Sharded Pub/Sub client for Redis Cluster (Redis 7+).

Uses SSUBSCRIBE / SUNSUBSCRIBE / SPUBLISH to route messages by hash slot. Unlike regular pub/sub which broadcasts to every node, sharded pub/sub only involves the node that owns the channel's hash slot.

Usage

{:ok, sharded} = Redis.PubSub.Sharded.start_link(
  nodes: [{"127.0.0.1", 7000}, {"127.0.0.1", 7001}, {"127.0.0.1", 7002}]
)

:ok = Redis.PubSub.Sharded.ssubscribe(sharded, "orders:123")

receive do
  {:redis_pubsub, :smessage, channel, payload} ->
    IO.puts("sharded message on " <> channel <> ": " <> payload)
end

:ok = Redis.PubSub.Sharded.sunsubscribe(sharded, "orders:123")

Options

• :nodes - list of seed nodes as {host, port} tuples or "host:port" strings
• :cluster - pid of an existing Redis.Cluster (used to discover topology)
• :password - Redis password (applied to all nodes)
• :timeout - connection timeout ms (default: 5_000)
• :name - GenServer name registration

Message Format

{:redis_pubsub, :smessage, channel, payload}