Support group applications

Currently OAuth applications can be only global or per-user.  This adds
applications on a group level.

app/controllers/groups/settings/applications_controller.rb

+# frozen_string_literal: true
+
+module Groups
+  module Settings
+    class ApplicationsController < Groups::ApplicationController
+      include OauthApplications
+
+      prepend_before_action :authorize_admin_group!
+      before_action :set_application, only: [:show, :edit, :update, :destroy]
+      before_action :load_scopes, only: [:index, :create, :edit, :update]
+
+      feature_category :authentication_and_authorization
+
+      def index
+        set_index_vars
+      end
+
+      def show
+      end
+
+      def edit
+      end
+
+      def create
+        @application = Applications::CreateService.new(current_user, application_params).execute(request)
+
+        if @application.persisted?
+          flash[:notice] = I18n.t(:notice, scope: [:doorkeeper, :flash, :applications, :create])
+
+          redirect_to group_settings_application_url(@group, @application)
+        else
+          set_index_vars
+          render :index
+        end
+      end
+
+      def update
+        if @application.update(application_params)
+          redirect_to group_settings_application_path(@group, @application), notice: _('Application was successfully updated.')
+        else
+          render :edit
+        end
+      end
+
+      def destroy
+        @application.destroy
+        redirect_to group_settings_applications_url(@group), status: :found, notice: _('Application was successfully destroyed.')
+      end
+
+      private
+
+      def set_index_vars
+        # TODO: Remove limit(100) and implement pagination
+        # https://gitlab.com/gitlab-org/gitlab/-/issues/324187
+        @applications = @group.oauth_applications.limit(100)
+
+        # Don't overwrite a value possibly set by `create`
+        @application ||= Doorkeeper::Application.new
+      end
+
+      def set_application
+        @application = @group.oauth_applications.find(params[:id])
+      end
+
+      def application_params
+        params
+          .require(:doorkeeper_application)
+          .permit(:name, :redirect_uri, :trusted, :scopes, :confidential)
+          .tap do |params|
+            params[:owner] = @group
+          end
+      end
+    end
+  end
+end

app/finders/applications_finder.rb

@@ -17,6 +17,6 @@ class ApplicationsFinder
   def by_id(applications)
     return applications unless params[:id]
 
-    Doorkeeper::Application.find_by(id: params[:id]) # rubocop: disable CodeReuse/ActiveRecord
+    applications.find_by(id: params[:id]) # rubocop: disable CodeReuse/ActiveRecord
   end
 end

app/helpers/groups_helper.rb

@@ -22,6 +22,9 @@ module GroupsHelper
       ldap_group_links#index
       hooks#index
       pipeline_quota#index
+      applications#index
+      applications#show
+      applications#edit
       packages_and_registries#index
     ]
   end

app/models/group.rb

@@ -70,6 +70,7 @@ class Group < Namespace
   has_many :group_deploy_keys, through: :group_deploy_keys_groups
   has_many :group_deploy_tokens
   has_many :deploy_tokens, through: :group_deploy_tokens
+  has_many :oauth_applications, class_name: 'Doorkeeper::Application', as: :owner, dependent: :destroy # rubocop:disable Cop/ActiveRecordDependent
 
   has_one :dependency_proxy_setting, class_name: 'DependencyProxy::GroupSetting'
   has_many :dependency_proxy_blobs, class_name: 'DependencyProxy::Blob'

app/views/doorkeeper/applications/edit.html.haml

 - page_title _("Edit"), @application.name, _("Applications")
 - @content_class = "limit-container-width" unless fluid_layout
+
 %h3.page-title= _('Edit application')
-= render 'form', application: @application
+= render 'shared/doorkeeper/applications/form', url: doorkeeper_submit_path(@application)

app/views/doorkeeper/applications/index.html.haml

 - page_title _("Applications")
-- @content_class = "limit-container-width" unless fluid_layout
 
