Merge branch 'sourcegraph' into 'master'

Add Sourcegraph integration

Closes #20642

See merge request gitlab-org/gitlab!16556

app/assets/javascripts/pages/projects/blob/show/index.js

@@ -3,6 +3,7 @@ import commitPipelineStatus from '~/projects/tree/components/commit_pipeline_sta
 import BlobViewer from '~/blob/viewer/index';
 import initBlob from '~/pages/projects/init_blob';
 import GpgBadges from '~/gpg_badges';
+import '~/sourcegraph/load';
 
 document.addEventListener('DOMContentLoaded', () => {
   new BlobViewer(); // eslint-disable-line no-new

app/assets/javascripts/pages/projects/commit/show/index.js

@@ -9,6 +9,7 @@ import initNotes from '~/init_notes';
 import initChangesDropdown from '~/init_changes_dropdown';
 import initDiffNotes from '~/diff_notes/diff_notes_bundle';
 import { fetchCommitMergeRequests } from '~/commit_merge_requests';
+import '~/sourcegraph/load';
 
 document.addEventListener('DOMContentLoaded', () => {
   const hasPerfBar = document.querySelector('.with-performance-bar');

app/assets/javascripts/pages/projects/merge_requests/init_merge_request_show.js

@@ -5,6 +5,7 @@ import { handleLocationHash } from '~/lib/utils/common_utils';
 import howToMerge from '~/how_to_merge';
 import initPipelines from '~/commit/pipelines/pipelines_bundle';
 import initVueIssuableSidebarApp from '~/issuable_sidebar/sidebar_bundle';
+import initSourcegraph from '~/sourcegraph';
 import initWidget from '../../../vue_merge_request_widget';
 
 export default function() {
@@ -19,4 +20,5 @@ export default function() {
   handleLocationHash();
   howToMerge();
   initWidget();
+  initSourcegraph();
 }

app/assets/javascripts/sourcegraph/index.js

+function loadScript(path) {
+  const script = document.createElement('script');
+  script.type = 'application/javascript';
+  script.src = path;
+  script.defer = true;
+  document.head.appendChild(script);
+}
+
+/**
+ * Loads the Sourcegraph integration for support for Sourcegraph extensions and
+ * code intelligence.
+ */
+export default function initSourcegraph() {
+  const { url } = gon.sourcegraph || {};
+
+  if (!url) {
+    return;
+  }
+
+  const assetsUrl = new URL('/assets/webpack/sourcegraph/', window.location.href);
+  const scriptPath = new URL('scripts/integration.bundle.js', assetsUrl).href;
+
+  window.SOURCEGRAPH_ASSETS_URL = assetsUrl.href;
+  window.SOURCEGRAPH_URL = url;
+  window.SOURCEGRAPH_INTEGRATION = 'gitlab-integration';
+
+  loadScript(scriptPath);
+}

app/assets/javascripts/sourcegraph/load.js

+import initSourcegraph from './index';
+
+/**
+ * Load sourcegraph in it's own listener so that it's isolated from failures.
+ */
+document.addEventListener('DOMContentLoaded', initSourcegraph);

app/controllers/concerns/sourcegraph_gon.rb

+# frozen_string_literal: true
+
+module SourcegraphGon
+  extend ActiveSupport::Concern
+
+  included do
+    before_action :push_sourcegraph_gon, if: :html_request?
+  end
+
+  private
+
+  def push_sourcegraph_gon
+    return unless sourcegraph_enabled?
+
+    gon.push({
+      sourcegraph: { url: Gitlab::CurrentSettings.sourcegraph_url }
+    })
+  end
+
+  def sourcegraph_enabled?
+    Gitlab::CurrentSettings.sourcegraph_enabled && sourcegraph_enabled_for_project? && current_user&.sourcegraph_enabled
+  end
+
+  def sourcegraph_enabled_for_project?
+    return false unless project && Gitlab::Sourcegraph.feature_enabled?(project)
+    return project.public? if Gitlab::CurrentSettings.sourcegraph_public_only
+
+    true
+  end
+end

app/controllers/profiles/preferences_controller.rb

@@ -47,7 +47,8 @@ class Profiles::PreferencesController < Profiles::ApplicationController
       :preferred_language,
       :time_display_relative,
       :time_format_in_24h,
-      :show_whitespace_in_diffs
+      :show_whitespace_in_diffs,
+      :sourcegraph_enabled
     ]
   end
 end

app/controllers/projects/blob_controller.rb

@@ -8,6 +8,8 @@ class Projects::BlobController < Projects::ApplicationController
   include NotesHelper
   include ActionView::Helpers::SanitizeHelper
   include RedirectsForMissingPathOnTree
+  include SourcegraphGon
+
   prepend_before_action :authenticate_user!, only: [:edit]
 
   around_action :allow_gitaly_ref_name_caching, only: [:show]

app/controllers/projects/commit_controller.rb

@@ -8,6 +8,7 @@ class Projects::CommitController < Projects::ApplicationController
   include CreatesCommit
   include DiffForPath
   include DiffHelper
+  include SourcegraphGon
 
