metrics for request queue

lib/travis/api/app.rb

@@ -64,7 +64,7 @@ module Travis::Api
 
     def initialize
       @app = Rack::Builder.app do
-        use(Rack::Config) { |env| env["HTTP_X_MIDDLEWARE_START"] ||= "t=#{(Time.now.to_f * 1000000).to_i}" }
+        use(Rack::Config) { |env| env['metriks.request.start'] ||= Time.now.utc }
 
         Rack::Utils::HTTP_STATUS_CODES[420] = "Enhance Your Calm"
         use Rack::Attack

lib/travis/api/app/middleware/metriks.rb

@@ -7,10 +7,15 @@ class Travis::Api::App
       include Helpers::Accept
 
       before do
-        env['metriks.request.start'] = Time.now.utc
+        env['metriks.request.start'] ||= Time.now.utc
       end
 
       after do
+        if queue_start = time(env['HTTP_X_QUEUE_START'])
+          time = env['metriks.request.start'] - queue_start
+          ::Metriks.timer('api.request_queue').update(time)
+        end
+
         if response.status < 400
           time = Time.now.utc - env['metriks.request.start']
           if headers['X-Pattern'].present? and headers['X-Endpoint'].present?
@@ -21,9 +26,17 @@ class Travis::Api::App
           end
           ::Metriks.meter("api.request.#{request.request_method.downcase}").mark
         end
+
         ::Metriks.meter("api.request.status.#{response.status.to_s[0]}").mark
         ::Metriks.meter("api.request.version.#{accept_version}").mark
       end
+
+      def time(value)
+        value = value.to_f
+        start = env['metriks.request.start'].to_f
+        value /= 1000 while value > start
+        value if value > 946684800
+      end
     end
   end
 end