Measure proxy timing: needs influxdb code

config/initializers/proxy_timing.rb

+Rails.application.config.middleware.use(Gitlab::Middleware::ProxyTiming)

lib/gitlab/middleware/proxy_timing.rb

+# This Rack middleware is intended to measure the latency between
+# gitlab-workhorse forwarding a request to the Rails application and the
+# time this middleware is reached.
+
+module Gitlab
+  module Middleware
+    class ProxyTiming
+      def initialize(app)
+        @app = app
+      end
+      
+      def call(env)
+        proxy_start = env['HTTP_GITLAB_WORHORSE_PROXY_START'].to_f / 1_000_000_000
+        if proxy_start > 0
+          # send measurement
+          puts "\n\n\n#{(Time.now - proxy_start).to_f}\n\n\n"
+        end
+        @app.call(env)
+      end
+    end
+  end
+end