   # Authorize
   before_action :require_non_empty_project

app/controllers/projects/merge_requests_controller.rb

@@ -9,6 +9,7 @@ class Projects::MergeRequestsController < Projects::MergeRequests::ApplicationCo
   include ToggleAwardEmoji
   include IssuableCollections
   include RecordUserLastActivity
+  include SourcegraphGon
 
   skip_before_action :merge_request, only: [:index, :bulk_update]
   before_action :whitelist_query_limiting, only: [:assign_related_issues, :update]

app/helpers/application_settings_helper.rb

@@ -259,6 +259,9 @@ module ApplicationSettingsHelper
       :shared_runners_text,
       :sign_in_text,
       :signup_enabled,
+      :sourcegraph_enabled,
+      :sourcegraph_url,
+      :sourcegraph_public_only,
       :terminal_max_session_time,
       :terms,
       :throttle_authenticated_api_enabled,

app/helpers/sourcegraph_helper.rb

+# frozen_string_literal: true
+
+module SourcegraphHelper
+  def sourcegraph_url_message
+    link_start = '<a href="%{url}" target="_blank" rel="noopener noreferrer">'.html_safe % { url: Gitlab::CurrentSettings.sourcegraph_url }
+    link_end = "#{sprite_icon('external-link', size: 12, css_class: 'ml-1 vertical-align-center')}</a>".html_safe
+
+    message =
+      if Gitlab::CurrentSettings.sourcegraph_url_is_com?
+        s_('SourcegraphPreferences|Uses %{link_start}Sourcegraph.com%{link_end}.').html_safe
+      else
+        s_('SourcegraphPreferences|Uses a custom %{link_start}Sourcegraph instance%{link_end}.').html_safe
+      end
+
+    message % { link_start: link_start, link_end: link_end }
+  end
+
+  def sourcegraph_experimental_message
+    if Gitlab::Sourcegraph.feature_conditional?
+      s_("SourcegraphPreferences|This feature is experimental and currently limited to certain projects.")
+    elsif Gitlab::CurrentSettings.sourcegraph_public_only
+      s_("SourcegraphPreferences|This feature is experimental and limited to public projects.")
+    else
+      s_("SourcegraphPreferences|This feature is experimental.")
+    end
+  end
+end

app/models/application_setting.rb

@@ -99,6 +99,10 @@ class ApplicationSetting < ApplicationRecord
             presence: true,
             if: :plantuml_enabled
 
+  validates :sourcegraph_url,
+            presence: true,
+            if: :sourcegraph_enabled
+
   validates :snowplow_collector_hostname,
             presence: true,
             hostname: true,
@@ -343,6 +347,10 @@ class ApplicationSetting < ApplicationRecord
   end
   after_commit :expire_performance_bar_allowed_user_ids_cache, if: -> { previous_changes.key?('performance_bar_allowed_group_id') }
 
+  def sourcegraph_url_is_com?
+    !!(sourcegraph_url =~ /\Ahttps:\/\/(www\.)?sourcegraph\.com/)
+  end
+
   def self.create_from_defaults
     transaction(requires_new: true) do
       super

app/models/application_setting_implementation.rb

@@ -102,6 +102,9 @@ module ApplicationSettingImplementation
         shared_runners_text: nil,
         sign_in_text: nil,
         signup_enabled: Settings.gitlab['signup_enabled'],
+        sourcegraph_enabled: false,
+        sourcegraph_url: nil,
+        sourcegraph_public_only: true,
         terminal_max_session_time: 0,
         throttle_authenticated_api_enabled: false,
         throttle_authenticated_api_period_in_seconds: 3600,

app/models/user.rb

@@ -240,6 +240,7 @@ class User < ApplicationRecord
   delegate :time_display_relative, :time_display_relative=, to: :user_preference
   delegate :time_format_in_24h, :time_format_in_24h=, to: :user_preference
   delegate :show_whitespace_in_diffs, :show_whitespace_in_diffs=, to: :user_preference
+  delegate :sourcegraph_enabled, :sourcegraph_enabled=, to: :user_preference
   delegate :setup_for_company, :setup_for_company=, to: :user_preference
 
   accepts_nested_attributes_for :user_preference, update_only: true

app/views/admin/application_settings/_sourcegraph.html.haml

+- return unless Gitlab::Sourcegraph.feature_available?
+- expanded = integration_expanded?('sourcegraph_')
+
+%section.settings.as-sourcegraph.no-animate#js-sourcegraph-settings{ class: ('expanded' if expanded) }
+  .settings-header
+    %h4
+      = _('Sourcegraph')
+    %button.btn.btn-default.js-settings-toggle{ type: 'button' }
+      = expanded ? _('Collapse') : _('Expand')
+    %p
+      - link_start = '<a href="%{url}" target="_blank" rel="noopener noreferrer">'.html_safe % { url: 'https://sourcegraph.com/' }
+      - link_end = "#{sprite_icon('external-link', size: 12, css_class: 'ml-1 vertical-align-center')}</a>".html_safe
+      = s_('SourcegraphAdmin|Enable code intelligence powered by %{link_start}Sourcegraph%{link_end} on your GitLab instance\'s code views and merge requests.').html_safe % { link_start: link_start, link_end: link_end }
+      %span
+        = link_to s_('SourcegraphAdmin|More information'), help_page_path('integration/sourcegraph.md'), target: '_blank'
+
+
+  .settings-content
+    = form_for @application_setting, url: integrations_admin_application_settings_path(anchor: 'js-sourcegraph-settings'), html: { class: 'fieldset-form' } do |f|
+      = form_errors(@application_setting)
+
+      %fieldset
+        .form-group
+          .form-check
+            = f.check_box :sourcegraph_enabled, class: 'form-check-input'
+            = f.label :sourcegraph_enabled, s_('SourcegraphAdmin|Enable Sourcegraph'), class: 'form-check-label'
+        .form-group
+          .form-check
+            = f.check_box :sourcegraph_public_only, class: 'form-check-input'
+            = f.label :sourcegraph_public_only, s_('SourcegraphAdmin|Block on private and internal projects'), class: 'form-check-label'
+            .form-text.text-muted
+              = s_('SourcegraphAdmin|If checked, only public projects will have code intelligence and communicate with Sourcegraph.')
+        .form-group
+          = f.label :sourcegraph_url, s_('SourcegraphAdmin|Sourcegraph URL'), class: 'label-bold'
+          = f.text_field :sourcegraph_url, class: 'form-control', placeholder: s_('SourcegraphAdmin|e.g. https://sourcegraph.example.com')
+          .form-text.text-muted
+            = s_('SourcegraphAdmin|Configure the URL to a Sourcegraph instance which can read your GitLab projects.')
+      = f.submit s_('SourcegraphAdmin|Save changes'), class: 'btn btn-success'

