mirror of
https://github.com/home-assistant/core
synced 2024-08-02 23:40:32 +02:00
119 lines
3.1 KiB
Python
119 lines
3.1 KiB
Python
"""
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homeassistant.loader
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~~~~~~~~~~~~~~~~~~~~
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Provides methods for loading Home Assistant components.
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"""
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import sys
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import pkgutil
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import importlib
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import logging
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# List of available components
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AVAILABLE_COMPONENTS = []
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# Dict of loaded components mapped name => module
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_COMPONENT_CACHE = {}
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_LOGGER = logging.getLogger(__name__)
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def prepare(hass):
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""" Prepares the loading of components. """
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# Load the built-in components
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import homeassistant.components as components
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AVAILABLE_COMPONENTS.clear()
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AVAILABLE_COMPONENTS.extend(
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item[1] for item in
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pkgutil.iter_modules(components.__path__, 'homeassistant.components.'))
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# Look for available custom components
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# Ensure we can load custom components from the config dir
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sys.path.append(hass.config_dir)
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try:
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# pylint: disable=import-error
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import custom_components
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AVAILABLE_COMPONENTS.extend(
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item[1] for item in
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pkgutil.iter_modules(
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custom_components.__path__, 'custom_components.'))
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except ImportError:
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# No folder custom_components exist in the config directory
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pass
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def get_component(comp_name):
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""" Tries to load specified component.
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Looks in config dir first, then built-in components.
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Only returns it if also found to be valid. """
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if comp_name in _COMPONENT_CACHE:
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return _COMPONENT_CACHE[comp_name]
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# First check config dir, then built-in
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potential_paths = [path for path in
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['custom_components.{}'.format(comp_name),
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'homeassistant.components.{}'.format(comp_name)]
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if path in AVAILABLE_COMPONENTS]
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if not potential_paths:
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_LOGGER.error("Failed to find component {}".format(comp_name))
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return None
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for path in potential_paths:
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comp = _get_component(path)
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if comp is not None:
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_LOGGER.info("Loaded component {} from {}".format(
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comp_name, path))
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_COMPONENT_CACHE[comp_name] = comp
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return comp
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# We did find components but were unable to load them
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_LOGGER.error("Unable to load component {}".format(comp_name))
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return None
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def _get_component(module):
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""" Tries to load specified component.
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Only returns it if also found to be valid."""
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try:
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comp = importlib.import_module(module)
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except ImportError:
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_LOGGER.exception(("Error loading {}. Make sure all "
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"dependencies are installed").format(module))
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return None
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# Validation if component has required methods and attributes
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errors = []
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if not hasattr(comp, 'DOMAIN'):
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errors.append("missing DOMAIN attribute")
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if not hasattr(comp, 'DEPENDENCIES'):
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errors.append("missing DEPENDENCIES attribute")
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if not hasattr(comp, 'setup'):
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errors.append("missing setup method")
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if errors:
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_LOGGER.error("Found invalid component {}: {}".format(
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module, ", ".join(errors)))
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return None
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else:
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return comp
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