Merge pull request #8548 from matrix-org/rav/deferred_cache

Rename Cache to DeferredCache, and related changes
This commit is contained in:
Richard van der Hoff 2020-10-15 11:42:07 +01:00 committed by GitHub
commit 0a08cd1065
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
12 changed files with 454 additions and 374 deletions

1
changelog.d/8548.misc Normal file
View File

@ -0,0 +1 @@
Rename `Cache` to `DeferredCache`, to better reflect its purpose.

View File

@ -15,7 +15,7 @@
from synapse.storage.database import DatabasePool
from synapse.storage.databases.main.client_ips import LAST_SEEN_GRANULARITY
from synapse.util.caches.descriptors import Cache
from synapse.util.caches.deferred_cache import DeferredCache
from ._base import BaseSlavedStore
@ -24,9 +24,9 @@ class SlavedClientIpStore(BaseSlavedStore):
def __init__(self, database: DatabasePool, db_conn, hs):
super().__init__(database, db_conn, hs)
self.client_ip_last_seen = Cache(
self.client_ip_last_seen = DeferredCache(
name="client_ip_last_seen", keylen=4, max_entries=50000
)
) # type: DeferredCache[tuple, int]
async def insert_client_ip(self, user_id, access_token, ip, user_agent, device_id):
now = int(self._clock.time_msec())

View File

@ -19,7 +19,7 @@ from typing import Dict, Optional, Tuple
from synapse.metrics.background_process_metrics import wrap_as_background_process
from synapse.storage._base import SQLBaseStore
from synapse.storage.database import DatabasePool, make_tuple_comparison_clause
from synapse.util.caches.descriptors import Cache
from synapse.util.caches.deferred_cache import DeferredCache
logger = logging.getLogger(__name__)
@ -410,7 +410,7 @@ class ClientIpWorkerStore(ClientIpBackgroundUpdateStore):
class ClientIpStore(ClientIpWorkerStore):
def __init__(self, database: DatabasePool, db_conn, hs):
self.client_ip_last_seen = Cache(
self.client_ip_last_seen = DeferredCache(
name="client_ip_last_seen", keylen=4, max_entries=50000
)

View File

@ -34,7 +34,8 @@ from synapse.storage.database import (
)
from synapse.types import Collection, JsonDict, get_verify_key_from_cross_signing_key
from synapse.util import json_decoder, json_encoder
from synapse.util.caches.descriptors import Cache, cached, cachedList
from synapse.util.caches.deferred_cache import DeferredCache
from synapse.util.caches.descriptors import cached, cachedList
from synapse.util.iterutils import batch_iter
from synapse.util.stringutils import shortstr
@ -1004,7 +1005,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
# Map of (user_id, device_id) -> bool. If there is an entry that implies
# the device exists.
self.device_id_exists_cache = Cache(
self.device_id_exists_cache = DeferredCache(
name="device_id_exists", keylen=2, max_entries=10000
)

View File

@ -42,7 +42,8 @@ from synapse.storage.database import DatabasePool
from synapse.storage.engines import PostgresEngine
from synapse.storage.util.id_generators import MultiWriterIdGenerator, StreamIdGenerator
from synapse.types import Collection, get_domain_from_id
from synapse.util.caches.descriptors import Cache, cached
from synapse.util.caches.deferred_cache import DeferredCache
from synapse.util.caches.descriptors import cached
from synapse.util.iterutils import batch_iter
from synapse.util.metrics import Measure
@ -145,7 +146,7 @@ class EventsWorkerStore(SQLBaseStore):
self._cleanup_old_transaction_ids,
)
self._get_event_cache = Cache(
self._get_event_cache = DeferredCache(
"*getEvent*",
keylen=3,
max_entries=hs.config.caches.event_cache_size,

