def test_cache_metric(self):
"""
Caches produce metrics reflecting their state when scraped.
"""
CACHE_NAME = "cache_metrics_test_fgjkbdfg"
cache = DeferredCache(CACHE_NAME, max_entries=777)
items = {
x.split(b"{")[0].decode("ascii"): x.split(b" ")[1].decode("ascii")
for x in filter(
lambda x: b"cache_metrics_test_fgjkbdfg" in x,
generate_latest(REGISTRY).split(b"\n"),
)
}
self.assertEqual(items["synapse_util_caches_cache_size"], "0.0")
self.assertEqual(items["synapse_util_caches_cache_max_size"], "777.0")
cache.prefill("1", "hi")
items = {
x.split(b"{")[0].decode("ascii"): x.split(b" ")[1].decode("ascii")
for x in filter(
lambda x: b"cache_metrics_test_fgjkbdfg" in x,
generate_latest(REGISTRY).split(b"\n"),
)
}
self.assertEqual(items["synapse_util_caches_cache_size"], "1.0")
self.assertEqual(items["synapse_util_caches_cache_max_size"], "777.0")
def test_invalidate(self):
cache = DeferredCache("test")
cache.prefill(("foo",), 123)
cache.invalidate(("foo",))
with self.assertRaises(KeyError):
cache.get(("foo",))
def test_callbacks(self):
"""Invalidation callbacks are called at the right time"""
cache = DeferredCache("test")
callbacks = set()
# start with an entry, with a callback
cache.prefill("k1", 10, callback=lambda: callbacks.add("prefill"))
# now replace that entry with a pending result
origin_d = defer.Deferred()
set_d = cache.set("k1", origin_d, callback=lambda: callbacks.add("set"))
# ... and also make a get request
get_d = cache.get("k1", callback=lambda: callbacks.add("get"))
# we don't expect the invalidation callback for the original value to have
# been called yet, even though get() will now return a different result.
# I'm not sure if that is by design or not.
self.assertEqual(callbacks, set())
# now fire off all the deferreds
origin_d.callback(20)
self.assertEqual(self.successResultOf(set_d), 20)
self.assertEqual(self.successResultOf(get_d), 20)
# now the original invalidation callback should have been called, but none of
# the others
self.assertEqual(callbacks, {"prefill"})
callbacks.clear()
# another update should invalidate both the previous results
cache.prefill("k1", 30)
self.assertEqual(callbacks, {"set", "get"})
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_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
with self.assertRaises(KeyError):
cache.get(1)
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")
with self.assertRaises(KeyError):
cache.get(2)
cache.get(1)
cache.get(3)
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 __get__(self, obj, owner):
cache = DeferredCache(
name=self.orig.__name__,
max_entries=self.max_entries,
keylen=self.num_args,
tree=self.tree,
iterable=self.iterable,
) # type: DeferredCache[CacheKey, Any]
get_cache_key = self.cache_key_builder
@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)
cache_key = get_cache_key(args, kwargs)
try:
ret = cache.get(cache_key, callback=invalidate_callback)
except KeyError:
# 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.get_instance(
cache, cache_key
)
ret = defer.maybeDeferred(preserve_fn(self.orig), obj, *args, **kwargs)
ret = cache.set(cache_key, ret, callback=invalidate_callback)
return make_deferred_yieldable(ret)
wrapped = cast(_CachedFunction, _wrapped)
if self.num_args == 1:
wrapped.invalidate = lambda key: cache.invalidate(key[0])
wrapped.prefill = lambda key, val: cache.prefill(key[0], val)
else:
wrapped.invalidate = cache.invalidate
wrapped.invalidate_many = cache.invalidate_many
wrapped.prefill = cache.prefill
wrapped.invalidate_all = cache.invalidate_all
wrapped.cache = cache
wrapped.num_args = self.num_args
obj.__dict__[self.orig.__name__] = wrapped
return wrapped
def test_set_fail(self):
cache = DeferredCache("test")
callbacks = set()
# start with an entry, with a callback
cache.prefill("k1", 10, callback=lambda: callbacks.add("prefill"))
# now replace that entry with a pending result
origin_d = defer.Deferred()
set_d = cache.set("k1",
origin_d,
callback=lambda: callbacks.add("set"))
# ... and also make a get request
get_d = cache.get("k1", callback=lambda: callbacks.add("get"))
# none of the callbacks should have been called yet
self.assertEqual(callbacks, set())
# oh noes! fails!
e = Exception("oops")
origin_d.errback(e)
self.assertIs(self.failureResultOf(set_d, Exception).value, e)
self.assertIs(self.failureResultOf(get_d, Exception).value, e)
