Rename metric to 'rails queue duration'

config/initializers/metrics.rb

@@ -12,7 +12,7 @@ if Gitlab::Metrics.enabled?
 
   Gitlab::Application.configure do |config|
     config.middleware.use(Gitlab::Metrics::RackMiddleware)
-    config.middleware.use(Gitlab::Middleware::ProxyFlightTime)
+    config.middleware.use(Gitlab::Middleware::RailsQueueDuration)
   end
 
   Sidekiq.configure_server do |config|

lib/gitlab/middleware/proxy_flight_time.rb → lib/gitlab/middleware/rails_queue_duration.rb

@@ -4,7 +4,7 @@
 
 module Gitlab
   module Middleware
-    class ProxyFlightTime
+    class RailsQueueDuration
       def initialize(app)
         @app = app
       end
@@ -14,7 +14,7 @@ module Gitlab
         proxy_start = env['HTTP_GITLAB_WORHORSE_PROXY_START'].presence
         if trans && proxy_start
           # Time in milliseconds since gitlab-workhorse started the request
-          trans.set(:proxy_flight_time, Time.now.to_f * 1_000 - proxy_start.to_f / 1_000_000)
+          trans.set(:rails_queue_duration, Time.now.to_f * 1_000 - proxy_start.to_f / 1_000_000)
         end
 
         @app.call(env)

spec/lib/gitlab/middleware/proxy_flight_time_spec.rb → spec/lib/gitlab/middleware/rails_queue_duration_spec.rb

 require 'spec_helper'
 
-describe Gitlab::Middleware::ProxyFlightTime do
+describe Gitlab::Middleware::RailsQueueDuration do
   let(:app) { double(:app) }
   let(:middleware) { described_class.new(app) }
   let(:env) { {} }
@@ -23,7 +23,7 @@ describe Gitlab::Middleware::ProxyFlightTime do
 
       it 'sets proxy_flight_time and calls the app when the header is present' do
         env['HTTP_GITLAB_WORHORSE_PROXY_START'] = '123'
-        expect(transaction).to receive(:set).with(:proxy_flight_time, an_instance_of(Float))
+        expect(transaction).to receive(:set).with(:rails_queue_duration, an_instance_of(Float))
         expect(middleware.call(env)).to eq('yay')
       end
     end