View File

@ -0,0 +1,292 @@
# -*- coding: utf-8 -*-
# Copyright 2015, 2016 OpenMarket Ltd
# Copyright 2018 New Vector Ltd
# 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.
import enum
import threading
from typing import Callable, Generic, Iterable, MutableMapping, Optional, TypeVar, cast
from prometheus_client import Gauge
from twisted.internet import defer
from synapse.util.async_helpers import ObservableDeferred
from synapse.util.caches import register_cache
from synapse.util.caches.lrucache import LruCache
from synapse.util.caches.treecache import TreeCache, iterate_tree_cache_entry
cache_pending_metric = Gauge(
"synapse_util_caches_cache_pending",
"Number of lookups currently pending for this cache",
["name"],
)
KT = TypeVar("KT")
VT = TypeVar("VT")
class _Sentinel(enum.Enum):
# defining a sentinel in this way allows mypy to correctly handle the
# type of a dictionary lookup.
sentinel = object()
class DeferredCache(Generic[KT, VT]):
"""Wraps an LruCache, adding support for Deferred results.
It expects that each entry added with set() will be a Deferred; likewise get()
may return an ObservableDeferred.
"""
__slots__ = (
"cache",
"name",
"keylen",
"thread",
"metrics",
"_pending_deferred_cache",
)
def __init__(
self,
name: str,
max_entries: int = 1000,
keylen: int = 1,
tree: bool = False,
iterable: bool = False,
apply_cache_factor_from_config: bool = True,
):
"""
Args:
name: The name of the cache
max_entries: Maximum amount of entries that the cache will hold
keylen: The length of the tuple used as the cache key. Ignored unless
`tree` is True.
tree: Use a TreeCache instead of a dict as the underlying cache type
iterable: If True, count each item in the cached object as an entry,
rather than each cached object
apply_cache_factor_from_config: Whether cache factors specified in the
config file affect `max_entries`
"""
cache_type = TreeCache if tree else dict
# _pending_deferred_cache maps from the key value to a `CacheEntry` object.
self._pending_deferred_cache = (
cache_type()
) # type: MutableMapping[KT, CacheEntry]
# cache is used for completed results and maps to the result itself, rather than
# a Deferred.
self.cache = LruCache(
max_size=max_entries,
keylen=keylen,
cache_type=cache_type,
size_callback=(lambda d: len(d)) if iterable else None,
evicted_callback=self._on_evicted,
apply_cache_factor_from_config=apply_cache_factor_from_config,
)
self.name = name
self.keylen = keylen
self.thread = None # type: Optional[threading.Thread]
self.metrics = register_cache(
"cache",
name,
self.cache,
collect_callback=self._metrics_collection_callback,
)
@property
def max_entries(self):
return self.cache.max_size
def _on_evicted(self, evicted_count):
self.metrics.inc_evictions(evicted_count)
def _metrics_collection_callback(self):
cache_pending_metric.labels(self.name).set(len(self._pending_deferred_cache))
def check_thread(self):
expected_thread = self.thread
if expected_thread is None:
self.thread = threading.current_thread()
else:
if expected_thread is not threading.current_thread():
raise ValueError(
"Cache objects can only be accessed from the main thread"
)
def get(
self,
key: KT,
default=_Sentinel.sentinel,
callback: Optional[Callable[[], None]] = None,
update_metrics: bool = True,
):
"""Looks the key up in the caches.
Args:
key(tuple)
default: What is returned if key is not in the caches. If not
specified then function throws KeyError instead
callback(fn): Gets called when the entry in the cache is invalidated
update_metrics (bool): whether to update the cache hit rate metrics
Returns:
Either an ObservableDeferred or the result itself
"""
callbacks = [callback] if callback else []
val = self._pending_deferred_cache.get(key, _Sentinel.sentinel)
if val is not _Sentinel.sentinel:
val.callbacks.update(callbacks)
if update_metrics:
self.metrics.inc_hits()
return val.deferred
val = self.cache.get(key, _Sentinel.sentinel, callbacks=callbacks)
if val is not _Sentinel.sentinel:
self.metrics.inc_hits()
return val
if update_metrics:
self.metrics.inc_misses()
if default is _Sentinel.sentinel:
raise KeyError()
else:
return default
def set(
self,
key: KT,
value: defer.Deferred,
callback: Optional[Callable[[], None]] = None,
) -> ObservableDeferred:
if not isinstance(value, defer.Deferred):
raise TypeError("not a Deferred")
callbacks = [callback] if callback else []
self.check_thread()
observable = ObservableDeferred(value, consumeErrors=True)
observer = observable.observe()
entry = CacheEntry(deferred=observable, callbacks=callbacks)
existing_entry = self._pending_deferred_cache.pop(key, None)
if existing_entry:
existing_entry.invalidate()
self._pending_deferred_cache[key] = entry
def compare_and_pop():
"""Check if our entry is still the one in _pending_deferred_cache, and
if so, pop it.
Returns true if the entries matched.
"""
existing_entry = self._pending_deferred_cache.pop(key, None)
if existing_entry is entry:
return True
# oops, the _pending_deferred_cache has been updated since
# we started our query, so we are out of date.
#
# Better put back whatever we took out. (We do it this way
# round, rather than peeking into the _pending_deferred_cache
# and then removing on a match, to make the common case faster)
if existing_entry is not None:
self._pending_deferred_cache[key] = existing_entry
return False
def cb(result):
if compare_and_pop():
self.cache.set(key, result, entry.callbacks)
else:
# we're not going to put this entry into the cache, so need
# to make sure that the invalidation callbacks are called.
# That was probably done when _pending_deferred_cache was
# updated, but it's possible that `set` was called without
# `invalidate` being previously called, in which case it may
# not have been. Either way, let's double-check now.
entry.invalidate()
def eb(_fail):
compare_and_pop()
entry.invalidate()
# once the deferred completes, we can move the entry from the
# _pending_deferred_cache to the real cache.
#
observer.addCallbacks(cb, eb)
return observable
def prefill(self, key: KT, value: VT, callback: Callable[[], None] = None):
callbacks = [callback] if callback else []
self.cache.set(key, value, callbacks=callbacks)
def invalidate(self, key):
self.check_thread()
self.cache.pop(key, None)
# if we have a pending lookup for this key, remove it from the
# _pending_deferred_cache, which will (a) stop it being returned
# for future queries and (b) stop it being persisted as a proper entry
# in self.cache.
entry = self._pending_deferred_cache.pop(key, None)
# run the invalidation callbacks now, rather than waiting for the
# deferred to resolve.
if entry:
entry.invalidate()
def invalidate_many(self, key: KT):
self.check_thread()
if not isinstance(key, tuple):
raise TypeError("The cache key must be a tuple not %r" % (type(key),))
self.cache.del_multi(key)
# if we have a pending lookup for this key, remove it from the
# _pending_deferred_cache, as above
entry_dict = self._pending_deferred_cache.pop(cast(KT, key), None)
if entry_dict is not None:
for entry in iterate_tree_cache_entry(entry_dict):
entry.invalidate()
def invalidate_all(self):
self.check_thread()
self.cache.clear()
for entry in self._pending_deferred_cache.values():
entry.invalidate()
self._pending_deferred_cache.clear()
class CacheEntry:
__slots__ = ["deferred", "callbacks", "invalidated"]
def __init__(
self, deferred: ObservableDeferred, callbacks: Iterable[Callable[[], None]]
):
self.deferred = deferred
self.callbacks = set(callbacks)
self.invalidated = False
def invalidate(self):
if not self.invalidated:
self.invalidated = True
for callback in self.callbacks:
callback()
self.callbacks.clear()

