# -*- coding: utf-8 -*-
#
# Copyright 2018-2022 Univention GmbH
#
# https://www.univention.de/
#
# All rights reserved.
#
# The source code of this program is made available
# under the terms of the GNU Affero General Public License version 3
# (GNU AGPL V3) as published by the Free Software Foundation.
#
# Binary versions of this program provided by Univention to you as
# well as other copyrighted, protected or trademarked materials like
# Logos, graphics, fonts, specific documentations and configurations,
# cryptographic keys etc. are subject to a license agreement between
# you and Univention.
#
# This program is provided in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public
# License with the Debian GNU/Linux or Univention distribution in file
# /usr/share/common-licenses/AGPL-3; if not, see
# <https://www.gnu.org/licenses/>.
import importlib
import os.path
from glob import glob
[docs]class Plugin(type):
"""
Meta class for plugins.
"""
def __new__(mcs, name, bases, attrs):
new_cls = super(Plugin, mcs).__new__(mcs, name, bases, attrs)
Plugins.add_plugin(new_cls)
return new_cls
[docs]class Plugins(object):
"""
Register `Plugin` subclasses and iterate over them.
"""
_plugins = []
_imported = {}
def __init__(self, python_path):
"""
:param str python_path: fully dotted Python path that the plugins will
be found below
"""
self.python_path = python_path
self._imported.setdefault(python_path, False)
[docs] @classmethod
def add_plugin(cls, plugin):
"""
Called by `Plugin` meta class to register a new `Plugin` subclass.
:param type plugin: a `Plugin` subclass
"""
cls._plugins.append(plugin)
def __iter__(self):
"""
Iterator for registered `Plugin` subclasses.
:return: `Plugin` subclass
:rtype: type
"""
self.load()
for plugin in self._plugins:
if plugin.__module__.startswith(self.python_path):
yield plugin
[docs] def load(self):
"""Load plugins."""
if self._imported.get(self.python_path):
return
base_module = importlib.import_module(self.python_path)
base_module_dir = os.path.dirname(base_module.__file__)
path = os.path.join(base_module_dir, '*.py')
for pymodule in glob(path):
pymodule_name = os.path.basename(pymodule)[:-3] # without .py
importlib.import_module('{}.{}'.format(self.python_path, pymodule_name))
self._imported[self.python_path] = True
