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Fix caching of remote servers' signature keys 

The `@cached` decorator on `KeyStore._get_server_verify_key` was missing
its `num_args` parameter, which meant that it was returning the wrong key for
any server which had more than one recorded key.

By way of a fix, change the default for `num_args` to be *all* arguments. To
implement that, factor out a common base class for `CacheDescriptor` and `CacheListDescriptor`.
This commit is contained in:
Richard van der Hoff 2017-03-22 13:54:20 +00:00
parent 37a187bfab
commit 95f21c7a66
4 changed files with 226 additions and 64 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

137
synapse/util/caches/descriptors.py
View File

@ -189,7 +189,55 @@ class Cache(object):
self.cache.clear()
class CacheDescriptor(object):
class _CacheDescriptorBase(object):
def __init__(self, orig, num_args, inlineCallbacks, cache_context=False):
self.orig = orig
if inlineCallbacks:
self.function_to_call = defer.inlineCallbacks(orig)
else:
self.function_to_call = orig
arg_spec = inspect.getargspec(orig)
all_args = arg_spec.args
if "cache_context" in all_args:
if not cache_context:
raise ValueError(
"Cannot have a 'cache_context' arg without setting"
" cache_context=True"
)
elif cache_context:
raise ValueError(
"Cannot have cache_context=True without having an arg"
" named `cache_context`"
)
if num_args is None:
num_args = len(all_args) - 1
if cache_context:
num_args -= 1
if len(all_args) < num_args + 1:
raise Exception(
"Not enough explicit positional arguments to key off for %r: "
"got %i args, but wanted %i. (@cached cannot key off *args or "
"**kwargs)"
% (orig.__name__, len(all_args), num_args)
)
self.num_args = num_args
self.arg_names = all_args[1:num_args + 1]
if "cache_context" in self.arg_names:
raise Exception(
"cache_context arg cannot be included among the cache keys"
)
self.add_cache_context = cache_context
class CacheDescriptor(_CacheDescriptorBase):
""" A method decorator that applies a memoizing cache around the function.
This caches deferreds, rather than the results themselves. Deferreds that
@ -217,52 +265,24 @@ class CacheDescriptor(object):
r2 = yield self.bar2(key, on_invalidate=cache_context.invalidate)
defer.returnValue(r1 + r2)
Args:
num_args (int): number of positional arguments (excluding ``self`` and
``cache_context``) to use as cache keys. Defaults to all named
args of the function.
"""
def __init__(self, orig, max_entries=1000, num_args=1, tree=False,
def __init__(self, orig, max_entries=1000, num_args=None, tree=False,
inlineCallbacks=False, cache_context=False, iterable=False):
super(CacheDescriptor, self).__init__(
orig, num_args=num_args, inlineCallbacks=inlineCallbacks,
cache_context=cache_context)
max_entries = int(max_entries * CACHE_SIZE_FACTOR)
self.orig = orig
if inlineCallbacks:
self.function_to_call = defer.inlineCallbacks(orig)
else:
self.function_to_call = orig
self.max_entries = max_entries
self.num_args = num_args
self.tree = tree
self.iterable = iterable
all_args = inspect.getargspec(orig)
self.arg_names = all_args.args[1:num_args + 1]
if "cache_context" in all_args.args:
if not cache_context:
raise ValueError(
"Cannot have a 'cache_context' arg without setting"
" cache_context=True"
)
try:
self.arg_names.remove("cache_context")
except ValueError:
pass
elif cache_context:
raise ValueError(
"Cannot have cache_context=True without having an arg"
" named `cache_context`"
)
self.add_cache_context = cache_context
if len(self.arg_names) < self.num_args:
raise Exception(
"Not enough explicit positional arguments to key off of for %r."
" (@cached cannot key off of *args or **kwargs)"
% (orig.__name__,)
)
def __get__(self, obj, objtype=None):
cache = Cache(
name=self.orig.__name__,
@ -338,48 +358,36 @@ class CacheDescriptor(object):
return wrapped
class CacheListDescriptor(object):
class CacheListDescriptor(_CacheDescriptorBase):
"""Wraps an existing cache to support bulk fetching of keys.
Given a list of keys it looks in the cache to find any hits, then passes
the list of missing keys to the wrapped fucntion.
"""
def __init__(self, orig, cached_method_name, list_name, num_args=1,
def __init__(self, orig, cached_method_name, list_name, num_args=None,
inlineCallbacks=False):
"""
Args:
orig (function)
method_name (str); The name of the chached method.
cached_method_name (str): The name of the chached method.
list_name (str): Name of the argument which is the bulk lookup list
num_args (int)
num_args (int): number of positional arguments (excluding ``self``,
but including list_name) to use as cache keys. Defaults to all
named args of the function.
inlineCallbacks (bool): Whether orig is a generator that should
be wrapped by defer.inlineCallbacks
"""
self.orig = orig
super(CacheListDescriptor, self).__init__(
orig, num_args=num_args, inlineCallbacks=inlineCallbacks)
if inlineCallbacks:
self.function_to_call = defer.inlineCallbacks(orig)
else:
self.function_to_call = orig
self.num_args = num_args
self.list_name = list_name
self.arg_names = inspect.getargspec(orig).args[1:num_args + 1]
self.list_pos = self.arg_names.index(self.list_name)
self.cached_method_name = cached_method_name
self.sentinel = object()
if len(self.arg_names) < self.num_args:
raise Exception(
"Not enough explicit positional arguments to key off of for %r."
" (@cached cannot key off of *args or **kwars)"
% (orig.__name__,)
)
if self.list_name not in self.arg_names:
raise Exception(
"Couldn't see arguments %r for %r."
@ -487,7 +495,7 @@ class _CacheContext(namedtuple("_CacheContext", ("cache", "key"))):
self.cache.invalidate(self.key)
def cached(max_entries=1000, num_args=1, tree=False, cache_context=False,
def cached(max_entries=1000, num_args=None, tree=False, cache_context=False,
iterable=False):
return lambda orig: CacheDescriptor(
orig,
@ -499,8 +507,8 @@ def cached(max_entries=1000, num_args=1, tree=False, cache_context=False,
)
def cachedInlineCallbacks(max_entries=1000, num_args=1, tree=False, cache_context=False,
iterable=False):
def cachedInlineCallbacks(max_entries=1000, num_args=None, tree=False,
cache_context=False, iterable=False):
return lambda orig: CacheDescriptor(
orig,
max_entries=max_entries,
@ -512,7 +520,7 @@ def cachedInlineCallbacks(max_entries=1000, num_args=1, tree=False, cache_contex
)
def cachedList(cached_method_name, list_name, num_args=1, inlineCallbacks=False):
def cachedList(cached_method_name, list_name, num_args=None, inlineCallbacks=False):
"""Creates a descriptor that wraps a function in a `CacheListDescriptor`.
Used to do batch lookups for an already created cache. A single argument
@ -525,7 +533,8 @@ def cachedList(cached_method_name, list_name, num_args=1, inlineCallbacks=False)
cache (Cache): The underlying cache to use.
list_name (str): The name of the argument that is the list to use to
do batch lookups in the cache.
num_args (int): Number of arguments to use as the key in the cache.
num_args (int): Number of arguments to use as the key in the cache
(including list_name). Defaults to all named parameters.
inlineCallbacks (bool): Should the function be wrapped in an
`defer.inlineCallbacks`?