View File

@ -13,25 +13,18 @@
# 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 functools
import inspect
import logging
import threading
from typing import Any, Callable, Generic, Optional, Tuple, TypeVar, Union, cast
from weakref import WeakValueDictionary
from prometheus_client import Gauge
from twisted.internet import defer
from synapse.logging.context import make_deferred_yieldable, preserve_fn
from synapse.util import unwrapFirstError
from synapse.util.async_helpers import ObservableDeferred
from synapse.util.caches.lrucache import LruCache
from synapse.util.caches.treecache import TreeCache, iterate_tree_cache_entry
from . import register_cache
from synapse.util.caches.deferred_cache import DeferredCache
logger = logging.getLogger(__name__)
@ -55,239 +48,6 @@ class _CachedFunction(Generic[F]):
__call__ = None # type: F
cache_pending_metric = Gauge(
"synapse_util_caches_cache_pending",
"Number of lookups currently pending for this cache",
["name"],
)
_CacheSentinel = object()
class CacheEntry:
__slots__ = ["deferred", "callbacks", "invalidated"]
def __init__(self, deferred, callbacks):
self.deferred = deferred
self.callbacks = set(callbacks)
self.invalidated = False
def invalidate(self):
if not self.invalidated:
self.invalidated = True
for callback in self.callbacks:
callback()
self.callbacks.clear()
class Cache:
__slots__ = (
"cache",
"name",
"keylen",
"thread",
"metrics",
"_pending_deferred_cache",
)
def __init__(
self,
name: str,
max_entries: int = 1000,
keylen: int = 1,
tree: bool = False,
iterable: bool = False,
apply_cache_factor_from_config: bool = True,
):
"""
Args:
name: The name of the cache
max_entries: Maximum amount of entries that the cache will hold
keylen: The length of the tuple used as the cache key
tree: Use a TreeCache instead of a dict as the underlying cache type
iterable: If True, count each item in the cached object as an entry,
rather than each cached object
apply_cache_factor_from_config: Whether cache factors specified in the
config file affect `max_entries`
Returns:
Cache
"""
cache_type = TreeCache if tree else dict
self._pending_deferred_cache = cache_type()
self.cache = LruCache(
max_size=max_entries,
keylen=keylen,
cache_type=cache_type,
size_callback=(lambda d: len(d)) if iterable else None,
evicted_callback=self._on_evicted,
apply_cache_factor_from_config=apply_cache_factor_from_config,
)
self.name = name
self.keylen = keylen
self.thread = None # type: Optional[threading.Thread]
self.metrics = register_cache(
"cache",
name,
self.cache,
collect_callback=self._metrics_collection_callback,
)
@property
def max_entries(self):
return self.cache.max_size
def _on_evicted(self, evicted_count):
self.metrics.inc_evictions(evicted_count)
def _metrics_collection_callback(self):
cache_pending_metric.labels(self.name).set(len(self._pending_deferred_cache))
def check_thread(self):
expected_thread = self.thread
if expected_thread is None:
self.thread = threading.current_thread()
else:
if expected_thread is not threading.current_thread():
raise ValueError(
"Cache objects can only be accessed from the main thread"
)
def get(self, key, default=_CacheSentinel, callback=None, update_metrics=True):
"""Looks the key up in the caches.
Args:
key(tuple)
default: What is returned if key is not in the caches. If not
specified then function throws KeyError instead
callback(fn): Gets called when the entry in the cache is invalidated
update_metrics (bool): whether to update the cache hit rate metrics
Returns:
Either an ObservableDeferred or the raw result
"""
callbacks = [callback] if callback else []
val = self._pending_deferred_cache.get(key, _CacheSentinel)
if val is not _CacheSentinel:
val.callbacks.update(callbacks)
if update_metrics:
self.metrics.inc_hits()
return val.deferred
val = self.cache.get(key, _CacheSentinel, callbacks=callbacks)
if val is not _CacheSentinel:
self.metrics.inc_hits()
return val
if update_metrics:
self.metrics.inc_misses()
if default is _CacheSentinel:
raise KeyError()
else:
return default
def set(self, key, value, callback=None):
if not isinstance(value, defer.Deferred):
raise TypeError("not a Deferred")
callbacks = [callback] if callback else []
self.check_thread()
