From 796e51df629969405ec0973620f588aa38026ace Mon Sep 17 00:00:00 2001
From: Ankush Menat <ankush@frappe.io>
Date: Thu, 2 Jan 2025 13:17:22 +0530
Subject: [PATCH] fix: limit # of keys by maxsize

Picking 1024 keys assuming 4kb avg size. In practice most things are
smaller so 1024 should be good enough!

This will likely only affect multitenant deploy with many sites.
---
 frappe/utils/redis_wrapper.py | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/frappe/utils/redis_wrapper.py b/frappe/utils/redis_wrapper.py
index 9a8615273f..326daad4cd 100644
--- a/frappe/utils/redis_wrapper.py
+++ b/frappe/utils/redis_wrapper.py
@@ -410,9 +410,10 @@ class _TrackedConnection(redis.Connection):
 
 
 class _ClientCache:
-	def __init__(self) -> None:
+	def __init__(self, maxsize: int = 1024) -> None:
 		self.monitor = RedisWrapper.from_url(frappe.conf.get("redis_cache"))
 		self.monitor_id = self.monitor.client_id()
+		self.maxsize = maxsize or 1024  # Expect 1024 * 4kb objects ~ 4MB
 
 		self.redis: RedisWrapper = RedisWrapper.from_url(
 			frappe.conf.get("redis_cache"),
@@ -434,9 +435,15 @@ class _ClientCache:
 			pass  # cache miss
 		val = self.redis.get_value(key, shared=True)
 
-		# TODO: distinguish between none result and miss
-		if val is not None:
-			self.local_cache[key] = val
+		# TODO: distinguish between None result and miss
+		if val is None:
+			return None
+
+		if len(self.local_cache) >= self.maxsize:
+			with suppress(RuntimeError):
+				self.local_cache.pop(next(iter(self.local_cache)), None)
+
+		self.local_cache[key] = val
 		return val
 
 	def set_value(self, key, val):