Revert "Eliminate the EventMachine dependency"

16 files changed, 46 insertions, 349 deletions

diff --git a/actioncable/lib/action_cable/channel/periodic_timers.rb b/actioncable/lib/action_cable/channel/periodic_timers.rb
index 56597d02d7..7f0fb37afc 100644
--- a/actioncable/lib/action_cable/channel/periodic_timers.rb
+++ b/actioncable/lib/action_cable/channel/periodic_timers.rb
@@ -27,14 +27,14 @@ module ActionCable
 
         def start_periodic_timers
           self.class.periodic_timers.each do |callback, options|
-            active_periodic_timers << Concurrent::TimerTask.new(execution_interval: options[:every]) do
+            active_periodic_timers << EventMachine::PeriodicTimer.new(options[:every]) do
               connection.worker_pool.async_run_periodic_timer(self, callback)
             end
           end
         end
 
         def stop_periodic_timers
-          active_periodic_timers.each { |timer| timer.shutdown }
+          active_periodic_timers.each { |timer| timer.cancel }
         end
     end
   end
diff --git a/actioncable/lib/action_cable/channel/streams.rb b/actioncable/lib/action_cable/channel/streams.rb
index a26373e387..e2876ef6fa 100644
--- a/actioncable/lib/action_cable/channel/streams.rb
+++ b/actioncable/lib/action_cable/channel/streams.rb
@@ -75,7 +75,7 @@ module ActionCable
         callback ||= default_stream_callback(broadcasting)
         streams << [ broadcasting, callback ]
 
-        Concurrent.global_io_executor.post do
+        EM.next_tick do
           pubsub.subscribe(broadcasting, callback, lambda do
             transmit_subscription_confirmation
             logger.info "#{self.class.name} is streaming from #{broadcasting}"
diff --git a/actioncable/lib/action_cable/connection.rb b/actioncable/lib/action_cable/connection.rb
index 902efb07e2..b672e00682 100644
--- a/actioncable/lib/action_cable/connection.rb
+++ b/actioncable/lib/action_cable/connection.rb
@@ -5,15 +5,12 @@ module ActionCable
     eager_autoload do
       autoload :Authorization
       autoload :Base
-      autoload :ClientSocket
       autoload :Identification
       autoload :InternalChannel
       autoload :MessageBuffer
-      autoload :Stream
-      autoload :StreamEventLoop
+      autoload :WebSocket
       autoload :Subscriptions
       autoload :TaggedLoggerProxy
-      autoload :WebSocket
     end
   end
 end
diff --git a/actioncable/lib/action_cable/connection/base.rb b/actioncable/lib/action_cable/connection/base.rb
index 0016d1a1a4..bb8850aaa0 100644
--- a/actioncable/lib/action_cable/connection/base.rb
+++ b/actioncable/lib/action_cable/connection/base.rb
@@ -49,14 +49,14 @@ module ActionCable
       include Authorization
 
       attr_reader :server, :env, :subscriptions, :logger
-      delegate :stream_event_loop, :worker_pool, :pubsub, to: :server
+      delegate :worker_pool, :pubsub, to: :server
 
       def initialize(server, env)
         @server, @env = server, env
 
         @logger = new_tagged_logger
 
-        @websocket      = ActionCable::Connection::WebSocket.new(env, self, stream_event_loop)
+        @websocket      = ActionCable::Connection::WebSocket.new(env)
         @subscriptions  = ActionCable::Connection::Subscriptions.new(self)
         @message_buffer = ActionCable::Connection::MessageBuffer.new(self)
 
@@ -70,6 +70,10 @@ module ActionCable
         logger.info started_request_message
 
         if websocket.possible? && allow_request_origin?
+          websocket.on(:open)    { |event| send_async :on_open   }
+          websocket.on(:message) { |event| on_message event.data }
+          websocket.on(:close)   { |event| send_async :on_close  }
+
           respond_to_successful_request
         else
           respond_to_invalid_request
@@ -117,22 +121,6 @@ module ActionCable
         transmit ActiveSupport::JSON.encode(identifier: ActionCable::INTERNAL[:identifiers][:ping], message: Time.now.to_i)
       end
 
