diff options
Diffstat (limited to 'synapse/util/caches')
| -rw-r--r-- | synapse/util/caches/__init__.py | 27 | ||||
| -rw-r--r-- | synapse/util/caches/descriptors.py | 377 | ||||
| -rw-r--r-- | synapse/util/caches/dictionary_cache.py | 103 | ||||
| -rw-r--r-- | synapse/util/caches/expiringcache.py | 115 | ||||
| -rw-r--r-- | synapse/util/caches/lrucache.py | 149 |
5 files changed, 771 insertions, 0 deletions
diff --git a/synapse/util/caches/__init__.py b/synapse/util/caches/__init__.py new file mode 100644 index 0000000000..da0e06a468 --- /dev/null +++ b/synapse/util/caches/__init__.py @@ -0,0 +1,27 @@ +# -*- coding: utf-8 -*- +# Copyright 2015 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 synapse.metrics + +DEBUG_CACHES = False + +metrics = synapse.metrics.get_metrics_for("synapse.util.caches") + +caches_by_name = {} +cache_counter = metrics.register_cache( + "cache", + lambda: {(name,): len(caches_by_name[name]) for name in caches_by_name.keys()}, + labels=["name"], +) diff --git a/synapse/util/caches/descriptors.py b/synapse/util/caches/descriptors.py new file mode 100644 index 0000000000..83bfec2f02 --- /dev/null +++ b/synapse/util/caches/descriptors.py @@ -0,0 +1,377 @@ +# -*- coding: utf-8 -*- +# Copyright 2015 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 + +from synapse.util.async import ObservableDeferred +from synapse.util import unwrapFirstError +from synapse.util.caches.lrucache import LruCache + +from . import caches_by_name, DEBUG_CACHES, cache_counter + +from twisted.internet import defer + +from collections import OrderedDict + +import functools +import inspect +import threading + +logger = logging.getLogger(__name__) + + +_CacheSentinel = object() + + +class Cache(object): + + def __init__(self, name, max_entries=1000, keylen=1, lru=True): + if lru: + self.cache = LruCache(max_size=max_entries) + self.max_entries = None + else: + self.cache = OrderedDict() + self.max_entries = max_entries + + self.name = name + self.keylen = keylen + self.sequence = 0 + self.thread = None + caches_by_name[name] = self.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): + val = self.cache.get(key, _CacheSentinel) + if val is not _CacheSentinel: + cache_counter.inc_hits(self.name) + return val + + cache_counter.inc_misses(self.name) + + if default is _CacheSentinel: + raise KeyError() + else: + return default + + def update(self, sequence, key, value): + self.check_thread() + if self.sequence == sequence: + # Only update the cache if the caches sequence number matches the + # number that the cache had before the SELECT was started (SYN-369) + self.prefill(key, value) + + def prefill(self, key, value): + if self.max_entries is not None: + while len(self.cache) >= self.max_entries: + self.cache.popitem(last=False) + + self.cache[key] = value + + def invalidate(self, key): + self.check_thread() + if not isinstance(key, tuple): + raise TypeError( + "The cache key must be a tuple not %r" % (type(key),) + ) + + # Increment the sequence number so that any SELECT statements that + # raced with the INSERT don't update the cache (SYN-369) + self.sequence += 1 + self.cache.pop(key, None) + + def invalidate_all(self): + self.check_thread() + self.sequence += 1 + self.cache.clear() + + +class CacheDescriptor(object): + """ A method decorator that applies a memoizing cache around the function. + + This caches deferreds, rather than the results themselves. Deferreds that + fail are removed from the cache. + + The function is presumed to take zero or more arguments, which are used in + a tuple as the key for the cache. Hits are served directly from the cache; + misses use the function body to generate the value. + + The wrapped function has an additional member, a callable called + "invalidate". This can be used to remove individual entries from the cache. + + The wrapped function has another additional callable, called "prefill", + which can be used to insert values into the cache specifically, without + calling the calculation function. + """ + def __init__(self, orig, max_entries=1000, num_args=1, lru=True, + inlineCallbacks=False): + 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.lru = lru + + self.arg_names = inspect.getargspec(orig).args[1:num_args+1] + + 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__,) + ) + + self.cache = Cache( + name=self.orig.