lora-irrigation/util_load.py

# Copyright P G Jones 2018.
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation
# files (the "Software"), to deal in the Software without
# restriction, including without limitation the rights to use,
# copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following
# conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
# OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
# WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
# OTHER DEALINGS IN THE SOFTWARE.
#

# Obtained from:
# https://github.com/pgjones/hypercorn/blob/master/src/hypercorn/utils.py
#
# Slightly modified to adapt to my uses.
#
# Remove import path from sys.path as part of clean up.
#
# Use getattr instead of eval.

import sys

from pathlib import Path
from importlib import import_module

def load_application(path: str):
	try:
		module_name, app_name = path.split(":", 1)
	except ValueError:
		module_name, app_name = path, "func"
	except AttributeError:
		raise ValueError()

	module_path = Path(module_name).resolve()
	added_module = str(module_path.parent)
	sys.path.insert(0, added_module)
	try:
		if module_path.is_file():
			import_name = module_path.with_suffix("").name
		else:
			import_name = module_path.name
		try:
			module = import_module(import_name)
		except ModuleNotFoundError as error:
			if error.name == import_name:
				raise ValueError('module %s not found' %
				    repr(import_name))
			else:
				raise

		try:
			for i in app_name.split('.'):
				module = getattr(module, i)
			return module
		except AttributeError:
			raise ValueError('attribute %s not found on %s' %
			    (repr(i), repr(module)))
	finally:
		sys.path.remove(added_module)