GenServer managing a single TCP/TLS connection to a Redis server.
Handles the socket lifecycle, RESP3 handshake, command sending/receiving, pipeline buffering, and automatic reconnection with exponential backoff.
Options
:host- Redis host (default: "127.0.0.1"):port- Redis port (default: 6379):password- auth password (string or{mod, fun, args}MFA tuple):username- auth username (Redis 6+ ACL):database- database number to SELECT:ssl- enable TLS (default: false):ssl_opts- SSL options list:socket- Unix domain socket path (overrides host/port):name- GenServer name registration:sync_connect- connect synchronously in init (default: true):backoff_initial- initial reconnect delay ms (default: 500):backoff_max- max reconnect delay ms (default: 30_000):protocol-:resp3or:resp2(default::resp3):client_name- CLIENT SETNAME value:timeout- command timeout ms (default: 5_000):credential_provider-{module, opts}implementingRedis.CredentialProviderfor dynamic/rotating credentials (e.g., cloud IAM tokens). When set,:passwordand:usernameare ignored.:exit_on_disconnection- exit instead of reconnecting (default: false):hibernate_after- idle ms before hibernation (default: nil):hooks- list ofRedis.Hookmodules for command middleware (default: [])
A Redis URI string may be passed as the first (sole) argument:
Connection.start_link("redis://:secret@localhost:6380/2")Summary
Functions
Returns a child spec for supervision trees.
Sends a command without waiting for a reply. Uses CLIENT REPLY OFF/ON internally.
Sends multiple commands without waiting for replies.
Executes a WATCH-based optimistic locking transaction.
Functions
Returns a child spec for supervision trees.
children = [
{Redis.Connection, port: 6379, name: :redis}
]@spec noreply_command(GenServer.server(), [String.t()], keyword()) :: :ok | {:error, term()}
Sends a command without waiting for a reply. Uses CLIENT REPLY OFF/ON internally.
@spec noreply_pipeline(GenServer.server(), [[String.t()]], keyword()) :: :ok | {:error, term()}
Sends multiple commands without waiting for replies.
@spec start_link(keyword() | String.t()) :: GenServer.on_start()
@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.
Watches the given keys, calls fun with the connection to read current
values and compute commands, then executes those commands in a MULTI/EXEC
block. If any watched key was modified by another client, EXEC returns nil
and the function is retried (up to :max_retries times, default 3).
The function fun receives the connection and must return either:
- a list of commands to execute in the transaction
{:abort, reason}to abort without executing
Returns {:ok, results} on success, {:error, :watch_conflict} if all
retries are exhausted, or {:error, reason} on other failures.
Example
Redis.Connection.watch_transaction(conn, ["account:1", "account:2"], fn conn ->
{:ok, bal1} = Redis.Connection.command(conn, ["GET", "account:1"])
{:ok, bal2} = Redis.Connection.command(conn, ["GET", "account:2"])
amount = 100
new1 = String.to_integer(bal1) - amount
new2 = String.to_integer(bal2) + amount
[
["SET", "account:1", to_string(new1)],
["SET", "account:2", to_string(new2)]
]
end)