53
tests/storage/test_keys.py Normal file
View File

@ -0,0 +1,53 @@
# -*- coding: utf-8 -*-
# Copyright 2017 Vector Creations 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 signedjson.key
from twisted.internet import defer
import tests.unittest
import tests.utils
class KeyStoreTestCase(tests.unittest.TestCase):
def __init__(self, *args, **kwargs):
super(KeyStoreTestCase, self).__init__(*args, **kwargs)
self.store = None # type: synapse.storage.keys.KeyStore
@defer.inlineCallbacks
def setUp(self):
hs = yield tests.utils.setup_test_homeserver()
self.store = hs.get_datastore()
@defer.inlineCallbacks
def test_get_server_verify_keys(self):
key1 = signedjson.key.decode_verify_key_base64(
"ed25519", "key1", "fP5l4JzpZPq/zdbBg5xx6lQGAAOM9/3w94cqiJ5jPrw"
)
key2 = signedjson.key.decode_verify_key_base64(
"ed25519", "key2", "Noi6WqcDj0QmPxCNQqgezwTlBKrfqehY1u2FyWP9uYw"
)
yield self.store.store_server_verify_key(
"server1", "from_server", 0, key1
)
yield self.store.store_server_verify_key(
"server1", "from_server", 0, key2
)
res = yield self.store.get_server_verify_keys(
"server1", ["ed25519:key1", "ed25519:key2", "ed25519:key3"])
self.assertEqual(len(res.keys()), 2)
self.assertEqual(res["ed25519:key1"].version, "key1")
self.assertEqual(res["ed25519:key2"].version, "key2")

14
tests/util/caches/__init__.py Normal file
View File

@ -0,0 +1,14 @@
# -*- coding: utf-8 -*-
# Copyright 2017 Vector Creations 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.

86
tests/util/caches/test_descriptors.py Normal file
View File

@ -0,0 +1,86 @@
# -*- 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 mock
from twisted.internet import defer
from synapse.util.caches import descriptors
from tests import unittest
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()