Create template automation

homeassistant/components/automation/template.py

@@ -0,0 +1,63 @@
+"""
+homeassistant.components.automation.template
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Offers template automation rules.
+
+For more details about this automation rule, please refer to the documentation
+at https://home-assistant.io/components/automation/#template-trigger
+"""
+import logging
+
+from homeassistant.const import CONF_VALUE_TEMPLATE
+from homeassistant.exceptions import TemplateError
+from homeassistant.helpers.event import track_state_change
+from homeassistant.util import template
+
+_LOGGER = logging.getLogger(__name__)
+
+
+def trigger(hass, config, action):
+    """ Listen for state changes based on `config`. """
+    value_template = config.get(CONF_VALUE_TEMPLATE)
+
+    if value_template is None:
+        _LOGGER.error("Missing configuration key %s", CONF_VALUE_TEMPLATE)
+        return False
+
+    # Get all entity ids
+    all_entity_ids = hass.states.entity_ids()
+
+    # pylint: disable=unused-argument
+    def state_automation_listener(entity, from_s, to_s):
+        """ Listens for state changes and calls action. """
+
+        # Check to see if template returns true
+        if _check_template(hass, value_template):
+            action()
+
+    track_state_change(hass, all_entity_ids, state_automation_listener)
+
+    return True
+
+
+def if_action(hass, config):
+    """ Wraps action method with state based condition. """
+
+    value_template = config.get(CONF_VALUE_TEMPLATE)
+
+    if value_template is None:
+        _LOGGER.error("Missing configuration key %s", CONF_VALUE_TEMPLATE)
+        return False
+
+    return lambda: _check_template(hass, value_template)
+
+
+def _check_template(hass, value_template):
+    """ Checks if result of template is true """
+    try:
+        value = template.render(hass, value_template, {})
+    except TemplateError:
+        _LOGGER.exception('Error parsing template')
+        return False
+
+    return value.lower() == 'true'