Note: ActionCable is experimental, and enabling it in the in-app mode also enables experimental features.

This service is disabled by default. To enable:

actioncable['enable'] = true

By default, ActionCable is run as a separate Puma server that only handles websocket connections. To run ActionCable on the existing Puma web server:

actioncable['in_app'] = true

Note: Action Cable is currently not supported for the Unicorn web server in GitLab.

Configuring the worker pool size

ActionCable uses a separate thread pool to handle the websocket connections. The number of threads can be configured using the actioncable['worker_pool_size'] option.