-.row.gl-mt-3
-  .col-lg-4.profile-settings-sidebar
-    %h4.gl-mt-0
-      = page_title
-    %p
-      - if user_oauth_applications?
-        = _("Manage applications that can use GitLab as an OAuth provider, and applications that you've authorized to use your account.")
-      - else
-        = _("Manage applications that you've authorized to use your account.")
-  .col-lg-8
-    - if user_oauth_applications?
-      %h5.gl-mt-0
-        = _('Add new application')
-      = render 'form', application: @application
-      %hr
-    - else
-      .bs-callout.bs-callout-disabled
-        = _('Adding new applications is disabled in your GitLab instance. Please contact your GitLab administrator to get the permission')
-    - if user_oauth_applications?
-      .oauth-applications
-        %h5
-          = _("Your applications (%{size})") % { size: @applications.size }
-        - if @applications.any?
-          .table-responsive
-            %table.table
-              %thead
-                %tr
-                  %th= _('Name')
-                  %th= _('Callback URL')
-                  %th= _('Clients')
-                  %th.last-heading
-              %tbody
-                - @applications.each do |application|
-                  %tr{ id: "application_#{application.id}" }
-                    %td= link_to application.name, oauth_application_path(application)
-                    %td
-                      - application.redirect_uri.split.each do |uri|
-                        %div= uri
-                    %td= application.access_tokens.count
-                    %td.gl-display-flex
-                      = link_to edit_oauth_application_path(application), class: "gl-button btn btn-default gl-mr-2" do
-                        %span.sr-only
-                          = _('Edit')
-                        = sprite_icon('pencil')
-                      = render 'delete_form', application: application, small: true
-        - else
-          .settings-message.text-center
-            = _("You don't have any applications")
-    .oauth-authorized-applications.prepend-top-20.gl-mb-3
-      - if user_oauth_applications?
-        %h5
-          = _("Authorized applications (%{size})") % { size: @authorized_apps.size + @authorized_anonymous_tokens.size }
-
-      - if @authorized_tokens.any?
-        .table-responsive
-          %table.table.table-striped
-            %thead
-              %tr
-                %th= _('Name')
-                %th= _('Authorized At')
-                %th= _('Scope')
-                %th
-            %tbody
-              - @authorized_apps.each do |app|
-                - token = app.authorized_tokens.order('created_at desc').first # rubocop: disable CodeReuse/ActiveRecord
-                %tr{ id: "application_#{app.id}" }
-                  %td= app.name
-                  %td= token.created_at
-                  %td= token.scopes
-                  %td= render 'doorkeeper/authorized_applications/delete_form', application: app
-              - @authorized_anonymous_tokens.each do |token|
-                %tr
-                  %td
-                    = _('Anonymous')
-                    .form-text.text-muted
-                      %em= _("Authorization was granted by entering your username and password in the application.")
-                  %td= token.created_at
-                  %td= token.scopes
-                  %td= render 'doorkeeper/authorized_applications/delete_form', token: token
-      - else
-        .settings-message.text-center
-          = _("You don't have any authorized applications")
+= render 'shared/doorkeeper/applications/index',
+        oauth_applications_enabled: user_oauth_applications?,
+        oauth_authorized_applications_enabled: true,
+        form_url: doorkeeper_submit_path(@application),
+        application_url: ->(application) { oauth_application_path(application) },
+        edit_application_url: ->(application) { edit_oauth_application_path(application) }

app/views/doorkeeper/applications/show.html.haml

@@ -6,42 +6,4 @@
 %h3.page-title
   = _("Application: %{name}") % { name: @application.name }
 
-.table-holder.oauth-application-show
-  %table.table
-    %tr
-      %td
-        = _('Application ID')
-      %td
-        .clipboard-group
-          .input-group
-            %input.label.label-monospace.monospace{ id: "application_id", type: "text", autocomplete: 'off', value: @application.uid, readonly: true }
-            .input-group-append
-              = clipboard_button(target: '#application_id', title: _("Copy ID"), class: "gl-button btn btn-default")
-    %tr
-      %td
-        = _('Secret')
-      %td
-        .clipboard-group
-          .input-group
-            %input.label.label-monospace.monospace{ id: "secret", type: "text", autocomplete: 'off', value: @application.secret, readonly: true }
-            .input-group-append
-              = clipboard_button(target: '#secret', title: _("Copy secret"), class: "gl-button btn btn-default")
-    %tr
-      %td
-        = _('Callback URL')
-      %td
-        - @application.redirect_uri.split.each do |uri|
-          %div
-            %span.monospace= uri
-
-    %tr
-      %td
-        = _('Confidential')
-      %td
-        = @application.confidential? ? _('Yes') : _('No')
-
-    = render "shared/tokens/scopes_list", token: @application
-
-.form-actions
-  = link_to _('Edit'), edit_oauth_application_path(@application), class: 'gl-button btn btn-confirm wide float-left'
-  = render 'delete_form', application: @application, submit_btn_css: 'gl-button btn btn-danger gl-ml-3'
+= render 'shared/doorkeeper/applications/show', edit_path: edit_oauth_application_path(@application), delete_path: oauth_application_path(@application)

