OpenStack Study: __init__.py

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# 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.openstack.common import log as logging

from cinder.openstack.common.scheduler import base_filter

LOG = logging.getLogger(__name__)

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class BaseHostFilter(base_filter.BaseFilter):

"""Base class for host filters."""

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    def _filter_one(self, obj, filter_properties):

        """Return True if the object passes the filter, otherwise False."""

        return self.host_passes(obj, filter_properties)

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    def host_passes(self, host_state, filter_properties):

        """Return True if the HostState passes the filter, otherwise False.

        Override this in a subclass.

        """

        raise NotImplementedError()

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class HostFilterHandler(base_filter.BaseFilterHandler):

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    def __init__(self, namespace):

        super(HostFilterHandler, self).__init__(BaseHostFilter, namespace)