7a42473002
Adds context tracking decorators that were missing from router interface methods. Without them, new sessions were being created instead of using the existing context which was causing transaction issues. Modifies the servermanager to store context references as weakrefs so if multiple functions are called before the rest functions are called, the first one doesn't steal the only context reference with a pop() call. Removes a DB lock for update in the server manager that occured during rest calls that was triggering deadlocks due to the file lock synchronization for the rest calls. Closes-Bug: #1336251 Change-Id: Iad3d61e2c23832b3ad760a999fbab7feaa13f805
83 lines
3.1 KiB
Python
83 lines
3.1 KiB
Python
# Copyright 2014, Big Switch Networks
|
|
# 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.
|
|
import sqlalchemy as sa
|
|
|
|
from neutron.common import exceptions
|
|
from neutron.db import api as db
|
|
from neutron.db import model_base
|
|
from neutron.openstack.common import log as logging
|
|
|
|
LOG = logging.getLogger(__name__)
|
|
|
|
|
|
class MultipleReadForUpdateCalls(exceptions.NeutronException):
|
|
message = _("Only one read_for_update call may be made at a time.")
|
|
|
|
|
|
class ConsistencyHash(model_base.BASEV2):
|
|
'''
|
|
A simple table to store the latest consistency hash
|
|
received from a server.
|
|
For now we only support one global state so the
|
|
hash_id will always be '1'
|
|
'''
|
|
__tablename__ = 'consistencyhashes'
|
|
hash_id = sa.Column(sa.String(255),
|
|
primary_key=True)
|
|
hash = sa.Column(sa.String(255), nullable=False)
|
|
|
|
|
|
class HashHandler(object):
|
|
'''
|
|
A wrapper object to keep track of the session and hold the SQL
|
|
lock between the read and the update to prevent other servers
|
|
from reading the hash during a transaction.
|
|
'''
|
|
def __init__(self, context=None, hash_id='1'):
|
|
self.hash_id = hash_id
|
|
self.session = db.get_session() if not context else context.session
|
|
self.hash_db_obj = None
|
|
self.transaction = None
|
|
|
|
def read_for_update(self):
|
|
if self.transaction:
|
|
raise MultipleReadForUpdateCalls()
|
|
self.transaction = self.session.begin(subtransactions=True)
|
|
# REVISIT(kevinbenton): locking here with the DB is prone to deadlocks
|
|
# in various multi-REST-call scenarios (router intfs, flips, etc).
|
|
# Since it doesn't work in Galera deployments anyway, another sync
|
|
# mechanism will have to be introduced to prevent inefficient double
|
|
# syncs in HA deployments.
|
|
res = (self.session.query(ConsistencyHash).
|
|
filter_by(hash_id=self.hash_id).first())
|
|
if not res:
|
|
return ''
|
|
self.hash_db_obj = res
|
|
return res.hash
|
|
|
|
def put_hash(self, hash):
|
|
hash = hash or ''
|
|
if not self.transaction:
|
|
self.transaction = self.session.begin(subtransactions=True)
|
|
if self.hash_db_obj is not None:
|
|
self.hash_db_obj.hash = hash
|
|
else:
|
|
conhash = ConsistencyHash(hash_id=self.hash_id, hash=hash)
|
|
self.session.merge(conhash)
|
|
self.transaction.commit()
|
|
self.transaction = None
|
|
LOG.debug(_("Consistency hash for group %(hash_id)s updated "
|
|
"to %(hash)s"), {'hash_id': self.hash_id, 'hash': hash})
|