Sentinel-aware Redis connection.

Queries sentinels to discover the current primary or replica, then maintains a connection. On disconnection, re-queries sentinels to find the (possibly new) primary.

With :read_preference, the client maintains primary and replica connections, routes eligible reads to replicas, and keeps writes and transactions on the primary:

{:ok, conn} = Redis.Sentinel.start_link(
  sentinels: [{"sentinel1", 26379}, {"sentinel2", 26379}],
  group: "mymaster",
  read_preference: :prefer_replica
)

Usage

{:ok, conn} = Redis.Sentinel.start_link(
  sentinels: [{"sentinel1", 26379}, {"sentinel2", 26379}],
  group: "mymaster",
  role: :primary,
  password: "secret"
)

# Use like a normal connection — failover is transparent
{:ok, "OK"} = Redis.Sentinel.command(conn, ["SET", "key", "value"])

Options

• :sentinels - list of sentinel addresses as {host, port} tuples or "host:port" strings (required)
• :group - sentinel group name (required)
• :role - :primary or :replica (default: :primary)
• :read_preference - :master (default), :replica, or :prefer_replica. Cannot be combined with role: :replica.
• :read_only_commands - extra command names that are safe to run on replicas
• :password - password for the Redis server (not the sentinel)
• :sentinel_password - password for sentinel connections
• :sentinel_username - username for sentinel connections
• :username - username for the Redis server
• :database - database number
• :timeout - connection timeout ms (default: 5_000)
• :sentinel_timeout - sentinel query timeout ms (default: 500)
• :topology_refresh_interval - Sentinel topology refresh interval in milliseconds for replica routing (default: 30_000; nil disables it)
• :name - GenServer name registration
• :protocol - :resp3 or :resp2 (default: :resp3)

Command, pipeline, and transaction calls accept response: :typed; see Redis.Response.