Merge branch 'instrument-service-classes' into 'master'

Instrument all service classes

This will help us see where (mostly) Sidekiq code is spending time.

See merge request !3675

CHANGELOG

 Please view this file on the master branch, on stable branches it's out of date.
 v 8.7.0 (unreleased)
+  - All service classes (those residing in app/services) are now instrumented (Yorick Peterse)
   - Enable gzip for assets, makes the page size significantly smaller. !3544 / !3632 (Connor Shea)
   - Load award emoji images separately unless opening the full picker. Saves several hundred KBs of data for most pages. (Connor Shea)
   - All images in discussions and wikis now link to their source files !3464 (Connor Shea).

config/initializers/metrics.rb

 if Gitlab::Metrics.enabled?
+  require 'pathname'
   require 'influxdb'
   require 'connection_pool'
   require 'method_source'
@@ -95,6 +96,17 @@ if Gitlab::Metrics.enabled?
     config.instrument_methods(Gitlab::ReferenceExtractor)
     config.instrument_instance_methods(Gitlab::ReferenceExtractor)
+
+    # Instrument all service classes
+    services = Rails.root.join('app', 'services')
+
+    Dir[services.join('**', '*.rb')].each do |file_path|
+      path = Pathname.new(file_path).relative_path_from(services)
+      const = path.to_s.sub('.rb', '').camelize.constantize
+
+      config.instrument_methods(const)
+      config.instrument_instance_methods(const)
+    end
   end
   GC::Profiler.enable