app/views/admin/application_settings/integrations.html.haml

@@ -4,6 +4,7 @@
 
 = render_if_exists 'admin/application_settings/elasticsearch_form'
 = render 'admin/application_settings/plantuml'
+= render 'admin/application_settings/sourcegraph'
 = render_if_exists 'admin/application_settings/slack'
 = render 'admin/application_settings/third_party_offers'
 = render 'admin/application_settings/snowplow'

app/views/profiles/preferences/_sourcegraph.html.haml

+- return unless Gitlab::Sourcegraph::feature_available? && Gitlab::CurrentSettings.sourcegraph_enabled
+- sourcegraph_url = Gitlab::CurrentSettings.sourcegraph_url
+
+.col-sm-12
+  %hr
+
+.col-lg-4.profile-settings-sidebar
+  %h4.prepend-top-0
+    = s_('Preferences|Integrations')
+  %p
+    = s_('Preferences|Customize integrations with third party services.')
+    = succeed '.' do
+      = link_to _('Learn more'), help_page_path('user/profile/preferences.md', anchor: 'integrations'), target: '_blank'
+.col-lg-8
+  %label.label-bold
+    = s_('Preferences|Sourcegraph')
+  = link_to icon('question-circle'), help_page_path('user/profile/preferences.md', anchor: 'sourcegraph'), target: '_blank', class: 'has-tooltip', title: _('More information')
+  .form-group.form-check
+    = f.check_box :sourcegraph_enabled, class: 'form-check-input'
+    = f.label :sourcegraph_enabled, class: 'form-check-label' do
+      - link_start = '<a href="%{url}">'.html_safe % { url: sourcegraph_url }
+      - link_end = '</a>'.html_safe
+      = s_('Preferences|Enable integrated code intelligence on code views').html_safe % { link_start: link_start, link_end: link_end }
+    .form-text.text-muted
+      = sourcegraph_url_message
+      = sourcegraph_experimental_message

app/views/profiles/preferences/show.html.haml

@@ -111,6 +111,9 @@
             = time_display_label
           .form-text.text-muted
             = s_('Preferences|For example: 30 mins ago.')
+
+  = render 'sourcegraph', f: f
+
   .col-lg-4.profile-settings-sidebar
   .col-lg-8
     .form-group

config/webpack.config.js

@@ -299,6 +299,11 @@ module.exports = {
         from: path.join(ROOT_PATH, 'node_modules/pdfjs-dist/cmaps/'),
         to: path.join(ROOT_PATH, 'public/assets/webpack/cmaps/'),
       },
+      {
+        from: path.join(ROOT_PATH, 'node_modules/@sourcegraph/code-host-integration/'),
+        to: path.join(ROOT_PATH, 'public/assets/webpack/sourcegraph/'),
+        ignore: ['package.json'],
+      },
       {
         from: path.join(
           ROOT_PATH,

db/migrate/20190827222124_add_sourcegraph_configuration_to_application_settings.rb

+# frozen_string_literal: true
+
+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class AddSourcegraphConfigurationToApplicationSettings < ActiveRecord::Migration[5.2]
+  include Gitlab::Database::MigrationHelpers
+
+  # Set this constant to true if this migration requires downtime.
+  DOWNTIME = false
+
+  def up
+    add_column(:application_settings, :sourcegraph_enabled, :boolean, default: false, null: false)
+    add_column(:application_settings, :sourcegraph_url, :string, null: true, limit: 255)
+  end
+
+  def down
+    remove_column(:application_settings, :sourcegraph_enabled)
+    remove_column(:application_settings, :sourcegraph_url)
+  end
+end

db/migrate/20191107173446_add_sourcegraph_admin_and_user_preferences.rb

+# frozen_string_literal: true
+
+class AddSourcegraphAdminAndUserPreferences < ActiveRecord::Migration[5.2]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  def up
+    add_column(:application_settings, :sourcegraph_public_only, :boolean, default: true, null: false)
+    add_column(:user_preferences, :sourcegraph_enabled, :boolean)
+  end
+
+  def down
+    remove_column(:application_settings, :sourcegraph_public_only)
+    remove_column(:user_preferences, :sourcegraph_enabled)
+  end
+end

db/schema.rb

@@ -352,6 +352,9 @@ ActiveRecord::Schema.define(version: 2019_11_14_173624) do
     t.string "snowplow_app_id"
     t.datetime_with_timezone "productivity_analytics_start_date"
     t.string "default_ci_config_path", limit: 255
+    t.boolean "sourcegraph_enabled", default: false, null: false
+    t.string "sourcegraph_url", limit: 255
+    t.boolean "sourcegraph_public_only", default: true, null: false
     t.index ["custom_project_templates_group_id"], name: "index_application_settings_on_custom_project_templates_group_id"
     t.index ["file_template_project_id"], name: "index_application_settings_on_file_template_project_id"
     t.index ["instance_administration_project_id"], name: "index_applicationsettings_on_instance_administration_project_id"
@@ -3771,6 +3774,7 @@ ActiveRecord::Schema.define(version: 2019_11_14_173624) do
     t.boolean "time_format_in_24h"
     t.string "projects_sort", limit: 64
     t.boolean "show_whitespace_in_diffs", default: true, null: false
+    t.boolean "sourcegraph_enabled"
     t.boolean "setup_for_company"
     t.index ["user_id"], name: "index_user_preferences_on_user_id", unique: true
   end

