Redis Cluster client.
Maintains topology awareness, routes commands to the correct node based on hash slot, and handles MOVED/ASK redirects transparently.
Usage
{:ok, cluster} = Redis.Cluster.start_link(
nodes: [{"127.0.0.1", 7000}, {"127.0.0.1", 7001}],
password: "secret"
)
{:ok, "OK"} = Redis.Cluster.command(cluster, ["SET", "mykey", "myvalue"])
{:ok, "myvalue"} = Redis.Cluster.command(cluster, ["GET", "mykey"])Options
:nodes- list of seed nodes as{host, port}tuples or"host:port"strings:password- Redis password (applied to all nodes):name- GenServer name registration:timeout- command timeout ms (default: 5_000):max_redirects- max MOVED/ASK redirects before failing (default: 5)
Summary
Functions
Returns a specification to start this module under a supervisor.
Sends a command, routed to the correct node by key hash slot.
Returns cluster info: nodes, slot coverage.
Sends a pipeline of commands. If all commands target the same hash slot, they are sent as a single pipeline. Otherwise, commands are automatically split by slot, sent in parallel to the correct nodes, and results are reassembled in the original command order.
Forces a topology refresh.
Executes a MULTI/EXEC transaction in cluster mode.
Executes a WATCH-based optimistic locking transaction in cluster mode.
Functions
Returns a specification to start this module under a supervisor.
See Supervisor.
@spec command(GenServer.server(), [String.t()], keyword()) :: {:ok, term()} | {:error, term()}
Sends a command, routed to the correct node by key hash slot.
@spec info(GenServer.server()) :: map()
Returns cluster info: nodes, slot coverage.
@spec pipeline(GenServer.server(), [[String.t()]], keyword()) :: {:ok, [term()]} | {:error, term()}
Sends a pipeline of commands. If all commands target the same hash slot, they are sent as a single pipeline. Otherwise, commands are automatically split by slot, sent in parallel to the correct nodes, and results are reassembled in the original command order.
@spec refresh(GenServer.server()) :: :ok | {:error, term()}
Forces a topology refresh.
@spec start_link(keyword()) :: GenServer.on_start()
@spec stop(GenServer.server()) :: :ok
@spec transaction(GenServer.server(), [[String.t()]], keyword()) :: {:ok, [term()]} | {:error, term()}
Executes a MULTI/EXEC transaction in cluster mode.
All commands must target the same hash slot. Returns {:error, :cross_slot}
if commands span multiple slots. Use hash tags (e.g. {user}.name) to
ensure related keys land in the same slot.
Cluster.transaction(cluster, [
["SET", "{user:1}.name", "Alice"],
["SET", "{user:1}.email", "alice@example.com"]
])@spec watch_transaction( GenServer.server(), [String.t()], (GenServer.server() -> [[String.t()]] | {:abort, term()}), keyword() ) :: {:ok, [term()]} | {:error, term()}
Executes a WATCH-based optimistic locking transaction in cluster mode.
All watched keys and all commands produced by the function must target
the same hash slot. Returns {:error, :cross_slot} if they don't.
Cluster.watch_transaction(cluster, ["{acct:1}.balance"], fn conn ->
{:ok, bal} = Redis.Connection.command(conn, ["GET", "{acct:1}.balance"])
new_bal = String.to_integer(bal) + 100
[["SET", "{acct:1}.balance", to_string(new_bal)]]
end)