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Class: ActionCable::Server::Base

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Instance Chain:
self, Connections, Broadcasting
Inherits: Object
Defined in: actioncable/lib/action_cable/server/base.rb

Overview

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 ::ActionCable::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.

Constant Summary

Connections - Included

BEAT_INTERVAL

Class Attribute Summary

Class Method Summary

Instance Attribute Summary

Instance Method Summary

Connections - Included

#add_connection, #connections, #open_connections_statistics, #remove_connection,
#setup_heartbeat_timer

WebSocket connection implementations differ on when they’ll mark a connection as stale.

Broadcasting - Included

#broadcast

Broadcast a hash directly to a named broadcasting.
#broadcaster_for

Returns a broadcaster for a named broadcasting that can be reused.

Constructor Details

.new(config: self.class.config) ⇒ Base

[ GitHub ] 

  


# File 'actioncable/lib/action_cable/server/base.rb', line 31



def initialize(config: self.class.config)
  @config = config
  @mutex = Monitor.new
  @remote_connections = @event_loop = @worker_pool = @pubsub = nil
end


  







Class Attribute Details



  

    .config   (rw)
  

  [ GitHub ]


  

  


# File 'actioncable/lib/action_cable/server/base.rb', line 22



cattr_accessor :config, instance_accessor: false, default: ActionCable::Server::Configuration.new


  







Class Method Details



  

    .logger  
  

  [ GitHub ]


  

  


# File 'actioncable/lib/action_cable/server/base.rb', line 26



def self.logger; config.logger; end


  







Instance Attribute Details



  

    #config   (readonly)
  

  [ GitHub ]


  

  


# File 'actioncable/lib/action_cable/server/base.rb', line 24



attr_reader :config


  








  

    #logger   (readonly)
  

  [ GitHub ]


  

  


# File 'actioncable/lib/action_cable/server/base.rb', line 27



delegate :logger, to: :config


  








  

    #mutex   (readonly)
  

  [ GitHub ]


  

  


# File 'actioncable/lib/action_cable/server/base.rb', line 29



attr_reader :mutex


  







Instance Method Details



  

    #call(env)  
  



  

    

Called by ::Rack to set up the server.


  



  [ GitHub ]


  

  


# File 'actioncable/lib/action_cable/server/base.rb', line 38



def call(env)
  return config.health_check_application.call(env) if env["PATH_INFO"] == config.health_check_path
  setup_heartbeat_timer
  config.connection_class.call.new(self, env).process
end


  








  

    #connection_identifiers  
  



  

    

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


  



  [ GitHub ]


  

  


# File 'actioncable/lib/action_cable/server/base.rb', line 102



def connection_identifiers
  config.connection_class.call.identifiers
end


  








  

    #disconnect(identifiers)  
  



  

    

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


  



  [ GitHub ]


  

  


# File 'actioncable/lib/action_cable/server/base.rb', line 46



def disconnect(identifiers)
  remote_connections.where(identifiers).disconnect
end


  








  

    #event_loop  
  

  [ GitHub ]


  

  


# File 'actioncable/lib/action_cable/server/base.rb', line 71



def event_loop
  @event_loop || @mutex.synchronize { @event_loop ||= ActionCable::Connection::StreamEventLoop.new }
end


  








  

    #pubsub  
  



  

    

Adapter used for all streams/broadcasting.


  



  [ GitHub ]


  

  


# File 'actioncable/lib/action_cable/server/base.rb', line 96



def pubsub
  @pubsub || @mutex.synchronize { @pubsub ||= config.pubsub_adapter.new(self) }
end


  








  

    #remote_connections  
  



  

    

Gateway to ::ActionCable::RemoteConnections. See that class for details.


  



  [ GitHub ]


  

  


# File 'actioncable/lib/action_cable/server/base.rb', line 67



def remote_connections
  @remote_connections || @mutex.synchronize { @remote_connections ||= RemoteConnections.new(self) }
end


  








  

    #restart  
  

  [ GitHub ]


  

  


# File 'actioncable/lib/action_cable/server/base.rb', line 50



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  
  



  

    

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.


  



  [ GitHub ]


  

  


# File 'actioncable/lib/action_cable/server/base.rb', line 91



def worker_pool
  @worker_pool || @mutex.synchronize { @worker_pool ||= ActionCable::Server::Worker.new(max_size: config.worker_pool_size) }
end