anvil/devstack/importer.py

56 lines
1.8 KiB
Python

# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright (C) 2012 Yahoo! Inc. All Rights Reserved.
# Copyright (C) 2012 New Dream Network, LLC (DreamHost) All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import sys
def partition(fullname):
"""
The name should be in dotted.path:ClassName syntax.
"""
if ':' not in fullname:
raise ValueError('Invalid entry point specifier %r' % fullname)
(module_name, _, classname) = fullname.partition(':')
return (module_name, classname)
def import_entry_point(fullname):
"""
Given a name import the class and return it.
"""
(module_name, classname) = partition(fullname)
try:
module = __import__(module_name)
for submodule in module_name.split('.')[1:]:
module = getattr(module, submodule)
cls = getattr(module, classname)
except (ImportError, AttributeError) as err:
raise RuntimeError('Could not load entry point %s: %s' %
(fullname, err))
return cls
def import_module(module_name, quiet=True):
try:
__import__(module_name)
return sys.modules.get(module_name, None)
except ImportError:
if quiet:
return None
else:
raise