cinder/cinder/scheduler/filters/__init__.py

48 lines
1.7 KiB
Python

# Copyright (c) 2011 OpenStack Foundation.
# 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.
"""
Scheduler host filters
"""
from cinder.scheduler import base_filter
class BaseBackendFilter(base_filter.BaseFilter):
"""Base class for host filters."""
def _filter_one(self, obj, filter_properties):
"""Return True if the object passes the filter, otherwise False."""
# For backward compatibility with out of tree filters
passes_method = getattr(self, 'host_passes', self.backend_passes)
return passes_method(obj, filter_properties)
def backend_passes(self, host_state, filter_properties):
"""Return True if the HostState passes the filter, otherwise False.
Override this in a subclass.
"""
raise NotImplementedError()
class BackendFilterHandler(base_filter.BaseFilterHandler):
def __init__(self, namespace):
super(BackendFilterHandler, self).__init__(BaseHostFilter, namespace)
# NOTE(geguileo): For backward compatibility with external filters that
# inherit from these classes
BaseHostFilter = BaseBackendFilter
HostFilterHandler = BackendFilterHandler