70 lines
2.2 KiB
Python
70 lines
2.2 KiB
Python
# Copyright 2013 Hewlett-Packard Development Company, L.P.
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import threading
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import time
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from tooz import hashring
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from ironic.common import exception
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from ironic.common.i18n import _
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from ironic.conf import CONF
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from ironic.db import api as dbapi
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class HashRingManager(object):
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_hash_rings = None
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_lock = threading.Lock()
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def __init__(self):
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self.dbapi = dbapi.get_instance()
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self.updated_at = time.time()
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@property
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def ring(self):
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interval = CONF.hash_ring_reset_interval
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limit = time.time() - interval
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# Hot path, no lock
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if self.__class__._hash_rings is not None and self.updated_at >= limit:
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return self.__class__._hash_rings
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with self._lock:
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if self.__class__._hash_rings is None or self.updated_at < limit:
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rings = self._load_hash_rings()
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self.__class__._hash_rings = rings
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self.updated_at = time.time()
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return self.__class__._hash_rings
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def _load_hash_rings(self):
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rings = {}
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d2c = self.dbapi.get_active_hardware_type_dict()
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for driver_name, hosts in d2c.items():
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rings[driver_name] = hashring.HashRing(
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hosts, partitions=2 ** CONF.hash_partition_exponent)
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return rings
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@classmethod
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def reset(cls):
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with cls._lock:
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cls._hash_rings = None
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def __getitem__(self, driver_name):
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try:
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return self.ring[driver_name]
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except KeyError:
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raise exception.DriverNotFound(
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_("The driver '%s' is unknown.") % driver_name)
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