feat: add Redis Sentinel URL scheme support (#213)

Add support for connecting to Redis through Sentinel using the redis+sentinel:// URL scheme.
This enables high availability Redis deployments with automatic failover.

URL format: redis+sentinel://[username:password@]host1:port1,host2:port2/service_name[/db]

- Add Sentinel URL parsing in RedisConnectionFactory
- Support both sync and async Redis connections via Sentinel
- Add comprehensive unit tests for Sentinel URL handling

Fixes #213

Author: bsbodden

redisvl/redis/connection.py

@@ -1,5 +1,6 @@
 import os
-from typing import Any, Dict, List, Optional, Type
+from typing import Any, Dict, List, Optional, Type, TypeVar, Union, overload
+from urllib.parse import urlparse
 from warnings import warn
 
 from redis import Redis, RedisCluster
@@ -11,6 +12,7 @@
 from redis.asyncio.connection import SSLConnection as AsyncSSLConnection
 from redis.connection import SSLConnection
 from redis.exceptions import ResponseError
+from redis.sentinel import Sentinel
 
 from redisvl import __version__
 from redisvl.redis.constants import REDIS_URL_ENV_VAR
@@ -192,6 +194,9 @@ def parse_attrs(attrs):
     }
 
 
+T = TypeVar("T", Redis, AsyncRedis)
+
+
 class RedisConnectionFactory:
     """Builds connections to a Redis database, supporting both synchronous and
     asynchronous clients.
@@ -253,7 +258,9 @@ def get_redis_connection(
                 variable is not set.
         """
         url = redis_url or get_address_from_env()
-        if is_cluster_url(url, **kwargs):
+        if url.startswith("redis+sentinel"):
+            client = RedisConnectionFactory._redis_sentinel_client(url, Redis, **kwargs)
+        elif is_cluster_url(url, **kwargs):
             client = RedisCluster.from_url(url, **kwargs)
         else:
             client = Redis.from_url(url, **kwargs)
@@ -293,7 +300,11 @@ async def _get_aredis_connection(
         """
         url = url or get_address_from_env()
 
-        if is_cluster_url(url, **kwargs):
+        if url.startswith("redis+sentinel"):
+            client = RedisConnectionFactory._redis_sentinel_client(
+                url, AsyncRedis, **kwargs
+            )
+        elif is_cluster_url(url, **kwargs):
             client = AsyncRedisCluster.from_url(url, **kwargs)
         else:
             client = AsyncRedis.from_url(url, **kwargs)
@@ -334,6 +345,10 @@ def get_async_redis_connection(
             DeprecationWarning,
         )
         url = url or get_address_from_env()
+        if url.startswith("redis+sentinel"):
+            return RedisConnectionFactory._redis_sentinel_client(
+                url, AsyncRedis, **kwargs
+            )
         return AsyncRedis.from_url(url, **kwargs)
 
     @staticmethod
@@ -440,3 +455,60 @@ async def validate_async_redis(
                 await redis_client.echo(_lib_name)
 
         # Module validation removed - operations will fail naturally if modules are missing
+
+    @staticmethod
+    @overload
+    def _redis_sentinel_client(
+        redis_url: str, redis_class: type[Redis], **kwargs: Any
+    ) -> Redis: ...
+
+    @staticmethod
+    @overload
+    def _redis_sentinel_client(
+        redis_url: str, redis_class: type[AsyncRedis], **kwargs: Any
+    ) -> AsyncRedis: ...
+
+    @staticmethod
+    def _redis_sentinel_client(
+        redis_url: str, redis_class: Union[type[Redis], type[AsyncRedis]], **kwargs: Any
+    ) -> Union[Redis, AsyncRedis]:
+        sentinel_list, service_name, db, username, password = (
+            RedisConnectionFactory._parse_sentinel_url(redis_url)
+        )
+
+        sentinel_kwargs = {}
+        if username:
+            sentinel_kwargs["username"] = username
+            kwargs["username"] = username
+        if password:
+            sentinel_kwargs["password"] = password
+            kwargs["password"] = password
+        if db:
+            kwargs["db"] = db
+
+        sentinel = Sentinel(sentinel_list, sentinel_kwargs=sentinel_kwargs, **kwargs)
+        return sentinel.master_for(service_name, redis_class=redis_class, **kwargs)
+
+    @staticmethod
+    def _parse_sentinel_url(url: str) -> tuple:
+        parsed_url = urlparse(url)
+        hosts_part = parsed_url.netloc.split("@")[-1]
+        sentinel_hosts = hosts_part.split(",")
+
+        sentinel_list = []
+        for host in sentinel_hosts:
+            host_parts = host.split(":")
+            if len(host_parts) == 2:
+                sentinel_list.append((host_parts[0], int(host_parts[1])))
+            else:
+                sentinel_list.append((host_parts[0], 26379))
+
+        service_name = "mymaster"
+        db = None
+        if parsed_url.path:
+            path_parts = parsed_url.path.split("/")
+            service_name = path_parts[1] or "mymaster"
+            if len(path_parts) > 2:
+                db = path_parts[2]
+
+        return sentinel_list, service_name, db, parsed_url.username, parsed_url.password

