Crono fails to start with Web UI route active on Rails 5 #52
Description
First thanks for your work. We use Crono in production for over a year now and it has kicked of tens of thousands of jobs on our servers.
Upgrading one of our apps to Rails 5 we encountered a problem though:
Running the Crono gem works as long as the route to the Web UI (mount Crono::Web, at: '/crono') is not active. With the route added, crono doesn't start locally as well as on our production machine (Heroku).
We can reproduce this problem within a clean new Rails 5.0.0.1 app with only the Crono gem added as well.
Error log from development machine (macOS 10.11.6 with Ruby 2.3.1, paths shortened for readability):
bundler: failed to load command: crono (/bin/crono)
LoadError: cannot load such file -- rack/showexceptions
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:293:in `require'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:293:in `block in require'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:259:in `load_dependency'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:293:in `require'
/lib/ruby/gems/2.3.0/gems/sinatra-1.0/lib/sinatra/showexceptions.rb:1:in `<top (required)>'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:293:in `require'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:293:in `block in require'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:259:in `load_dependency'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:293:in `require'
/lib/ruby/gems/2.3.0/gems/sinatra-1.0/lib/sinatra/base.rb:6:in `<top (required)>'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:293:in `require'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:293:in `block in require'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:259:in `load_dependency'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:293:in `require'
/lib/ruby/gems/2.3.0/gems/crono-1.0.3/lib/crono/web.rb:2:in `<top (required)>'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:293:in `require'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:293:in `block in require'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:259:in `load_dependency'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:293:in `require'
/Users/chris/Sites/crono/config/routes.rb:2:in `block in <top (required)>'
/lib/ruby/gems/2.3.0/gems/actionpack-5.0.0.1/lib/action_dispatch/routing/route_set.rb:389:in `instance_exec'
/lib/ruby/gems/2.3.0/gems/actionpack-5.0.0.1/lib/action_dispatch/routing/route_set.rb:389:in `eval_block'
/lib/ruby/gems/2.3.0/gems/actionpack-5.0.0.1/lib/action_dispatch/routing/route_set.rb:371:in `draw'
/Users/chris/Sites/crono/config/routes.rb:1:in `<top (required)>'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:287:in `load'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:287:in `block in load'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:259:in `load_dependency'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:287:in `load'
/lib/ruby/gems/2.3.0/gems/railties-5.0.0.1/lib/rails/application/routes_reloader.rb:40:in `block in load_paths'
/lib/ruby/gems/2.3.0/gems/railties-5.0.0.1/lib/rails/application/routes_reloader.rb:40:in `each'
/lib/ruby/gems/2.3.0/gems/railties-5.0.0.1/lib/rails/application/routes_reloader.rb:40:in `load_paths'
/lib/ruby/gems/2.3.0/gems/railties-5.0.0.1/lib/rails/application/routes_reloader.rb:16:in `reload!'
/lib/ruby/gems/2.3.0/gems/railties-5.0.0.1/lib/rails/application/routes_reloader.rb:26:in `block in updater'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/file_update_checker.rb:77:in `execute'
/lib/ruby/gems/2.3.0/gems/railties-5.0.0.1/lib/rails/application/routes_reloader.rb:27:in `updater'
/lib/ruby/gems/2.3.0/gems/railties-5.0.0.1/lib/rails/application/routes_reloader.rb:7:in `execute_if_updated'
/lib/ruby/gems/2.3.0/gems/railties-5.0.0.1/lib/rails/application/finisher.rb:119:in `block in <module:Finisher>'
/lib/ruby/gems/2.3.0/gems/railties-5.0.0.1/lib/rails/initializable.rb:30:in `instance_exec'
/lib/ruby/gems/2.3.0/gems/railties-5.0.0.1/lib/rails/initializable.rb:30:in `run'
/lib/ruby/gems/2.3.0/gems/railties-5.0.0.1/lib/rails/initializable.rb:55:in `block in run_initializers'
/lib/ruby/2.3.0/tsort.rb:228:in `block in tsort_each'
/lib/ruby/2.3.0/tsort.rb:350:in `block (2 levels) in each_strongly_connected_component'
/lib/ruby/2.3.0/tsort.rb:431:in `each_strongly_connected_component_from'
/lib/ruby/2.3.0/tsort.rb:349:in `block in each_strongly_connected_component'
/lib/ruby/2.3.0/tsort.rb:347:in `each'
/lib/ruby/2.3.0/tsort.rb:347:in `call'
/lib/ruby/2.3.0/tsort.rb:347:in `each_strongly_connected_component'
/lib/ruby/2.3.0/tsort.rb:226:in `tsort_each'
/lib/ruby/2.3.0/tsort.rb:205:in `tsort_each'
/lib/ruby/gems/2.3.0/gems/railties-5.0.0.1/lib/rails/initializable.rb:54:in `run_initializers'
/lib/ruby/gems/2.3.0/gems/railties-5.0.0.1/lib/rails/application.rb:352:in `initialize!'
/Users/chris/Sites/crono/config/environment.rb:5:in `<top (required)>'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:293:in `require'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:293:in `block in require'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:259:in `load_dependency'
/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/dependencies.rb:293:in `require'
/lib/ruby/gems/2.3.0/gems/crono-1.0.3/lib/crono/cli.rb:84:in `load_rails'
/lib/ruby/gems/2.3.0/gems/crono-1.0.3/lib/crono/cli.rb:28:in `run'
/lib/ruby/gems/2.3.0/gems/crono-1.0.3/exe/crono:8:in `<top (required)>'
/bin/crono:23:in `load'
/bin/crono:23:in `<top (required)>'