NoMethodError: undefined method `sub!' for nil:NilClass error when using Cockpit

[ehelms]

Copied from http://projects.theforeman.org/issues/18483

Using Foreman 1.14.1 with Katello 3.3rc2, when the cockpit plugin is enabled, an error is generated when editing or provisioning a host. The error generates the attached stack trace.

Also:
[~]{117}# rpm -qa | grep cockpit
tfm-rubygem-foreman_cockpit-2.0.2-1.fm1_13.el7.noarch

NoMethodError
undefined method `sub!' for nil:NilClass
/opt/theforeman/tfm/root/usr/share/gems/gems/foreman_cockpit-2.0.2/app/controllers/concerns/foreman_cockpit/hosts_controller_extensions.rb:26:in `allow_cockpit_iframe'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:432:in `block in make_lambda'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:145:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:145:in `block in halting_and_conditional'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:504:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:504:in `block in call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:504:in `each'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:504:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:498:in `block (2 levels) in around'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:313:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:313:in `block (2 levels) in halting'
/opt/theforeman/tfm/root/usr/share/gems/gems/rails-observers-0.1.2/lib/rails/observers/action_controller/caching/sweeping.rb:73:in `around'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:455:in `public_send'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:455:in `block in make_lambda'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:312:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:312:in `block in halting'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:497:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:497:in `block in around'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:505:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:505:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:498:in `block (2 levels) in around'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:313:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:313:in `block (2 levels) in halting'
/usr/share/foreman/app/controllers/concerns/application_shared.rb:14:in `set_timezone'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:432:in `block in make_lambda'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:312:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:312:in `block in halting'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:497:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:497:in `block in around'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:505:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:505:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:498:in `block (2 levels) in around'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:313:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:313:in `block (2 levels) in halting'
/usr/share/foreman/app/models/concerns/foreman/thread_session.rb:32:in `clear_thread'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:432:in `block in make_lambda'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:312:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:312:in `block in halting'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:497:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:497:in `block in around'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:505:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:505:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:498:in `block (2 levels) in around'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:313:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:313:in `block (2 levels) in halting'
/opt/theforeman/tfm/root/usr/share/gems/gems/rails-observers-0.1.2/lib/rails/observers/action_controller/caching/sweeping.rb:73:in `around'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:455:in `public_send'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:455:in `block in make_lambda'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:312:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:312:in `block in halting'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:497:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:497:in `block in around'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:505:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:505:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:92:in `__run_callbacks__'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:778:in `_run_process_action_callbacks'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:81:in `run_callbacks'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/abstract_controller/callbacks.rb:19:in `process_action'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_controller/metal/rescue.rb:29:in `process_action'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_controller/metal/instrumentation.rb:32:in `block in process_action'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/notifications.rb:164:in `block in instrument'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/notifications.rb:164:in `instrument'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_controller/metal/instrumentation.rb:30:in `process_action'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_controller/metal/params_wrapper.rb:250:in `process_action'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activerecord-4.2.5.1/lib/active_record/railties/controller_runtime.rb:18:in `process_action'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/abstract_controller/base.rb:137:in `process'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionview-4.2.5.1/lib/action_view/rendering.rb:30:in `process'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_controller/metal.rb:196:in `dispatch'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_controller/metal/rack_delegation.rb:13:in `dispatch'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_controller/metal.rb:237:in `block in action'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/routing/route_set.rb:74:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/routing/route_set.rb:74:in `dispatch'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/routing/route_set.rb:43:in `serve'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/journey/router.rb:43:in `block in serve'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/journey/router.rb:30:in `each'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/journey/router.rb:30:in `serve'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/routing/route_set.rb:815:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/middleware/static.rb:116:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/middleware/static.rb:116:in `call'
/opt/theforeman/tfm/root/usr/share/gems/gems/apipie-rails-0.3.7/lib/apipie/static_dispatcher.rb:65:in `call'
/opt/theforeman/tfm/root/usr/share/gems/gems/apipie-rails-0.3.7/lib/apipie/extractor/recorder.rb:132:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/middleware/static.rb:116:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/middleware/static.rb:116:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/middleware/static.rb:116:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/middleware/static.rb:116:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/middleware/static.rb:116:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/middleware/static.rb:116:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/middleware/static.rb:116:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/middleware/static.rb:116:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/middleware/static.rb:116:in `call'
/opt/theforeman/tfm/root/usr/share/gems/gems/apipie-rails-0.3.7/lib/apipie/middleware/checksum_in_headers.rb:27:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/rack-1.6.2/lib/rack/etag.rb:24:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/rack-1.6.2/lib/rack/conditionalget.rb:25:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/rack-1.6.2/lib/rack/head.rb:13:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/middleware/params_parser.rb:27:in `call'
/usr/share/foreman/lib/middleware/catch_json_parse_errors.rb:8:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/middleware/flash.rb:260:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/rack-1.6.2/lib/rack/session/abstract/id.rb:225:in `context'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/rack-1.6.2/lib/rack/session/abstract/id.rb:220:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/middleware/cookies.rb:560:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activerecord-4.2.5.1/lib/active_record/query_cache.rb:36:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activerecord-4.2.5.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:653:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:88:in `__run_callbacks__'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:778:in `_run_call_callbacks'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:81:in `run_callbacks'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/middleware/callbacks.rb:27:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/middleware/remote_ip.rb:78:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/railties-4.2.5.1/lib/rails/rack/logger.rb:38:in `call_app'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/railties-4.2.5.1/lib/rails/rack/logger.rb:22:in `call'
/usr/share/foreman/lib/middleware/tagged_logging.rb:18:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/middleware/request_id.rb:21:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/rack-1.6.2/lib/rack/methodoverride.rb:22:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/rack-1.6.2/lib/rack/runtime.rb:18:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/activesupport-4.2.5.1/lib/active_support/cache/strategy/local_cache_middleware.rb:28:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/actionpack-4.2.5.1/lib/action_dispatch/middleware/static.rb:116:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/rack-1.6.2/lib/rack/sendfile.rb:113:in `call'
/opt/theforeman/tfm/root/usr/share/gems/gems/secure_headers-3.4.1/lib/secure_headers/middleware.rb:12:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/railties-4.2.5.1/lib/rails/engine.rb:518:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/railties-4.2.5.1/lib/rails/application.rb:165:in `call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/railties-4.2.5.1/lib/rails/railtie.rb:194:in `public_send'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/railties-4.2.5.1/lib/rails/railtie.rb:194:in `method_missing'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/rack-1.6.2/lib/rack/urlmap.rb:66:in `block in call'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/rack-1.6.2/lib/rack/urlmap.rb:50:in `each'
/opt/rh/sclo-ror42/root/usr/share/gems/gems/rack-1.6.2/lib/rack/urlmap.rb:50:in `call'
/usr/share/passenger/phusion_passenger/rack/thread_handler_extension.rb:74:in `process_request'
/usr/share/passenger/phusion_passenger/request_handler/thread_handler.rb:141:in `accept_and_process_next_request'
/usr/share/passenger/phusion_passenger/request_handler/thread_handler.rb:109:in `main_loop'
/usr/share/passenger/phusion_passenger/request_handler.rb:455:in `block (3 levels) in start_threads'
/opt/theforeman/tfm/root/usr/share/gems/gems/logging-1.8.2/lib/logging/diagnostic_context.rb:323:in `call'
/opt/theforeman/tfm/root/usr/share/gems/gems/logging-1.8.2/lib/logging/diagnostic_context.rb:323:in `block in create_with_logging_context'

[domcleal]

Also #12, already fixed in master.