forked-synapse/tests/util/caches/test_descriptors.py
Richard van der Hoff f9b4bb05e0 Fix the logcontext handling in the cache wrappers (#2077)
The cache wrappers had a habit of leaking the logcontext into the reactor while
the lookup function was running, and then not restoring it correctly when the
lookup function had completed. It's all the fault of
`preserve_context_over_{fn,deferred}` which are basically a bit broken.
2017-03-30 13:22:24 +01:00

178 lines
5.6 KiB
Python

# -*- coding: utf-8 -*-
# Copyright 2016 OpenMarket Ltd
#
# 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 logging
import mock
from synapse.api.errors import SynapseError
from synapse.util import async
from synapse.util import logcontext
from twisted.internet import defer
from synapse.util.caches import descriptors
from tests import unittest
logger = logging.getLogger(__name__)
class DescriptorTestCase(unittest.TestCase):
@defer.inlineCallbacks
def test_cache(self):
class Cls(object):
def __init__(self):
self.mock = mock.Mock()
@descriptors.cached()
def fn(self, arg1, arg2):
return self.mock(arg1, arg2)
obj = Cls()
obj.mock.return_value = 'fish'
r = yield obj.fn(1, 2)
self.assertEqual(r, 'fish')
obj.mock.assert_called_once_with(1, 2)
obj.mock.reset_mock()
# a call with different params should call the mock again
obj.mock.return_value = 'chips'
r = yield obj.fn(1, 3)
self.assertEqual(r, 'chips')
obj.mock.assert_called_once_with(1, 3)
obj.mock.reset_mock()
# the two values should now be cached
r = yield obj.fn(1, 2)
self.assertEqual(r, 'fish')
r = yield obj.fn(1, 3)
self.assertEqual(r, 'chips')
obj.mock.assert_not_called()
@defer.inlineCallbacks
def test_cache_num_args(self):
"""Only the first num_args arguments should matter to the cache"""
class Cls(object):
def __init__(self):
self.mock = mock.Mock()
@descriptors.cached(num_args=1)
def fn(self, arg1, arg2):
return self.mock(arg1, arg2)
obj = Cls()
obj.mock.return_value = 'fish'
r = yield obj.fn(1, 2)
self.assertEqual(r, 'fish')
obj.mock.assert_called_once_with(1, 2)
obj.mock.reset_mock()
# a call with different params should call the mock again
obj.mock.return_value = 'chips'
r = yield obj.fn(2, 3)
self.assertEqual(r, 'chips')
obj.mock.assert_called_once_with(2, 3)
obj.mock.reset_mock()
# the two values should now be cached; we should be able to vary
# the second argument and still get the cached result.
r = yield obj.fn(1, 4)
self.assertEqual(r, 'fish')
r = yield obj.fn(2, 5)
self.assertEqual(r, 'chips')
obj.mock.assert_not_called()
def test_cache_logcontexts(self):
"""Check that logcontexts are set and restored correctly when
using the cache."""
complete_lookup = defer.Deferred()
class Cls(object):
@descriptors.cached()
def fn(self, arg1):
@defer.inlineCallbacks
def inner_fn():
with logcontext.PreserveLoggingContext():
yield complete_lookup
defer.returnValue(1)
return inner_fn()
@defer.inlineCallbacks
def do_lookup():
with logcontext.LoggingContext() as c1:
c1.name = "c1"
r = yield obj.fn(1)
self.assertEqual(logcontext.LoggingContext.current_context(),
c1)
defer.returnValue(r)
def check_result(r):
self.assertEqual(r, 1)
obj = Cls()
# set off a deferred which will do a cache lookup
d1 = do_lookup()
self.assertEqual(logcontext.LoggingContext.current_context(),
logcontext.LoggingContext.sentinel)
d1.addCallback(check_result)
# and another
d2 = do_lookup()
self.assertEqual(logcontext.LoggingContext.current_context(),
logcontext.LoggingContext.sentinel)
d2.addCallback(check_result)
# let the lookup complete
complete_lookup.callback(None)
return defer.gatherResults([d1, d2])
def test_cache_logcontexts_with_exception(self):
"""Check that the cache sets and restores logcontexts correctly when
the lookup function throws an exception"""
class Cls(object):
@descriptors.cached()
def fn(self, arg1):
@defer.inlineCallbacks
def inner_fn():
yield async.run_on_reactor()
raise SynapseError(400, "blah")
return inner_fn()
@defer.inlineCallbacks
def do_lookup():
with logcontext.LoggingContext() as c1:
c1.name = "c1"
try:
yield obj.fn(1)
self.fail("No exception thrown")
except SynapseError:
pass
self.assertEqual(logcontext.LoggingContext.current_context(),
c1)
obj = Cls()
# set off a deferred which will do a cache lookup
d1 = do_lookup()
self.assertEqual(logcontext.LoggingContext.current_context(),
logcontext.LoggingContext.sentinel)
return d1