app/views/groups/settings/applications/edit.html.haml

+- page_title _("Edit"), @application.name, _("Group applications")
+- @content_class = "limit-container-width" unless fluid_layout
+
+%h3.page-title= _('Edit group application')
+= render 'shared/doorkeeper/applications/form', url: group_settings_application_path(@group, @application)

app/views/groups/settings/applications/index.html.haml

+- page_title _("Group applications")
+
+= render 'shared/doorkeeper/applications/index',
+        oauth_applications_enabled: user_oauth_applications?,
+        oauth_authorized_applications_enabled: false,
+        form_url: group_settings_applications_path(@group),
+        application_url: ->(application) { group_settings_application_path(@group, application) },
+        edit_application_url: ->(application) { edit_group_settings_application_path(@group, application) }

app/views/groups/settings/applications/show.html.haml

+- add_to_breadcrumbs _("Group applications"), group_settings_applications_path(@group)
+- breadcrumb_title @application.name
+- page_title @application.name, _("Group applications")
+- @content_class = "limit-container-width" unless fluid_layout
+
+%h3.page-title
+  = _("Group application: %{name}") % { name: @application.name }
+
+= render 'shared/doorkeeper/applications/show', edit_path: edit_group_settings_application_path(@group, @application), delete_path: group_settings_application_path(@group, @application)

app/views/layouts/nav/sidebar/_group.html.haml

@@ -145,7 +145,7 @@
             %span.nav-item-name.qa-group-settings-item
               = _('Settings')
           %ul.sidebar-sub-level-items.qa-group-sidebar-submenu{ data: { testid: 'group-settings-menu' } }
-            = nav_link(path: %w[groups#projects groups#edit badges#index ci_cd#show], html_options: { class: "fly-out-top-item" } ) do
+            = nav_link(path: %w[groups#projects groups#edit badges#index ci_cd#show groups/applications#index], html_options: { class: "fly-out-top-item" } ) do
               = link_to edit_group_path(@group) do
                 %strong.fly-out-top-item-name
                   = _('Settings')
@@ -175,6 +175,11 @@
                 %span
                   = _('CI/CD')
 
+            = nav_link(controller: :applications) do
+              = link_to group_settings_applications_path(@group), title: _('Applications') do
+                %span
+                  = _('Applications')
+
             = render 'groups/sidebar/packages_settings'
 
             = render_if_exists "groups/ee/settings_nav"

app/views/doorkeeper/applications/_delete_form.html.haml → app/views/shared/doorkeeper/applications/_delete_form.html.haml

 - submit_btn_css ||= 'gl-button btn btn-danger btn-sm'
-= form_tag oauth_application_path(application) do
-  %input{ :name => "_method", :type => "hidden", :value => "delete" }/
+= form_tag path do
+  %input{ :name => "_method", :type => "hidden", :value => "delete" }
   - if defined? small
     = button_tag type: "submit", class: "gl-button btn btn-default", data: { confirm: _("Are you sure?") } do
       %span.sr-only

app/views/doorkeeper/applications/_form.html.haml → app/views/shared/doorkeeper/applications/_form.html.haml

-= form_for application, url: doorkeeper_submit_path(application), html: { role: 'form', class: 'doorkeeper-app-form' } do |f|
-  = form_errors(application)
+= form_for @application, url: url, html: { role: 'form', class: 'doorkeeper-app-form' } do |f|
+  = form_errors(@application)
 
   .form-group
     = f.label :name, class: 'label-bold'
@@ -20,7 +20,7 @@
 
   .form-group
     = f.label :scopes, class: 'label-bold'
-    = render 'shared/tokens/scopes_form', prefix: 'doorkeeper_application', token: application, scopes: @scopes
+    = render 'shared/tokens/scopes_form', prefix: 'doorkeeper_application', token: @application, scopes: @scopes
 
