Fixes #36898 - Add rack-mini-profiler for profiling

bundler.d/profiling.rb

@@ -0,0 +1,9 @@
+group :profiling, optional: true do
+  gem 'rack-mini-profiler'
+
+  # For memory profiling
+  gem 'memory_profiler'
+
+  # For call-stack profiling flamegraphs
+  gem 'stackprof'
+end

config/application.rb

@@ -41,7 +41,7 @@
     Bundler.ui = Bundler::UI::Silent.new if Rails.env.production?
 
     Bundler.require(*Rails.groups)
-    optional_bundler_groups = %w[assets ec2 fog libvirt openstack vmware redis]
+    optional_bundler_groups = %w[assets ec2 fog libvirt openstack profiling vmware redis]
     optional_bundler_groups.each do |group|
       Bundler.require(group)
     rescue LoadError

config/initializers/rack_mini_profiler.rb

@@ -0,0 +1,7 @@
+if defined? Rack::MiniProfiler
+  # enable profiling for all pages; per-default it is disabled on production-env
+  Rack::MiniProfiler.config.authorization_mode = SETTINGS.fetch(:profiler_authorization_mode, :allow_all)
+
+  # enable additional profiling-features
+  Rack::MiniProfiler.config.enable_advanced_debugging_tools = true
+end

config/settings.yaml.example

@@ -144,3 +144,7 @@
 #   :options:
 #     :compress: true
 #     :namespace: foreman
+
+# set to :allow_authorized to not run rack-mini-profiler on all pages
+# see https://github.com/MiniProfiler/rack-mini-profiler#access-control-in-non-development-environments
+# :profiler_authorization_mode: :allow_all