tests/unit/test_sentinel_url.py

@@ -0,0 +1,84 @@
+from unittest.mock import MagicMock, patch
+
+import pytest
+from redis.exceptions import ConnectionError
+
+from redisvl.redis.connection import RedisConnectionFactory
+
+
+@pytest.mark.parametrize("use_async", [False, True])
+def test_sentinel_url_connection(use_async):
+    sentinel_url = (
+        "redis+sentinel://username:password@host1:26379,host2:26380/mymaster/0"
+    )
+
+    with patch("redisvl.redis.connection.Sentinel") as mock_sentinel:
+        mock_master = MagicMock()
+        mock_sentinel.return_value.master_for.return_value = mock_master
+
+        if use_async:
+            client = RedisConnectionFactory.get_async_redis_connection(sentinel_url)
+        else:
+            client = RedisConnectionFactory.get_redis_connection(sentinel_url)
+
+        mock_sentinel.assert_called_once()
+        call_args = mock_sentinel.call_args
+        assert call_args[0][0] == [("host1", 26379), ("host2", 26380)]
+        assert call_args[1]["sentinel_kwargs"] == {
+            "username": "username",
+            "password": "password",
+        }
+
+        mock_sentinel.return_value.master_for.assert_called_once()
+        master_for_args = mock_sentinel.return_value.master_for.call_args
+        assert master_for_args[0][0] == "mymaster"
+        assert master_for_args[1]["db"] == "0"
+
+        assert client == mock_master
+
+
+@pytest.mark.parametrize("use_async", [False, True])
+def test_sentinel_url_connection_no_auth_no_db(use_async):
+    sentinel_url = "redis+sentinel://host1:26379,host2:26380/mymaster"
+
+    with patch("redisvl.redis.connection.Sentinel") as mock_sentinel:
+        mock_master = MagicMock()
+        mock_sentinel.return_value.master_for.return_value = mock_master
+
+        if use_async:
+            client = RedisConnectionFactory.get_async_redis_connection(sentinel_url)
+        else:
+            client = RedisConnectionFactory.get_redis_connection(sentinel_url)
+
+        mock_sentinel.assert_called_once()
+        call_args = mock_sentinel.call_args
+        assert call_args[0][0] == [("host1", 26379), ("host2", 26380)]
+        assert (
+            "sentinel_kwargs" not in call_args[1]
+            or call_args[1]["sentinel_kwargs"] == {}
+        )
+
+        mock_sentinel.return_value.master_for.assert_called_once()
+        master_for_args = mock_sentinel.return_value.master_for.call_args
+        assert master_for_args[0][0] == "mymaster"
+        assert "db" not in master_for_args[1]
+
+        assert client == mock_master
+
+
+@pytest.mark.parametrize("use_async", [False, True])
+def test_sentinel_url_connection_error(use_async):
+    sentinel_url = "redis+sentinel://host1:26379,host2:26380/mymaster"
+
+    with patch("redisvl.redis.connection.Sentinel") as mock_sentinel:
+        mock_sentinel.return_value.master_for.side_effect = ConnectionError(
+            "Test connection error"
+        )
+
+        with pytest.raises(ConnectionError):
+            if use_async:
+                RedisConnectionFactory.get_async_redis_connection(sentinel_url)
+            else:
+                RedisConnectionFactory.get_redis_connection(sentinel_url)
+
+        mock_sentinel.assert_called_once()