diff options
Diffstat (limited to 'synapse/util/caches/descriptors.py')
| -rw-r--r-- | synapse/util/caches/descriptors.py | 117 |
1 files changed, 81 insertions, 36 deletions
diff --git a/synapse/util/caches/descriptors.py b/synapse/util/caches/descriptors.py index f31dfb22b7..8dba61d49f 100644 --- a/synapse/util/caches/descriptors.py +++ b/synapse/util/caches/descriptors.py @@ -25,8 +25,7 @@ from synapse.util.logcontext import ( from . import DEBUG_CACHES, register_cache from twisted.internet import defer - -from collections import OrderedDict +from collections import namedtuple import os import functools @@ -54,16 +53,11 @@ class Cache(object): "metrics", ) - def __init__(self, name, max_entries=1000, keylen=1, lru=True, tree=False): - if lru: - cache_type = TreeCache if tree else dict - self.cache = LruCache( - max_size=max_entries, keylen=keylen, cache_type=cache_type - ) - self.max_entries = None - else: - self.cache = OrderedDict() - self.max_entries = max_entries + def __init__(self, name, max_entries=1000, keylen=1, tree=False): + cache_type = TreeCache if tree else dict + self.cache = LruCache( + max_size=max_entries, keylen=keylen, cache_type=cache_type + ) self.name = name self.keylen = keylen @@ -81,8 +75,8 @@ class Cache(object): "Cache objects can only be accessed from the main thread" ) - def get(self, key, default=_CacheSentinel): - val = self.cache.get(key, _CacheSentinel) + def get(self, key, default=_CacheSentinel, callback=None): + val = self.cache.get(key, _CacheSentinel, callback=callback) if val is not _CacheSentinel: self.metrics.inc_hits() return val @@ -94,19 +88,15 @@ class Cache(object): else: return default - def update(self, sequence, key, value): + def update(self, sequence, key, value, callback=None): 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.prefill(key, value, callback=callback) - self.cache[key] = value + def prefill(self, key, value, callback=None): + self.cache.set(key, value, callback=callback) def invalidate(self, key): self.check_thread() @@ -151,9 +141,21 @@ class CacheDescriptor(object): 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. + + Cached functions can be "chained" (i.e. a cached function can call other cached + functions and get appropriately invalidated when they called caches are + invalidated) by adding a special "cache_context" argument to the function + and passing that as a kwarg to all caches called. For example:: + + @cachedInlineCallbacks(cache_context=True) + def foo(self, key, cache_context): + r1 = yield self.bar1(key, on_invalidate=cache_context.invalidate) + r2 = yield self.bar2(key, on_invalidate=cache_context.invalidate) + defer.returnValue(r1 + r2) + """ - def __init__(self, orig, max_entries=1000, num_args=1, lru=True, tree=False, - inlineCallbacks=False): + def __init__(self, orig, max_entries=1000, num_args=1, tree=False, + inlineCallbacks=False, cache_context=False): max_entries = int(max_entries * CACHE_SIZE_FACTOR) self.orig = orig @@ -165,15 +167,33 @@ class CacheDescriptor(object): self.max_entries = max_entries self.num_args = num_args - self.lru = lru self.tree = tree - self.arg_names = inspect.getargspec(orig).args[1:num_args + 1] + 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 **kwars)" + " (@cached cannot key off of *args or **kwargs)" % (orig.__name__,) ) @@ -182,16 +202,29 @@ class CacheDescriptor(object): name=self.orig.__name__, max_entries=self.max_entries, keylen=self.num_args, - lru=self.lru, tree=self.tree, ) @functools.wraps(self.orig) def wrapped(*args, **kwargs): + # If we're passed a cache_context then we'll want to call its invalidate() + # whenever we are invalidated + invalidate_callback = kwargs.pop("on_invalidate", None) + + # Add temp cache_context so inspect.getcallargs doesn't explode + if self.add_cache_context: + kwargs["cache_context"] = None + arg_dict = inspect.getcallargs(self.orig, obj, *args, **kwargs) cache_key = tuple(arg_dict[arg_nm] for arg_nm in self.arg_names) + + # Add our own `cache_context` to argument list if the wrapped function + # has asked for one + if self.add_cache_context: + kwargs["cache_context"] = _CacheContext(cache, cache_key) + try: - cached_result_d = cache.get(cache_key) + cached_result_d = cache.get(cache_key, callback=invalidate_callback) observer = cached_result_d.observe() if DEBUG_CACHES: @@ -228,7 +261,7 @@ class CacheDescriptor(object): ret.addErrback(onErr) ret = ObservableDeferred(ret, consumeErrors=True) - cache.update(sequence, cache_key, ret) + cache.update(sequence, cache_key, ret, callback=invalidate_callback) return preserve_context_over_deferred(ret.observe()) @@ -297,6 +330,10 @@ class CacheListDescriptor(object): @functools.wraps(self.orig) def wrapped(*args, **kwargs): + # If we're passed a cache_context then we'll want to call its invalidate() + # whenever we are invalidated + invalidate_callback = kwargs.pop("on_invalidate", None) + 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] @@ -311,7 +348,7 @@ class CacheListDescriptor(object): key[self.list_pos] = arg try: - res = cache.get(tuple(key)) + res = cache.get(tuple(key), callback=invalidate_callback) if not res.has_succeeded(): res = res.observe() res.addCallback(lambda r, arg: (arg, r), arg) @@ -345,7 +382,10 @@ class CacheListDescriptor(object): key = list(keyargs) key[self.list_pos] = arg - cache.update(sequence, tuple(key), observer) + cache.update( + sequence, tuple(key), observer, + callback=invalidate_callback + ) def invalidate(f, key): cache.invalidate(key) @@ -376,24 +416,29 @@ class CacheListDescriptor(object): return wrapped -def cached(max_entries=1000, num_args=1, lru=True, tree=False): +class _CacheContext(namedtuple("_CacheContext", ("cache", "key"))): + def invalidate(self): + self.cache.invalidate(self.key) + + +def cached(max_entries=1000, num_args=1, tree=False, cache_context=False): return lambda orig: CacheDescriptor( orig, max_entries=max_entries, num_args=num_args, - lru=lru, tree=tree, + cache_context=cache_context, ) -def cachedInlineCallbacks(max_entries=1000, num_args=1, lru=False, tree=False): +def cachedInlineCallbacks(max_entries=1000, num_args=1, tree=False, cache_context=False): return lambda orig: CacheDescriptor( orig, max_entries=max_entries, num_args=num_args, - lru=lru, tree=tree, inlineCallbacks=True, + cache_context=cache_context, ) |