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synapse/tests/util/caches/test_descriptors.py
Richard van der Hoff 618bd1ee76
Fix some error cases in the caching layer. (#5749)
There was some inconsistent behaviour in the caching layer around how
exceptions were handled - particularly synchronously-thrown ones.

This seems to be most easily handled by pushing the creation of
ObservableDeferreds down from CacheDescriptor to the Cache.
2019-07-25 15:59:45 +01:00

445 lines
14 KiB
Python

# -*- coding: utf-8 -*-
# Copyright 2016 OpenMarket Ltd
# Copyright 2018 New Vector 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
from functools import partial
import mock
from twisted.internet import defer, reactor
from synapse.api.errors import SynapseError
from synapse.logging.context import (
LoggingContext,
PreserveLoggingContext,
make_deferred_yieldable,
)
from synapse.util.caches import descriptors
from synapse.util.caches.descriptors import cached
from tests import unittest
logger = logging.getLogger(__name__)
def run_on_reactor():
d = defer.Deferred()
reactor.callLater(0, d.callback, 0)
return make_deferred_yieldable(d)
class CacheTestCase(unittest.TestCase):
def test_invalidate_all(self):
cache = descriptors.Cache("testcache")
callback_record = [False, False]
def record_callback(idx):
callback_record[idx] = True
# add a couple of pending entries
d1 = defer.Deferred()
cache.set("key1", d1, partial(record_callback, 0))
d2 = defer.Deferred()
cache.set("key2", d2, partial(record_callback, 1))
# lookup should return observable deferreds
self.assertFalse(cache.get("key1").has_called())
self.assertFalse(cache.get("key2").has_called())
# let one of the lookups complete
d2.callback("result2")
# for now at least, the cache will return real results rather than an
# observabledeferred
self.assertEqual(cache.get("key2"), "result2")
# now do the invalidation
cache.invalidate_all()
# lookup should return none
self.assertIsNone(cache.get("key1", None))
self.assertIsNone(cache.get("key2", None))
# both callbacks should have been callbacked
self.assertTrue(callback_record[0], "Invalidation callback for key1 not called")
self.assertTrue(callback_record[1], "Invalidation callback for key2 not called")
# letting the other lookup complete should do nothing
d1.callback("result1")
self.assertIsNone(cache.get("key1", None))
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_with_sync_exception(self):
"""If the wrapped function throws synchronously, things should continue to work
"""
class Cls(object):
@cached()
def fn(self, arg1):
raise SynapseError(100, "mai spoon iz too big!!1")
obj = Cls()
# this should fail immediately
d = obj.fn(1)
self.failureResultOf(d, SynapseError)
# ... leaving the cache empty
self.assertEqual(len(obj.fn.cache.cache), 0)
# and a second call should result in a second exception
d = obj.fn(1)
self.failureResultOf(d, SynapseError)
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 PreserveLoggingContext():
yield complete_lookup
return 1
return inner_fn()
@defer.inlineCallbacks
def do_lookup():
with LoggingContext() as c1:
c1.name = "c1"
r = yield obj.fn(1)
self.assertEqual(LoggingContext.current_context(), c1)
return 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(LoggingContext.current_context(), LoggingContext.sentinel)
d1.addCallback(check_result)
# and another
d2 = do_lookup()
self.assertEqual(LoggingContext.current_context(), 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():
# we want this to behave like an asynchronous function
yield run_on_reactor()
raise SynapseError(400, "blah")
return inner_fn()
@defer.inlineCallbacks
def do_lookup():
with LoggingContext() as c1:
c1.name = "c1"
try:
d = obj.fn(1)
self.assertEqual(
LoggingContext.current_context(), LoggingContext.sentinel
)
yield d
self.fail("No exception thrown")
except SynapseError:
pass
self.assertEqual(LoggingContext.current_context(), c1)
# the cache should now be empty
self.assertEqual(len(obj.fn.cache.cache), 0)
obj = Cls()
# set off a deferred which will do a cache lookup
d1 = do_lookup()
self.assertEqual(LoggingContext.current_context(), LoggingContext.sentinel)
return d1
@defer.inlineCallbacks
def test_cache_default_args(self):
class Cls(object):
