diff --git a/synapse/util/caches/__init__.py b/synapse/util/caches/__init__.py
index 8fc05be278..89f0b38535 100644
--- a/synapse/util/caches/__init__.py
+++ b/synapse/util/caches/__init__.py
@@ -16,7 +16,7 @@
import logging
from sys import intern
-from typing import Callable, Dict, Optional
+from typing import Callable, Dict, Optional, Sized
import attr
from prometheus_client.core import Gauge
@@ -92,7 +92,7 @@ class CacheMetric:
def register_cache(
cache_type: str,
cache_name: str,
- cache,
+ cache: Sized,
collect_callback: Optional[Callable] = None,
resizable: bool = True,
resize_callback: Optional[Callable] = None,
@@ -100,12 +100,15 @@ def register_cache(
"""Register a cache object for metric collection and resizing.
Args:
- cache_type
+ cache_type: a string indicating the "type" of the cache. This is used
+ only for deduplication so isn't too important provided it's constant.
cache_name: name of the cache
- cache: cache itself
+ cache: cache itself, which must implement __len__(), and may optionally implement
+ a max_size property
collect_callback: If given, a function which is called during metric
collection to update additional metrics.
- resizable: Whether this cache supports being resized.
+ resizable: Whether this cache supports being resized, in which case either
+ resize_callback must be provided, or the cache must support set_max_size().
resize_callback: A function which can be called to resize the cache.
Returns:
|