observable = ObservableDeferred(value, consumeErrors=True)
observer = observable.observe()
entry = CacheEntry(deferred=observable, callbacks=callbacks)
existing_entry = self._pending_deferred_cache.pop(key, None)
if existing_entry:
existing_entry.invalidate()
self._pending_deferred_cache[key] = entry
def compare_and_pop():
"""Check if our entry is still the one in _pending_deferred_cache, and
if so, pop it.
Returns true if the entries matched.
"""
existing_entry = self._pending_deferred_cache.pop(key, None)
if existing_entry is entry:
return True
# oops, the _pending_deferred_cache has been updated since
# we started our query, so we are out of date.
#
# Better put back whatever we took out. (We do it this way
# round, rather than peeking into the _pending_deferred_cache
# and then removing on a match, to make the common case faster)
if existing_entry is not None:
self._pending_deferred_cache[key] = existing_entry
return False
def cb(result):
if compare_and_pop():
self.cache.set(key, result, entry.callbacks)
else:
# we're not going to put this entry into the cache, so need
# to make sure that the invalidation callbacks are called.
# That was probably done when _pending_deferred_cache was
# updated, but it's possible that `set` was called without
# `invalidate` being previously called, in which case it may
# not have been. Either way, let's double-check now.
entry.invalidate()
def eb(_fail):
compare_and_pop()
entry.invalidate()
# once the deferred completes, we can move the entry from the
# _pending_deferred_cache to the real cache.
#
observer.addCallbacks(cb, eb)
return observable
def prefill(self, key, value, callback=None):
callbacks = [callback] if callback else []
self.cache.set(key, value, callbacks=callbacks)
def invalidate(self, key):
self.check_thread()
self.cache.pop(key, None)
# if we have a pending lookup for this key, remove it from the
# _pending_deferred_cache, which will (a) stop it being returned
# for future queries and (b) stop it being persisted as a proper entry
# in self.cache.
entry = self._pending_deferred_cache.pop(key, None)
# run the invalidation callbacks now, rather than waiting for the
# deferred to resolve.
if entry:
entry.invalidate()
def invalidate_many(self, key):
self.check_thread()
if not isinstance(key, tuple):
raise TypeError("The cache key must be a tuple not %r" % (type(key),))
self.cache.del_multi(key)
# if we have a pending lookup for this key, remove it from the
# _pending_deferred_cache, as above
entry_dict = self._pending_deferred_cache.pop(key, None)
if entry_dict is not None:
for entry in iterate_tree_cache_entry(entry_dict):
entry.invalidate()
def invalidate_all(self):
self.check_thread()
self.cache.clear()
for entry in self._pending_deferred_cache.values():
entry.invalidate()
self._pending_deferred_cache.clear()
class _CacheDescriptorBase:
def __init__(self, orig: _CachedFunction, num_args, cache_context=False):
self.orig = orig
@ -390,13 +150,13 @@ class CacheDescriptor(_CacheDescriptorBase):
self.iterable = iterable
def __get__(self, obj, owner):
cache = Cache(
cache = DeferredCache(
name=self.orig.__name__,
max_entries=self.max_entries,
keylen=self.num_args,
tree=self.tree,
iterable=self.iterable,
)
) # type: DeferredCache[Tuple, Any]
def get_cache_key_gen(args, kwargs):
"""Given some args/kwargs return a generator that resolves into
@ -640,9 +400,9 @@ class _CacheContext:
_cache_context_objects = (
WeakValueDictionary()
) # type: WeakValueDictionary[Tuple[Cache, CacheKey], _CacheContext]
) # type: WeakValueDictionary[Tuple[DeferredCache, CacheKey], _CacheContext]
def __init__(self, cache, cache_key): # type: (Cache, CacheKey) -> None
def __init__(self, cache, cache_key): # type: (DeferredCache, CacheKey) -> None
self._cache = cache
self._cache_key = cache_key
@ -651,7 +411,9 @@ class _CacheContext:
self._cache.invalidate(self._cache_key)
@classmethod
def get_instance(cls, cache, cache_key): # type: (Cache, CacheKey) -> _CacheContext
def get_instance(
cls, cache, cache_key
): # type: (DeferredCache, CacheKey) -> _CacheContext
"""Returns an instance constructed with the given arguments.
A new instance is only created if none already exists.

