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OpenStack Study: base_weight.py**** CubicPower OpenStack Study ****
# Copyright (c) 2011-2012 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. """ Pluggable Weighing support """ from cinder.openstack.common.scheduler import base_handler
**** CubicPower OpenStack Study **** class WeighedObject(object): """Object with weight information."""
**** CubicPower OpenStack Study **** def __init__(self, obj, weight): self.obj = obj self.weight = weight
**** CubicPower OpenStack Study **** def __repr__(self): return "
**** CubicPower OpenStack Study **** class BaseWeigher(object): """Base class for pluggable weighers."""
**** CubicPower OpenStack Study **** def _weight_multiplier(self): """How weighted this weigher should be. Normally this would be overridden in a subclass based on a config value. """ return 1.0
**** CubicPower OpenStack Study **** def _weigh_object(self, obj, weight_properties): """Override in a subclass to specify a weight for a specific object. """ return 0.0
**** CubicPower OpenStack Study **** def weigh_objects(self, weighed_obj_list, weight_properties): """Weigh multiple objects. Override in a subclass if you need need access to all objects in order to manipulate weights. """ constant = self._weight_multiplier() for obj in weighed_obj_list: obj.weight += (constant * self._weigh_object(obj.obj, weight_properties))
**** CubicPower OpenStack Study **** class BaseWeightHandler(base_handler.BaseHandler): object_class = WeighedObject
**** CubicPower OpenStack Study **** def get_weighed_objects(self, weigher_classes, obj_list, weighing_properties): """Return a sorted (highest score first) list of WeighedObjects.""" if not obj_list: return [] weighed_objs = [self.object_class(obj, 0.0) for obj in obj_list] for weigher_cls in weigher_classes: weigher = weigher_cls() weigher.weigh_objects(weighed_objs, weighing_properties) return sorted(weighed_objs, key=lambda x: x.weight, reverse=True)
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