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

@@ -1,6 +1,7 @@
 Please view this file on the master branch, on stable branches it's out of date.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

@@ -1,4 +1,5 @@
 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