__name__, + max_entries=self.max_entries, + keylen=self.num_args, + lru=self.lru, + ) + + def __get__(self, obj, objtype=None): + + @functools.wraps(self.orig) + def wrapped(*args, **kwargs): + arg_dict = inspect.getcallargs(self.orig, obj, *args, **kwargs) + cache_key = tuple(arg_dict[arg_nm] for arg_nm in self.arg_names) + try: + cached_result_d = self.cache.get(cache_key) + + observer = cached_result_d.observe() + if DEBUG_CACHES: + @defer.inlineCallbacks + def check_result(cached_result): + actual_result = yield self.function_to_call(obj, *args, **kwargs) + if actual_result != cached_result: + logger.error( + "Stale cache entry %s%r: cached: %r, actual %r", + self.orig.__name__, cache_key, + cached_result, actual_result, + ) + raise ValueError("Stale cache entry") + defer.returnValue(cached_result) + observer.addCallback(check_result) + + return observer + except KeyError: + # Get the sequence number of the cache before reading from the + # database so that we can tell if the cache is invalidated + # while the SELECT is executing (SYN-369) + sequence = self.cache.sequence + + ret = defer.maybeDeferred( + self.function_to_call, + obj, *args, **kwargs + ) + + def onErr(f): + self.cache.invalidate(cache_key) + return f + + ret.addErrback(onErr) + + ret = ObservableDeferred(ret, consumeErrors=True) + self.cache.update(sequence, cache_key, ret) + + return ret.observe() + + wrapped.invalidate = self.cache.invalidate + wrapped.invalidate_all = self.cache.invalidate_all + wrapped.prefill = self.cache.prefill + + obj.__dict__[self.orig.__name__] = wrapped + + return wrapped + + +class CacheListDescriptor(object): + """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, cache, list_name, num_args=1, inlineCallbacks=False): + """ + Args: + orig (function) + cache (Cache) + list_name (str): Name of the argument which is the bulk lookup list + num_args (int) + inlineCallbacks (bool): Whether orig is a generator that should + be wrapped by defer.inlineCallbacks + """ + self.orig = orig + + 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.cache = cache + + 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." + % (self.list_name, cache.name,) + ) + + def __get__(self, obj, objtype=None): + + @functools.wraps(self.orig) + def wrapped(*args, **kwargs): + arg_dict = inspect.getcallargs(self.orig, obj, *args, **kwargs) + keyargs = [arg_dict[arg_nm] for arg_nm in self.arg_names] + list_args = arg_dict[self.list_name] + + # cached is a dict arg -> deferred, where deferred results in a + # 2-tuple (`arg`, `result`) + cached = {} + missing = [] + for arg in list_args: + key = list(keyargs) + key[self.list_pos] = arg + + try: + res = self.cache.get(tuple(key)).observe() + res.addCallback(lambda r, arg: (arg, r), arg) + cached[arg] = res + except KeyError: + missing.append(arg) + + if missing: + sequence = self.cache.sequence + args_to_call = dict(arg_dict) + args_to_call[self.list_name] = missing + + ret_d = defer.maybeDeferred( + self.function_to_call, + **args_to_call + ) + + ret_d = ObservableDeferred(ret_d) + + # We need to create deferreds for each arg in the list so that + # we can insert the new deferred into the cache. + for arg in missing: + observer = ret_d.observe() + observer.addCallback(lambda r, arg: r[arg], arg) + + observer = ObservableDeferred(observer) + + key = list(keyargs) + key[self.list_pos] = arg + self.cache.update(sequence, tuple(key), observer) + + def invalidate(f, key): + self.cache.invalidate(key) + return f + observer.addErrback(invalidate, tuple(key)) + + res = observer.observe() + res.addCallback(lambda r, arg: (arg, r), arg) + + cached[arg] = res + + return defer.gatherResults( + cached.values(), + consumeErrors=True, + ).addErrback(unwrapFirstError).addCallback(lambda res: dict(res)) + + obj.__dict__[self.orig.__name__] = wrapped + + return wrapped + + +def cached(max_entries=1000, num_args=1, lru=True): + return lambda orig: CacheDescriptor( + orig, + max_entries=max_entries, + num_args=num_args, + lru=lru + ) + + +def cachedInlineCallbacks(max_entries=1000, num_args=1, lru=False): + return lambda orig: CacheDescriptor( + orig, + max_entries=max_entries, + num_args=num_args, + lru=lru, + inlineCallbacks=True, + ) + + +def cachedList(cache, list_name, num_args=1, 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 + is specified as a list that is iterated through to lookup keys in the + original cache. A new list consisting of the keys that weren't in the cache + get passed to the