doc/api/settings.md

@@ -324,6 +324,9 @@ are listed in the descriptions of the relevant settings.
 | `snowplow_enabled`                       | boolean          | no                                   | Enable snowplow tracking. |
 | `snowplow_app_id`                        | string           | no                                   | The Snowplow site name / application id. (e.g. `gitlab`) |
 | `snowplow_iglu_registry_url`             | string           | no                                   | The Snowplow base Iglu Schema Registry URL to use for custom context and self describing events'|
+| `sourcegraph_enabled`                    | boolean          | no                                    | Enables Sourcegraph integration. Default is `false`. **If enabled, requires** `sourcegraph_url`. |
+| `sourcegraph_url`                        | string           | required by: `sourcegraph_enabled`    | The Sourcegraph instance URL for integration. |
+| `sourcegraph_public_only`                | boolean          | no                                   | Blocks Sourcegraph from being loaded on private and internal projects. Defaul is `true`. |
 | `terminal_max_session_time`              | integer          | no                                   | Maximum time for web terminal websocket connection (in seconds). Set to `0` for unlimited time. |
 | `terms`                                  | text             | required by: `enforce_terms`         | (**Required by:** `enforce_terms`) Markdown content for the ToS. |
 | `throttle_authenticated_api_enabled`     | boolean          | no                                   | (**If enabled, requires:** `throttle_authenticated_api_period_in_seconds` and `throttle_authenticated_api_requests_per_period`) Enable authenticated API request rate limit. Helps reduce request volume (e.g. from crawlers or abusive bots). |

doc/integration/README.md

@@ -54,6 +54,7 @@ GitLab can be integrated with the following enhancements:
 - Add GitLab actions to [Gmail actions buttons](gmail_action_buttons_for_gitlab.md).
 - Configure [PlantUML](../administration/integration/plantuml.md) to use diagrams in AsciiDoc documents.
 - Attach merge requests to [Trello](trello_power_up.md) cards.
+- Enable integrated code intelligence powered by [Sourcegraph](sourcegraph.md).
 
 ## Project services
 

doc/integration/sourcegraph.md

+---
+type: reference, how-to
+---
+
+# Sourcegraph integration
+
+> [Introduced](https://gitlab.com/gitlab-org/gitlab/merge_requests/16556) in GitLab 12.5. Please note that this integration is [behind a feature flag](#enable-the-sourcegraph-feature-flag).
+
+[Sourcegraph](https://sourcegraph.com) provides code intelligence features, natively integrated into the GitLab UI.
+
+For GitLab.com users, see [Sourcegraph for GitLab.com](#sourcegraph-for-gitlabcom).
+
+![Sourcegraph demo](img/sourcegraph_demo_v12_5.png)
+
+NOTE: **Note:**
+This feature requires user opt-in. After Sourcegraph has been enabled for your GitLab instance,
+you can choose to enable Sourcegraph [through your user preferences](#enable-sourcegraph-in-user-preferences).
+
+## Set up for self-managed GitLab instances **(CORE ONLY)**
+
+Before you can enable Sourcegraph code intelligence in GitLab you will need to:
+
+- Enable the `sourcegraph` feature flag for your GitLab instance.
+- Configure a Sourcegraph instance with your GitLab instance as an external service.
+
+### Enable the Sourcegraph feature flag
+
+NOTE: **Note:**
+If you are running a self-managed instance, the Sourcegraph integration will not be available
+unless the feature flag `sourcegraph` is enabled. This can be done from the Rails console
+by instance administrators.
+
+Use these commands to start the Rails console:
+
+```sh
+# Omnibus GitLab
+gitlab-rails console
+
+# Installation from source
+cd /home/git/gitlab
+sudo -u git -H bin/rails console RAILS_ENV=production
+```
+
+Then run the following command to enable the feature flag:
+
+```
+Feature.enable(:sourcegraph)
+```
+
+You can also enable the feature flag only for specific projects with:
+
+```
+Feature.enable(:sourcegraph, Project.find_by_full_path('my_group/my_project'))
+```
+
+### Set up a self-managed Sourcegraph instance
+
+If you are new to Sourcegraph, head over to the [Sourcegraph installation documentation](https://docs.sourcegraph.com/admin) and get your instance up and running.
+
+### Connect your Sourcegraph instance to your GitLab instance
+
+1. Navigate to the site admin area in Sourcegraph.
+1. [Configure your GitLab external service](https://docs.sourcegraph.com/admin/external_service/gitlab).
+You can skip this step if you already have your GitLab repositories searchable in Sourcegraph.
+1. Validate that you can search your repositories from GitLab in your Sourcegraph instance by running a test query.
+1. Add your GitLab instance URL to the [`corsOrigin` setting](https://docs.sourcegraph.com/admin/config/site_config#corsOrigin) in your site configuration.
+
+### Configure your GitLab instance with Sourcegraph
+
+1. In GitLab, go to **Admin Area > Settings > Integrations**.
+1. Expand the **Sourcegraph** configuration section.
+1. Check **Enable Sourcegraph**.
+1. Set the Sourcegraph URL to your Sourcegraph instance, e.g., `https://sourcegraph.example.com`.
+
+![Sourcegraph admin settings](img/sourcegraph_admin_v12_5.png)
+
+## Enable Sourcegraph in user preferences
+
+If a GitLab administrator has enabled Sourcegraph, you can enable this feature in your user preferences.
+
+1. In GitLab, click your avatar in the top-right corner, then click **Settings**. On the left-hand nav, click **Preferences**.
+1. Under **Integrations**, find the **Sourcegraph** section.
+1. Check **Enable Sourcegraph**.
+
+![Sourcegraph user preferences](img/sourcegraph_user_preferences_v12_5.png)
+
+## Using Sourcegraph code intelligence
+
+Once enabled, participating projects will have a code intelligence popover available in
+the following code views:
+
+- Merge request diffs
+- Commit view
+- File view
+
+When visiting one of these views, you can now hover over a code reference to see a popover with:
+
+- Details on how this reference was defined.
+- **Go to definition**, which navigates to the line of code where this reference was defined.
+- **Find references**, which navigates to the configured Sourcegraph instance, showing a list of references to the hilighted code.
+
+![Sourcegraph demo](img/sourcegraph_popover_v12_5.png)
+
+## Sourcegraph for GitLab.com
+
+Sourcegraph powered code intelligence will be incrementally rolled out on GitLab.com. It will eventually be
+available for all public projects, but for now, it is only available for some specific [`gitlab-org` projects](https://gitlab.com/gitlab-org/).
+
+If you have a private or internal project and would like integrated code intelligence, please consider
+setting up a self-managed GitLab instance.
+
+## Sourcegraph and Privacy
+
+From Sourcegraph's [extension documentation](https://docs.sourcegraph.com/integration/browser_extension#privacy) which is the
+engine behind the native GitLab integration:
+
+> Sourcegraph integrations never send any logs, pings, usage statistics, or telemetry to Sourcegraph.com.
+> They will only connect to Sourcegraph.com as required to provide code intelligence or other functionality on public code.
+> As a result, no private code, private repository names, usernames, or any other specific data is sent to Sourcegraph.com.

