diff options
Diffstat (limited to 'synapse/util/caches/response_cache.py')
| -rw-r--r-- | synapse/util/caches/response_cache.py | 50 |
1 files changed, 28 insertions, 22 deletions
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: |