Merge branch 'auto-fsck' into 'master'

Auto git fsck

Closes https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/3232

See merge request !3232

29 files changed, 445 insertions, 8 deletions

diff --git a/CHANGELOG b/CHANGELOG
index 9aa40fae18e..ec210867e7f 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -34,6 +34,7 @@ v 8.7.0 (unreleased)
   - Fix a bug whith trailing slash in bamboo_url
   - Add links to CI setup documentation from project settings and builds pages
   - Handle nil descriptions in Slack issue messages (Stan Hu)
+  - Add automated repository integrity checks
   - API: Expose open_issues_count, closed_issues_count, open_merge_requests_count for labels (Robert Schilling)
   - API: Ability to star and unstar a project (Robert Schilling)
   - Add default scope to projects to exclude projects pending deletion
diff --git a/app/controllers/admin/application_settings_controller.rb b/app/controllers/admin/application_settings_controller.rb
index f010436bd36..b4a28b8dd3f 100644
--- a/app/controllers/admin/application_settings_controller.rb
+++ b/app/controllers/admin/application_settings_controller.rb
@@ -19,6 +19,15 @@ class Admin::ApplicationSettingsController < Admin::ApplicationController
     redirect_to admin_runners_path
   end
 
+  def clear_repository_check_states
+    RepositoryCheck::ClearWorker.perform_async
+
+    redirect_to(
+      admin_application_settings_path,
+      notice: 'Started asynchronous removal of all repository check states.'
+    )
+  end
+
   private
 
   def set_application_setting
@@ -82,6 +91,7 @@ class Admin::ApplicationSettingsController < Admin::ApplicationController
       :akismet_enabled,
       :akismet_api_key,
       :email_author_in_body,
+      :repository_checks_enabled,
       restricted_visibility_levels: [],
       import_sources: []
     )
diff --git a/app/controllers/admin/projects_controller.rb b/app/controllers/admin/projects_controller.rb
index c6b3105544a..87986fdf8b1 100644
--- a/app/controllers/admin/projects_controller.rb
+++ b/app/controllers/admin/projects_controller.rb
@@ -1,5 +1,5 @@
 class Admin::ProjectsController < Admin::ApplicationController
-  before_action :project, only: [:show, :transfer]
+  before_action :project, only: [:show, :transfer, :repository_check]
   before_action :group, only: [:show, :transfer]
 
   def index
@@ -8,6 +8,7 @@ class Admin::ProjectsController < Admin::ApplicationController
     @projects = @projects.where("projects.visibility_level IN (?)", params[:visibility_levels]) if params[:visibility_levels].present?
     @projects = @projects.with_push if params[:with_push].present?
     @projects = @projects.abandoned if params[:abandoned].present?
+    @projects = @projects.where(last_repository_check_failed: true) if params[:last_repository_check_failed].present?
     @projects = @projects.non_archived unless params[:with_archived].present?
     @projects = @projects.search(params[:name]) if params[:name].present?
     @projects = @projects.sort(@sort = params[:sort])
@@ -30,6 +31,15 @@ class Admin::ProjectsController < Admin::ApplicationController
     redirect_to admin_namespace_project_path(@project.namespace, @project)
   end
 
+  def repository_check
+    RepositoryCheck::SingleRepositoryWorker.perform_async(@project.id)
+
+    redirect_to(
+      admin_namespace_project_path(@project.namespace, @project),
+      notice: 'Repository check was triggered.'
+    )
+  end
+
   protected
 
   def project
diff --git a/app/mailers/repository_check_mailer.rb b/app/mailers/repository_check_mailer.rb
new file mode 100644
index 00000000000..2bff5b63cc4
--- /dev/null
+++ b/app/mailers/repository_check_mailer.rb
@@ -0,0 +1,14 @@
+class RepositoryCheckMailer < BaseMailer
+  def notify(failed_count)
+    if failed_count == 1
+      @message = "One project failed its last repository check"
+    else
+      @message = "#{failed_count} projects failed their last repository check"
+    end
+
+    mail(
+      to: User.admins.pluck(:email),
+      subject: @message
+    )
+  end
+end
diff --git a/app/models/application_setting.rb b/app/models/application_setting.rb
index 052cd874733..36f88154232 100644
--- a/app/models/application_setting.rb
+++ b/app/models/application_setting.rb
@@ -153,7 +153,8 @@ class ApplicationSetting < ActiveRecord::Base
       require_two_factor_authentication: false,
       two_factor_grace_period: 48,
       recaptcha_enabled: false,
-      akismet_enabled: false
+      akismet_enabled: false,
+      repository_checks_enabled: true,
     )
   end
 
