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# -*- coding: utf-8 -*-
# Copyright 2020 The Matrix.org Foundation C.I.C.
#
# 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.
from functools import partial
from twisted.internet import defer
from synapse.util.caches.deferred_cache import DeferredCache
from tests.unittest import TestCase
class DeferredCacheTestCase(TestCase):
def test_empty(self):
cache = DeferredCache("test")
failed = False
try:
cache.get("foo")
except KeyError:
failed = True
self.assertTrue(failed)
def test_hit(self):
cache = DeferredCache("test")
cache.prefill("foo", 123)
self.assertEquals(self.successResultOf(cache.get("foo")), 123)
def test_hit_deferred(self):
cache = DeferredCache("test")
origin_d = defer.Deferred()
set_d = cache.set("k1", origin_d)
# get should return an incomplete deferred
get_d = cache.get("k1")
self.assertFalse(get_d.called)
# add a callback that will make sure that the set_d gets called before the get_d
def check1(r):
self.assertTrue(set_d.called)
return r
# TODO: Actually ObservableDeferred *doesn't* run its tests in order on py3.8.
# maybe we should fix that?
# get_d.addCallback(check1)
# now fire off all the deferreds
origin_d.callback(99)
self.assertEqual(self.successResultOf(origin_d), 99)
self.assertEqual(self.successResultOf(set_d), 99)
self.assertEqual(self.successResultOf(get_d), 99)
def test_callbacks(self):
"""Invalidation callbacks are called at the right time"""
cache = DeferredCache("test")
callbacks = set()
# start with an entry, with a callback
cache.prefill("k1", 10, callback=lambda: callbacks.add("prefill"))
# now replace that entry with a pending result
origin_d = defer.Deferred()
set_d = cache.set("k1", origin_d, callback=lambda: callbacks.add("set"))
# ... and also make a get request
get_d = cache.get("k1", callback=lambda: callbacks.add("get"))
# we don't expect the invalidation callback for the original value to have
# been called yet, even though get() will now return a different result.
# I'm not sure if that is by design or not.
self.assertEqual(callbacks, set())
# now fire off all the deferreds
origin_d.callback(20)
self.assertEqual(self.successResultOf(set_d), 20)
self.assertEqual(self.successResultOf(get_d), 20)
# now the original invalidation callback should have been called, but none of
# the others
self.assertEqual(callbacks, {"prefill"})
callbacks.clear()
# another update should invalidate both the previous results
cache.prefill("k1", 30)
self.assertEqual(callbacks, {"set", "get"})
def test_set_fail(self):
cache = DeferredCache("test")
callbacks = set()
# start with an entry, with a callback
cache.prefill("k1", 10, callback=lambda: callbacks.add("prefill"))
# now replace that entry with a pending result
origin_d = defer.Deferred()
set_d = cache.set("k1", origin_d, callback=lambda: callbacks.add("set"))
# ... and also make a get request
get_d = cache.get("k1", callback=lambda: callbacks.add("get"))
# none of the callbacks should have been called yet
self.assertEqual(callbacks, set())
# oh noes! fails!
e = Exception("oops")
origin_d.errback(e)
self.assertIs(self.failureResultOf(set_d, Exception).value, e)
self.assertIs(self.failureResultOf(get_d, Exception).value, e)
# the callbacks for the failed requests should have been called.
# I'm not sure if this is deliberate or not.
self.assertEqual(callbacks, {"get", "set"})
callbacks.clear()
# the old value should still be returned now?
get_d2 = cache.get("k1", callback=lambda: callbacks.add("get2"))
self.assertEqual(self.successResultOf(get_d2), 10)
# replacing the value now should run the callbacks for those requests
# which got the original result
cache.prefill("k1", 30)
self.assertEqual(callbacks, {"prefill", "get2"})
def test_get_immediate(self):
cache = DeferredCache("test")
d1 = defer.Deferred()
cache.set("key1", d1)
# get_immediate should return default
v = cache.get_immediate("key1", 1)
self.assertEqual(v, 1)
# now complete the set
d1.callback(2)
# get_immediate should return result
v = cache.get_immediate("key1", 1)
self.assertEqual(v, 2)
def test_invalidate(self):
cache = DeferredCache("test")
cache.prefill(("foo",), 123)
cache.invalidate(("foo",))
failed = False
try:
cache.get(("foo",))
except KeyError:
failed = True
self.assertTrue(failed)
def test_invalidate_all(self):
cache = DeferredCache("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 pending deferreds
self.assertFalse(cache.get("key1").called)
self.assertFalse(cache.get("key2").called)
# let one of the lookups complete
d2.callback("result2")
# now the cache will return a completed deferred
self.assertEqual(self.successResultOf(cache.get("key2")), "result2")
# now do the invalidation
cache.invalidate_all()
# lookup should fail
with self.assertRaises(KeyError):
cache.get("key1")
with self.assertRaises(KeyError):
cache.get("key2")
# 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")
with self.assertRaises(KeyError):
cache.get("key1", None)
def test_eviction(self):
cache = DeferredCache(
"test", max_entries=2, apply_cache_factor_from_config=False
)
cache.prefill(1, "one")
cache.prefill(2, "two")
cache.prefill(3, "three") # 1 will be evicted
failed = False
try:
cache.get(1)
except KeyError:
failed = True
self.assertTrue(failed)
cache.get(2)
cache.get(3)
def test_eviction_lru(self):
cache = DeferredCache(
"test", max_entries=2, apply_cache_factor_from_config=False
)
cache.prefill(1, "one")
cache.prefill(2, "two")
# Now access 1 again, thus causing 2 to be least-recently used
cache.get(1)
cache.prefill(3, "three")
failed = False
try:
cache.get(2)
except KeyError:
failed = True
self.assertTrue(failed)
cache.get(1)
cache.get(3)
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