Behaviour for Redis command hooks (middleware).

Hooks allow you to intercept commands before they are sent to Redis and inspect or transform results after they return. Common uses include logging, metrics, command rewriting, and access control.

Defining a hook

Implement the callbacks you need and use Redis.Hook to get defaults for the rest:

defmodule MyApp.LoggingHook do
  use Redis.Hook

  @impl Redis.Hook
  def before_command(command, _context) do
    Logger.info("redis command: #{inspect(command)}")
    {:ok, command}
  end
end

Using hooks

Pass hooks when starting a connection:

Redis.Connection.start_link(
  port: 6379,
  hooks: [MyApp.LoggingHook, MyApp.MetricsHook]
)

before_* hooks run in the order given. after_* hooks run in reverse order (outermost hook sees the final result last, like middleware).

If any before_* hook returns {:error, reason}, the command is short-circuited and the error is returned to the caller without reaching Redis.