diff --git a/app/views/admin/application_settings/_form.html.haml b/app/views/admin/application_settings/_form.html.haml
index a8cca1a81cb..555aea554f0 100644
--- a/app/views/admin/application_settings/_form.html.haml
+++ b/app/views/admin/application_settings/_form.html.haml
@@ -271,5 +271,24 @@
       .col-sm-10
         = f.text_field :sentry_dsn, class: 'form-control'
 
+  %fieldset
+    %legend Repository Checks
+    .form-group
+      .col-sm-offset-2.col-sm-10
+        .checkbox
+          = f.label :repository_checks_enabled do
+            = f.check_box :repository_checks_enabled
+            Enable Repository Checks
+          .help-block
+            GitLab will periodically run 
+            %a{ href: 'https://www.kernel.org/pub/software/scm/git/docs/git-fsck.html', target: 'blank' } 'git fsck'
+            in all project and wiki repositories to look for silent disk corruption issues.
+    .form-group
+      .col-sm-offset-2.col-sm-10
+        = link_to 'Clear all repository checks', clear_repository_check_states_admin_application_settings_path, data: { confirm: 'This will clear repository check states for ALL projects in the database. This cannot be undone. Are you sure?' }, method: :put, class: "btn btn-sm btn-remove"
+        .help-block
+          If you got a lot of false alarms from repository checks you can choose to clear all repository check information from the database.
+ 
+
   .form-actions
     = f.submit 'Save', class: 'btn btn-save'
diff --git a/app/views/admin/logs/show.html.haml b/app/views/admin/logs/show.html.haml
index af9fdeb0734..4b475a4d8fa 100644
--- a/app/views/admin/logs/show.html.haml
+++ b/app/views/admin/logs/show.html.haml
@@ -1,6 +1,7 @@
 - page_title "Logs"
 - loggers = [Gitlab::GitLogger, Gitlab::AppLogger,
-             Gitlab::ProductionLogger, Gitlab::SidekiqLogger]
+             Gitlab::ProductionLogger, Gitlab::SidekiqLogger,
+             Gitlab::RepositoryCheckLogger]
 %ul.nav-links.log-tabs
   - loggers.each do |klass|
     %li{ class: (klass == Gitlab::GitLogger ? 'active' : '') }
diff --git a/app/views/admin/projects/index.html.haml b/app/views/admin/projects/index.html.haml
index d39c0f44031..aa07afa0d62 100644
--- a/app/views/admin/projects/index.html.haml
+++ b/app/views/admin/projects/index.html.haml
@@ -3,7 +3,7 @@
 
 .row.prepend-top-default
   %aside.col-md-3
-    .admin-filter
+    .panel.admin-filter
       = form_tag admin_namespaces_projects_path, method: :get, class: '' do
         .form-group
           = label_tag :name, 'Name:'
@@ -38,7 +38,13 @@
                   %span.descr
                     = visibility_level_icon(level)
                     = label
-        %hr
+        %fieldset
+          %strong Problems
+          .checkbox
+            = label_tag :last_repository_check_failed do
+              = check_box_tag :last_repository_check_failed, 1, params[:last_repository_check_failed]
+              %span Last repository check failed
+
         = hidden_field_tag :sort, params[:sort]
         = button_tag "Search", class: "btn submit btn-primary"
         = link_to "Reset", admin_namespaces_projects_path, class: "btn btn-cancel"
diff --git a/app/views/admin/projects/show.html.haml b/app/views/admin/projects/show.html.haml
index c638c32a654..73986d21bcf 100644
--- a/app/views/admin/projects/show.html.haml
+++ b/app/views/admin/projects/show.html.haml
@@ -5,6 +5,16 @@
     %i.fa.fa-pencil-square-o
     Edit
 %hr
+- if @project.last_repository_check_failed?
+  .row
+    .col-md-12
+      .panel
+        .panel-heading.alert.alert-danger
+          Last repository check
+          = "(#{time_ago_in_words(@project.last_repository_check_at)} ago)"
+          failed. See
+          = link_to 'repocheck.log', admin_logs_path
+          for error messages.
 .row
   .col-md-6
     .panel.panel-default
@@ -95,6 +105,32 @@
             .col-sm-offset-2.col-sm-10
               = f.submit 'Transfer', class: 'btn btn-primary'
 
