feat: add Redis Sentinel support (#81)

  - Add is_sentinel_url() method to RedisConfig for Sentinel URL detection
  - Update RedisConfig.redis() to use RedisVL ConnectionFactory for Sentinel URLs
  - Add Sentinel support to RedisCache and RedisSemanticCache
  - Add Sentinel support to RedisChatMessageHistory
  - Add comprehensive unit tests for Sentinel connections
  - Update README with Sentinel configuration examples and usage

  All components now support redis+sentinel:// URLs for high availability Redis deployments.

  Closes #81

Author: bsbodden

libs/redis/README.md

@@ -20,6 +20,79 @@ export REDIS_URL="redis://username:password@localhost:6379"
 
 Alternatively, you can pass the Redis URL directly when initializing the components or use the `RedisConfig` class for more detailed configuration.
 
+### Redis Connection Options
+
+This package supports various Redis deployment modes through different connection URL schemes:
+
+#### Standard Redis Connection
+```python
+# Standard Redis
+redis_url = "redis://localhost:6379"
+
+# Redis with authentication
+redis_url = "redis://username:password@localhost:6379"
+
+# Redis SSL/TLS
+redis_url = "rediss://localhost:6380"
+```
+
+#### Redis Sentinel Connection
+
+Redis Sentinel provides high availability for Redis. You can connect to a Sentinel-managed Redis deployment using the `redis+sentinel://` URL scheme:
+
+```python
+# Single Sentinel node
+redis_url = "redis+sentinel://sentinel-host:26379/mymaster"
+
+# Multiple Sentinel nodes (recommended for high availability)
+redis_url = "redis+sentinel://sentinel1:26379,sentinel2:26379,sentinel3:26379/mymaster"
+
+# Sentinel with authentication
+redis_url = "redis+sentinel://username:password@sentinel1:26379,sentinel2:26379/mymaster"
+```
+
+The Sentinel URL format is: `redis+sentinel://[username:password@]host1:port1[,host2:port2,...]/service_name`
+
+Where:
+- `host:port` - One or more Sentinel node addresses
+- `service_name` - The name of the Redis master service (e.g., "mymaster")
+
+**Example using Sentinel with RedisVectorStore:**
+```python
+from langchain_redis import RedisVectorStore, RedisConfig
+from langchain_openai import OpenAIEmbeddings
+
+config = RedisConfig(
+    redis_url="redis+sentinel://sentinel1:26379,sentinel2:26379/mymaster",
+    index_name="my_index"
+)
+
+vector_store = RedisVectorStore(
+    embeddings=OpenAIEmbeddings(),
+    config=config
+)
+```
+
+**Example using Sentinel with RedisCache:**
+```python
+from langchain_redis import RedisCache
+
+cache = RedisCache(
+    redis_url="redis+sentinel://sentinel1:26379,sentinel2:26379/mymaster",
+    ttl=3600
+)
+```
+
+**Example using Sentinel with RedisChatMessageHistory:**
+```python
+from langchain_redis import RedisChatMessageHistory
+
+history = RedisChatMessageHistory(
+    session_id="user_123",
+    redis_url="redis+sentinel://sentinel1:26379,sentinel2:26379/mymaster"
+)
+```
+
 ## Features
 
 ### 1. Vector Store

libs/redis/langchain_redis/cache.py

@@ -132,7 +132,20 @@ def __init__(
         prefix: Optional[str] = "redis",
         redis_client: Optional[Redis] = None,
     ):
-        self.redis = redis_client or Redis.from_url(redis_url)
+        if redis_client is not None:
+            self.redis = redis_client
+        elif redis_url.startswith("redis+sentinel://"):
+            # For Sentinel URLs, use RedisVL's connection factory
+            from redisvl.redis.connection import (  # type: ignore[import-untyped]
+                RedisConnectionFactory,
+            )
+
+            self.redis = RedisConnectionFactory.get_redis_connection(
+                redis_url=redis_url
+            )
+        else:
+            self.redis = Redis.from_url(redis_url)
+
         try:
             self.redis.client_setinfo("LIB-NAME", __full_lib_name__)  # type: ignore
         except ResponseError:
@@ -359,7 +372,20 @@ def __init__(
         prefix: Optional[str] = "llmcache",
         redis_client: Optional[Redis] = None,
     ):
-        self.redis = redis_client or Redis.from_url(redis_url)
+        if redis_client is not None:
+            self.redis = redis_client
+        elif redis_url.startswith("redis+sentinel://"):
+            # For Sentinel URLs, use RedisVL's connection factory
+            from redisvl.redis.connection import (  # type: ignore[import-untyped]
+                RedisConnectionFactory,
+            )
+
+            self.redis = RedisConnectionFactory.get_redis_connection(
+                redis_url=redis_url
+            )
+        else:
+            self.redis = Redis.from_url(redis_url)
+
         self.embeddings = embeddings
         self.prefix = prefix
         vectorizer = EmbeddingsVectorizer(embeddings=self.embeddings)

libs/redis/langchain_redis/chat_message_history.py

@@ -124,7 +124,19 @@ def __init__(
         if not session_id or not isinstance(session_id, str):
             raise ValueError("session_id must be a non-empty, valid string")
 
-        self.redis_client = redis_client or Redis.from_url(redis_url, **kwargs)
+        if redis_client is not None:
+            self.redis_client = redis_client
+        elif redis_url.startswith("redis+sentinel://"):
+            # For Sentinel URLs, use RedisVL's connection factory
+            from redisvl.redis.connection import (  # type: ignore[import-untyped]
+                RedisConnectionFactory,
+            )
+
+            self.redis_client = RedisConnectionFactory.get_redis_connection(
+                redis_url=redis_url, **kwargs
+            )
+        else:
+            self.redis_client = Redis.from_url(redis_url, **kwargs)
 
         # Configure Redis client to use a no-op push handler when PubSub is initialized
         if hasattr(self.redis_client, "pubsub_configs"):

libs/redis/langchain_redis/config.py

@@ -496,13 +496,35 @@ def to_index_schema(self) -> IndexSchema:
 
             return IndexSchema.from_dict({"index": index_info, "fields": fields})
 
+    def is_sentinel_url(self) -> bool:
+        """Check if the redis_url is a Sentinel URL.
+
+        Returns:
+            bool: True if the URL uses the redis+sentinel:// scheme, False otherwise.
+        """
+        return self.redis_url is not None and self.redis_url.startswith(
+            "redis+sentinel://"
+        )
+
     def redis(self) -> Redis:
         if self.redis_client is not None:
             return self.redis_client
         elif self.redis_url is not None:
-            if self.connection_args is not None:
-                return Redis.from_url(self.redis_url, **self.connection_args)
+            if self.is_sentinel_url():
+                # For Sentinel URLs, use RedisVL's connection factory
+                # which properly handles Sentinel connections
+                from redisvl.redis.connection import (  # type: ignore[import-untyped]
+                    RedisConnectionFactory,
+                )
+
+                return RedisConnectionFactory.get_redis_connection(
+                    redis_url=self.redis_url, **(self.connection_args or {})
+                )
             else:
-                return Redis.from_url(self.redis_url)
+                # For standard URLs, use Redis.from_url
+                if self.connection_args is not None:
+                    return Redis.from_url(self.redis_url, **self.connection_args)
+                else:
+                    return Redis.from_url(self.redis_url)
         else:
             raise ValueError("Either redis_client or redis_url must be provided")