   .gl-mt-3
     = f.submit _('Save application'), class: "gl-button btn btn-confirm"

app/views/shared/doorkeeper/applications/_index.html.haml

+- @content_class = "limit-container-width" unless fluid_layout
+
+.row.gl-mt-3
+  .col-lg-4.profile-settings-sidebar
+    %h4.gl-mt-0
+      = page_title
+    %p
+      - if oauth_applications_enabled
+        - if oauth_authorized_applications_enabled
+          = _("Manage applications that can use GitLab as an OAuth provider, and applications that you've authorized to use your account.")
+        - else
+          = _("Manage applications that can use GitLab as an OAuth provider.")
+      - else
+        = _("Manage applications that you've authorized to use your account.")
+  .col-lg-8
+    - if oauth_applications_enabled
+      %h5.gl-mt-0
+        = _('Add new application')
+      = render 'shared/doorkeeper/applications/form', url: form_url
+      %hr
+    - else
+      .bs-callout.bs-callout-disabled
+        = _('Adding new applications is disabled in your GitLab instance. Please contact your GitLab administrator to get the permission')
+    - if oauth_applications_enabled
+      .oauth-applications
+        %h5
+          = _("Your applications (%{size})") % { size: @applications.size }
+        - if @applications.any?
+          .table-responsive
+            %table.table
+              %thead
+                %tr
+                  %th= _('Name')
+                  %th= _('Callback URL')
+                  %th= _('Clients')
+                  %th.last-heading
+              %tbody
+                - @applications.each do |application|
+                  %tr{ id: "application_#{application.id}" }
+                    %td= link_to application.name, application_url.call(application)
+                    %td
+                      - application.redirect_uri.split.each do |uri|
+                        %div= uri
+                    %td= application.access_tokens.count
+                    %td.gl-display-flex
+                      = link_to edit_application_url.call(application), class: "gl-button btn btn-default gl-mr-2" do
+                        %span.sr-only
+                          = _('Edit')
+                        = sprite_icon('pencil')
+                      = render 'shared/doorkeeper/applications/delete_form', path: application_url.call(application), small: true
+        - else
+          .settings-message.text-center
+            = _("You don't have any applications")
+    - if oauth_authorized_applications_enabled
+      .oauth-authorized-applications.prepend-top-20.gl-mb-3
+        - if oauth_applications_enabled
+          %h5
+            = _("Authorized applications (%{size})") % { size: @authorized_apps.size + @authorized_anonymous_tokens.size }
+
+        - if @authorized_tokens.any?
+          .table-responsive
+            %table.table.table-striped
+              %thead
+                %tr
+                  %th= _('Name')
+                  %th= _('Authorized At')
+                  %th= _('Scope')
+                  %th
+              %tbody
+                - @authorized_apps.each do |app|
+                  - token = app.authorized_tokens.order('created_at desc').first # rubocop: disable CodeReuse/ActiveRecord
+                  %tr{ id: "application_#{app.id}" }
+                    %td= app.name
+                    %td= token.created_at
+                    %td= token.scopes
+                    %td= render 'doorkeeper/authorized_applications/delete_form', application: app
+                - @authorized_anonymous_tokens.each do |token|
+                  %tr
+                    %td
+                      = _('Anonymous')
+                      .form-text.text-muted
+                        %em= _("Authorization was granted by entering your username and password in the application.")
+                    %td= token.created_at
+                    %td= token.scopes
+                    %td= render 'doorkeeper/authorized_applications/delete_form', token: token
+        - else
+          .settings-message.text-center
+            = _("You don't have any authorized applications")

