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# Copyright 2014 Mirantis.inc
# 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 copy
import logging
import threading
from oslo_config import cfg
from oslo_db._i18n import _LE
from oslo_db import api
LOG = logging.getLogger(__name__)
tpool_opts = [
cfg.BoolOpt('use_tpool',
default=False,
deprecated_name='dbapi_use_tpool',
deprecated_group='DEFAULT',
help='Enable the experimental use of thread pooling for '
'all DB API calls'),
]
class TpoolDbapiWrapper(object):
"""DB API wrapper class.
This wraps the oslo DB API with an option to be able to use eventlet's
thread pooling. Since the CONF variable may not be loaded at the time
this class is instantiated, we must look at it on the first DB API call.
"""
def __init__(self, conf, backend_mapping):
self._db_api = None
self._backend_mapping = backend_mapping
self._conf = conf
self._conf.register_opts(tpool_opts, 'database')
self._lock = threading.Lock()
@property
def _api(self):
if not self._db_api:
with self._lock:
if not self._db_api:
db_api = api.DBAPI.from_config(
conf=self._conf, backend_mapping=self._backend_mapping)
if self._conf.database.use_tpool:
try:
from eventlet import tpool
except ImportError:
LOG.exception(_LE("'eventlet' is required for "
"TpoolDbapiWrapper."))
raise
self._db_api = tpool.Proxy(db_api)
else:
self._db_api = db_api
return self._db_api
def __getattr__(self, key):
return getattr(self._api, key)
def list_opts():
"""Returns a list of oslo.config options available in this module.
:returns: a list of (group_name, opts) tuples
"""
return [('database', copy.deepcopy(tpool_opts))]
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