feat(redis): enable read_from_replicas for Redis Cluster by default

api/app/settings/common.py

@@ -852,6 +852,12 @@
     "DJANGO_REDIS_LOG_IGNORED_EXCEPTIONS", True
 )
 
+# Enable reading from replicas in Redis Cluster mode.
+# Distributes read traffic to replica nodes (port 6380 on ElastiCache Serverless).
+REDIS_CLUSTER_READ_FROM_REPLICAS = env.bool(
+    "REDIS_CLUSTER_READ_FROM_REPLICAS", default=True
+)
+
 CACHES = {
     "default": {
         "BACKEND": "django.core.cache.backends.locmem.LocMemCache",

api/core/redis_cluster.py

@@ -24,6 +24,7 @@
 import threading
 from copy import deepcopy
 
+from django.conf import settings
 from django.core.exceptions import ImproperlyConfigured
 from django_redis.client.default import DefaultClient  # type: ignore[import-untyped]
 from django_redis.exceptions import (  # type: ignore[import-untyped]
@@ -125,6 +126,9 @@ def get_connection(self, connection_params: dict) -> RedisCluster:  # type: igno
             # Add explicit socket timeout
             client_cls_kwargs["socket_timeout"] = SOCKET_TIMEOUT
             client_cls_kwargs["socket_keepalive"] = True
+            client_cls_kwargs["read_from_replicas"] = (
+                settings.REDIS_CLUSTER_READ_FROM_REPLICAS
+            )
             # ... and then build and return the client
             return RedisCluster(**client_cls_kwargs)  # type: ignore[abstract]
         except Exception as e:

api/tests/unit/core/test_redis_cluster.py

@@ -2,6 +2,7 @@
 from django_redis.exceptions import (  # type: ignore[import-untyped]
     ConnectionInterrupted,
 )
+from pytest_django.fixtures import SettingsWrapper
 from pytest_mock import MockerFixture
 from redis.exceptions import RedisClusterException
 
@@ -42,8 +43,10 @@ def test_cluster_connection_factory__connect_cache(mocker: MockerFixture):  # ty
 
 def test_cluster_connection_factory__get_connection_with_non_conflicting_params(  # type: ignore[no-untyped-def]
     mocker: MockerFixture,
+    settings: SettingsWrapper,
 ):
     # Given
+    settings.REDIS_CLUSTER_READ_FROM_REPLICAS = False
     mockRedisCluster = mocker.patch("core.redis_cluster.RedisCluster")
     connection_factory = ClusterConnectionFactory(
         options={"REDIS_CLIENT_KWARGS": {"decode_responses": False}}
@@ -60,6 +63,7 @@ def test_cluster_connection_factory__get_connection_with_non_conflicting_params(
         port=6379,
         socket_keepalive=True,
         socket_timeout=0.2,
+        read_from_replicas=False,
     )