app/views/shared/doorkeeper/applications/_show.html.haml

+.table-holder.oauth-application-show
+  %table.table
+    %tr
+      %td
+        = _('Application ID')
+      %td
+        .clipboard-group
+          .input-group
+            %input.label.label-monospace.monospace{ id: "application_id", type: "text", autocomplete: 'off', value: @application.uid, readonly: true }
+            .input-group-append
+              = clipboard_button(target: '#application_id', title: _("Copy ID"), class: "gl-button btn btn-default")
+    %tr
+      %td
+        = _('Secret')
+      %td
+        .clipboard-group
+          .input-group
+            %input.label.label-monospace.monospace{ id: "secret", type: "text", autocomplete: 'off', value: @application.secret, readonly: true }
+            .input-group-append
+              = clipboard_button(target: '#secret', title: _("Copy secret"), class: "gl-button btn btn-default")
+    %tr
+      %td
+        = _('Callback URL')
+      %td
+        - @application.redirect_uri.split.each do |uri|
+          %div
+            %span.monospace= uri
+
+    %tr
+      %td
+        = _('Confidential')
+      %td
+        = @application.confidential? ? _('Yes') : _('No')
+
+    = render "shared/tokens/scopes_list", token: @application
+
+.form-actions
+  = link_to _('Edit'), edit_path, class: 'gl-button btn btn-confirm wide float-left'
+  = render 'shared/doorkeeper/applications/delete_form', path: delete_path, submit_btn_css: 'gl-button btn btn-danger gl-ml-3'

changelogs/unreleased/group-applications.yml

+---
+title: Support group applications
+merge_request: 55152
+author: Jonas Wälter @wwwjon, Bastian Blank
+type: added

config/routes/group.rb

@@ -50,6 +50,8 @@ constraints(::Constraints::GroupUrlConstrainer.new) do
         end
       end
 
+      resources :applications
+
       resources :packages_and_registries, only: [:index]
     end
 

doc/administration/pages/source.md

@@ -407,7 +407,7 @@ Pages access control is disabled by default. To enable it:
    ```
 
 1. [Restart GitLab](../restart_gitlab.md#installations-from-source).
-1. Create a new [system OAuth application](../../integration/oauth_provider.md#add-an-application-through-the-profile).
+1. Create a new [system OAuth application](../../integration/oauth_provider.md#user-owned-applications).
    This should be called `GitLab Pages` and have a `Redirect URL` of
    `https://projects.example.io/auth`. It does not need to be a "trusted"
    application, but it does need the `api` scope.

doc/api/applications.md

@@ -8,11 +8,13 @@ info: To determine the technical writer assigned to the Stage/Group associated w
 
 > [Introduced](https://gitlab.com/gitlab-org/gitlab-foss/-/merge_requests/8160) in GitLab 10.5.
 
-Applications API operates on OAuth applications for:
+The Applications API operates on instance-wide OAuth applications for:
 
 - [Using GitLab as an authentication provider](../integration/oauth_provider.md).
 - [Allowing access to GitLab resources on a user's behalf](oauth2.md).
 
+The Applications API cannot be used to manage group applications or applications of individual users.
+
 NOTE:
 Only administrator users can use the Applications API.
 

doc/integration/oauth_provider.md

@@ -33,17 +33,18 @@ OAuth 2 can be used:
 The 'GitLab Importer' feature also uses OAuth 2 to give access
 to repositories without sharing user credentials to your GitLab.com account.
 
-GitLab supports two ways of adding a new OAuth 2 application to an instance:
+GitLab supports several ways of adding a new OAuth 2 application to an instance:
 
-- As a regular user, for applications owned by an individual.
-- Through the Admin Area menu for instance-wide apps.
+- [User owned applications](#user-owned-applications)
+- [Group owned applications](#group-owned-applications)
+- [Instance-wide applications](#instance-wide-applications)
 
-The only difference between these two methods is the [permission](../user/permissions.md)
+The only difference between these methods is the [permission](../user/permissions.md)
 levels. The default callback URL is `http://your-gitlab.example.com/users/auth/gitlab/callback`.
 
-## Add an application through the profile
+## User owned applications
 
-To add a new application via your profile:
+To add a new application for your user:
 
 1. In the top-right corner, select your avatar.
 1. Select **Edit profile**.
@@ -55,7 +56,20 @@ To add a new application via your profile:
    - Application ID: OAuth 2 Client ID.
    - Secret: OAuth 2 Client Secret.
 
