class ActionCable::Server::Base

Parent:: Object
Included modules:: ActionCable::Server::Broadcasting

A singleton ActionCable::Server instance is available via ActionCable.server. It's used by the Rack process that starts the Action Cable server, but is also used by the user to reach the RemoteConnections object, which is used for finding and disconnecting connections across all servers.

Also, this is the server instance used for broadcasting. See Broadcasting for more information.

Attributes

config[R]

mutex[R]

Public Class Methods

logger() Show source

# File actioncable/lib/action_cable/server/base.rb, line 19
def self.logger; config.logger; end

new(config: self.class.config) Show source

# File actioncable/lib/action_cable/server/base.rb, line 24
def initialize(config: self.class.config)
  @config = config
  @mutex = Monitor.new
  @remote_connections = @event_loop = @worker_pool = @pubsub = nil
end

Public Instance Methods

call(env) Show source

# File actioncable/lib/action_cable/server/base.rb, line 31
def call(env)
  setup_heartbeat_timer
  config.connection_class.call.new(self, env).process
end

Called by Rack to setup the server.

connection_identifiers() Show source

# File actioncable/lib/action_cable/server/base.rb, line 87
def connection_identifiers
  config.connection_class.call.identifiers
end

All of the identifiers applied to the connection class associated with this server.

disconnect(identifiers) Show source

# File actioncable/lib/action_cable/server/base.rb, line 37
def disconnect(identifiers)
  remote_connections.where(identifiers).disconnect
end

Disconnect all the connections identified by identifiers on this server or any others via RemoteConnections.

event_loop() Show source

# File actioncable/lib/action_cable/server/base.rb, line 62
def event_loop
  @event_loop || @mutex.synchronize { @event_loop ||= ActionCable::Connection::StreamEventLoop.new }
end

pubsub() Show source

# File actioncable/lib/action_cable/server/base.rb, line 82
def pubsub
  @pubsub || @mutex.synchronize { @pubsub ||= config.pubsub_adapter.new(self) }
end

Adapter used for all streams/broadcasting.

remote_connections() Show source

# File actioncable/lib/action_cable/server/base.rb, line 58
def remote_connections
  @remote_connections || @mutex.synchronize { @remote_connections ||= RemoteConnections.new(self) }
end

Gateway to RemoteConnections. See that class for details.

restart() Show source

# File actioncable/lib/action_cable/server/base.rb, line 41
def restart
  connections.each do |connection|
    connection.close(reason: ActionCable::INTERNAL[:disconnect_reasons][:server_restart])
  end

  @mutex.synchronize do
    # Shutdown the worker pool
    @worker_pool.halt if @worker_pool
    @worker_pool = nil

    # Shutdown the pub/sub adapter
    @pubsub.shutdown if @pubsub
    @pubsub = nil
  end
end

worker_pool() Show source

# File actioncable/lib/action_cable/server/base.rb, line 77
def worker_pool
  @worker_pool || @mutex.synchronize { @worker_pool ||= ActionCable::Server::Worker.new(max_size: config.worker_pool_size) }
end

The worker pool is where we run connection callbacks and channel actions. We do as little as possible on the server's main thread. The worker pool is an executor service that's backed by a pool of threads working from a task queue. The thread pool size maxes out at 4 worker threads by default. Tune the size yourself with config.action_cable.worker_pool_size.

Using Active Record, Redis, etc within your channel actions means you'll get a separate connection from each thread in the worker pool. Plan your deployment accordingly: 5 servers each running 5 Puma workers each running an 8-thread worker pool means at least 200 database connections.

Also, ensure that your database connection pool size is as least as large as your worker pool size. Otherwise, workers may oversubscribe the database connection pool and block while they wait for other workers to release their connections. Use a smaller worker pool or a larger database connection pool instead.