diff --git a/synapse/util/caches/response_cache.py b/synapse/util/caches/response_cache.py
index df1a721add..32228f42ee 100644
--- a/synapse/util/caches/response_cache.py
+++ b/synapse/util/caches/response_cache.py
@@ -13,6 +13,7 @@
# See the License for the specific language governing permissions and
# limitations under the License.
import logging
+from typing import TYPE_CHECKING, Any, Callable, Dict, Generic, Optional, TypeVar
from twisted.internet import defer
@@ -20,10 +21,15 @@ from synapse.logging.context import make_deferred_yieldable, run_in_background
from synapse.util.async_helpers import ObservableDeferred
from synapse.util.caches import register_cache
+if TYPE_CHECKING:
+ from synapse.app.homeserver import HomeServer
+
logger = logging.getLogger(__name__)
+T = TypeVar("T")
+
-class ResponseCache:
+class ResponseCache(Generic[T]):
"""
This caches a deferred response. Until the deferred completes it will be
returned from the cache. This means that if the client retries the request
@@ -31,8 +37,9 @@ class ResponseCache:
used rather than trying to compute a new response.
"""
- def __init__(self, hs, name, timeout_ms=0):
- self.pending_result_cache = {} # Requests that haven't finished yet.
+ def __init__(self, hs: "HomeServer", name: str, timeout_ms: float = 0):
+ # Requests that haven't finished yet.
+ self.pending_result_cache = {} # type: Dict[T, ObservableDeferred]
self.clock = hs.get_clock()
self.timeout_sec = timeout_ms / 1000.0
@@ -40,13 +47,13 @@ class ResponseCache:
self._name = name
self._metrics = register_cache("response_cache", name, self, resizable=False)
- def size(self):
+ def size(self) -> int:
return len(self.pending_result_cache)
- def __len__(self):
+ def __len__(self) -> int:
return self.size()
- def get(self, key):
+ def get(self, key: T) -> Optional[defer.Deferred]:
"""Look up the given key.
Can return either a new Deferred (which also doesn't follow the synapse
@@ -58,12 +65,11 @@ class ResponseCache:
from an absent cache entry.
Args:
- key (hashable):
+ key: key to get/set in the cache
Returns:
- twisted.internet.defer.Deferred|None|E: None if there is no entry
- for this key; otherwise either a deferred result or the result
- itself.
+ None if there is no entry for this key; otherwise a deferred which
+ resolves to the result.
"""
result = self.pending_result_cache.get(key)
if result is not None:
@@ -73,7 +79,7 @@ class ResponseCache:
self._metrics.inc_misses()
return None
- def set(self, key, deferred):
+ def set(self, key: T, deferred: defer.Deferred) -> defer.Deferred:
"""Set the entry for the given key to the given deferred.
*deferred* should run its callbacks in the sentinel logcontext (ie,
@@ -85,12 +91,11 @@ class ResponseCache:
result. You will probably want to make_deferred_yieldable the result.
Args:
- key (hashable):
- deferred (twisted.internet.defer.Deferred[T):
+ key: key to get/set in the cache
+ deferred: The deferred which resolves to the result.
Returns:
- twisted.internet.defer.Deferred[T]|T: a new deferred, or the actual
- result.
+ A new deferred which resolves to the actual result.
"""
result = ObservableDeferred(deferred, consumeErrors=True)
self.pending_result_cache[key] = result
@@ -107,7 +112,9 @@ class ResponseCache:
result.addBoth(remove)
return result.observe()
- def wrap(self, key, callback, *args, **kwargs):
+ def wrap(
+ self, key: T, callback: "Callable[..., Any]", *args: Any, **kwargs: Any
+ ) -> defer.Deferred:
"""Wrap together a *get* and *set* call, taking care of logcontexts
First looks up the key in the cache, and if it is present makes it
@@ -118,21 +125,20 @@ class ResponseCache:
Example usage:
- @defer.inlineCallbacks
- def handle_request(request):
+ async def handle_request(request):
# etc
return result
- result = yield response_cache.wrap(
+ result = await response_cache.wrap(
key,
handle_request,
request,
)
Args:
- key (hashable): key to get/set in the cache
+ key: key to get/set in the cache
- callback (callable): function to call if the key is not found in
+ callback: function to call if the key is not found in
the cache
*args: positional parameters to pass to the callback, if it is used
@@ -140,7 +146,7 @@ class ResponseCache:
**kwargs: named parameters to pass to the callback, if it is used
Returns:
- twisted.internet.defer.Deferred: yieldable result
+ Deferred which resolves to the result
"""
result = self.get(key)
if not result:
|