-## OAuth applications in the Admin Area
+## Group owned applications
+
+To add a new application for a group:
+
+1. Navigate to the desired group.
+1. In the left sidebar, select **Settings > Applications**.
+1. Enter a **Name**, **Redirect URI** and OAuth 2 scopes as defined in [Authorized Applications](#authorized-applications).
+   The **Redirect URI** is the URL where users are sent after they authorize with GitLab.
+1. Select **Save application**. GitLab displays:
+
+   - Application ID: OAuth 2 Client ID.
+   - Secret: OAuth 2 Client Secret.
+
+## Instance-wide applications
 
 To create an application for your GitLab instance, select
 **Admin Area > Applications > New application**.

ee/app/services/ee/applications/create_service.rb

@@ -8,15 +8,16 @@ module EE
       override :execute
       def execute(request)
         super.tap do |application|
-          audit_event_service(request.remote_ip).for_user(full_path: application.name, entity_id: application.id).security_event
+          entity = application.owner || current_user
+          audit_event_service(entity, request.remote_ip).for_user(full_path: application.name, entity_id: application.id).security_event
         end
       end
 
-      def audit_event_service(ip_address)
+      def audit_event_service(entity, ip_address)
         ::AuditEventService.new(current_user,
-                                current_user,
+                                entity,
                                 action: :custom,
-                                custom_message: 'OAuth access granted',
+                                custom_message: 'OAuth application added',
                                 ip_address: ip_address)
       end
     end

ee/spec/services/applications/create_service_spec.rb

@@ -3,15 +3,33 @@
 require 'spec_helper'
 
 RSpec.describe ::Applications::CreateService do
+  include TestRequestHelpers
+
   let(:user) { create(:user) }
+  let(:group) { create(:group) }
   let(:params) { attributes_for(:application) }
-  let(:request) { ActionController::TestRequest.new({ remote_ip: "127.0.0.1" }, ActionController::TestSession.new, nil) }
 
   subject { described_class.new(user, params) }
 
-  it 'creates an AuditEvent' do
+  describe '#audit_event_service' do
+    using RSpec::Parameterized::TableSyntax
+
+    where(:case_name, :owner, :entity_type) do
+      'instance application' | nil   | 'User'
+      'group application'    | group | 'Group'
+      'user application'     | user  | 'User'
+    end
+
+    with_them do
+      before do
         stub_licensed_features(extended_audit_events: true)
+        params[:owner] = owner
+      end
 
-    expect { subject.execute(request) }.to change { AuditEvent.count }.by(1)
+      it 'creates AuditEvent with correct entity type' do
+        expect { subject.execute(test_request) }.to change(AuditEvent, :count).by(1)
+        expect(AuditEvent.last.entity_type).to eq(entity_type)
+      end
+    end
   end
 end

lib/api/applications.rb

@@ -41,6 +41,8 @@ module API
       desc 'Delete an application'
       delete ':id' do
         application = ApplicationsFinder.new(params).execute
+        break not_found!('Application') unless application
+
         application.destroy
 
         no_content!

locale/gitlab.pot

@@ -11203,6 +11203,9 @@ msgstr ""
 msgid "Edit fork in Web IDE"
 msgstr ""
 
+msgid "Edit group application"
+msgstr ""
+
 msgid "Edit group: %{group_name}"
 msgstr ""
 
@@ -14553,6 +14556,12 @@ msgstr ""
 msgid "Group Wikis"
 msgstr ""
 
+msgid "Group application: %{name}"
+msgstr ""
+
+msgid "Group applications"
+msgstr ""
+
 msgid "Group avatar"
 msgstr ""
 
@@ -18547,6 +18556,9 @@ msgstr ""
 msgid "Manage applications that can use GitLab as an OAuth provider, and applications that you've authorized to use your account."
 msgstr ""
 
+msgid "Manage applications that can use GitLab as an OAuth provider."
+msgstr ""
+
 msgid "Manage applications that you've authorized to use your account."
 msgstr ""
 