-      def on_open # :nodoc:
-        send_async :handle_open
-      end
-
-      def on_message(message) # :nodoc:
-        message_buffer.append message
-      end
-
-      def on_error(message) # :nodoc:
-        # ignore
-      end
-
-      def on_close # :nodoc:
-        send_async :handle_close
-      end
-
       protected
         # The request that initiated the WebSocket connection is available here. This gives access to the environment, cookies, etc.
         def request
@@ -151,7 +139,7 @@ module ActionCable
         attr_reader :message_buffer
 
       private
-        def handle_open
+        def on_open
           connect if respond_to?(:connect)
           subscribe_to_internal_channel
           beat
@@ -162,7 +150,11 @@ module ActionCable
           respond_to_invalid_request
         end
 
-        def handle_close
+        def on_message(message)
+          message_buffer.append message
+        end
+
+        def on_close
           logger.info finished_request_message
 
           server.remove_connection(self)
diff --git a/actioncable/lib/action_cable/connection/client_socket.rb b/actioncable/lib/action_cable/connection/client_socket.rb
deleted file mode 100644
index 62dd753646..0000000000
--- a/actioncable/lib/action_cable/connection/client_socket.rb
+++ /dev/null
@@ -1,152 +0,0 @@
-require 'websocket/driver'
-
-module ActionCable
-  module Connection
-    #--
-    # This class is heavily based on faye-websocket-ruby
-    #
-    # Copyright (c) 2010-2015 James Coglan
-    class ClientSocket # :nodoc:
-      def self.determine_url(env)
-        scheme = secure_request?(env) ? 'wss:' : 'ws:'
-        "#{ scheme }//#{ env['HTTP_HOST'] }#{ env['REQUEST_URI'] }"
-      end
-
-      def self.secure_request?(env)
-        return true if env['HTTPS'] == 'on'
-        return true if env['HTTP_X_FORWARDED_SSL'] == 'on'
-        return true if env['HTTP_X_FORWARDED_SCHEME'] == 'https'
-        return true if env['HTTP_X_FORWARDED_PROTO'] == 'https'
-        return true if env['rack.url_scheme'] == 'https'
-
-        return false
-      end
-
-      CONNECTING = 0
-      OPEN       = 1
-      CLOSING    = 2
-      CLOSED     = 3
-
-      attr_reader :env, :url
-
-      def initialize(env, event_target, stream_event_loop)
-        @env               = env
-        @event_target      = event_target
-        @stream_event_loop = stream_event_loop
-
-        @url = ClientSocket.determine_url(@env)
-
-        @driver = @driver_started = nil
-
-        @ready_state = CONNECTING
-
-        # The driver calls +env+, +url+, and +write+
-        @driver = ::WebSocket::Driver.rack(self)
-
-        @driver.on(:open)    { |e| open }
-        @driver.on(:message) { |e| receive_message(e.data) }
-        @driver.on(:close)   { |e| begin_close(e.reason, e.code) }
-        @driver.on(:error)   { |e| emit_error(e.message) }
-
-        @stream = ActionCable::Connection::Stream.new(@stream_event_loop, self)
-
-        if callback = @env['async.callback']
-          callback.call([101, {}, @stream])
-        end
-      end
-
-      def start_driver
-        return if @driver.nil? || @driver_started
-        @driver_started = true
-        @driver.start
-      end
-
-      def rack_response
-        start_driver
-        [ -1, {}, [] ]
-      end
-
-      def write(data)
-        @stream.write(data)
-      end
-
-      def transmit(message)
-        return false if @ready_state > OPEN
-        case message
-          when Numeric then @driver.text(message.to_s)
-          when String  then @driver.text(message)
-          when Array   then @driver.binary(message)
-          else false
-        end
-      end
-
-      def close(code = nil, reason = nil)
-        code   ||= 1000
-        reason ||= ''
-
-        unless code == 1000 or (code >= 3000 and code <= 4999)
-          raise ArgumentError, "Failed to execute 'close' on WebSocket: " +
-                               "The code must be either 1000, or between 3000 and 4999. " +
-                               "#{code} is neither."
-        end
-
-        @ready_state = CLOSING unless @ready_state == CLOSED
-        @driver.close(reason, code)
-      end
-
-      def parse(data)
-        @driver.parse(data)
-      end
-
-      def client_gone
-        finalize_close
-      end
-
-      def alive?
-        @ready_state == OPEN
-      end
-
-      private
-        def open
-          return unless @ready_state == CONNECTING
-          @ready_state = OPEN
-
-          @event_target.on_open
-        end
-
-        def receive_message(data)
-          return unless @ready_state == OPEN
-
-          @event_target.on_message(data)
-        end
-
-        def emit_error(message)
-          return if @ready_state >= CLOSING
-
-          @event_target.on_error(message)
-        end
-
-        def begin_close(reason, code)
-          return if @ready_state == CLOSED
-          @ready_state = CLOSING
-          @close_params = [reason, code]
-
-          if @stream
-            @stream.shutdown
-          else
-            finalize_close
-          end
-        end
-
-        def finalize_close
-          return if @ready_state == CLOSED
-          @ready_state = CLOSED
-
-          reason = @close_params ? @close_params[0] : ''
-          code   = @close_params ? @close_params[1] : 1006
-
-          @event_target.on_close(code, reason)
-        end
-    end
-  end
-end
diff --git a/actioncable/lib/action_cable/connection/internal_channel.rb b/actioncable/lib/action_cable/connection/internal_channel.rb
index 27826792b3..54ed7672d2 100644
--- a/actioncable/lib/action_cable/connection/internal_channel.rb
+++ b/actioncable/lib/action_cable/connection/internal_channel.rb
@@ -15,14 +15,14 @@ module ActionCable
             @_internal_subscriptions ||= []
             @_internal_subscriptions << [ internal_channel, callback ]
 
