. Template values will be updated whenever the state changes for any of the tracked entities listed below tracked_entity_id.

var:
  waldo_location_status:
    friendly_name: "Waldo Location Status"
    value_template: >-
      {% if states('device_tracker.waldo_phone_wifi') == 'home' and states('device_tracker.waldo_phone_bluetooth') == 'home' %}
        Home
      {% else %}
        Unknown
      {% endif %}
    entity_picture_template: >-
      {% if states('var.waldo_location_status') == 'Home' %}
        /local/home.jpg
      {% else %}
        /local/question_mark.jpg
      {% endif %}
    tracked_entity_id:
      - device_tracker.waldo_phone_wifi
      - device_tracker.waldo_phone_bluetooth
      - var.waldo_location_status

SQL Queries

The var component also shares features with the SQL sensor. When a variable updates, it will run the SQL query against the Home Assistant database updating the variable with the value of the query.

DYNAMIC VARIABLE UPDATES USING AN SQL QUERY

This example shows how the value, and other attributes of the variable, can be set to update automatically based on an SQL query. Template values will be updated whenever the state changes for any of the tracked entities listed below tracked_entity_id or when any event fires with the same event type as any of the event types listed below tracked_event_type.

var:
  todays_diaper_count:
    friendly_name: "Today's Diaper Count"
    icon: mdi:toilet
    query: "SELECT COUNT(*) AS diaper_count FROM events WHERE event_type = 'diaper_event' AND time_fired BETWEEN DATETIME('now', 'start of day') AND DATETIME('now');"
    column: 'diaper_count'
    tracked_event_type: diaper_event

FILTERING EVENT DATA USING AN SQL QUERY

This example shows how to use an SQL query to filter events based on their event_data. In the example, diaper_event contains an event_data entry called type that is either wet, dirty, or both.

var:
  todays_wet_diaper_count:
    friendly_name: "Today's Wet Diaper Count"
    icon: mdi:water
    query: "SELECT COUNT(*) AS diaper_count FROM events WHERE event_type = 'diaper_event' AND JSON_EXTRACT(event_data, '$.type') LIKE '%wet%' AND time_fired BETWEEN DATETIME('now', 'start of day') AND DATETIME('now');"
    column: 'diaper_count'
    tracked_event_type: diaper_event

USING AN SQL QUERY IN A TEMPLATE

The result of a variable's SQL query can also be used within templates. This example computes the average formula volume over the past week and adds it to the variable z. In this example, bottle_event contains an event_data entry called volume that contains the volume of formula.

var:
  avg_formula_plus_z:
    friendly_name: "Average Formula Plus z"
    value_template: "{{ ( avg_formula | float) + ( states('var.z') | float) }}"
    query: "SELECT COALESCE(SUM(CAST(JSON_EXTRACT(event_data, '$.volume') AS FLOAT))/7.0, 0) AS avg_formula FROM events WHERE event_type = 'bottle_event' AND time_fired BETWEEN DATETIME('now', 'start of day', '-7 days') AND DATETIME('now', 'start of day');"
    column: 'avg_formula'
    tracked_event_type: bottle_event

Lovelace UI

Variables can be displayed in the Lovelace frontend like other entities.

cards:
  - type: entities
    title: "Baby Variables"
    entities:
      - entity: var.daily_diaper_count
      - entity: var.daily_bottle_feed_volume_milk
      - entity: var.daily_bottle_feed_volume_formula

Setting a unit_of_measurement will prompt Home Assistant to display a two dimensional graph in its history panel and history-graph card.

cards:
  - type: history-graph
    title: "Baby Plots"
    hours_to_show: 24
    entities:
      - entity: var.daily_bottle_feed_volume_milk
      - entity: var.daily_bottle_feed_volume_formula

Tip: Using a unit of ' ' can be useful if you want to group unit-less variables together in a single 2D graph.

Why?

I assembled this component for a few reasons:

  • It was tedious to create a corresponding separate template sensor for each entity in the UI.
  • I wanted a single general-purpose component, with a generic name, that could be used to store, update, and display values using templates.
  • I didn't like using named UI components to store first-class data (e.g. input_text).
  • I wanted to be able to work with data directly from the home assistant database (especially custom events) without having to create and flip-flop between a bunch of different entities.
  • I wanted a custom component that I could extend with more features in the future.

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