Merge branch 'top_level_clusters_controller' into 'master'

Top level clusters controller

See merge request gitlab-org/gitlab-ce!22438

31 files changed, 444 insertions, 282 deletions

diff --git a/app/assets/javascripts/pages/projects/clusters/gcp/new/index.js b/app/assets/javascripts/pages/projects/clusters/gcp/new/index.js
deleted file mode 100644
index d4f34e32a48..00000000000
--- a/app/assets/javascripts/pages/projects/clusters/gcp/new/index.js
+++ /dev/null
@@ -1,5 +0,0 @@
-import initGkeDropdowns from '~/projects/gke_cluster_dropdowns';
-
-document.addEventListener('DOMContentLoaded', () => {
-  initGkeDropdowns();
-});
diff --git a/app/controllers/clusters/applications_controller.rb b/app/controllers/clusters/applications_controller.rb
new file mode 100644
index 00000000000..250f42f3096
--- /dev/null
+++ b/app/controllers/clusters/applications_controller.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+class Clusters::ApplicationsController < Clusters::BaseController
+  before_action :cluster
+  before_action :authorize_create_cluster!, only: [:create]
+
+  def create
+    Clusters::Applications::CreateService
+      .new(@cluster, current_user, create_cluster_application_params)
+      .execute(request)
+
+    head :no_content
+  rescue Clusters::Applications::CreateService::InvalidApplicationError
+    render_404
+  rescue StandardError
+    head :bad_request
+  end
+
+  private
+
+  def cluster
+    @cluster ||= clusterable.clusters.find(params[:id]) || render_404
+  end
+
+  def create_cluster_application_params
+    params.permit(:application, :hostname)
+  end
+end
diff --git a/app/controllers/clusters/base_controller.rb b/app/controllers/clusters/base_controller.rb
new file mode 100644
index 00000000000..ef42f7c4074
--- /dev/null
+++ b/app/controllers/clusters/base_controller.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+class Clusters::BaseController < ApplicationController
+  include RoutableActions
+
+  skip_before_action :authenticate_user!
+  before_action :authorize_read_cluster!
+
+  helper_method :clusterable
+
+  private
+
+  def cluster
+    @cluster ||= clusterable.clusters.find(params[:id])
+                                 .present(current_user: current_user)
+  end
+
+  def authorize_update_cluster!
+    access_denied! unless can?(current_user, :update_cluster, cluster)
+  end
+
+  def authorize_admin_cluster!
+    access_denied! unless can?(current_user, :admin_cluster, cluster)
+  end
+
+  def authorize_read_cluster!
+    access_denied! unless can?(current_user, :read_cluster, clusterable)
+  end
+
+  def authorize_create_cluster!
+    access_denied! unless can?(current_user, :create_cluster, clusterable)
+  end
+
+  def clusterable
+    raise NotImplementedError
+  end
+end
diff --git a/app/controllers/clusters/clusters_controller.rb b/app/controllers/clusters/clusters_controller.rb
new file mode 100644
index 00000000000..f6f2060ebb5
--- /dev/null
+++ b/app/controllers/clusters/clusters_controller.rb
@@ -0,0 +1,218 @@
+# frozen_string_literal: true
+
+class Clusters::ClustersController < Clusters::BaseController
+  include RoutableActions
+
+  before_action :cluster, except: [:index, :new, :create_gcp, :create_user]
+  before_action :generate_gcp_authorize_url, only: [:new]
+  before_action :validate_gcp_token, only: [:new]
+  before_action :gcp_cluster, only: [:new]
+  before_action :user_cluster, only: [:new]
+  before_action :authorize_create_cluster!, only: [:new]
+  before_action :authorize_update_cluster!, only: [:update]
+  before_action :authorize_admin_cluster!, only: [:destroy]
+  before_action :update_applications_status, only: [:cluster_status]
+
+  helper_method :token_in_session
+
+  STATUS_POLLING_INTERVAL = 10_000
+
+  def index
+    clusters = ClustersFinder.new(clusterable, current_user, :all).execute
+    @clusters = clusters.page(params[:page]).per(20)