doc/user/profile/preferences.md

@@ -128,6 +128,19 @@ You can choose one of the following options as the first day of the week:
 
 If you select **System Default**, the system-wide default setting will be used.
 
+## Integrations
+
+Configure your preferences with third-party services which provide enhancements to your GitLab experience.
+
+### Sourcegraph
+
+NOTE: **Note:**
+This setting is only visible if Sourcegraph has been enabled by a GitLab administrator.
+
+Manage the availability of integrated code intelligence features powered by
+Sourcegraph. View [the Sourcegraph feature documentation](../../integration/sourcegraph.md#enable-sourcegraph-in-user-preferences)
+for more information.
+
 <!-- ## Troubleshooting
 
 Include any troubleshooting steps that you can foresee. If you know beforehand what issues

lib/api/settings.rb

@@ -136,6 +136,11 @@ module API
       optional :sign_in_text, type: String, desc: 'The sign in text of the GitLab application'
       optional :signin_enabled, type: Boolean, desc: 'Flag indicating if password authentication is enabled for the web interface' # support legacy names, can be removed in v5
       optional :signup_enabled, type: Boolean, desc: 'Flag indicating if sign up is enabled'
+      optional :sourcegraph_enabled, type: Boolean, desc: 'Enable Sourcegraph'
+      optional :sourcegraph_public_only, type: Boolean, desc: 'Only allow public projects to communicate with Sourcegraph'
+      given sourcegraph_enabled: ->(val) { val } do
+        requires :sourcegraph_url, type: String, desc: 'The configured Sourcegraph instance URL'
+      end
       optional :terminal_max_session_time, type: Integer, desc: 'Maximum time for web terminal websocket connection (in seconds). Set to 0 for unlimited time.'
       optional :usage_ping_enabled, type: Boolean, desc: 'Every week GitLab will report license usage back to GitLab, Inc.'
       optional :instance_statistics_visibility_private, type: Boolean, desc: 'When set to `true` Instance statistics will only be available to admins'

lib/gitlab/sourcegraph.rb

+# frozen_string_literal: true
+
+module Gitlab
+  class Sourcegraph
+    class << self
+      def feature_conditional?
+        feature.conditional?
+      end
+
+      def feature_available?
+        # The sourcegraph_bundle feature could be conditionally applied, so check if `!off?`
+        !feature.off?
+      end
+
+      def feature_enabled?(thing = nil)
+        feature.enabled?(thing)
+      end
+
+      private
+
+      def feature
+        Feature.get(:sourcegraph)
+      end
+    end
+  end
+end

locale/gitlab.pot

@@ -12541,6 +12541,9 @@ msgstr ""
 msgid "Preferences|Choose what content you want to see on a project’s overview page."
 msgstr ""
 
+msgid "Preferences|Customize integrations with third party services."
+msgstr ""
+
 msgid "Preferences|Customize the appearance of the application header and navigation sidebar."
 msgstr ""
 
@@ -12550,9 +12553,15 @@ msgstr ""
 msgid "Preferences|Display time in 24-hour format"
 msgstr ""
 
+msgid "Preferences|Enable integrated code intelligence on code views"
+msgstr ""
+
 msgid "Preferences|For example: 30 mins ago."
 msgstr ""
 
+msgid "Preferences|Integrations"
+msgstr ""
+
 msgid "Preferences|Layout width"
 msgstr ""
 
@@ -12565,6 +12574,9 @@ msgstr ""
 msgid "Preferences|Show whitespace in diffs"
 msgstr ""
 
+msgid "Preferences|Sourcegraph"
+msgstr ""
+
 msgid "Preferences|Syntax highlighting theme"
 msgstr ""
 
@@ -16172,6 +16184,51 @@ msgstr ""
 msgid "Source project cannot be found."
 msgstr ""
 
