diff --git a/synapse/util/caches/deferred_cache.py b/synapse/util/caches/deferred_cache.py
index 4026e1f8fa..faeef75506 100644
--- a/synapse/util/caches/deferred_cache.py
+++ b/synapse/util/caches/deferred_cache.py
@@ -17,7 +17,16 @@
import enum
import threading
-from typing import Callable, Generic, Iterable, MutableMapping, Optional, TypeVar, cast
+from typing import (
+ Callable,
+ Generic,
+ Iterable,
+ MutableMapping,
+ Optional,
+ TypeVar,
+ Union,
+ cast,
+)
from prometheus_client import Gauge
@@ -33,7 +42,7 @@ cache_pending_metric = Gauge(
["name"],
)
-
+T = TypeVar("T")
KT = TypeVar("KT")
VT = TypeVar("VT")
@@ -119,21 +128,21 @@ class DeferredCache(Generic[KT, VT]):
def get(
self,
key: KT,
- default=_Sentinel.sentinel,
callback: Optional[Callable[[], None]] = None,
update_metrics: bool = True,
- ):
+ ) -> Union[ObservableDeferred, VT]:
"""Looks the key up in the caches.
Args:
key(tuple)
- default: What is returned if key is not in the caches. If not
- specified then function throws KeyError instead
callback(fn): Gets called when the entry in the cache is invalidated
update_metrics (bool): whether to update the cache hit rate metrics
Returns:
Either an ObservableDeferred or the result itself
+
+ Raises:
+ KeyError if the key is not found in the cache
"""
callbacks = [callback] if callback else []
val = self._pending_deferred_cache.get(key, _Sentinel.sentinel)
@@ -145,13 +154,19 @@ class DeferredCache(Generic[KT, VT]):
m.inc_hits()
return val.deferred
- val = self.cache.get(
- key, default, callbacks=callbacks, update_metrics=update_metrics
+ val2 = self.cache.get(
+ key, _Sentinel.sentinel, callbacks=callbacks, update_metrics=update_metrics
)
- if val is _Sentinel.sentinel:
+ if val2 is _Sentinel.sentinel:
raise KeyError()
else:
- return val
+ return val2
+
+ def get_immediate(
+ self, key: KT, default: T, update_metrics: bool = True
+ ) -> Union[VT, T]:
+ """If we have a *completed* cached value, return it."""
+ return self.cache.get(key, default, update_metrics=update_metrics)
def set(
self,
|
