#
# Copyright 2012 New Dream Network, LLC (DreamHost)
#
# Author: Doug Hellmann <doug.hellmann@dreamhost.com>
#
# 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.
"""Base class for plugins used by the central agent.
"""

from ceilometer.openstack.common.gettextutils import _
from ceilometer.openstack.common import log
from ceilometer import plugin

LOG = log.getLogger(__name__)


class CentralPollster(plugin.PollsterBase):
    """Base class for plugins that support the polling API."""


def check_keystone(f):
    """Decorator function to check if manager has valid keystone client."""
    def func(self, *args, **kwargs):
        manager = kwargs.get('manager')
        if not manager and len(args) > 0:
            manager = args[0]
        keystone = getattr(manager, 'keystone', None)
        if not keystone or isinstance(keystone, Exception):
            LOG.error(_('Skip due to keystone error %s'),
                      str(keystone) if keystone else '')
            return iter([])
        return f(self, *args, **kwargs)
    return func