+msgid "Sourcegraph"
+msgstr ""
+
+msgid "SourcegraphAdmin|Block on private and internal projects"
+msgstr ""
+
+msgid "SourcegraphAdmin|Configure the URL to a Sourcegraph instance which can read your GitLab projects."
+msgstr ""
+
+msgid "SourcegraphAdmin|Enable Sourcegraph"
+msgstr ""
+
+msgid "SourcegraphAdmin|Enable code intelligence powered by %{link_start}Sourcegraph%{link_end} on your GitLab instance's code views and merge requests."
+msgstr ""
+
+msgid "SourcegraphAdmin|If checked, only public projects will have code intelligence and communicate with Sourcegraph."
+msgstr ""
+
+msgid "SourcegraphAdmin|More information"
+msgstr ""
+
+msgid "SourcegraphAdmin|Save changes"
+msgstr ""
+
+msgid "SourcegraphAdmin|Sourcegraph URL"
+msgstr ""
+
+msgid "SourcegraphAdmin|e.g. https://sourcegraph.example.com"
+msgstr ""
+
+msgid "SourcegraphPreferences|This feature is experimental and currently limited to certain projects."
+msgstr ""
+
+msgid "SourcegraphPreferences|This feature is experimental and limited to public projects."
+msgstr ""
+
+msgid "SourcegraphPreferences|This feature is experimental."
+msgstr ""
+
+msgid "SourcegraphPreferences|Uses %{link_start}Sourcegraph.com%{link_end}."
+msgstr ""
+
+msgid "SourcegraphPreferences|Uses a custom %{link_start}Sourcegraph instance%{link_end}."
+msgstr ""
+
 msgid "Spam Logs"
 msgstr ""
 

package.json

@@ -40,6 +40,7 @@
     "@gitlab/svgs": "^1.82.0",
     "@gitlab/ui": "7.11.0",
     "@gitlab/visual-review-tools": "1.2.0",
+    "@sourcegraph/code-host-integration": "^0.0.13",
     "@sentry/browser": "^5.7.1",
     "apollo-cache-inmemory": "^1.6.3",
     "apollo-client": "^2.6.4",

spec/controllers/concerns/sourcegraph_gon_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe SourcegraphGon do
+  let_it_be(:enabled_user) { create(:user, sourcegraph_enabled: true) }
+  let_it_be(:disabled_user) { create(:user, sourcegraph_enabled: false) }
+  let_it_be(:public_project) { create(:project, :public) }
+  let_it_be(:internal_project) { create(:project, :internal) }
+
+  let(:sourcegraph_url) { 'http://sourcegraph.gitlab.com' }
+  let(:feature_enabled) { true }
+  let(:sourcegraph_enabled) { true }
+  let(:sourcegraph_public_only) { false }
+  let(:format) { :html }
+  let(:user) { enabled_user }
+  let(:project) { internal_project }
+
+  controller(ApplicationController) do
+    include SourcegraphGon # rubocop:disable RSpec/DescribedClass
+
+    def index
+      head :ok
+    end
+  end
+
+  before do
+    Feature.get(:sourcegraph).enable(feature_enabled)
+
+    stub_application_setting(sourcegraph_url: sourcegraph_url, sourcegraph_enabled: sourcegraph_enabled, sourcegraph_public_only: sourcegraph_public_only)
+
+    allow(controller).to receive(:project).and_return(project)
+
+    Gon.clear
+
+    sign_in user if user
+  end
+
+  after do
+    Feature.get(:sourcegraph).disable
+  end
+
+  subject do
+    get :index, format: format
+
+    Gon.sourcegraph
+  end
+
+  shared_examples 'enabled' do
+    it { is_expected.to eq({ url: sourcegraph_url }) }
+  end
+
+  shared_examples 'disabled' do
+    it { is_expected.to be_nil }
+  end
+
+  context 'with feature enabled, application enabled, and user enabled' do
+    it_behaves_like 'enabled'
+  end
+
+  context 'with feature enabled for specific project' do
+    let(:feature_enabled) { project }
+
+    it_behaves_like 'enabled'
+  end
+
+  context 'with feature enabled for different project' do
+    let(:feature_enabled) { create(:project) }
+
+    it_behaves_like 'disabled'
+  end
+
+  context 'with feature disabled' do
+    let(:feature_enabled) { false }
+
+    it_behaves_like 'disabled'
+  end
+
+  context 'with admin settings disabled' do
+    let(:sourcegraph_enabled) { false }
+
+    it_behaves_like 'disabled'
+  end
+
+  context 'with public only' do
+    let(:sourcegraph_public_only) { true }
+
+    context 'with internal project' do
+      let(:project) { internal_project }
+
+      it_behaves_like 'disabled'
+    end
+
+    context 'with public project' do
+      let(:project) { public_project }
+
+      it_behaves_like 'enabled'
+    end
+  end
+
+  context 'with user disabled' do
+    let(:user) { disabled_user }
+
+    it_behaves_like 'disabled'
+  end
+
+  context 'with no user' do
+    let(:user) { nil }
+
+    it_behaves_like 'disabled'
+  end
+
+  context 'with non-html format' do
+    let(:format) { :json }
+
+    it_behaves_like 'disabled'
+  end
+end