def __init__(self):
self.mock = mock.Mock()
@descriptors.cached()
def fn(self, arg1, arg2=2, arg3=3):
return self.mock(arg1, arg2, arg3)
obj = Cls()
obj.mock.return_value = "fish"
r = yield obj.fn(1, 2, 3)
self.assertEqual(r, "fish")
obj.mock.assert_called_once_with(1, 2, 3)
obj.mock.reset_mock()
# a call with same params shouldn't call the mock again
r = yield obj.fn(1, 2)
self.assertEqual(r, "fish")
obj.mock.assert_not_called()
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, 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(2, 3)
self.assertEqual(r, "chips")
obj.mock.assert_not_called()
def test_cache_iterable(self):
class Cls(object):
def __init__(self):
self.mock = mock.Mock()
@descriptors.cached(iterable=True)
def fn(self, arg1, arg2):
return self.mock(arg1, arg2)
obj = Cls()
obj.mock.return_value = ["spam", "eggs"]
r = obj.fn(1, 2)
self.assertEqual(r, ["spam", "eggs"])
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 = 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
self.assertEqual(len(obj.fn.cache.cache), 3)
r = obj.fn(1, 2)
self.assertEqual(r, ["spam", "eggs"])
r = obj.fn(1, 3)
self.assertEqual(r, ["chips"])
obj.mock.assert_not_called()
def test_cache_iterable_with_sync_exception(self):
"""If the wrapped function throws synchronously, things should continue to work
"""
class Cls(object):
@descriptors.cached(iterable=True)
def fn(self, arg1):
raise SynapseError(100, "mai spoon iz too big!!1")
obj = Cls()
# this should fail immediately
d = obj.fn(1)
self.failureResultOf(d, SynapseError)
# ... leaving the cache empty
self.assertEqual(len(obj.fn.cache.cache), 0)
# and a second call should result in a second exception
d = obj.fn(1)
self.failureResultOf(d, SynapseError)
class CachedListDescriptorTestCase(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):
pass
@descriptors.cachedList("fn", "args1", inlineCallbacks=True)
def list_fn(self, args1, arg2):
assert LoggingContext.current_context().request == "c1"
# we want this to behave like an asynchronous function
yield run_on_reactor()
assert LoggingContext.current_context().request == "c1"
return self.mock(args1, arg2)
with LoggingContext() as c1:
c1.request = "c1"
obj = Cls()
obj.mock.return_value = {10: "fish", 20: "chips"}
d1 = obj.list_fn([10, 20], 2)
self.assertEqual(LoggingContext.current_context(), LoggingContext.sentinel)
r = yield d1
self.assertEqual(LoggingContext.current_context(), c1)
obj.mock.assert_called_once_with([10, 20], 2)
self.assertEqual(r, {10: "fish", 20: "chips"})
obj.mock.reset_mock()
# a call with different params should call the mock again
obj.mock.return_value = {30: "peas"}
r = yield obj.list_fn([20, 30], 2)
obj.mock.assert_called_once_with([30], 2)
self.assertEqual(r, {20: "chips", 30: "peas"})
obj.mock.reset_mock()
# all the values should now be cached
r = yield obj.fn(10, 2)
self.assertEqual(r, "fish")
r = yield obj.fn(20, 2)
self.assertEqual(r, "chips")
r = yield obj.fn(30, 2)
self.assertEqual(r, "peas")
r = yield obj.list_fn([10, 20, 30], 2)
obj.mock.assert_not_called()
self.assertEqual(r, {10: "fish", 20: "chips", 30: "peas"})
@defer.inlineCallbacks
def test_invalidate(self):
"""Make sure that invalidation callbacks are called."""
class Cls(object):
def __init__(self):
self.mock = mock.Mock()
@descriptors.cached()
def fn(self, arg1, arg2):
pass
@descriptors.cachedList("fn", "args1", inlineCallbacks=True)
def list_fn(self, args1, arg2):
# we want this to behave like an asynchronous function
yield run_on_reactor()
return self.mock(args1, arg2)
obj = Cls()
invalidate0 = mock.Mock()
invalidate1 = mock.Mock()
# cache miss
obj.mock.return_value = {10: "fish", 20: "chips"}
r1 = yield obj.list_fn([10, 20], 2, on_invalidate=invalidate0)
obj.mock.assert_called_once_with([10, 20], 2)
self.assertEqual(r1, {10: "fish", 20: "chips"})
obj.mock.reset_mock()
# cache hit
r2 = yield obj.list_fn([10, 20], 2, on_invalidate=invalidate1)
obj.mock.assert_not_called()
self.assertEqual(r2, {10: "fish", 20: "chips"})
invalidate0.assert_not_called()
invalidate1.assert_not_called()
# now if we invalidate the keys, both invalidations should get called
obj.fn.invalidate((10, 2))
invalidate0.assert_called_once()
invalidate1.assert_called_once()