2 files changed, 27 insertions, 18 deletions

diff --git a/actioncable/lib/action_cable/server/base.rb b/actioncable/lib/action_cable/server/base.rb
index b00abd208c..fe48c112df 100644
--- a/actioncable/lib/action_cable/server/base.rb
+++ b/actioncable/lib/action_cable/server/base.rb
@@ -1,3 +1,5 @@
+require 'thread'
+
 module ActionCable
   module Server
     # A singleton ActionCable::Server instance is available via ActionCable.server. It's used by the rack process that starts the cable server, but
@@ -13,7 +15,12 @@ module ActionCable
       def self.logger; config.logger; end
       delegate :logger, to: :config
 
+      attr_reader :mutex
+
       def initialize
+        @mutex = Mutex.new
+
+        @remote_connections = @stream_event_loop = @worker_pool = @channel_classes = @pubsub = nil
       end
 
       # Called by rack to setup the server.
@@ -29,29 +36,31 @@ module ActionCable
 
       # Gateway to RemoteConnections. See that class for details.
       def remote_connections
-        @remote_connections ||= RemoteConnections.new(self)
+        @remote_connections || @mutex.synchronize { @remote_connections ||= RemoteConnections.new(self) }
       end
 
       def stream_event_loop
-        @stream_event_loop ||= ActionCable::Connection::StreamEventLoop.new
+        @stream_event_loop || @mutex.synchronize { @stream_event_loop ||= ActionCable::Connection::StreamEventLoop.new }
       end
 
       # The thread worker pool for handling all the connection work on this server. Default size is set by config.worker_pool_size.
       def worker_pool
-        @worker_pool ||= ActionCable::Server::Worker.new(max_size: config.worker_pool_size)
+        @worker_pool || @mutex.synchronize { @worker_pool ||= ActionCable::Server::Worker.new(max_size: config.worker_pool_size) }
       end
 
       # Requires and returns a hash of all the channel class constants keyed by name.
       def channel_classes
-        @channel_classes ||= begin
-          config.channel_paths.each { |channel_path| require channel_path }
-          config.channel_class_names.each_with_object({}) { |name, hash| hash[name] = name.constantize }
+        @channel_classes || @mutex.synchronize do
+          @channel_classes ||= begin
+            config.channel_paths.each { |channel_path| require channel_path }
+            config.channel_class_names.each_with_object({}) { |name, hash| hash[name] = name.constantize }
+          end
         end
       end
 
       # Adapter used for all streams/broadcasting.
       def pubsub
-        @pubsub ||= config.pubsub_adapter.new(self)
+        @pubsub || @mutex.synchronize { @pubsub ||= config.pubsub_adapter.new(self) }
       end
 
       # All the identifiers applied to the connection class associated with this server.
diff --git a/actioncable/lib/action_cable/server/broadcasting.rb b/actioncable/lib/action_cable/server/broadcasting.rb
index 4a26ed9269..7e8aef45f4 100644
--- a/actioncable/lib/action_cable/server/broadcasting.rb
+++ b/actioncable/lib/action_cable/server/broadcasting.rb
@@ -4,19 +4,19 @@ module ActionCable
     # broadcastings are streamed directly to the clients subscribed to the named broadcasting. Let's explain with a full-stack example:
     #
     #   class WebNotificationsChannel < ApplicationCable::Channel
-    #      def subscribed
-    #        stream_from "web_notifications_#{current_user.id}"
-    #      end
-    #    end
+    #     def subscribed
+    #       stream_from "web_notifications_#{current_user.id}"
+    #     end
+    #   end
     #
-    #    # Somewhere in your app this is called, perhaps from a NewCommentJob
-    #    ActionCable.server.broadcast \
-    #      "web_notifications_1", { title: 'New things!', body: 'All shit fit for print' }
+    #   # Somewhere in your app this is called, perhaps from a NewCommentJob
+    #   ActionCable.server.broadcast \
+    #     "web_notifications_1", { title: "New things!", body: "All that's fit for print" }
     #
-    #    # Client-side coffescript, which assumes you've already requested the right to send web notifications
-    #    App.cable.subscriptions.create "WebNotificationsChannel",
-    #      received: (data) ->
-    #        new Notification data['title'], body: data['body']
+    #   # Client-side CoffeeScript, which assumes you've already requested the right to send web notifications
+    #   App.cable.subscriptions.create "WebNotificationsChannel",
+    #     received: (data) ->
+    #       new Notification data['title'], body: data['body']
     module Broadcasting
       # Broadcast a hash directly to a named <tt>broadcasting</tt>. It'll automatically be JSON encoded.
       def broadcast(broadcasting, message)