Ruby on Rails question - where is the first point in rails code that a request hits?

Ruby on Rails question - where is the first point in rails code that a request hits?

(I can then add some logging code there as I want to measure some response times)

Regards

Check out this Railscast on Rack Middleware that will give you exactly that. Rack is the first place that a Rails 2.3+ app has requests hit and it handles the round trip of the request.