spec/helpers/sourcegraph_helper_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe SourcegraphHelper do
+  describe '#sourcegraph_url_message' do
+    let(:sourcegraph_url) { 'http://sourcegraph.example.com' }
+
+    before do
+      allow(Gitlab::CurrentSettings).to receive(:sourcegraph_url).and_return(sourcegraph_url)
+      allow(Gitlab::CurrentSettings).to receive(:sourcegraph_url_is_com?).and_return(is_com)
+    end
+
+    subject { helper.sourcegraph_url_message }
+
+    context 'with .com sourcegraph url' do
+      let(:is_com) { true }
+
+      it { is_expected.to have_text('Uses Sourcegraph.com') }
+      it { is_expected.to have_link('Sourcegraph.com', href: sourcegraph_url) }
+    end
+
+    context 'with custom sourcegraph url' do
+      let(:is_com) { false }
+
+      it { is_expected.to have_text('Uses a custom Sourcegraph instance') }
+      it { is_expected.to have_link('Sourcegraph instance', href: sourcegraph_url) }
+
+      context 'with unsafe url' do
+        let(:sourcegraph_url) { '\" onload=\"alert(1);\"' }
+
+        it { is_expected.to have_link('Sourcegraph instance', href: sourcegraph_url) }
+      end
+    end
+  end
+
+  context '#sourcegraph_experimental_message' do
+    let(:feature_conditional) { false }
+    let(:public_only) { false }
+
+    before do
+      allow(Gitlab::CurrentSettings).to receive(:sourcegraph_public_only).and_return(public_only)
+      allow(Gitlab::Sourcegraph).to receive(:feature_conditional?).and_return(feature_conditional)
+    end
+
+    subject { helper.sourcegraph_experimental_message }
+
+    context 'when not limited by feature or public only' do
+      it { is_expected.to eq "This feature is experimental." }
+    end
+
+    context 'when limited by feature' do
+      let(:feature_conditional) { true }
+
+      it { is_expected.to eq "This feature is experimental and currently limited to certain projects." }
+    end
+
+    context 'when limited by public only' do
+      let(:public_only) { true }
+
+      it { is_expected.to eq "This feature is experimental and limited to public projects." }
+    end
+  end
+end

spec/lib/gitlab/sourcegraph_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::Sourcegraph do
+  let_it_be(:user) { create(:user) }
+  let(:feature_scope) { true }
+
+  before do
+    Feature.enable(:sourcegraph, feature_scope)
+  end
+
+  describe '.feature_conditional?' do
+    subject { described_class.feature_conditional? }
+
+    context 'when feature is enabled globally' do
+      it { is_expected.to be_falsey }
+    end
+
+    context 'when feature is enabled only to a resource' do
+      let(:feature_scope) { user }
+
+      it { is_expected.to be_truthy }
+    end
+  end
+
+  describe '.feature_available?' do
+    subject { described_class.feature_available? }
+
+    context 'when feature is enabled globally' do
+      it { is_expected.to be_truthy }
+    end
+
+    context 'when feature is enabled only to a resource' do
+      let(:feature_scope) { user }
+
+      it { is_expected.to be_truthy }
+    end
+  end
+
+  describe '.feature_enabled?' do
+    let(:current_user) { nil }
+
+    subject { described_class.feature_enabled?(current_user) }
+
+    context 'when feature is enabled globally' do
+      it { is_expected.to be_truthy }
+    end
+
+    context 'when feature is enabled only to a resource' do
+      let(:feature_scope) { user }
+
+      context 'for the same resource' do
+        let(:current_user) { user }
+
+        it { is_expected.to be_truthy }
+      end
+
+      context 'for a different resource' do
+        let(:current_user) { create(:user) }
+
+        it { is_expected.to be_falsey }
+      end
+    end
+  end
+end

spec/models/application_setting_spec.rb

@@ -3,6 +3,8 @@
 require 'spec_helper'
 
 describe ApplicationSetting do
+  using RSpec::Parameterized::TableSyntax
+
   subject(:setting) { described_class.create_from_defaults }
 
   it { include(CacheableAttributes) }
@@ -495,6 +497,15 @@ describe ApplicationSetting do
         it { is_expected.not_to allow_value(nil).for(:static_objects_external_storage_auth_token) }
       end
     end
+
+    context 'sourcegraph settings' do
+      it 'is invalid if sourcegraph is enabled and no url is provided' do
+        allow(subject).to receive(:sourcegraph_enabled).and_return(true)
+
+        expect(subject.sourcegraph_url).to be_nil
+        is_expected.to be_invalid
+      end
+    end
   end
 
   context 'restrict creating duplicates' do
@@ -583,5 +594,24 @@ describe ApplicationSetting do
     end
   end
 
+  describe '#sourcegraph_url_is_com?' do
+    where(:url, :is_com) do
+      'https://sourcegraph.com' | true
+      'https://sourcegraph.com/' | true
+      'https://www.sourcegraph.com' | true
+      'shttps://www.sourcegraph.com' | false
+      'https://sourcegraph.example.com/' | false
+      'https://sourcegraph.org/' | false
+    end
+
+    with_them do
+      it 'matches the url with sourcegraph.com' do
+        setting.sourcegraph_url = url
+
+        expect(setting.sourcegraph_url_is_com?).to eq(is_com)
+      end
+    end
+  end
+
   it_behaves_like 'application settings examples'
 end

spec/requests/api/settings_spec.rb

@@ -19,6 +19,9 @@ describe API::Settings, 'Settings' do
       expect(json_response['plantuml_enabled']).to be_falsey
       expect(json_response['plantuml_url']).to be_nil
       expect(json_response['default_ci_config_path']).to be_nil
+      expect(json_response['sourcegraph_enabled']).to be_falsey
+      expect(json_response['sourcegraph_url']).to be_nil
+      expect(json_response['sourcegraph_public_only']).to be_truthy
       expect(json_response['default_project_visibility']).to be_a String
       expect(json_response['default_snippet_visibility']).to be_a String
       expect(json_response['default_group_visibility']).to be_a String
@@ -45,6 +48,7 @@ describe API::Settings, 'Settings' do
         storages = Gitlab.config.repositories.storages
                      .merge({ 'custom' => 'tmp/tests/custom_repositories' })
         allow(Gitlab.config.repositories).to receive(:storages).and_return(storages)
+        Feature.get(:sourcegraph).enable
       end
 
