forked from MirrorHub/synapse
Make @cached cache deferreds rather than the deferreds' values
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parent
39e21ea51c
commit
7eea3e356f
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@ -15,6 +15,7 @@
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import logging
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from synapse.api.errors import StoreError
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from synapse.util.async import ObservableDeferred
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from synapse.util.logutils import log_function
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from synapse.util.logcontext import preserve_context_over_fn, LoggingContext
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from synapse.util.lrucache import LruCache
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@ -173,33 +174,27 @@ class CacheDescriptor(object):
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)
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@functools.wraps(self.orig)
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@defer.inlineCallbacks
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def wrapped(*args, **kwargs):
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arg_dict = inspect.getcallargs(self.orig, obj, *args, **kwargs)
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keyargs = [arg_dict[arg_nm] for arg_nm in self.arg_names]
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try:
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cached_result = cache.get(*keyargs)
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if DEBUG_CACHES:
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actual_result = yield self.function_to_call(obj, *args, **kwargs)
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if actual_result != cached_result:
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logger.error(
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"Stale cache entry %s%r: cached: %r, actual %r",
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self.orig.__name__, keyargs,
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cached_result, actual_result,
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)
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raise ValueError("Stale cache entry")
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defer.returnValue(cached_result)
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return cached_result.observe()
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except KeyError:
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# Get the sequence number of the cache before reading from the
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# database so that we can tell if the cache is invalidated
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# while the SELECT is executing (SYN-369)
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sequence = cache.sequence
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ret = yield self.function_to_call(obj, *args, **kwargs)
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ret = defer.maybeDeferred(
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self.function_to_call,
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obj, *args, **kwargs
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)
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ret = ObservableDeferred(ret, consumeErrors=False)
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cache.update(sequence, *(keyargs + [ret]))
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defer.returnValue(ret)
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return ret.observe()
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wrapped.invalidate = cache.invalidate
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wrapped.invalidate_all = cache.invalidate_all
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@ -51,7 +51,7 @@ class ObservableDeferred(object):
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object.__setattr__(self, "_observers", set())
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def callback(r):
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self._result = (True, r)
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object.__setattr__(self, "_result", (True, r))
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while self._observers:
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try:
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self._observers.pop().callback(r)
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@ -60,7 +60,7 @@ class ObservableDeferred(object):
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return r
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def errback(f):
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self._result = (False, f)
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object.__setattr__(self, "_result", (False, f))
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while self._observers:
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try:
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self._observers.pop().errback(f)
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@ -97,3 +97,8 @@ class ObservableDeferred(object):
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def __setattr__(self, name, value):
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setattr(self._deferred, name, value)
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def __repr__(self):
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return "<ObservableDeferred object at %s, result=%r, _deferred=%r>" % (
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id(self), self._result, self._deferred,
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)
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@ -17,6 +17,8 @@
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from tests import unittest
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from twisted.internet import defer
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from synapse.util.async import ObservableDeferred
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from synapse.storage._base import Cache, cached
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@ -178,19 +180,20 @@ class CacheDecoratorTestCase(unittest.TestCase):
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self.assertTrue(callcount[0] >= 14,
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msg="Expected callcount >= 14, got %d" % (callcount[0]))
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@defer.inlineCallbacks
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def test_prefill(self):
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callcount = [0]
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d = defer.succeed(123)
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class A(object):
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@cached()
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def func(self, key):
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callcount[0] += 1
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return key
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return d
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a = A()
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a.func.prefill("foo", 123)
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a.func.prefill("foo", ObservableDeferred(d))
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self.assertEquals((yield a.func("foo")), 123)
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self.assertEquals(a.func("foo").result, d.result)
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self.assertEquals(callcount[0], 0)
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