+    .panel.panel-default.repository-check
+      .panel-heading
+        Repository check
+      .panel-body
+        = form_for @project, url: repository_check_admin_namespace_project_path(@project.namespace, @project), method: :post do |f|
+          .form-group
+            - if @project.last_repository_check_at.nil?
+              This repository has never been checked.
+            - else
+              This repository was last checked
+              = @project.last_repository_check_at.to_s(:medium) + '.'
+              The check
+              - if @project.last_repository_check_failed?
+                = succeed '.' do
+                  %strong.cred failed
+                See
+                = link_to 'repocheck.log', admin_logs_path
+                for error messages.
+              - else
+                passed.
+
+            = link_to icon('question-circle'), help_page_path('administration', 'repository_checks')
+
+          .form-group
+            = f.submit 'Trigger repository check', class: 'btn btn-primary'
+
   .col-md-6
     - if @group
       .panel.panel-default
diff --git a/app/views/repository_check_mailer/notify.html.haml b/app/views/repository_check_mailer/notify.html.haml
new file mode 100644
index 00000000000..df16f503570
--- /dev/null
+++ b/app/views/repository_check_mailer/notify.html.haml
@@ -0,0 +1,5 @@
+%p
+  #{@message}.
+
+%p
+  = link_to "See the affected projects in the GitLab admin panel", admin_namespaces_projects_url(last_repository_check_failed: 1)
diff --git a/app/views/repository_check_mailer/notify.text.haml b/app/views/repository_check_mailer/notify.text.haml
new file mode 100644
index 00000000000..02f3f80288a
--- /dev/null
+++ b/app/views/repository_check_mailer/notify.text.haml
@@ -0,0 +1,3 @@
+#{@message}.
+\
+View details: #{admin_namespaces_projects_url(last_repository_check_failed: 1)}
diff --git a/app/workers/admin_email_worker.rb b/app/workers/admin_email_worker.rb
new file mode 100644
index 00000000000..667fff031dd
--- /dev/null
+++ b/app/workers/admin_email_worker.rb
@@ -0,0 +1,12 @@
+class AdminEmailWorker
+  include Sidekiq::Worker
+
+  sidekiq_options retry: false # this job auto-repeats via sidekiq-cron
+
+  def perform
+    repository_check_failed_count = Project.where(last_repository_check_failed: true).count
+    return if repository_check_failed_count.zero?
+
+    RepositoryCheckMailer.notify(repository_check_failed_count).deliver_now
+  end
+end
diff --git a/app/workers/repository_check/batch_worker.rb b/app/workers/repository_check/batch_worker.rb
new file mode 100644
index 00000000000..44b3145d50f
--- /dev/null
+++ b/app/workers/repository_check/batch_worker.rb
@@ -0,0 +1,63 @@
+module RepositoryCheck
+  class BatchWorker
+    include Sidekiq::Worker
+  
+    RUN_TIME = 3600
+  
+    sidekiq_options retry: false
+  
+    def perform
+      start = Time.now
+  
+      # This loop will break after a little more than one hour ('a little
+      # more' because `git fsck` may take a few minutes), or if it runs out of
+      # projects to check. By default sidekiq-cron will start a new
+      # RepositoryCheckWorker each hour so that as long as there are repositories to
+      # check, only one (or two) will be checked at a time.
+      project_ids.each do |project_id|
+        break if Time.now - start >= RUN_TIME
+        break unless current_settings.repository_checks_enabled
+  
+        next unless try_obtain_lease(project_id)
+  
+        SingleRepositoryWorker.new.perform(project_id)
+      end
+    end
+  
+    private
+  
+    # Project.find_each does not support WHERE clauses and
+    # Project.find_in_batches does not support ordering. So we just build an
+    # array of ID's. This is OK because we do it only once an hour, because
+    # getting ID's from Postgres is not terribly slow, and because no user
+    # has to sit and wait for this query to finish.
+    def project_ids
+      limit = 10_000
+      never_checked_projects = Project.where('last_repository_check_at IS NULL').limit(limit).
+        pluck(:id)
+      old_check_projects = Project.where('last_repository_check_at < ?', 1.month.ago).
+        reorder('last_repository_check_at ASC').limit(limit).pluck(:id)
+      never_checked_projects + old_check_projects
+    end
+  
+    def try_obtain_lease(id)
+      # Use a 24-hour timeout because on servers/projects where 'git fsck' is
+      # super slow we definitely do not want to run it twice in parallel.
+      Gitlab::ExclusiveLease.new(
+        "project_repository_check:#{id}",
+        timeout: 24.hours
+      ).try_obtain
+    end
+  
+    def current_settings
+      # No caching of the settings! If we cache them and an admin disables
+      # this feature, an active RepositoryCheckWorker would keep going for up
+      # to 1 hour after the feature was disabled.
+      if Rails.env.test?
+        Gitlab::CurrentSettings.fake_application_settings
+      else
+        ApplicationSetting.current
+      end
+    end
+  end
+end
diff --git a/app/workers/repository_check/clear_worker.rb b/app/workers/repository_check/clear_worker.rb
new file mode 100644
index 00000000000..b7202ddff34
--- /dev/null
+++ b/app/workers/repository_check/clear_worker.rb
@@ -0,0 +1,17 @@
+module RepositoryCheck
+  class ClearWorker
+    include Sidekiq::Worker
+
+    sidekiq_options retry: false
+
+    def perform
+      # Do small batched updates because these updates will be slow and locking
+      Project.select(:id).find_in_batches(batch_size: 100) do |batch|
+        Project.where(id: batch.map(&:id)).update_all(
+          last_repository_check_failed: nil,
+          last_repository_check_at: nil,
+        )
+      end
+    end
+  end
+end
diff --git a/app/workers/repository_check/single_repository_worker.rb b/app/workers/repository_check/single_repository_worker.rb
new file mode 100644
index 00000000000..e54ae86d06c
--- /dev/null
+++ b/app/workers/repository_check/single_repository_worker.rb
@@ -0,0 +1,36 @@
+module RepositoryCheck
+  class SingleRepositoryWorker
+    include Sidekiq::Worker
+  
+    sidekiq_options retry: false
+  
+    def perform(project_id)
+      project = Project.find(project_id)
+      project.update_columns(
+        last_repository_check_failed: !check(project),
+        last_repository_check_at: Time.now,
+      )
+    end
+  
+    private
+  
+    def check(project)
+      # Use 'map do', not 'all? do', to prevent short-circuiting
+      [project.repository, project.wiki.repository].map do |repository|
+        git_fsck(repository.path_to_repo)
+      end.all?
+    end
+  
+    def git_fsck(path)
+      cmd = %W(nice git --git-dir=#{path} fsck)
+      output, status = Gitlab::Popen.popen(cmd)
+  
+      if status.zero?
+        true
+      else
+        Gitlab::RepositoryCheckLogger.error("command failed: #{cmd.join(' ')}\n#{output}")
+        false
+      end
+    end
+  end
+end
diff --git a/config/gitlab.yml.example b/config/gitlab.yml.example
index b28fc5c8e01..d9c15f81404 100644
--- a/config/gitlab.yml.example
+++ b/config/gitlab.yml.example
@@ -164,6 +164,13 @@ production: &base
     # Flag stuck CI builds as failed
     stuck_ci_builds_worker:
       cron: "0 0 * * *"
+    # Periodically run 'git fsck' on all repositories. If started more than
+    # once per hour you will have concurrent 'git fsck' jobs.
+    repository_check_worker:
+      cron: "20 * * * *"
+    # Send admin emails once a day
+    admin_email_worker:
+      cron: "0 0 * * *"
 
