Merge branch 'sidekiq-job-throttling' into 'master'

Allow certain Sidekiq jobs to be throttled

## What does this MR do?

Allows certain slow running Sidekiq jobs to be throttled. It is disabled by default and can be enabled via the Application Settings. 

![Screen_Shot_2016-11-04_at_4.51.24_PM](/uploads/a1f1d24c693fcdb278602765cd404d94/Screen_Shot_2016-11-04_at_4.51.24_PM.png)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG.md) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing

## What are the relevant issue numbers?

Related to #23352

See merge request !7292

4 files changed, 44 insertions, 1 deletions

diff --git a/app/controllers/admin/application_settings_controller.rb b/app/controllers/admin/application_settings_controller.rb
index 52e0256943a..b81842e319b 100644
--- a/app/controllers/admin/application_settings_controller.rb
+++ b/app/controllers/admin/application_settings_controller.rb
@@ -117,6 +117,8 @@ class Admin::ApplicationSettingsController < Admin::ApplicationController
       :send_user_confirmation_email,
       :container_registry_token_expire_delay,
       :enabled_git_access_protocol,
+      :sidekiq_throttling_enabled,
+      :sidekiq_throttling_factor,
       :housekeeping_enabled,
       :housekeeping_bitmaps_enabled,
       :housekeeping_incremental_repack_period,
@@ -125,7 +127,8 @@ class Admin::ApplicationSettingsController < Admin::ApplicationController
       repository_storages: [],
       restricted_visibility_levels: [],
       import_sources: [],
-      disabled_oauth_sign_in_sources: []
+      disabled_oauth_sign_in_sources: [],
+      sidekiq_throttling_queues: []
     )
   end
 end
diff --git a/app/helpers/application_settings_helper.rb b/app/helpers/application_settings_helper.rb
index 45a567a1eba..be5e0301a43 100644
--- a/app/helpers/application_settings_helper.rb
+++ b/app/helpers/application_settings_helper.rb
@@ -100,4 +100,8 @@ module ApplicationSettingsHelper
 
     options_for_select(options, @application_setting.repository_storages)
   end
+
+  def sidekiq_queue_options_for_select
+    options_for_select(Sidekiq::Queue.all.map(&:name), @application_setting.sidekiq_throttling_queues)
+  end
 end
diff --git a/app/models/application_setting.rb b/app/models/application_setting.rb
index bb60cc8736c..d1e1b45ab43 100644
--- a/app/models/application_setting.rb
+++ b/app/models/application_setting.rb
@@ -19,6 +19,7 @@ class ApplicationSetting < ActiveRecord::Base
   serialize :domain_whitelist, Array
   serialize :domain_blacklist, Array
   serialize :repository_storages
+  serialize :sidekiq_throttling_queues, Array
 
   cache_markdown_field :sign_in_text
   cache_markdown_field :help_page_text
@@ -85,6 +86,15 @@ class ApplicationSetting < ActiveRecord::Base
             presence: { message: 'Domain blacklist cannot be empty if Blacklist is enabled.' },
             if: :domain_blacklist_enabled?
 
+  validates :sidekiq_throttling_factor,
+            numericality: { greater_than: 0, less_than: 1 },
+            presence: { message: 'Throttling factor cannot be empty if Sidekiq Throttling is enabled.' },
+            if: :sidekiq_throttling_enabled?
+
+  validates :sidekiq_throttling_queues,
+            presence: { message: 'Queues to throttle cannot be empty if Sidekiq Throttling is enabled.' },
+            if: :sidekiq_throttling_enabled?
+
   validates :housekeeping_incremental_repack_period,
             presence: true,
             numericality: { only_integer: true, greater_than: 0 }
@@ -180,6 +190,7 @@ class ApplicationSetting < ActiveRecord::Base
       container_registry_token_expire_delay: 5,
       repository_storages: ['default'],
       user_default_external: false,
+      sidekiq_throttling_enabled: false,
       housekeeping_enabled: true,
       housekeeping_bitmaps_enabled: true,
       housekeeping_incremental_repack_period: 10,
diff --git a/app/views/admin/application_settings/_form.html.haml b/app/views/admin/application_settings/_form.html.haml
index 450ec322f2c..a236335131a 100644
--- a/app/views/admin/application_settings/_form.html.haml
+++ b/app/views/admin/application_settings/_form.html.haml
@@ -284,6 +284,31 @@
           results in fewer but larger UDP packets being sent.
 
   %fieldset
+    %legend Background Jobs
+    %p
+      These settings require a restart to take effect.
+    .form-group
+      .col-sm-offset-2.col-sm-10
+        .checkbox
+          = f.label :sidekiq_throttling_enabled do
+            = f.check_box :sidekiq_throttling_enabled
+            Enable Sidekiq Job Throttling
+          .help-block
+            Limit the amount of resources slow running jobs are assigned.
+    .form-group
+      = f.label :sidekiq_throttling_queues, 'Sidekiq queues to throttle', class: 'control-label col-sm-2'
+      .col-sm-10
+        = f.select :sidekiq_throttling_queues, sidekiq_queue_options_for_select, { include_hidden: false }, multiple: true, class: 'select2 select-wide', data: { field: 'sidekiq_throttling_queues' }
+        .help-block
+          Choose which queues you wish to throttle.
+    .form-group
+      = f.label :sidekiq_throttling_factor, 'Throttling Factor', class: 'control-label col-sm-2'
+      .col-sm-10
+        = f.number_field :sidekiq_throttling_factor, class: 'form-control', min: '0.01', max: '0.99', step: '0.01'
+        .help-block
+          The factor by which the queues should be throttled. A value between 0.0 and 1.0, exclusive.
+
+  %fieldset
     %legend Spam and Anti-bot Protection
     .form-group
       .col-sm-offset-2.col-sm-10