-            Concurrent.global_io_executor.post { pubsub.subscribe(internal_channel, callback) }
+            EM.next_tick { pubsub.subscribe(internal_channel, callback) }
             logger.info "Registered connection (#{connection_identifier})"
           end
         end
 
         def unsubscribe_from_internal_channel
           if @_internal_subscriptions.present?
-            @_internal_subscriptions.each { |channel, callback| Concurrent.global_io_executor.post { pubsub.unsubscribe(channel, callback) } }
+            @_internal_subscriptions.each { |channel, callback| EM.next_tick { pubsub.unsubscribe(channel, callback) } }
           end
         end
 
diff --git a/actioncable/lib/action_cable/connection/stream.rb b/actioncable/lib/action_cable/connection/stream.rb
deleted file mode 100644
index ace250cd16..0000000000
--- a/actioncable/lib/action_cable/connection/stream.rb
+++ /dev/null
@@ -1,59 +0,0 @@
-module ActionCable
-  module Connection
-    #--
-    # This class is heavily based on faye-websocket-ruby
-    #
-    # Copyright (c) 2010-2015 James Coglan
-    class Stream
-      def initialize(event_loop, socket)
-        @event_loop    = event_loop
-        @socket_object = socket
-        @stream_send   = socket.env['stream.send']
-
-        @rack_hijack_io = nil
-
-        hijack_rack_socket
-      end
-
-      def each(&callback)
-        @stream_send ||= callback
-      end
-
-      def close
-        shutdown
-        @socket_object.client_gone
-      end
-
-      def shutdown
-        clean_rack_hijack
-      end
-
-      def write(data)
-        return @rack_hijack_io.write(data) if @rack_hijack_io
-        return @stream_send.call(data) if @stream_send
-      rescue EOFError
-        @socket_object.client_gone
-      end
-
-      def receive(data)
-        @socket_object.parse(data)
-      end
-
-      private
-        def hijack_rack_socket
-          return unless @socket_object.env['rack.hijack']
-
-          @socket_object.env['rack.hijack'].call
-          @rack_hijack_io = @socket_object.env['rack.hijack_io']
-
-          @event_loop.attach(@rack_hijack_io, self)
-        end
-
-        def clean_rack_hijack
-          return unless @rack_hijack_io
-          @event_loop.detach(@rack_hijack_io, self)
-          @rack_hijack_io = nil
-        end
-    end
-  end
-end
diff --git a/actioncable/lib/action_cable/connection/stream_event_loop.rb b/actioncable/lib/action_cable/connection/stream_event_loop.rb
deleted file mode 100644
index f773814973..0000000000
--- a/actioncable/lib/action_cable/connection/stream_event_loop.rb
+++ /dev/null
@@ -1,68 +0,0 @@
-require 'nio'
-
-module ActionCable
-  module Connection
-    class StreamEventLoop
-      def initialize
-        @nio = NIO::Selector.new
-        @map = {}
-        @stopping = false
-        @todo = Queue.new
-
-        Thread.new do
-          Thread.current.abort_on_exception = true
-          run
-        end
-      end
-
-      def attach(io, stream)
-        @todo << lambda do
-          @map[io] = stream
-          @nio.register(io, :r)
-        end
-        @nio.wakeup
-      end
-
-      def detach(io, stream)
-        @todo << lambda do
-          @nio.deregister(io)
-          @map.delete io
-        end
-        @nio.wakeup
-      end
-
-      def stop
-        @stopping = true
-        @nio.wakeup
-      end
-
-      def run
-        loop do
-          if @stopping
-            @nio.close
-            break
-          end
-
-          until @todo.empty?
-            @todo.pop(true).call
-          end
-
-          if monitors = @nio.select
-            monitors.each do |monitor|
-              io = monitor.io
-              stream = @map[io]
-
-              begin
-                stream.receive io.read_nonblock(4096)
-              rescue IO::WaitReadable
-                next
-              rescue EOFError
-                stream.close
-              end
-            end
-          end
-        end
-      end
-    end
-  end
-end
diff --git a/actioncable/lib/action_cable/connection/web_socket.rb b/actioncable/lib/action_cable/connection/web_socket.rb
index 5e89fb9b72..670d5690ae 100644
--- a/actioncable/lib/action_cable/connection/web_socket.rb
+++ b/actioncable/lib/action_cable/connection/web_socket.rb
@@ -1,11 +1,13 @@
-require 'websocket/driver'
+require 'faye/websocket'
 