     # Remove outdated repository archives
     repository_archive_cache_worker:
diff --git a/config/initializers/1_settings.rb b/config/initializers/1_settings.rb
index 287f99c724d..10c25044b75 100644
--- a/config/initializers/1_settings.rb
+++ b/config/initializers/1_settings.rb
@@ -241,11 +241,16 @@ Settings['cron_jobs'] ||= Settingslogic.new({})
 Settings.cron_jobs['stuck_ci_builds_worker'] ||= Settingslogic.new({})
 Settings.cron_jobs['stuck_ci_builds_worker']['cron'] ||= '0 0 * * *'
 Settings.cron_jobs['stuck_ci_builds_worker']['job_class'] = 'StuckCiBuildsWorker'
+Settings.cron_jobs['repository_check_worker'] ||= Settingslogic.new({})
+Settings.cron_jobs['repository_check_worker']['cron'] ||= '20 * * * *'
+Settings.cron_jobs['repository_check_worker']['job_class'] = 'RepositoryCheck::BatchWorker'
+Settings.cron_jobs['admin_email_worker'] ||= Settingslogic.new({})
+Settings.cron_jobs['admin_email_worker']['cron'] ||= '0 0 * * *'
+Settings.cron_jobs['admin_email_worker']['job_class'] = 'AdminEmailWorker'
 Settings.cron_jobs['repository_archive_cache_worker'] ||= Settingslogic.new({})
 Settings.cron_jobs['repository_archive_cache_worker']['cron'] ||= '0 * * * *'
 Settings.cron_jobs['repository_archive_cache_worker']['job_class'] = 'RepositoryArchiveCacheWorker'
 