spec/controllers/groups/settings/applications_controller_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Groups::Settings::ApplicationsController do
+  let_it_be(:user)  { create(:user) }
+  let_it_be(:group) { create(:group) }
+  let_it_be(:application) { create(:oauth_application, owner_id: group.id, owner_type: 'Namespace') }
+
+  before do
+    sign_in(user)
+  end
+
+  describe 'GET #index' do
+    context 'when user is owner' do
+      before do
+        group.add_owner(user)
+      end
+
+      it 'renders the application form' do
+        get :index, params: { group_id: group }
+
+        expect(response).to render_template :index
+        expect(assigns[:scopes]).to be_kind_of(Doorkeeper::OAuth::Scopes)
+      end
+    end
+
+    context 'when user is not owner' do
+      before do
+        group.add_maintainer(user)
+      end
+
+      it 'renders a 404' do
+        get :index, params: { group_id: group }
+
+        expect(response).to have_gitlab_http_status(:not_found)
+      end
+    end
+  end
+
+  describe 'GET #edit' do
+    context 'when user is owner' do
+      before do
+        group.add_owner(user)
+      end
+
+      it 'renders the application form' do
+        get :edit, params: { group_id: group, id: application.id }
+
+        expect(response).to render_template :edit
+        expect(assigns[:scopes]).to be_kind_of(Doorkeeper::OAuth::Scopes)
+      end
+    end
+
+    context 'when user is not owner' do
+      before do
+        group.add_maintainer(user)
+      end
+
+      it 'renders a 404' do
+        get :edit, params: { group_id: group, id: application.id }
+
+        expect(response).to have_gitlab_http_status(:not_found)
+      end
+    end
+  end
+
+  describe 'POST #create' do
+    context 'when user is owner' do
+      before do
+        group.add_owner(user)
+      end
+
+      it 'creates the application' do
+        create_params = attributes_for(:application, trusted: true, confidential: false, scopes: ['api'])
+
+        expect do
+          post :create, params: { group_id: group, doorkeeper_application: create_params }
+        end.to change { Doorkeeper::Application.count }.by(1)
+
+        application = Doorkeeper::Application.last
+
+        expect(response).to redirect_to(group_settings_application_path(group, application))
+        expect(application).to have_attributes(create_params.except(:uid, :owner_type))
+      end
+
+      it 'renders the application form on errors' do
+        expect do
+          post :create, params: { group_id: group, doorkeeper_application: attributes_for(:application).merge(redirect_uri: nil) }
+        end.not_to change { Doorkeeper::Application.count }
+
+        expect(response).to render_template :index
+        expect(assigns[:scopes]).to be_kind_of(Doorkeeper::OAuth::Scopes)
+      end
+
+      context 'when the params are for a confidential application' do
+        it 'creates a confidential application' do
+          create_params = attributes_for(:application, confidential: true, scopes: ['read_user'])
+
+          expect do
+            post :create, params: { group_id: group, doorkeeper_application: create_params }
+          end.to change { Doorkeeper::Application.count }.by(1)
+
+          application = Doorkeeper::Application.last
+
+          expect(response).to redirect_to(group_settings_application_path(group, application))
+          expect(application).to have_attributes(create_params.except(:uid, :owner_type))
+        end
+      end
+
+      context 'when scopes are not present' do
+        it 'renders the application form on errors' do
+          create_params = attributes_for(:application, trusted: true, confidential: false)
+
+          expect do
+            post :create, params: { group_id: group, doorkeeper_application: create_params }
+          end.not_to change { Doorkeeper::Application.count }
+
+          expect(response).to render_template :index
+        end
+      end
+    end
+
+    context 'when user is not owner' do
+      before do
+        group.add_maintainer(user)
+      end
+
+      it 'renders a 404' do
+        create_params = attributes_for(:application, trusted: true, confidential: false, scopes: ['api'])
+
+        post :create, params: { group_id: group, doorkeeper_application: create_params }
+
+        expect(response).to have_gitlab_http_status(:not_found)
+      end
+    end
+  end
+
+  describe 'PATCH #update' do
+    context 'when user is owner' do
+      before do
+        group.add_owner(user)
+      end
+
+      it 'updates the application' do
+        doorkeeper_params = { redirect_uri: 'http://example.com/', trusted: true, confidential: false }
+
+        patch :update, params: { group_id: group, id: application.id, doorkeeper_application: doorkeeper_params }
+
+        application.reload
+
+        expect(response).to redirect_to(group_settings_application_path(group, application))
+        expect(application)
+          .to have_attributes(redirect_uri: 'http://example.com/', trusted: true, confidential: false)
+      end
+
+      it 'renders the application form on errors' do
+        patch :update, params: { group_id: group, id: application.id, doorkeeper_application: { redirect_uri: nil } }
+
+        expect(response).to render_template :edit
+        expect(assigns[:scopes]).to be_kind_of(Doorkeeper::OAuth::Scopes)
+      end
+
+      context 'when updating the application to be confidential' do
+        it 'successfully sets the application to confidential' do
+          doorkeeper_params = { confidential: true }
+
+          patch :update, params: { group_id: group, id: application.id, doorkeeper_application: doorkeeper_params }
+
+          application.reload
+
+          expect(response).to redirect_to(group_settings_application_path(group, application))
+          expect(application).to be_confidential
+        end
+      end
+    end
+
+    context 'when user is not owner' do
+      before do
+        group.add_maintainer(user)
+      end
+
+      it 'renders a 404' do
+        doorkeeper_params = { redirect_uri: 'http://example.com/', trusted: true, confidential: false }
+
+        patch :update, params: { group_id: group, id: application.id, doorkeeper_application: doorkeeper_params }
+
+        expect(response).to have_gitlab_http_status(:not_found)
+      end
+    end
+  end
+
+  describe 'DELETE #destroy' do
+    context 'when user is owner' do
+      before do
+        group.add_owner(user)
+      end
+
+      it 'deletes the application' do
+        delete :destroy, params: { group_id: group, id: application.id }
+
+        expect(Doorkeeper::Application.exists?(application.id)).to be_falsy
+        expect(response).to redirect_to(group_settings_applications_url(group))
+      end
+    end
+
+    context 'when user is not owner' do
+      before do
+        group.add_maintainer(user)
+      end
+
+      it 'renders a 404' do
+        delete :destroy, params: { group_id: group, id: application.id }
+
+        expect(response).to have_gitlab_http_status(:not_found)
+      end
+    end
+  end
+end

