class ActionCable::Server::Base

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

mutex[R]

Public Class Methods

logger() click to toggle source
# File lib/action_cable/server/base.rb, line 17
def self.logger; config.logger; end
new() click to toggle source
# File lib/action_cable/server/base.rb, line 22
def initialize
  @mutex = Monitor.new
  @remote_connections = @event_loop = @worker_pool = @pubsub = nil
end

Public Instance Methods

call(env) click to toggle source

Called by Rack to setup the server.

# File lib/action_cable/server/base.rb, line 28
def call(env)
  setup_heartbeat_timer
  config.connection_class.call.new(self, env).process
end
connection_identifiers() click to toggle source

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

# File lib/action_cable/server/base.rb, line 82
def connection_identifiers
  config.connection_class.call.identifiers
end
disconnect(identifiers) click to toggle source

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

# File lib/action_cable/server/base.rb, line 34
def disconnect(identifiers)
  remote_connections.where(identifiers).disconnect
end
event_loop() click to toggle source
# File lib/action_cable/server/base.rb, line 57
def event_loop
  @event_loop || @mutex.synchronize { @event_loop ||= ActionCable::Connection::StreamEventLoop.new }
end
pubsub() click to toggle source

Adapter used for all streams/broadcasting.

# File lib/action_cable/server/base.rb, line 77
def pubsub
  @pubsub || @mutex.synchronize { @pubsub ||= config.pubsub_adapter.new(self) }
end
remote_connections() click to toggle source

Gateway to RemoteConnections. See that class for details.

# File lib/action_cable/server/base.rb, line 53
def remote_connections
  @remote_connections || @mutex.synchronize { @remote_connections ||= RemoteConnections.new(self) }
end
restart() click to toggle source
# File lib/action_cable/server/base.rb, line 38
def restart
  connections.each(&:close)

  @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() click to toggle source

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.

# File lib/action_cable/server/base.rb, line 72
def worker_pool
  @worker_pool || @mutex.synchronize { @worker_pool ||= ActionCable::Server::Worker.new(max_size: config.worker_pool_size) }
end