-
 #
 # GitLab Shell
 #
diff --git a/config/routes.rb b/config/routes.rb
index 688b83d2c95..408132f4217 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -264,6 +264,7 @@ Rails.application.routes.draw do
 
         member do
           put :transfer
+          post :repository_check
         end
 
         resources :runner_projects
@@ -281,6 +282,7 @@ Rails.application.routes.draw do
     resource :application_settings, only: [:show, :update] do
       resources :services
       put :reset_runners_token
+      put :clear_repository_check_states
     end
 
     resources :labels
diff --git a/db/migrate/20160315135439_project_add_repository_check.rb b/db/migrate/20160315135439_project_add_repository_check.rb
new file mode 100644
index 00000000000..8687d5d6296
--- /dev/null
+++ b/db/migrate/20160315135439_project_add_repository_check.rb
@@ -0,0 +1,8 @@
+class ProjectAddRepositoryCheck < ActiveRecord::Migration
+  def change
+    add_column :projects, :last_repository_check_failed, :boolean
+    add_index :projects, :last_repository_check_failed
+
+    add_column :projects, :last_repository_check_at, :datetime
+  end
+end
diff --git a/db/migrate/20160412140240_add_repository_checks_enabled_setting.rb b/db/migrate/20160412140240_add_repository_checks_enabled_setting.rb
new file mode 100644
index 00000000000..ebfa4bcbc7b
--- /dev/null
+++ b/db/migrate/20160412140240_add_repository_checks_enabled_setting.rb
@@ -0,0 +1,5 @@
+class AddRepositoryChecksEnabledSetting < ActiveRecord::Migration
+  def change
+    add_column :application_settings, :repository_checks_enabled, :boolean, default: true
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 44482de467e..d36e2b235e5 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20160331223143) do
+ActiveRecord::Schema.define(version: 20160412140240) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -77,6 +77,7 @@ ActiveRecord::Schema.define(version: 20160331223143) do
     t.string   "akismet_api_key"
     t.boolean  "email_author_in_body",              default: false
     t.integer  "default_group_visibility"
+    t.boolean  "repository_checks_enabled",         default: true
   end
 
   create_table "audit_events", force: :cascade do |t|
@@ -743,6 +744,8 @@ ActiveRecord::Schema.define(version: 20160331223143) do
     t.boolean  "public_builds",          default: true,     null: false
     t.string   "main_language"
     t.integer  "pushes_since_gc",        default: 0
+    t.boolean  "last_repository_check_failed"
+    t.datetime "last_repository_check_at"
   end
 
