140 lines
5.6 KiB
Python
140 lines
5.6 KiB
Python
# Copyright (c) 2014 Thales Services SAS
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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 random
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from oslo.db import exception as db_exc
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from neutron.common import exceptions as exc
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from neutron.openstack.common import log
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from neutron.plugins.ml2 import driver_api as api
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IDPOOL_SELECT_SIZE = 100
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LOG = log.getLogger(__name__)
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class TypeDriverHelper(api.TypeDriver):
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"""TypeDriver Helper for segment allocation.
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Provide methods helping to perform segment allocation fully or partially
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specified.
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"""
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def __init__(self, model):
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self.model = model
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self.primary_keys = set(dict(model.__table__.columns))
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self.primary_keys.remove("allocated")
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def allocate_fully_specified_segment(self, session, **raw_segment):
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"""Allocate segment fully specified by raw_segment.
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If segment exists, then try to allocate it and return db object
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If segment does not exists, then try to create it and return db object
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If allocation/creation failed, then return None
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"""
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network_type = self.get_type()
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try:
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with session.begin(subtransactions=True):
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alloc = (session.query(self.model).filter_by(**raw_segment).
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first())
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if alloc:
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if alloc.allocated:
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# Segment already allocated
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return
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else:
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# Segment not allocated
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LOG.debug("%(type)s segment %(segment)s allocate "
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"started ",
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{"type": network_type,
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"segment": raw_segment})
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count = (session.query(self.model).
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filter_by(allocated=False, **raw_segment).
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update({"allocated": True}))
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if count:
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LOG.debug("%(type)s segment %(segment)s allocate "
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"done ",
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{"type": network_type,
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"segment": raw_segment})
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return alloc
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# Segment allocated or deleted since select
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LOG.debug("%(type)s segment %(segment)s allocate "
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"failed: segment has been allocated or "
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"deleted",
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{"type": network_type,
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"segment": raw_segment})
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# Segment to create or already allocated
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LOG.debug("%(type)s segment %(segment)s create started",
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{"type": network_type, "segment": raw_segment})
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alloc = self.model(allocated=True, **raw_segment)
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alloc.save(session)
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LOG.debug("%(type)s segment %(segment)s create done",
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{"type": network_type, "segment": raw_segment})
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except db_exc.DBDuplicateEntry:
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# Segment already allocated (insert failure)
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alloc = None
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LOG.debug("%(type)s segment %(segment)s create failed",
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{"type": network_type, "segment": raw_segment})
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return alloc
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def allocate_partially_specified_segment(self, session, **filters):
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"""Allocate model segment from pool partially specified by filters.
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Return allocated db object or None.
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"""
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network_type = self.get_type()
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with session.begin(subtransactions=True):
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select = (session.query(self.model).
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filter_by(allocated=False, **filters))
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# Selected segment can be allocated before update by someone else,
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allocs = select.limit(IDPOOL_SELECT_SIZE).all()
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if not allocs:
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# No resource available
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return
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alloc = random.choice(allocs)
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raw_segment = dict((k, alloc[k]) for k in self.primary_keys)
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LOG.debug("%(type)s segment allocate from pool "
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"started with %(segment)s ",
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{"type": network_type,
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"segment": raw_segment})
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count = (session.query(self.model).
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filter_by(allocated=False, **raw_segment).
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update({"allocated": True}))
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if count:
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LOG.debug("%(type)s segment allocate from pool "
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"success with %(segment)s ",
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{"type": network_type,
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"segment": raw_segment})
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return alloc
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# Segment allocated since select
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LOG.debug("Allocate %(type)s segment from pool "
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"failed with segment %(segment)s",
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{"type": network_type,
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"segment": raw_segment})
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# saving real exception in case we exceeded amount of attempts
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raise exc.RetryRequest(
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exc.NoNetworkFoundInMaximumAllowedAttempts())
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