 module ActionCable
   module Connection
-    # Wrap the real socket to minimize the externally-presented API
+    # Decorate the Faye::WebSocket with helpers we need.
     class WebSocket
-      def initialize(env, event_target, stream_event_loop)
-        @websocket = ::WebSocket::Driver.websocket?(env) ? ClientSocket.new(env, event_target, stream_event_loop) : nil
+      delegate :rack_response, :close, :on, to: :websocket
+
+      def initialize(env)
+        @websocket = Faye::WebSocket.websocket?(env) ? Faye::WebSocket.new(env) : nil
       end
 
       def possible?
@@ -13,19 +15,11 @@ module ActionCable
       end
 
       def alive?
-        websocket && websocket.alive?
+        websocket && websocket.ready_state == Faye::WebSocket::API::OPEN
       end
 
       def transmit(data)
-        websocket.transmit data
-      end
-
-      def close
-        websocket.close
-      end
-
-      def rack_response
-        websocket.rack_response
+        websocket.send data
       end
 
       protected
diff --git a/actioncable/lib/action_cable/process/logging.rb b/actioncable/lib/action_cable/process/logging.rb
new file mode 100644
index 0000000000..dce637b3ca
--- /dev/null
+++ b/actioncable/lib/action_cable/process/logging.rb
@@ -0,0 +1,7 @@
+require 'action_cable/server'
+require 'eventmachine'
+
+EM.error_handler do |e|
+  puts "Error raised inside the event loop: #{e.message}"
+  puts e.backtrace.join("\n")
+end
diff --git a/actioncable/lib/action_cable/server.rb b/actioncable/lib/action_cable/server.rb
index bd6a3826a3..a2a89d5f1e 100644
--- a/actioncable/lib/action_cable/server.rb
+++ b/actioncable/lib/action_cable/server.rb
@@ -1,3 +1,7 @@
+require 'eventmachine'
+EventMachine.epoll  if EventMachine.epoll?
+EventMachine.kqueue if EventMachine.kqueue?
+
 module ActionCable
   module Server
     extend ActiveSupport::Autoload
diff --git a/actioncable/lib/action_cable/server/base.rb b/actioncable/lib/action_cable/server/base.rb
index b00abd208c..3385a4c9f3 100644
--- a/actioncable/lib/action_cable/server/base.rb
+++ b/actioncable/lib/action_cable/server/base.rb
@@ -32,10 +32,6 @@ module ActionCable
         @remote_connections ||= RemoteConnections.new(self)
       end
 
