New Relic API Rackup

new_relic_agent_instrumentation_api.rb

if Rails.env.production?

  require 'new_relic/agent/instrumentation/controller_instrumentation'

  module NewRelic
    module Agent
      module Instrumentation
        module API
          def newrelic_request_headers
            @newrelic_request.env
          end
          def call_with_newrelic(*args)
            @newrelic_request = ::Rack::Request.new(args.first)
            path = @newrelic_request.path.split('/').delete_if { |p| p.blank? }.join('_')
            method = @newrelic_request.request_method.downcase
            perform_action_with_newrelic_trace(
              :category => :rack, 
              :path => "#{path}\##{method}",
              :request => @newrelic_request) do
              result = call_without_newrelic(*args)
              # Ignore cascaded calls
              MetricFrame.abort_transaction! if result.first == 404
              result
            end
          end
          def self.included middleware #:nodoc:
            middleware.class_eval do
              alias call_without_newrelic call
              alias call call_with_newrelic
            end
          end
          include ControllerInstrumentation
          def self.extended middleware #:nodoc:
            middleware.class_eval do
              class << self
                alias call_without_newrelic call
                alias call call_with_newrelic
              end
            end
          end
        end
      end
    end
  end

end

We no longer use this instrumentation and have reworked it. Check out this blog post for details.