       it "updates application settings" do
@@ -57,6 +61,9 @@ describe API::Settings, 'Settings' do
             repository_storages: ['custom'],
             plantuml_enabled: true,
             plantuml_url: 'http://plantuml.example.com',
+            sourcegraph_enabled: true,
+            sourcegraph_url: 'https://sourcegraph.com',
+            sourcegraph_public_only: false,
             default_snippet_visibility: 'internal',
             restricted_visibility_levels: ['public'],
             default_artifacts_expire_in: '2 days',
@@ -89,6 +96,9 @@ describe API::Settings, 'Settings' do
         expect(json_response['repository_storages']).to eq(['custom'])
         expect(json_response['plantuml_enabled']).to be_truthy
         expect(json_response['plantuml_url']).to eq('http://plantuml.example.com')
+        expect(json_response['sourcegraph_enabled']).to be_truthy
+        expect(json_response['sourcegraph_url']).to eq('https://sourcegraph.com')
+        expect(json_response['sourcegraph_public_only']).to eq(false)
         expect(json_response['default_snippet_visibility']).to eq('internal')
         expect(json_response['restricted_visibility_levels']).to eq(['public'])
         expect(json_response['default_artifacts_expire_in']).to eq('2 days')
@@ -355,5 +365,14 @@ describe API::Settings, 'Settings' do
         expect(json_response['domain_blacklist']).to eq(['domain3.com', '*.domain4.com'])
       end
     end
+
+    context "missing sourcegraph_url value when sourcegraph_enabled is true" do
+      it "returns a blank parameter error message" do
+        put api("/application/settings", admin), params: { sourcegraph_enabled: true }
+
+        expect(response).to have_gitlab_http_status(400)
+        expect(json_response['error']).to eq('sourcegraph_url is missing')
+      end
+    end
   end
 end

spec/views/admin/application_settings/integrations.html.haml_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe 'admin/application_settings/integrations.html.haml' do
+  let(:app_settings) { build(:application_setting) }
+
+  describe 'sourcegraph integration' do
+    let(:sourcegraph_flag) { true }
+
+    before do
+      assign(:application_setting, app_settings)
+      allow(Gitlab::Sourcegraph).to receive(:feature_available?).and_return(sourcegraph_flag)
+    end
+
+    context 'when sourcegraph feature is enabled' do
+      it 'show the form' do
+        render
+
+        expect(rendered).to have_field('application_setting_sourcegraph_enabled')
+      end
+    end
+
+    context 'when sourcegraph feature is disabled' do
+      let(:sourcegraph_flag) { false }
+
+      it 'show the form' do
+        render
+
+        expect(rendered).not_to have_field('application_setting_sourcegraph_enabled')
+      end
+    end
+  end
+end

spec/views/profiles/preferences/show.html.haml_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe 'profiles/preferences/show' do
+  using RSpec::Parameterized::TableSyntax
+
+  let_it_be(:user) { build(:user) }
+
+  before do
+    assign(:user, user)
+    allow(controller).to receive(:current_user).and_return(user)
+  end
+
+  context 'sourcegraph' do
+    def have_sourcegraph_field(*args)
+      have_field('user_sourcegraph_enabled', *args)
+    end
+
+    def have_integrations_section
+      have_css('.profile-settings-sidebar', { text: 'Integrations' })
+    end
+
+    before do
+      # Can't use stub_feature_flags because we use Feature.get to check if conditinally applied
+      Feature.get(:sourcegraph).enable sourcegraph_feature
+      stub_application_setting(sourcegraph_enabled: sourcegraph_enabled)
+    end
+
+    context 'when not fully enabled' do
+      where(:feature, :admin_enabled) do
+        false | false
+        false | true
+        true | false
+      end
+
+      with_them do
+        let(:sourcegraph_feature) { feature }
+        let(:sourcegraph_enabled) { admin_enabled }
+
+        before do
+          render
+        end
+
+        it 'does not display sourcegraph field' do
+          expect(rendered).not_to have_sourcegraph_field
+        end
+
+        it 'does not display integrations settings' do
+          expect(rendered).not_to have_integrations_section
+        end
+      end
+    end
+
+    context 'when fully enabled' do
+      let(:sourcegraph_feature) { true }
+      let(:sourcegraph_enabled) { true }
+
+      before do
+        render
+      end
+
+      it 'displays the sourcegraph field' do
+        expect(rendered).to have_sourcegraph_field
+      end
+
+      it 'displays the integrations section' do
+        expect(rendered).to have_integrations_section
+      end
+    end
+  end
+end

yarn.lock

@@ -970,6 +970,11 @@
     "@sentry/types" "5.7.1"
     tslib "^1.9.3"
 
+"@sourcegraph/code-host-integration@^0.0.13":
+  version "0.0.13"
+  resolved "https://registry.yarnpkg.com/@sourcegraph/code-host-integration/-/code-host-integration-0.0.13.tgz#4fd5fe1e0088c63b2a26be231c5a2a4ca79b1596"
+  integrity sha512-IjF9gb9e8dG8p12DKg5Z7UMOVQO/ClH3AyMCPfX/qH7DH/0b55WH6stYVqZu6y776quFonO4Z9gWYM8pQZjzKw==
+
 "@types/anymatch@*":
   version "1.3.0"
   resolved "https://registry.yarnpkg.com/@types/anymatch/-/anymatch-1.3.0.tgz#d1d55958d1fccc5527d4aba29fc9c4b942f563ff"