在应用程序完全加载之前，Tomcat正在处理JRuby on Rails应用程序的请求

Question

I have an edge case, although a very customer visible one, where Tomcat begins processing requests before all dependencies are properly loaded for a Ruby on Rails stack running underneath JRuby.

Once Tomcat is restarted, there is something similar to the following happening:

undefined method `utc_offset' for nil:NilClass
 [RAILS_ROOT]/gems/gems/activesupport-2.3.8/lib/active_support/values/time_zone.rb:206:in `<=>'

This happens when the following code is invoked on one of my services:

  @timezones = ActiveSupport::TimeZone.all

If you wait a few more seconds and refresh the requesting page, it'll load no problem.

Is there a way to ensure that Tomcat does not start processing these requests until the entire stack, ActiveSupport, ActiveRecord etc is loaded? Has anyone experienced any similar symptoms?

Answer 1

This sounds like a possible bug in JRuby-Rack, assuming that's what you're using to run your Rails app in Tomcat. JRuby-Rack is supposed to load the entirety of config/environment.rb before it will process requests, so I'm not sure how this would happen to you, but perhaps I've overlooked something. Could you share some more data (or maybe code or an app that reproduces the issue) about how you induced the error at http://kenai.com/jira/browse/JRUBY_RACK or http://bugs.jruby.org ?

Answer 2

I'm not sure if there is something like that in Tomcat directly, but you can write a javax.servlet.Filter that will intercept all requests, and deny them until your application is loaded. When application is fully loaded, you ask filter to stop denying requests. (This isn't pure Ruby solution though).