   add_index "projects", ["builds_enabled", "shared_runners_enabled"], name: "index_projects_on_builds_enabled_and_shared_runners_enabled", using: :btree
@@ -752,6 +755,7 @@ ActiveRecord::Schema.define(version: 20160331223143) do
   add_index "projects", ["creator_id"], name: "index_projects_on_creator_id", using: :btree
   add_index "projects", ["description"], name: "index_projects_on_description_trigram", using: :gin, opclasses: {"description"=>"gin_trgm_ops"}
   add_index "projects", ["last_activity_at"], name: "index_projects_on_last_activity_at", using: :btree
+  add_index "projects", ["last_repository_check_failed"], name: "index_projects_on_last_repository_check_failed", using: :btree
   add_index "projects", ["name"], name: "index_projects_on_name_trigram", using: :gin, opclasses: {"name"=>"gin_trgm_ops"}
   add_index "projects", ["namespace_id"], name: "index_projects_on_namespace_id", using: :btree
   add_index "projects", ["path"], name: "index_projects_on_path", using: :btree
diff --git a/doc/README.md b/doc/README.md
index d2660930653..e6ac4794827 100644
--- a/doc/README.md
+++ b/doc/README.md
@@ -31,6 +31,7 @@
 - [Environment Variables](administration/environment_variables.md) to configure GitLab.
 - [Operations](operations/README.md) Keeping GitLab up and running
 - [Raketasks](raketasks/README.md) Backups, maintenance, automatic webhook setup and the importing of projects.
+- [Repository checks](administration/repository_checks.md) Periodic Git repository checks
 - [Security](security/README.md) Learn what you can do to further secure your GitLab instance.
 - [System hooks](system_hooks/system_hooks.md) Notifications when users, projects and keys are changed.
 - [Update](update/README.md) Update guides to upgrade your installation.
diff --git a/doc/administration/repository_checks.md b/doc/administration/repository_checks.md
new file mode 100644
index 00000000000..61bf8ce6161
--- /dev/null
+++ b/doc/administration/repository_checks.md
@@ -0,0 +1,43 @@
+# Repository checks
+
+>**Note:**
+This feature was [introduced][ce-3232] in GitLab 8.7.
+
+Git has a built-in mechanism, [git fsck][git-fsck], to verify the
+integrity of all data commited to a repository. GitLab administrators
+can trigger such a check for a project via the project page under the
+admin panel. The checks run asynchronously so it may take a few minutes
+before the check result is visible on the project admin page. If the
+checks failed you can see their output on the admin log page under
+'repocheck.log'.
+
+## Periodic checks
+
+GitLab periodically runs a repository check on all project repositories and
+wiki repositories in order to detect data corruption problems. A
+project will be checked no more than once per week. If any projects
+fail their repository checks all GitLab administrators will receive an email
+notification of the situation. This notification is sent out no more
+than once a day.
+
+## Disabling periodic checks
+
+You can disable the periodic checks on the 'Settings' page of the admin
+panel.
+
+## What to do if a check failed
+
+If the repository check fails for some repository you should look up the error
+in repocheck.log (in the admin panel or on disk; see
+`/var/log/gitlab/gitlab-rails` for Omnibus installations or
+`/home/git/gitlab/log` for installations from source). Once you have
+resolved the issue use the admin panel to trigger a new repository check on
+the project. This will clear the 'check failed' state.
+
+If for some reason the periodic repository check caused a lot of false
+alarms you can choose to clear ALL repository check states from the
+'Settings' page of the admin panel.
+
+---
+[ce-3232]: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/3232 "Auto git fsck"
+[git-fsck]: https://www.kernel.org/pub/software/scm/git/docs/git-fsck.html "git fsck documentation"
\ No newline at end of file
diff --git a/lib/gitlab/current_settings.rb b/lib/gitlab/current_settings.rb
index 1acc22fe5bf..f44d1b3a44e 100644
--- a/lib/gitlab/current_settings.rb
+++ b/lib/gitlab/current_settings.rb
@@ -34,7 +34,8 @@ module Gitlab
         max_artifacts_size: Settings.artifacts['max_size'],
         require_two_factor_authentication: false,
         two_factor_grace_period: 48,
-        akismet_enabled: false
+        akismet_enabled: false,
+        repository_checks_enabled: true,
       )
     end
 
