diff --git a/app/controllers/submissions_controller.rb b/app/controllers/submissions_controller.rb
index f26a1b2f..ac8f6560 100644
--- a/app/controllers/submissions_controller.rb
+++ b/app/controllers/submissions_controller.rb
@@ -142,7 +142,7 @@ class SubmissionsController < ApplicationController
     @waiting_for_container_time = Time.zone.now - @container_request_time
     @execution_request_time = Time.zone.now
 
-    socket.on :message do |data|
+    socket.on :output do |data|
       Rails.logger.info("#{Time.zone.now.getutc}: Docker sending: #{data}")
       handle_message(data, tubesock)
     end
diff --git a/app/models/submission.rb b/app/models/submission.rb
index eb9b7c47..3c590389 100644
--- a/app/models/submission.rb
+++ b/app/models/submission.rb
@@ -146,23 +146,23 @@ class Submission < ApplicationRecord
         score_command = command_for execution_environment.test_command, file.name_with_extension
         stdout = ""
         stderr = ""
-        exit_code = 0
+        exit_code = 1 # default to error
         container.execute_interactively(score_command) do |container, socket|
-          socket.on :stderr do
-            |data| stderr << data
+          socket.on :stderr do |data|
+            stderr << data
           end
-          socket.on :stdout do
-            |data| stdout << data
+          socket.on :stdout do |data|
+            stdout << data
           end
-          socket.on :close do |_exit_code|
+          socket.on :exit do |_exit_code|
             exit_code = _exit_code
             EventMachine.stop_event_loop
           end
         end
         output = {
           file_role: file.role,
-          waiting_for_container_time: 1.second, # TODO
-          container_execution_time: 1.second, # TODO
+          waiting_for_container_time: 1, # TODO
+          container_execution_time: 1, # TODO
           status: (exit_code == 0) ? :ok : :failed,
           stdout: stdout,
           stderr: stderr,
diff --git a/lib/container.rb b/lib/container.rb
index fee25f41..a34cc53f 100644
--- a/lib/container.rb
+++ b/lib/container.rb
@@ -3,7 +3,7 @@
 require 'container_connection'
 
 class Container
-  BASE_URL = "http://192.168.178.53:5000"
+  BASE_URL = CodeOcean::Config.new(:code_ocean).read[:container_management][:url]
 
   def initialize(execution_environment, time_limit = nil)
     url = "#{BASE_URL}/execution-environments/#{execution_environment.id}/containers/create"
@@ -40,7 +40,6 @@ class Container
   def execute_interactively(command)
     websocket_url = execute_command(command)[:websocket_url]
     EventMachine.run do
-      #socket = Faye::WebSocket::Client.new(websocket_url, [], ping: 0.1)
       socket = ContainerConnection.new(websocket_url)
       yield(self, socket) if block_given?
     end
diff --git a/lib/container_connection.rb b/lib/container_connection.rb
index fd51775c..f48c1b28 100644
--- a/lib/container_connection.rb
+++ b/lib/container_connection.rb
@@ -1,16 +1,18 @@
 require 'faye/websocket/client'
 
 class ContainerConnection
-  EVENTS = %i[start message exit stdout stderr].freeze
+  EVENTS = %i[start output exit stdout stderr].freeze
 
   def initialize(url)
     @socket = Faye::WebSocket::Client.new(url, [], ping: 0.1)
 
     %i[open message error close].each do |event_type|
-      @socket.on event_type, &:"on_#{event_type}"
+      @socket.on event_type do |event| __send__(:"on_#{event_type}", event) end
     end
 
-    EVENTS.each { |event_type| instance_variable_set(:"@#{event_type}_callback", lambda {}) }
+    EVENTS.each { |event_type| instance_variable_set(:"@#{event_type}_callback", lambda {|e|}) }
+    @start_callback = lambda {}
+    @exit_code = 0
   end
 
   def on(event, &block)
@@ -20,26 +22,30 @@ class ContainerConnection
   end
 
   def send(data)
-    @socket.send(data)
+    @socket.send(encode(data))
   end
 
   private
 
-  def parse(event)
-    JSON.parse(event.data).deep_symbolize_keys
+  def decode(event)
+    JSON.parse(event).deep_symbolize_keys
+  end
+
+  def encode(data)
+    data
   end
 
   def on_message(event)
-    event = parse(event)
-    case event[:type]
+    event = decode(event.data)
+    case event[:type].to_sym
     when :exit_code
       @exit_code = event[:data]
     when :stderr
       @stderr_callback.call event[:data]
-      @message_callback.call event[:data]
+      @output_callback.call event[:data]
     when :stdout
       @stdout_callback.call event[:data]
-      @message_callback.call event[:data]
+      @output_callback.call event[:data]
     else
       :error
     end