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# Copyright 2016 Hewlett Packard Enterprise Development Company, L.P.
#
# 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.
from oslo_config import cfg
from oslo_log import log as logging
from stevedore import named
from designate import exceptions
LOG = logging.getLogger(__name__)
class Scheduler(object):
"""Scheduler that schedules zones based on the filters provided on the zone
and other inputs.
:raises: NoFiltersConfigured
"""
filters = []
"""The list of filters enabled on this scheduler"""
def __init__(self, storage):
enabled_filters = cfg.CONF['service:central'].scheduler_filters
self.filters = list()
self.storage = storage
if not enabled_filters:
raise exceptions.NoFiltersConfigured(
'There are no scheduling filters configured'
)
extensions = named.NamedExtensionManager(
namespace='designate.scheduler.filters',
names=enabled_filters,
name_order=True,
)
for extension in extensions:
plugin = extension.plugin(storage=self.storage)
LOG.info('Loaded Scheduler Filter: %s', plugin.name)
self.filters.append(plugin)
def schedule_zone(self, context, zone):
"""Get a pool to create the new zone in.
:param context: :class:`designate.context.DesignateContext` - Context
Object from request
:param zone: :class:`designate.objects.zone.Zone` - Zone to be created
:return: string -- ID of pool to schedule the zone to.
:raises: MultiplePoolsFound, NoValidPoolFound
"""
pools = self.storage.find_pools(context)
if not self.filters:
raise exceptions.NoFiltersConfigured('There are no scheduling '
'filters configured')
for plugin in self.filters:
LOG.debug(
'Running %s filter with %d pools', plugin.name, len(pools)
)
pools = plugin.filter(context, pools, zone)
LOG.debug(
'%d candidate pools remaining after %s filter',
len(pools), plugin.name
)
if len(pools) > 1:
raise exceptions.MultiplePoolsFound()
if not pools:
raise exceptions.NoValidPoolFound(
'There are no pools that matched your request'
)
return pools[0].id
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