#   Copyright 2012-2013 OpenStack Foundation
#
#   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.
#

"""Manage access to the clients, including authenticating when needed."""

import copy
import logging
import pkg_resources
import sys

from oslo_utils import strutils
import requests

from openstackclient.api import auth
from openstackclient.common import session as osc_session
from openstackclient.identity import client as identity_client


LOG = logging.getLogger(__name__)

PLUGIN_MODULES = []

USER_AGENT = 'python-openstackclient'


class ClientCache(object):
    """Descriptor class for caching created client handles."""
    def __init__(self, factory):
        self.factory = factory
        self._handle = None

    def __get__(self, instance, owner):
        # Tell the ClientManager to login to keystone
        if self._handle is None:
            self._handle = self.factory(instance)
        return self._handle