original function, the result of which is stored in the + cache. + + Args: + 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. + inlineCallbacks (bool): Should the function be wrapped in an + `defer.inlineCallbacks`? + + Example: + + class Example(object): + @cached(num_args=2) + def do_something(self, first_arg): + ... + + @cachedList(do_something.cache, list_name="second_args", num_args=2) + def batch_do_something(self, first_arg, second_args): + ... + """ + return lambda orig: CacheListDescriptor( + orig, + cache=cache, + list_name=list_name, + num_args=num_args, + inlineCallbacks=inlineCallbacks, + ) diff --git a/synapse/util/caches/dictionary_cache.py b/synapse/util/caches/dictionary_cache.py new file mode 100644 index 0000000000..e69adf62fe --- /dev/null +++ b/synapse/util/caches/dictionary_cache.py @@ -0,0 +1,103 @@ +# -*- coding: utf-8 -*- +# Copyright 2015 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. + +from synapse.util.caches.lrucache import LruCache +from collections import namedtuple +from . import caches_by_name, cache_counter +import threading +import logging + + +logger = logging.getLogger(__name__) + + +DictionaryEntry = namedtuple("DictionaryEntry", ("full", "value")) + + +class DictionaryCache(object): + """Caches key -> dictionary lookups, supporting caching partial dicts, i.e. + fetching a subset of dictionary keys for a particular key. + """ + + def __init__(self, name, max_entries=1000): + self.cache = LruCache(max_size=max_entries) + + self.name = name + self.sequence = 0 + self.thread = None + # caches_by_name[name] = self.cache + + class Sentinel(object): + __slots__ = [] + + self.sentinel = Sentinel() + caches_by_name[name] = self.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, dict_keys=None): + entry = self.cache.get(key, self.sentinel) + if entry is not self.sentinel: + cache_counter.inc_hits(self.name) + + if dict_keys is None: + return DictionaryEntry(entry.full, dict(entry.value)) + else: + return DictionaryEntry(entry.full, { + k: entry.value[k] + for k in dict_keys + if k in entry.value + }) + + cache_counter.inc_misses(self.name) + return DictionaryEntry(False, {}) + + def invalidate(self, key): + self.check_thread() + + # Increment the sequence number so that any SELECT statements that + # raced with the INSERT don't update the cache (SYN-369) + self.sequence += 1 + self.cache.pop(key, None) + + def invalidate_all(self): + self.check_thread() + self.sequence += 1 + self.cache.clear() + + def update(self, sequence, key, value, full=False): + self.check_thread() + if self.sequence == sequence: + # Only update the cache if the caches sequence number matches the + # number that the cache had before the SELECT was started (SYN-369) + if full: + self._insert(key, value) + else: + self._update_or_insert(key, value) + + def _update_or_insert(self, key, value): + entry = self.cache.setdefault(key, DictionaryEntry(False, {})) + entry.value.update(value) + + def _insert(self, key, value): + self.cache[key] = DictionaryEntry(True, value) diff --git a/synapse/util/caches/expiringcache.py b/synapse/util/caches/expiringcache.py new file mode 100644 index 0000000000..06d1eea01b --- /dev/null +++ b/synapse/util/caches/expiringcache.py @@ -0,0 +1,115 @@ +# -*- coding: utf-8 -*- +# Copyright 2015 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 + + +logger = logging.getLogger(__name__) + + +class ExpiringCache(object): + def __init__(self, cache_name, clock, max_len=0, expiry_ms=0, + reset_expiry_on_get=False): + """ + Args: + cache_name (str): Name of this cache, used for logging. + clock (Clock) + max_len (int): Max size of dict. If the dict grows larger than this + then the oldest items get automatically evicted. Default is 0, + which indicates there is no max limit. + expiry_ms (int): How long before an item is evicted from the cache + in milliseconds. Default is 0, indicating items never get + evicted based on time. + reset_expiry_on_get (bool): If true, will reset the expiry time for + an item on access. Defaults to False. + + """ + self._cache_name = cache_name + + self._clock = clock + + self._max_len = max_len + self._expiry_ms = expiry_ms + + self._reset_expiry_on_get = reset_expiry_on_get + + self._cache = {} + + def start(self): + if not self._expiry_ms: + # Don't bother starting the loop if things never expire + return + + def f(): + self._prune_cache() + + self._clock.looping_call(f, self._expiry_ms/2) + + def __setitem__(self, key, value): + now = self._clock.time_msec() + self._cache[key] = _CacheEntry(now, value) + + # Evict if there are now too many items + if self._max_len and len(self._cache.keys()) > self._max_len: + sorted_entries = sorted( + self._cache.items(), + key=lambda (k, v): v.time, + ) + + for k, _ in sorted_entries[self._max_len:]: + self._cache.pop(k) + + def __getitem__(self, key): + entry = self._cache[key] + + if self._reset_expiry_on_get: + entry.time = self._clock.time_msec() + + return entry.value + + def get(self, key, default=None): + try: + return self[key] + except KeyError: + return default + + def _prune_cache(self): + if not self._expiry_ms: + # zero expiry time means don't expire. This should never get called + # since we have this check in start too. + return + begin_length = len(self._cache) + + now = self._clock.time_msec() + + keys_to_delete = set() + + for key, cache_entry in self._cache.items(): + if now - cache_entry.time > self._expiry_ms: + keys_to_delete.add(key) + + for k in keys_to_delete: + self._cache.pop(k) + + logger.debug( + "[%s] _prune_cache before: %d, after len: %d", + self._cache_name, begin_length, len(self._cache.keys()) + ) + + +class _CacheEntry(object): + def __init__(self, time, value): + self.time = time + self.value = value diff --git a/synapse/util/caches/lrucache.py b/synapse/util/caches/lrucache.py new file mode 100644 index 0000000000..cacd7e45fa --- /dev/null +++ b/synapse/util/caches/lrucache.py @@ -0,0 +1,149 @@ +# -*- coding: utf-8 -*- +# Copyright 2015 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. + + +from functools import wraps +import threading + + +class LruCache(object): + """Least-recently-used cache.""" + def __init__(self, max_size): + cache = {} + list_root = [] + list_root[:] = [list_root, list_root, None, None] + + PREV, NEXT, KEY, VALUE = 0, 1, 2, 3 + + lock = threading.Lock() + + def synchronized(f): + @wraps(f) + def inner(*args, **kwargs): + with lock: + return f(*args, **kwargs) + + return inner + + def add_node(key, value): + prev_node = list_root + next_node = prev_node[NEXT] + node = [prev_node, next_node, key, value] + prev_node[NEXT] = node + next_node[PREV] = node + cache[key] = node + + def move_node_to_front(node): + prev_node = node[PREV] + next_node = node[NEXT] + prev_node[NEXT] = next_node + next_node[PREV] = prev_node + prev_node = list_root + next_node = prev_node[NEXT] + node[PREV] = prev_node + node[NEXT] = next_node + prev_node[NEXT] = node + next_node[PREV] = node + + def delete_node(node): + prev_node = node[PREV] + next_node = node[NEXT] + prev_node[NEXT] = next_node + next_node[PREV] = prev_node + cache.pop(node[KEY], None) + + @synchronized + def cache_get(key, default=None): + node = cache.get(key, None) + if node is not None: + move_node_to_front(node) + return node[VALUE] + else: + return default + + @synchronized + def cache_set(key, value): + node = cache.get(key, None) + if node is not None: + move_node_to_front(node) + node[VALUE] = value + else: + add_node(key, value) + if len(cache) > max_size: + delete_node(list_root[PREV]) + + @synchronized + def cache_set_default(key, value): + node = cache.get(key, None) + if node is not None: + return node[VALUE] + else: + add_node(key, value) + if len(cache) > max_size: + delete_node(list_root[PREV]) + return value + + @synchronized + def cache_pop(key, default=None): + node = cache.get(key, None) + if node: + delete_node(node) + return node[VALUE] + else: + return default + + @synchronized + def cache_clear(): + list_root[NEXT] = list_root + list_root[PREV] = list_root + cache.clear() + + @synchronized + def cache_len(): + return len(cache) + + @synchronized + def cache_contains(key): + return key in cache + + self.sentinel = object() + self.get = cache_get + self.set = cache_set + self.setdefault = cache_set_default + self.pop = cache_pop + self.len = cache_len + self.contains = cache_contains + self.clear = cache_clear + + def __getitem__(self, key): + result = self.get(key, self.sentinel) + if result is self.sentinel: + raise KeyError() + else: + return result + + def __setitem__(self, key, value): + self.set(key, value) + + def __delitem__(self, key, value): + result = self.pop(key, self.sentinel) + if result is self.sentinel: + raise KeyError() + + def __len__(self): + return self.len() + + def __contains__(self, key): + return self.contains(key) |