# the callbacks for the failed requests should have been called.
# I'm not sure if this is deliberate or not.
self.assertEqual(callbacks, {"get", "set"})
callbacks.clear()
# the old value should still be returned now?
get_d2 = cache.get("k1", callback=lambda: callbacks.add("get2"))
self.assertEqual(self.successResultOf(get_d2), 10)
# replacing the value now should run the callbacks for those requests
# which got the original result
cache.prefill("k1", 30)
self.assertEqual(callbacks, {"prefill", "get2"})
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)
def test_hit(self):
cache = DeferredCache("test")
cache.prefill("foo", 123)
self.assertEquals(self.successResultOf(cache.get("foo")), 123)
def test_eviction_iterable(self):
cache = DeferredCache(
"test", max_entries=3, apply_cache_factor_from_config=False, iterable=True,
)
cache.prefill(1, ["one", "two"])
cache.prefill(2, ["three"])
# Now access 1 again, thus causing 2 to be least-recently used
cache.get(1)
# Now add an item to the cache, which evicts 2.
cache.prefill(3, ["four"])
with self.assertRaises(KeyError):
cache.get(2)
# Ensure 1 & 3 are in the cache.
cache.get(1)
cache.get(3)
# Now access 1 again, thus causing 3 to be least-recently used
cache.get(1)
# Now add an item with multiple elements to the cache
cache.prefill(4, ["five", "six"])
# Both 1 and 3 are evicted since there's too many elements.
with self.assertRaises(KeyError):
cache.get(1)
with self.assertRaises(KeyError):
cache.get(3)
# Now add another item to fill the cache again.
cache.prefill(5, ["seven"])
# Now access 4, thus causing 5 to be least-recently used
cache.get(4)
# Add an empty item.
cache.prefill(6, [])
# 5 gets evicted and replaced since an empty element counts as an item.
with self.assertRaises(KeyError):
cache.get(5)
cache.get(4)
cache.get(6)
def __get__(self, obj, owner):
cache = DeferredCache(
name=self.orig.__name__,
max_entries=self.max_entries,
keylen=self.num_args,
tree=self.tree,
iterable=self.iterable,
) # type: DeferredCache[CacheKey, Any]
def get_cache_key_gen(args, kwargs):
"""Given some args/kwargs return a generator that resolves into
the cache_key.
We loop through each arg name, looking up if its in the `kwargs`,
otherwise using the next argument in `args`. If there are no more
args then we try looking the arg name up in the defaults
"""
pos = 0
for nm in self.arg_names:
if nm in kwargs:
yield kwargs[nm]
elif pos < len(args):
yield args[pos]
pos += 1
else:
yield self.arg_defaults[nm]
# By default our cache key is a tuple, but if there is only one item
# then don't bother wrapping in a tuple. This is to save memory.
if self.num_args == 1:
nm = self.arg_names[0]
def get_cache_key(args, kwargs):
if nm in kwargs:
return kwargs[nm]
elif len(args):
return args[0]
else:
return self.arg_defaults[nm]
else:
def get_cache_key(args, kwargs):
return tuple(get_cache_key_gen(args, kwargs))
@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)
cache_key = get_cache_key(args, kwargs)
try:
ret = cache.get(cache_key, callback=invalidate_callback)
except KeyError:
# 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.get_instance(
cache, cache_key)
ret = defer.maybeDeferred(preserve_fn(self.orig), obj, *args,
**kwargs)
ret = cache.set(cache_key, ret, callback=invalidate_callback)
return make_deferred_yieldable(ret)
wrapped = cast(_CachedFunction, _wrapped)
if self.num_args == 1:
wrapped.invalidate = lambda key: cache.invalidate(key[0])
wrapped.prefill = lambda key, val: cache.prefill(key[0], val)
else:
wrapped.invalidate = cache.invalidate
wrapped.invalidate_all = cache.invalidate_all
wrapped.invalidate_many = cache.invalidate_many
wrapped.prefill = cache.prefill
wrapped.invalidate_all = cache.invalidate_all
wrapped.cache = cache
wrapped.num_args = self.num_args
obj.__dict__[self.orig.__name__] = wrapped
return wrapped