diff --git a/lib/gitlab/repository_check_logger.rb b/lib/gitlab/repository_check_logger.rb
new file mode 100644
index 00000000000..485b596ca57
--- /dev/null
+++ b/lib/gitlab/repository_check_logger.rb
@@ -0,0 +1,7 @@
+module Gitlab
+  class RepositoryCheckLogger < Gitlab::Logger
+    def self.file_name_noext
+      'repocheck'
+    end
+  end
+end
diff --git a/spec/features/admin/admin_uses_repository_checks_spec.rb b/spec/features/admin/admin_uses_repository_checks_spec.rb
new file mode 100644
index 00000000000..661fb761809
--- /dev/null
+++ b/spec/features/admin/admin_uses_repository_checks_spec.rb
@@ -0,0 +1,43 @@
+require 'rails_helper'
+
+feature 'Admin uses repository checks', feature: true do
+  before { login_as :admin }
+
+  scenario 'to trigger a single check' do
+    project = create(:empty_project)
+    visit_admin_project_page(project)
+
+    page.within('.repository-check') do
+      click_button 'Trigger repository check'
+    end
+
+    expect(page).to have_content('Repository check was triggered')
+  end
+
+  scenario 'to see a single failed repository check' do
+    project = create(:empty_project)
+    project.update_columns(
+      last_repository_check_failed: true,
+      last_repository_check_at: Time.now,
+    )
+    visit_admin_project_page(project)
+
+    page.within('.alert') do
+      expect(page.text).to match(/Last repository check \(.* ago\) failed/)
+    end
+  end
+
+  scenario 'to clear all repository checks', js: true do
+    visit admin_application_settings_path
+    
+    expect(RepositoryCheck::ClearWorker).to receive(:perform_async)
+
+    click_link 'Clear all repository checks'
+
+    expect(page).to have_content('Started asynchronous removal of all repository check states.')
+  end
+
+  def visit_admin_project_page(project)
+    visit admin_namespace_project_path(project.namespace, project)
+  end
+end
diff --git a/spec/mailers/repository_check_mailer_spec.rb b/spec/mailers/repository_check_mailer_spec.rb
new file mode 100644
index 00000000000..583bf15176f
--- /dev/null
+++ b/spec/mailers/repository_check_mailer_spec.rb
@@ -0,0 +1,21 @@
+require 'rails_helper'
+
+describe RepositoryCheckMailer do
+  include EmailSpec::Matchers
+
+  describe '.notify' do
+    it 'emails all admins' do
+      admins = create_list(:admin, 3)
+
+      mail = described_class.notify(1)
+
+      expect(mail).to deliver_to admins.map(&:email)
+    end
+
+    it 'mentions the number of failed checks' do
+      mail = described_class.notify(3)
+
+      expect(mail).to have_subject '3 projects failed their last repository check'
+    end
+  end
+end
diff --git a/spec/workers/repository_check/batch_worker_spec.rb b/spec/workers/repository_check/batch_worker_spec.rb
new file mode 100644
index 00000000000..f486e45ddad
--- /dev/null
+++ b/spec/workers/repository_check/batch_worker_spec.rb
@@ -0,0 +1,39 @@
+require 'spec_helper'
+
+describe RepositoryCheck::BatchWorker do
+  subject { described_class.new }
+
+  it 'prefers projects that have never been checked' do
+    projects = create_list(:project, 3)
+    projects[0].update_column(:last_repository_check_at, 4.months.ago)
+    projects[2].update_column(:last_repository_check_at, 3.months.ago)
+
+    expect(subject.perform).to eq(projects.values_at(1, 0, 2).map(&:id))
+  end
+
+  it 'sorts projects by last_repository_check_at' do
+    projects = create_list(:project, 3)
+    projects[0].update_column(:last_repository_check_at, 2.months.ago)
+    projects[1].update_column(:last_repository_check_at, 4.months.ago)
+    projects[2].update_column(:last_repository_check_at, 3.months.ago)
+
+    expect(subject.perform).to eq(projects.values_at(1, 2, 0).map(&:id))
+  end
+
+  it 'excludes projects that were checked recently' do
+    projects = create_list(:project, 3)
+    projects[0].update_column(:last_repository_check_at, 2.days.ago)
+    projects[1].update_column(:last_repository_check_at, 2.months.ago)
+    projects[2].update_column(:last_repository_check_at, 3.days.ago)
+
+    expect(subject.perform).to eq([projects[1].id])
+  end
+
+  it 'does nothing when repository checks are disabled' do
+    create(:empty_project)
+    current_settings = double('settings', repository_checks_enabled: false)
+    expect(subject).to receive(:current_settings) { current_settings }
+
+    expect(subject.perform).to eq(nil)
+  end
+end
diff --git a/spec/workers/repository_check/clear_worker_spec.rb b/spec/workers/repository_check/clear_worker_spec.rb
new file mode 100644
index 00000000000..a3b70c74787
--- /dev/null
+++ b/spec/workers/repository_check/clear_worker_spec.rb
@@ -0,0 +1,17 @@
+require 'spec_helper'
+
+describe RepositoryCheck::ClearWorker do
+  it 'clears repository check columns' do
+    project = create(:empty_project)
+    project.update_columns(
+      last_repository_check_failed: true,
+      last_repository_check_at: Time.now,
+    )
+
+    described_class.new.perform
+    project.reload
+
+    expect(project.last_repository_check_failed).to be_nil
+    expect(project.last_repository_check_at).to be_nil
+  end
+end