Python Scripts


This integration allows you to write Python scripts that are exposed as services in Home Assistant. Each Python file created in the <config>/python_scripts/ folder will be exposed as a service. The content is not cached so you can easily develop: edit file, save changes, call service. The scripts are run in a sandboxed environment. The following variables are available in the sandbox:

Name Description
hass The Home Assistant object. Access is only allowed to call services, set/remove states and fire events. API reference
data The data passed to the Python Script service call.
logger A logger to allow you to log messages: logger.info(), logger.warning(), logger.error(). API reference

It is not possible to use Python imports with this integration. If you want to do more advanced scripts, you can take a look at AppDaemon

Writing your first script

  • Add to configuration.yaml: python_script:
  • Create folder <config>/python_scripts
  • Create a file hello_world.py in the folder and give it this content:
name = data.get('name', 'world')
logger.info("Hello {}".format(name))
hass.bus.fire(name, { "wow": "from a Python script!" })
  • Start Home Assistant
  • Call service python_script.hello_world with parameters
name: you

Calling Services

The following example shows how to call a service from python_script. This script takes two parameters: entity_id (required), rgb_color (optional) and calls light.turn_on service by setting the brightness value to 255.

# turn_on_light.py
entity_id = data.get('entity_id')
rgb_color = data.get('rgb_color', [255, 255, 255])
if entity_id is not None:
    service_data = {'entity_id': entity_id, 'rgb_color': rgb_color, 'brightness': 255 }
    hass.services.call('light', 'turn_on', service_data, False)

The above python_script can be called using the following JSON as an input.

entity_id: light.bedroom
rgb_color: [255, 0, 0]

Documenting your Python scripts

You can add descriptions for your Python scripts that will be shown in the Call Services tab of the Developer Options page. To do so, simply create a services.yaml file in your <config>/python_scripts folder. Using the above Python script as an example, the services.yaml file would look like:

# services.yaml
turn_on_light:
  description: Turn on a light and set its color. 
  fields:
    entity_id:
      description: The light that will be turned on.
      example: light.bedroom
    rgb_color:
      description: The color to which the light will be set.
      example: [255, 0, 0]

For more examples, visit the Scripts section in our forum.