Add a cached helper to the module API (#14663)

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Brendan Abolivier 2022-12-28 14:48:21 +01:00 committed by GitHub
parent a4ca770655
commit 3854d0f949
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2 changed files with 40 additions and 1 deletions

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@ -0,0 +1 @@
Add a `cached` function to `synapse.module_api` that returns a decorator to cache return values of functions.

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@ -18,6 +18,7 @@ from typing import (
TYPE_CHECKING,
Any,
Callable,
Collection,
Dict,
Generator,
Iterable,
@ -126,7 +127,7 @@ from synapse.types import (
from synapse.types.state import StateFilter
from synapse.util import Clock
from synapse.util.async_helpers import maybe_awaitable
from synapse.util.caches.descriptors import CachedFunction, cached
from synapse.util.caches.descriptors import CachedFunction, cached as _cached
from synapse.util.frozenutils import freeze
if TYPE_CHECKING:
@ -136,6 +137,7 @@ if TYPE_CHECKING:
T = TypeVar("T")
P = ParamSpec("P")
F = TypeVar("F", bound=Callable[..., Any])
"""
This package defines the 'stable' API which can be used by extension modules which
@ -185,6 +187,42 @@ class UserIpAndAgent:
last_seen: int
def cached(
*,
max_entries: int = 1000,
num_args: Optional[int] = None,
uncached_args: Optional[Collection[str]] = None,
) -> Callable[[F], CachedFunction[F]]:
"""Returns a decorator that applies a memoizing cache around the function. This
decorator behaves similarly to functools.lru_cache.
Example:
@cached()
def foo('a', 'b'):
...
Added in Synapse v1.74.0.
Args:
max_entries: The maximum number of entries in the cache. If the cache is full
and a new entry is added, the least recently accessed entry will be evicted
from the cache.
num_args: The number of positional arguments (excluding `self`) to use as cache
keys. Defaults to all named args of the function.
uncached_args: A list of argument names to not use as the cache key. (`self` is
always ignored.) Cannot be used with num_args.
Returns:
A decorator that applies a memoizing cache around the function.
"""
return _cached(
max_entries=max_entries,
num_args=num_args,
uncached_args=uncached_args,
)
class ModuleApi:
"""A proxy object that gets passed to various plugin modules so they
can register new users etc if necessary.