Rails Mounted Engine url_helpers workaround for thread bug undefined method `url_options' for #<Module:0x007fb64b864d50>

output

$ rails runner route_helpers_debug.rb
Threads: 10, Iterations per thread: 10
Running Mounted Engine dummy_path...
4/-/2/-/3/-/8/-/6/-/1/-/9/-/7/-/0/-/4/-/2/-/3/-/8/-/6/-/1/-/9/-/7/-/0/-/4/-/2/-/3/-/8/-/6/-/1/-/9/-/7/-/0/-/4/-/2/-/3/-/8/-/6/-/1/-/9/-/7/-/0/-/4/-/2/-/3/-/8/-/6/-/1/-/9/-/7/-/0/-/4/-/2/-/3/-/8/-/6/-/1/-/9/-/7/-/0/-/4/-/2/-/3/-/8/-/6/-/1/-/9/-/7/-/0/-/4/-/2/-/3/-/8/-/6/-/1/-/9/-/7/-/0/-/4/-/2/-/3/-/8/-/6/-/1/-/9/-/7/-/0/-/2/-/3/-/4/-/8/-/1/-/9/-/7/-/0/-/
Finished thread 0.

Finished thread 1.

Finished thread 2.

Finished thread 3.

Finished thread 4.
6/-/
Finished thread 6.

Finished thread 7.

Finished thread 8.

Finished thread 9.

-------
ERRORS: 1

Exception in thread 5, iteration 0: undefined method `url_options' for #<Module:0x007fb64b864d50>
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/routing/route_set.rb:271:in `call'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/routing/route_set.rb:222:in `call'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/routing/route_set.rb:334:in `block (2 levels) in define_url_helper'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/routing/mapper.rb:637:in `block (2 levels) in define_generate_prefix'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/routing/route_set.rb:775:in `url_for'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/routing/route_set.rb:279:in `call'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/routing/route_set.rb:222:in `call'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/routing/route_set.rb:334:in `block (2 levels) in define_url_helper'
        route_helpers_debug.rb:77:in `block in method_missing'
        route_helpers_debug.rb:76:in `synchronize'
        route_helpers_debug.rb:76:in `method_missing'
        route_helpers_debug.rb:48:in `engine_test'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal/implicit_render.rb:4:in `send_action'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/actionpack-4.2.0/lib/abstract_controller/base.rb:198:in `process_action'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal/rendering.rb:10:in `process_action'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/actionpack-4.2.0/lib/abstract_controller/callbacks.rb:20:in `block in process_action'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:117:in `call'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:117:in `call'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:234:in `block in halting'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:169:in `call'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:169:in `block in halting'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:169:in `call'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:169:in `block in halting'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:234:in `call'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:234:in `block in halting'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:92:in `call'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:92:in `_run_callbacks'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:734:in `_run_process_action_callbacks'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:81:in `run_callbacks'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/actionpack-4.2.0/lib/abstract_controller/callbacks.rb:19:in `process_action'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal/rescue.rb:29:in `process_action'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal/instrumentation.rb:31:in `block in process_action'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/activesupport-4.2.0/lib/active_support/notifications.rb:164:in `block in instrument'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/activesupport-4.2.0/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/activesupport-4.2.0/lib/active_support/notifications.rb:164:in `instrument'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal/instrumentation.rb:30:in `process_action'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal/params_wrapper.rb:250:in `process_action'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/activerecord-4.2.0/lib/active_record/railties/controller_runtime.rb:18:in `process_action'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/actionpack-4.2.0/lib/abstract_controller/base.rb:137:in `process'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/actionview-4.2.0/lib/action_view/rendering.rb:30:in `process'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal.rb:195:in `dispatch'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal/rack_delegation.rb:13:in `dispatch'
        /home/steven/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal.rb:236:in `block in action'
        route_helpers_debug.rb:93:in `call'
        route_helpers_debug.rb:93:in `block in <top (required)>'
        route_helpers_debug.rb:15:in `call'
        route_helpers_debug.rb:15:in `block (3 levels) in run_threads'
        route_helpers_debug.rb:13:in `times'
        route_helpers_debug.rb:13:in `block (2 levels) in run_threads'

-------
ERRORS: 1

route_helpers_debug.rb

# via "rails runner"

NUM_THREADS = (ARGV[0] || 10).to_i
NUM_ITERATIONS = (ARGV[1] || NUM_THREADS).to_i

puts "Threads: #{NUM_THREADS}, Iterations per thread: #{NUM_ITERATIONS}"

def run_threads(&block)
  threads = []
  NUM_THREADS.times do |thread_num|
    threads << Thread.new(thread_num) do |num|
      Thread.current.thread_variable_set('num', num)
      NUM_ITERATIONS.times do |i|
        Thread.current.thread_variable_set('iter', i)
        print num.to_s + block.call.to_s
      end
    end
  end

  errors = []
  threads.each do |thr|
    begin
      thr.join
      print "\nFinished thread #{thr.thread_variable_get('num')}.\n"
    rescue => e
      errors << "\nException in thread #{thr.thread_variable_get('num')}, iteration #{thr.thread_variable_get('iter')}: #{e.message}\n"+e.backtrace.map{|bt| "\t#{bt}\n" }.join
    end
  end

  puts "\n-------\nERRORS: #{errors.length}"
  puts errors
  puts "\n-------\nERRORS: #{errors.length}"
end



class TestEngine < Rails::Engine; end
TestEngine.routes.draw do
  get '/' => 'dummy#index', as: :dummy
end

Rails.application.routes.draw do
  mount TestEngine, at: '-', as: 'test_routes'
end

class TestController < ActionController::Base
  def engine_test
    render plain: RouteHelper.one.dummy_path
  end
end



ROUTES_MUTEX = Mutex.new


class RouteHelper

  class UrlHelpers
    include TestEngine.routes.url_helpers
  end

  def self.one
    @@one
  end

  def self.one=(one)
    @@one = one
  end

  def self.url_helpers=(url_helpers)
    @@url_helpers = url_helpers
  end

  def method_missing(symbol, *args)
    ROUTES_MUTEX.synchronize {
      @@url_helpers.send(symbol, *args)
    }
  end

end

RouteHelper.one = RouteHelper.new
RouteHelper.url_helpers = RouteHelper::UrlHelpers.new



Rails.logger.level = 2

puts "Running Mounted Engine dummy_path..."
run_threads do
  env = { 'REQUEST_METHOD' => 'GET', 'rack.input' => StringIO.new }
  status, headers, rack_body = TestController.action('engine_test').call(env)
  rack_body.body
end