| # Copyright 2016 Mirantis, Inc. |
| # |
| # 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. |
| |
| |
| class SingletonMeta(type): |
| """Metaclass for Singleton |
| |
| Main goals: not need to implement __new__ in singleton classes |
| """ |
| _instances = {} |
| |
| def __call__(cls, *args, **kwargs): |
| if cls not in cls._instances: |
| cls._instances[cls] = super( |
| SingletonMeta, cls).__call__(*args, **kwargs) |
| return cls._instances[cls] |