fix: Apply max_connections configuration to Redis async client (#15797)

* fix: Apply max_connections configuration to Redis async client

- Add max_connections to available Redis cluster kwargs
- Add connection_pool parameter to get_redis_async_client()
- Pass connection_pool to Redis client if provided
- Prevents Redis connection exhaustion under high load

* test: Add tests for Redis max_connections feature

- Test max_connections is included in cluster kwargs
- Test connection_pool parameter is properly passed to async client
- Test async client works without connection_pool parameter

All 3 tests pass successfully

litellm/_redis.py

@@ -78,6 +78,7 @@ def _get_redis_cluster_kwargs(client=None):
     available_args.append("redis_connect_func")  # Needed for sync clusters and IAM detection
     available_args.append("gcp_service_account")
     available_args.append("gcp_ssl_ca_certs")
+    available_args.append("max_connections")
 
     return available_args
 
@@ -376,7 +377,7 @@ def get_redis_client(**env_overrides):
 
 
 def get_redis_async_client(
-    **env_overrides,
+    connection_pool: Optional[async_redis.BlockingConnectionPool] = None, **env_overrides,
 ) -> Union[async_redis.Redis, async_redis.RedisCluster]:
     redis_kwargs = _get_redis_client_logic(**env_overrides)
     if "url" in redis_kwargs and redis_kwargs["url"] is not None:
@@ -447,6 +448,10 @@ def get_redis_async_client(
     if "sentinel_nodes" in redis_kwargs and "service_name" in redis_kwargs:
         return _init_async_redis_sentinel(redis_kwargs)
     _pretty_print_redis_config(redis_kwargs=redis_kwargs)
+
+    if connection_pool is not None:
+        redis_kwargs["connection_pool"] = connection_pool
+
     return async_redis.Redis(
         **redis_kwargs,
     )

tests/test_litellm/test_redis.py

@@ -1,6 +1,8 @@
-from litellm._redis import get_redis_url_from_environment
+from litellm._redis import get_redis_url_from_environment, _get_redis_cluster_kwargs, get_redis_async_client
 import os
 import pytest
+from unittest.mock import MagicMock, patch
+import redis.asyncio as async_redis
 
 def test_get_redis_url_from_environment_single_url(monkeypatch):
     """Test when REDIS_URL is directly provided"""
@@ -117,3 +119,51 @@ def test_get_redis_url_from_environment_missing_port(monkeypatch):
     
     # Check the error message
     assert "Either 'REDIS_URL' or both 'REDIS_HOST' and 'REDIS_PORT' must be specified" in str(excinfo.value)
+
+def test_max_connections_in_cluster_kwargs():
+    """Test that max_connections is included in Redis cluster kwargs"""
+    kwargs = _get_redis_cluster_kwargs()
+    assert "max_connections" in kwargs, "max_connections should be in available Redis cluster kwargs"
+
+def test_get_redis_async_client_with_connection_pool():
+    """Test that connection_pool parameter is properly passed to Redis client"""
+    # Create a mock connection pool
+    mock_pool = MagicMock(spec=async_redis.BlockingConnectionPool)
+    
+    # Mock the Redis client creation
+    with patch('litellm._redis.async_redis.Redis') as mock_redis, \
+         patch('litellm._redis._get_redis_client_logic') as mock_logic:
+        
+        # Configure mock to return basic redis kwargs
+        mock_logic.return_value = {
+            "host": "localhost",
+            "port": 6379,
+            "db": 0
+        }
+        
+        # Call get_redis_async_client with connection_pool
+        get_redis_async_client(connection_pool=mock_pool)
+        
+        # Verify Redis was called with connection_pool in kwargs
+        call_kwargs = mock_redis.call_args[1]
+        assert "connection_pool" in call_kwargs, "connection_pool should be passed to Redis client"
+        assert call_kwargs["connection_pool"] == mock_pool, "connection_pool should match the provided pool"
+
+def test_get_redis_async_client_without_connection_pool():
+    """Test that Redis client works without connection_pool parameter"""
+    with patch('litellm._redis.async_redis.Redis') as mock_redis, \
+         patch('litellm._redis._get_redis_client_logic') as mock_logic:
+        
+        # Configure mock to return basic redis kwargs
+        mock_logic.return_value = {
+            "host": "localhost",
+            "port": 6379,
+            "db": 0
+        }
+        
+        # Call get_redis_async_client without connection_pool
+        get_redis_async_client()
+        
+        # Verify Redis was called without connection_pool in kwargs
+        call_kwargs = mock_redis.call_args[1]
+        assert "connection_pool" not in call_kwargs, "connection_pool should not be in kwargs when not provided"