home-assistant.io/source/_docs/automation/templating.markdown

layout	title	description	date	sidebar	comments	sharing	footer	redirect_from
page	Automation Templating	Advanced automation documentation using templating.	2016-04-24 08:30 +0100	true	false	true	true	/getting-started/automation-templating/

In Home Assistant 0.19 we introduced a new powerful feature: variables in scripts and automations. This makes it possible to adjust your condition and action based on the information of the trigger.

The trigger data made is available during template rendering as the trigger variable.

# Example configuration.yaml entries
automation:
  trigger:
    platform: state
    entity_id: device_tracker.paulus
  action:
    service: notify.notify
    data_template:
      message: >{% raw %}
        Paulus just changed from {{ trigger.from_state.state }}
        to {{ trigger.to_state.state }}{% endraw %}

automation 2:
  trigger:
    platform: mqtt
    topic: /notify/+
  action:
    service_template: >{% raw %}
      notify.{{ trigger.topic.split('/')[-1] }}{% endraw %}
    data_template:
      message: {% raw %}'{{ trigger.payload }}'{% endraw %}

{% linkable_title Important Template Rules %}

There are a few very important rules to remember when writing automation templates:

1. You must use data_template in place of data when using templates in the data section of a service call.
2. You must use service_template in place of service when using templates in the service section of a service call.
3. You must surround single-line templates with double quotes (") or single quotes (').
4. It is advised that you prepare for undefined variables by using if ... is not none or the default filter, or both.
5. It is advised that when comparing numbers, you convert the number(s) to a float or an int by using the respective filter.
6. While the float and int filters do allow a default fallback value if the conversion is unsuccessful, they do not provide the ability to catch undefined variables.

Remembering these simple rules will help save you from many headaches and endless hours of frustration when using automation templates.

{% linkable_title Trigger State Object %}

Knowing how to access the state object of a trigger entity could be one of the more common questions. Here are a few ways for the state, numeric_state and template triggers:

• trigger.from_state will return the previous state object of the entity.
• trigger.to_state will return the new state object that triggered trigger.
• states[trigger.to_state.domain][trigger.to_state.object_id] will return the current state object of the entity.

{% linkable_title Available Trigger Data %}

The following tables show the available trigger data per platform.

{% linkable_title event %}

Template variable	Data
trigger.platform	Hardcoded: event.
trigger.event	Event object that matched.
trigger.event.data	Optional data

{% linkable_title mqtt %}

Template variable	Data
trigger.platform	Hardcoded: mqtt.
trigger.topic	Topic that received payload.
trigger.payload	Payload.
trigger.payload_json	Dictonary of the JSON parsed payload.
trigger.qos	QOS of payload.

{% linkable_title numeric_state %}

Template variable	Data
trigger.platform	Hardcoded: numeric_state
trigger.entity_id	Entity ID that we observe.
trigger.below	The below threshold, if any.
trigger.above	The above threshold, if any.
trigger.from_state	The previous state object of the entity.
trigger.to_state	The new state object that triggered trigger.

{% linkable_title state %}

Template variable	Data
trigger.platform	Hardcoded: state
trigger.entity_id	Entity ID that we observe.
trigger.from_state	The previous state object of the entity.
trigger.to_state	The new state object that triggered trigger.
trigger.for	Timedelta object how long state has been to state, if any.

{% linkable_title sun %}

Template variable	Data
trigger.platform	Hardcoded: sun
trigger.event	The event that just happened: sunset or sunrise.
trigger.offset	Timedelta object with offset to the event, if any.

{% linkable_title template %}

Template variable	Data
trigger.platform	Hardcoded: template
trigger.entity_id	Entity ID that caused change.
trigger.from_state	Previous state object of entity that caused change.
trigger.to_state	New state object of entity that caused template to change.

{% linkable_title time %}

Template variable	Data
trigger.platform	Hardcoded: time
trigger.now	DateTime object that triggered the time trigger.

{% linkable_title zone %}

Template variable	Data
trigger.platform	Hardcoded: zone
trigger.entity_id	Entity ID that we are observing.
trigger.from_state	Previous state object of the entity.
trigger.to_state	New state object of the entity.
trigger.zone	State object of zone
trigger.event	Event that trigger observed: enter or leave.