spec/finders/applications_finder_spec.rb

@@ -5,18 +5,48 @@ require 'spec_helper'
 RSpec.describe ApplicationsFinder do
   let(:application1) { create(:application, name: 'some_application', owner: nil, redirect_uri: 'http://some_application.url', scopes: '') }
   let(:application2) { create(:application, name: 'another_application', owner: nil, redirect_uri: 'http://other_application.url', scopes: '') }
+  let(:user_application) { create(:application, name: 'user_application', owner: create(:user), redirect_uri: 'http://user_application.url', scopes: '') }
+  let(:group_application) { create(:application, name: 'group_application', owner: create(:group), redirect_uri: 'http://group_application.url', scopes: '') }
 
   describe '#execute' do
-    it 'returns an array of applications' do
+    it 'returns an array of instance applications' do
       found = described_class.new.execute
 
       expect(found).to match_array([application1, application2])
     end
-    it 'returns the application by id' do
+
+    context 'by_id' do
+      context 'with existing id' do
+        it 'returns the application' do
           params = { id: application1.id }
           found = described_class.new(params).execute
 
           expect(found).to match(application1)
         end
       end
+
+      context 'with invalid id' do
+        it 'returns nil for user application' do
+          params = { id: user_application.id }
+          found = described_class.new(params).execute
+
+          expect(found).to be_nil
+        end
+
+        it 'returns nil for group application' do
+          params = { id: group_application.id }
+          found = described_class.new(params).execute
+
+          expect(found).to be_nil
+        end
+
+        it 'returns nil for non-existing application' do
+          params = { id: non_existing_record_id }
+          found = described_class.new(params).execute
+
+          expect(found).to be_nil
+        end
+      end
+    end
+  end
 end

spec/requests/api/applications_spec.rb

@@ -5,7 +5,7 @@ require 'spec_helper'
 RSpec.describe API::Applications, :api do
   let(:admin_user) { create(:user, admin: true) }
   let(:user) { create(:user, admin: false) }
-  let!(:application) { create(:application, name: 'another_application', redirect_uri: 'http://other_application.url', scopes: '') }
+  let!(:application) { create(:application, name: 'another_application', owner: nil, redirect_uri: 'http://other_application.url', scopes: '') }
 
   describe 'POST /applications' do
     context 'authenticated and authorized user' do
@@ -143,6 +143,12 @@ RSpec.describe API::Applications, :api do
 
         expect(response).to have_gitlab_http_status(:no_content)
       end
+
+      it 'cannot delete non-existing application' do
+        delete api("/applications/#{non_existing_record_id}", admin_user)
+
+        expect(response).to have_gitlab_http_status(:not_found)
+      end
     end
 
     context 'authorized user without authorization' do

spec/support/shared_contexts/navbar_structure_context.rb

@@ -139,6 +139,7 @@ RSpec.shared_context 'group navbar structure' do
         _('Projects'),
         _('Repository'),
         _('CI/CD'),
+        _('Applications'),
         _('Packages & Registries'),
         _('Webhooks')
       ]