View File

@ -64,7 +64,8 @@ class LruCache:
Args:
max_size: The maximum amount of entries the cache can hold
keylen: The length of the tuple used as the cache key
keylen: The length of the tuple used as the cache key. Ignored unless
cache_type is `TreeCache`.
cache_type (type):
type of underlying cache to be used. Typically one of dict

View File

@ -20,82 +20,11 @@ from mock import Mock
from twisted.internet import defer
from synapse.util.async_helpers import ObservableDeferred
from synapse.util.caches.descriptors import Cache, cached
from synapse.util.caches.descriptors import cached
from tests import unittest
class CacheTestCase(unittest.HomeserverTestCase):
def prepare(self, reactor, clock, homeserver):
self.cache = Cache("test")
def test_empty(self):
failed = False
try:
self.cache.get("foo")
except KeyError:
failed = True
self.assertTrue(failed)
def test_hit(self):
self.cache.prefill("foo", 123)
self.assertEquals(self.cache.get("foo"), 123)
def test_invalidate(self):
self.cache.prefill(("foo",), 123)
self.cache.invalidate(("foo",))
failed = False
try:
self.cache.get(("foo",))
except KeyError:
failed = True
self.assertTrue(failed)
def test_eviction(self):
cache = Cache("test", max_entries=2)
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 = Cache("test", max_entries=2)
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)
class CacheDecoratorTestCase(unittest.HomeserverTestCase):
@defer.inlineCallbacks
def test_passthrough(self):

View File

@ -15,7 +15,7 @@
# limitations under the License.
from synapse.metrics import REGISTRY, InFlightGauge, generate_latest
from synapse.util.caches.descriptors import Cache
from synapse.util.caches.deferred_cache import DeferredCache
from tests import unittest
@ -138,7 +138,7 @@ class CacheMetricsTests(unittest.HomeserverTestCase):
Caches produce metrics reflecting their state when scraped.
"""
CACHE_NAME = "cache_metrics_test_fgjkbdfg"
cache = Cache(CACHE_NAME, max_entries=777)
cache = DeferredCache(CACHE_NAME, max_entries=777)
items = {
x.split(b"{")[0].decode("ascii"): x.split(b" ")[1].decode("ascii")

View File

@ -0,0 +1,137 @@
# -*- 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.
import unittest
from functools import partial
from twisted.internet import defer
from synapse.util.caches.deferred_cache import DeferredCache
class DeferredCacheTestCase(unittest.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(cache.get("foo"), 123)
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 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))
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)

View File

@ -14,7 +14,6 @@
# See the License for the specific language governing permissions and
# limitations under the License.
import logging
from functools import partial
import mock
@ -42,49 +41,6 @@ def run_on_reactor():
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):