-      def stream_event_loop
-        @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)
diff --git a/actioncable/lib/action_cable/server/connections.rb b/actioncable/lib/action_cable/server/connections.rb
index 8671dd5ebd..47dcea8c20 100644
--- a/actioncable/lib/action_cable/server/connections.rb
+++ b/actioncable/lib/action_cable/server/connections.rb
@@ -22,9 +22,11 @@ module ActionCable
       # then can't rely on being able to receive and send to it. So there's a 3 second heartbeat running on all connections. If the beat fails, we automatically
       # disconnect.
       def setup_heartbeat_timer
-        @heartbeat_timer ||= Concurrent::TimerTask.new(execution_interval: BEAT_INTERVAL) do
-          Concurrent.global_io_executor.post { connections.map(&:beat) }
-        end.tap(&:execute)
+        EM.next_tick do
+          @heartbeat_timer ||= EventMachine.add_periodic_timer(BEAT_INTERVAL) do
+            EM.next_tick { connections.map(&:beat) }
+          end
+        end
       end
 
       def open_connections_statistics
diff --git a/actioncable/lib/action_cable/subscription_adapter/async.rb b/actioncable/lib/action_cable/subscription_adapter/async.rb
index c88b03947a..85d4892e4c 100644
--- a/actioncable/lib/action_cable/subscription_adapter/async.rb
+++ b/actioncable/lib/action_cable/subscription_adapter/async.rb
@@ -10,11 +10,11 @@ module ActionCable
 
         class AsyncSubscriberMap < SubscriberMap
           def add_subscriber(*)
-            Concurrent.global_io_executor.post { super }
+            ::EM.next_tick { super }
           end
 
           def invoke_callback(*)
-            Concurrent.global_io_executor.post { super }
+            ::EM.next_tick { super }
           end
         end
     end
diff --git a/actioncable/lib/action_cable/subscription_adapter/postgresql.rb b/actioncable/lib/action_cable/subscription_adapter/postgresql.rb
index 3ce1bbed68..78f8aeb599 100644
--- a/actioncable/lib/action_cable/subscription_adapter/postgresql.rb
+++ b/actioncable/lib/action_cable/subscription_adapter/postgresql.rb
@@ -63,7 +63,7 @@ module ActionCable
                     case action
                     when :listen
                       pg_conn.exec("LISTEN #{pg_conn.escape_identifier channel}")
-                      Concurrent.global_io_executor << callback if callback
+                      ::EM.next_tick(&callback) if callback
                     when :unlisten
                       pg_conn.exec("UNLISTEN #{pg_conn.escape_identifier channel}")
                     when :shutdown
@@ -93,7 +93,7 @@ module ActionCable
           end
 
           def invoke_callback(*)
-            Concurrent.global_io_executor.post { super }
+            ::EM.next_tick { super }
           end
         end
     end
diff --git a/actioncable/lib/action_cable/subscription_adapter/redis.rb b/actioncable/lib/action_cable/subscription_adapter/redis.rb
index a035e3988d..3b86354621 100644
--- a/actioncable/lib/action_cable/subscription_adapter/redis.rb
+++ b/actioncable/lib/action_cable/subscription_adapter/redis.rb
@@ -1,18 +1,11 @@
-require 'thread'
-
 gem 'em-hiredis', '~> 0.3.0'
 gem 'redis', '~> 3.0'
 require 'em-hiredis'
 require 'redis'
 
-EventMachine.epoll  if EventMachine.epoll?
-EventMachine.kqueue if EventMachine.kqueue?
-
 module ActionCable
   module SubscriptionAdapter
     class Redis < Base # :nodoc:
-      @@mutex = Mutex.new
-
       def broadcast(channel, payload)
         redis_connection_for_broadcasts.publish(channel, payload)
       end
@@ -34,7 +27,6 @@ module ActionCable
 
       private
         def redis_connection_for_subscriptions
-          ensure_reactor_running
           @redis_connection_for_subscriptions ||= EM::Hiredis.connect(@server.config.cable[:url]).tap do |redis|
             redis.on(:reconnect_failed) do
               @logger.info "[ActionCable] Redis reconnect failed."
@@ -45,14 +37,6 @@ module ActionCable
         def redis_connection_for_broadcasts
           @redis_connection_for_broadcasts ||= ::Redis.new(@server.config.cable)
         end
-
-        def ensure_reactor_running
-          return if EventMachine.reactor_running?
-          @@mutex.synchronize do
-            Thread.new { EventMachine.run } unless EventMachine.reactor_running?
-            Thread.pass until EventMachine.reactor_running?
-          end
-        end
     end
   end
 end