> ## Documentation Index > Fetch the complete documentation index at: https://docs.prefect.io/llms.txt > Use this file to discover all available pages before exploring further. # connection # `prefect_redis.connection` Redis client construction from connection URLs, including Redis Sentinel. redis-py already parses standalone `redis://` and `rediss://` URLs (`Redis.from_url`) and handles Sentinel master discovery and failover (`redis.sentinel.Sentinel`), but it has no URL form for a Sentinel topology. This module adds that one convention and otherwise defers to redis-py:: redis+sentinel://\[user:pass@]host\[:port]\[,host2\[:port2],...]/service\_name\[/db]\[?options] rediss+sentinel://... (TLS for both the data nodes and the Sentinel daemons) Sentinel members default to port 26379. The `sentinel_username` and `sentinel_password` options authenticate to the Sentinel daemons; every other option is a standard redis-py URL option applied to the data-node connections with redis-py's own parsing, and on a TLS scheme the `ssl_*` options (from the URL or from caller defaults) are shared with the daemon connections so one private CA covers the whole topology. The grammar is the one docket accepts for `PREFECT_SERVER_DOCKET_URL`, so a single URL serves both. ## Functions ### `is_sentinel_url` ```python theme={null} is_sentinel_url(url: str) -> bool ``` Return True if the URL uses a Redis Sentinel scheme. Only the scheme is inspected: `urlsplit` rejects a member list with an IPv6 host (`redis+sentinel://s1:26379,[::1]:26379/mymaster`) as an invalid IPv6 URL. Schemes are matched case-insensitively per RFC 3986. ### `redis_from_url` ```python theme={null} redis_from_url(url: str, **kwargs: Any) -> redis.Redis | redis.asyncio.Redis ``` Build a Redis client from a connection URL. Standalone URLs are handed to `Redis.from_url` unchanged. Sentinel URLs resolve the current master through the listed Sentinel daemons, and the returned client follows failover automatically. In both cases `kwargs` are connection defaults that URL query options override, as with `Redis.from_url`. Building a client is lazy and opens no connection. Close it with `close_redis_client` / `aclose_redis_client` so a Sentinel-backed client's daemon connections are released too. **Raises:** * `ValueError`: If the URL is malformed. Messages do not echo the URL, so credentials embedded in it are never leaked. ### `close_redis_client` ```python theme={null} close_redis_client(client: redis.Redis) -> None ``` Close a sync client returned by `redis_from_url`. A Sentinel-backed client holds one extra Redis client per Sentinel daemon on its connection pool's `sentinel_manager`; closing only the returned client would leave those daemon connections to be reclaimed by the garbage collector (emitting `ResourceWarning`s). This closes both. ### `aclose_redis_client` ```python theme={null} aclose_redis_client(client: redis.asyncio.Redis) -> None ``` Async counterpart of `close_redis_client`.