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# Copyright (c) 2014 Rackspace Hosting
# 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.
"""Unit tests for SQLAlchemy and eventlet interaction."""
import logging
import unittest2
from oslo_utils import importutils
import sqlalchemy as sa
from sqlalchemy.ext import declarative as sa_decl
from oslo_db import exception as db_exc
from oslo_db.sqlalchemy import models
from oslo_db import tests
from oslo_db.tests.sqlalchemy import base as test_base
class EventletTestMixin(object):
def setUp(self):
super(EventletTestMixin, self).setUp()
BASE = sa_decl.declarative_base()
class TmpTable(BASE, models.ModelBase):
__tablename__ = 'test_async_eventlet'
id = sa.Column('id', sa.Integer, primary_key=True, nullable=False)
foo = sa.Column('foo', sa.Integer)
__table_args__ = (
sa.UniqueConstraint('foo', name='uniq_foo'),
)
self.test_table = TmpTable
TmpTable.__table__.create(self.engine)
self.addCleanup(lambda: TmpTable.__table__.drop(self.engine))
@unittest2.skipIf(not tests.should_run_eventlet_tests(),
'eventlet tests disabled unless TEST_EVENTLET=1')
def test_concurrent_transaction(self):
# Cause sqlalchemy to log executed SQL statements. Useful to
# determine exactly what and when was sent to DB.
sqla_logger = logging.getLogger('sqlalchemy.engine')
sqla_logger.setLevel(logging.INFO)
self.addCleanup(sqla_logger.setLevel, logging.NOTSET)
def operate_on_row(name, ready=None, proceed=None):
logging.debug('%s starting', name)
_session = self.sessionmaker()
with _session.begin():
logging.debug('%s ready', name)
# Modify the same row, inside transaction
tbl = self.test_table()
tbl.update({'foo': 10})
tbl.save(_session)
if ready is not None:
ready.send()
if proceed is not None:
logging.debug('%s waiting to proceed', name)
proceed.wait()
logging.debug('%s exiting transaction', name)
logging.debug('%s terminating', name)
return True
eventlet = importutils.try_import('eventlet')
if eventlet is None:
return self.skipTest('eventlet is required for this test')
a_ready = eventlet.event.Event()
a_proceed = eventlet.event.Event()
b_proceed = eventlet.event.Event()
# thread A opens transaction
logging.debug('spawning A')
a = eventlet.spawn(operate_on_row, 'A',
ready=a_ready, proceed=a_proceed)
logging.debug('waiting for A to enter transaction')
a_ready.wait()
# thread B opens transaction on same row
logging.debug('spawning B')
b = eventlet.spawn(operate_on_row, 'B',
proceed=b_proceed)
logging.debug('waiting for B to (attempt to) enter transaction')
eventlet.sleep(1) # should(?) advance B to blocking on transaction
# While B is still blocked, A should be able to proceed
a_proceed.send()
# Will block forever(*) if DB library isn't reentrant.
# (*) Until some form of timeout/deadlock detection kicks in.
# This is the key test that async is working. If this hangs
# (or raises a timeout/deadlock exception), then you have failed
# this test.
self.assertTrue(a.wait())
b_proceed.send()
# If everything proceeded without blocking, B will throw a
# "duplicate entry" exception when it tries to insert the same row
self.assertRaises(db_exc.DBDuplicateEntry, b.wait)
# Note that sqlite fails the above concurrency tests, and is not
# mentioned below.
# ie: This file performs no tests by default.
class MySQLEventletTestCase(EventletTestMixin,
test_base._MySQLOpportunisticTestCase):
pass
class PostgreSQLEventletTestCase(EventletTestMixin,
test_base._PostgreSQLOpportunisticTestCase):
pass
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