| # Licensed to the Apache Software Foundation (ASF) under one or more |
| # contributor license agreements. See the NOTICE file distributed with |
| # this work for additional information regarding copyright ownership. |
| # The ASF licenses this file to You 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. |
| |
| """ |
| Common methods for obtaining a reference to the provider driver class. |
| """ |
| |
| import sys |
| |
| __all__ = [ |
| 'get_driver', |
| 'set_driver' |
| ] |
| |
| |
| def get_driver(drivers, provider, deprecated_providers=None, |
| deprecated_constants=None): |
| """ |
| Get a driver. |
| |
| :param drivers: Dictionary containing valid providers. |
| :type drivers: ``dict`` |
| |
| :param provider: Id (constant) of provider to get the driver for. |
| :type provider: :class:`libcloud.types.Provider` |
| |
| :param: deprecated_providers: Dictionary with information about the |
| deprecated drivers. |
| :type deprecated_providers: ``dict`` |
| |
| :param: deprecated_constants: Dictionary with information about the |
| deprecated provider constants. |
| :type deprecated_constants: ``dict`` |
| """ |
| # Those providers have been shut down or similar. |
| deprecated_providers = deprecated_providers or {} |
| if provider in deprecated_providers: |
| url = deprecated_providers[provider]['url'] |
| reason = deprecated_providers[provider]['reason'] |
| msg = ('Provider no longer supported: %s, please visit: %s' % |
| (url, reason)) |
| raise Exception(msg) |
| |
| # Those drivers have moved to "region" constructor argument model |
| deprecated_constants = deprecated_constants or {} |
| if provider in deprecated_constants: |
| old_name = provider.upper() |
| new_name = deprecated_constants[provider].upper() |
| |
| url = 'https://s.apache.org/lc0140un' |
| msg = ('Provider constant "%s" has been removed. New constant ' |
| 'is now called "%s".\n' |
| 'For more information on this change and how to modify your ' |
| 'code to work with it, please visit: %s' % |
| (old_name, new_name, url)) |
| raise Exception(msg) |
| |
| if provider in drivers: |
| mod_name, driver_name = drivers[provider] |
| _mod = __import__(mod_name, globals(), locals(), [driver_name]) |
| return getattr(_mod, driver_name) |
| |
| raise AttributeError('Provider %s does not exist' % (provider)) |
| |
| |
| def set_driver(drivers, provider, module, klass): |
| """ |
| Sets a driver. |
| |
| :param drivers: Dictionary to store providers. |
| :param provider: Id of provider to set driver for |
| |
| :type provider: :class:`libcloud.types.Provider` |
| :param module: The module which contains the driver |
| |
| :type module: L |
| :param klass: The driver class name |
| |
| :type klass: |
| """ |
| |
| if provider in drivers: |
| raise AttributeError('Provider %s already registered' % (provider)) |
| |
| drivers[provider] = (module, klass) |
| |
| # Check if this driver is valid |
| try: |
| driver = get_driver(drivers, provider) |
| except (ImportError, AttributeError): |
| exp = sys.exc_info()[1] |
| drivers.pop(provider) |
| raise exp |
| |
| return driver |