diff --git a/synapse/util/async.py b/synapse/util/async.py
index 0d6f48e2d8..40be7fe7e3 100644
--- a/synapse/util/async.py
+++ b/synapse/util/async.py
@@ -102,6 +102,15 @@ class ObservableDeferred(object):
def observers(self):
return self._observers
+ def has_called(self):
+ return self._result is not None
+
+ def has_succeeded(self):
+ return self._result is not None and self._result[0] is True
+
+ def get_result(self):
+ return self._result[1]
+
def __getattr__(self, name):
return getattr(self._deferred, name)
diff --git a/synapse/util/caches/descriptors.py b/synapse/util/caches/descriptors.py
index 5d25c9e762..f31dfb22b7 100644
--- a/synapse/util/caches/descriptors.py
+++ b/synapse/util/caches/descriptors.py
@@ -33,6 +33,7 @@ import functools
import inspect
import threading
+
logger = logging.getLogger(__name__)
@@ -302,16 +303,21 @@ class CacheListDescriptor(object):
# cached is a dict arg -> deferred, where deferred results in a
# 2-tuple (`arg`, `result`)
- cached = {}
+ results = {}
+ cached_defers = {}
missing = []
for arg in list_args:
key = list(keyargs)
key[self.list_pos] = arg
try:
- res = cache.get(tuple(key)).observe()
- res.addCallback(lambda r, arg: (arg, r), arg)
- cached[arg] = res
+ res = cache.get(tuple(key))
+ if not res.has_succeeded():
+ res = res.observe()
+ res.addCallback(lambda r, arg: (arg, r), arg)
+ cached_defers[arg] = res
+ else:
+ results[arg] = res.get_result()
except KeyError:
missing.append(arg)
@@ -349,12 +355,21 @@ class CacheListDescriptor(object):
res = observer.observe()
res.addCallback(lambda r, arg: (arg, r), arg)
- cached[arg] = res
-
- return preserve_context_over_deferred(defer.gatherResults(
- cached.values(),
- consumeErrors=True,
- ).addErrback(unwrapFirstError).addCallback(lambda res: dict(res)))
+ cached_defers[arg] = res
+
+ if cached_defers:
+ def update_results_dict(res):
+ results.update(res)
+ return results
+
+ return preserve_context_over_deferred(defer.gatherResults(
+ cached_defers.values(),
+ consumeErrors=True,
+ ).addCallback(update_results_dict).addErrback(
+ unwrapFirstError
+ ))
+ else:
+ return results
obj.__dict__[self.orig.__name__] = wrapped
|