+  end
+
+  def new
+  end
+
+  # Overridding ActionController::Metal#status is NOT a good idea
+  def cluster_status
+    respond_to do |format|
+      format.json do
+        Gitlab::PollingInterval.set_header(response, interval: STATUS_POLLING_INTERVAL)
+
+        render json: ClusterSerializer
+          .new(current_user: @current_user)
+          .represent_status(@cluster)
+      end
+    end
+  end
+
+  def show
+  end
+
+  def update
+    Clusters::UpdateService
+      .new(current_user, update_params)
+      .execute(cluster)
+
+    if cluster.valid?
+      respond_to do |format|
+        format.json do
+          head :no_content
+        end
+        format.html do
+          flash[:notice] = _('Kubernetes cluster was successfully updated.')
+          redirect_to cluster.show_path
+        end
+      end
+    else
+      respond_to do |format|
+        format.json { head :bad_request }
+        format.html { render :show }
+      end
+    end
+  end
+
+  def destroy
+    if cluster.destroy
+      flash[:notice] = _('Kubernetes cluster integration was successfully removed.')
+      redirect_to clusterable.index_path, status: :found
+    else
+      flash[:notice] = _('Kubernetes cluster integration was not removed.')
+      render :show
+    end
+  end
+
+  def create_gcp
+    @gcp_cluster = ::Clusters::CreateService
+      .new(current_user, create_gcp_cluster_params)
+      .execute(access_token: token_in_session)
+      .present(current_user: current_user)
+
+    if @gcp_cluster.persisted?
+      redirect_to @gcp_cluster.show_path
+    else
+      generate_gcp_authorize_url
+      validate_gcp_token
+      user_cluster
+
+      render :new, locals: { active_tab: 'gcp' }
+    end
+  end
+
+  def create_user
+    @user_cluster = ::Clusters::CreateService
+      .new(current_user, create_user_cluster_params)
+      .execute(access_token: token_in_session)
+      .present(current_user: current_user)
+
+    if @user_cluster.persisted?
+      redirect_to @user_cluster.show_path
+    else
+      generate_gcp_authorize_url
+      validate_gcp_token
+      gcp_cluster
+
+      render :new, locals: { active_tab: 'user' }
+    end
+  end
+
+  private
+
+  def update_params
+    if cluster.managed?
+      params.require(:cluster).permit(
+        :enabled,
+        :environment_scope,
+        platform_kubernetes_attributes: [
+          :namespace
+        ]
+      )
+    else
+      params.require(:cluster).permit(
+        :enabled,
+        :name,
+        :environment_scope,
+        platform_kubernetes_attributes: [
+          :api_url,
+          :token,
+          :ca_cert,
+          :namespace
+        ]
+      )
+    end
+  end
+
+  def create_gcp_cluster_params
+    params.require(:cluster).permit(
+      :enabled,
+      :name,
+      :environment_scope,
+      provider_gcp_attributes: [
+        :gcp_project_id,
+        :zone,
+        :num_nodes,
+        :machine_type,
+        :legacy_abac
+      ]).merge(
+        provider_type: :gcp,
+        platform_type: :kubernetes,
+        clusterable: clusterable.subject
+      )
+  end
+
+  def create_user_cluster_params
+    params.require(:cluster).permit(
+      :enabled,
+      :name,
+      :environment_scope,
+      platform_kubernetes_attributes: [
+        :namespace,
+        :api_url,
+        :token,
+        :ca_cert,
+        :authorization_type
+      ]).merge(
+        provider_type: :user,
+        platform_type: :kubernetes,
+        clusterable: clusterable.subject
+      )
+  end
+
+  def generate_gcp_authorize_url
+    state = generate_session_key_redirect(clusterable.new_path.to_s)
+
+    @authorize_url = GoogleApi::CloudPlatform::Client.new(
+      nil, callback_google_api_auth_url,
+      state: state).authorize_url
+  rescue GoogleApi::Auth::ConfigMissingError
+    # no-op
+  end
+
+  def gcp_cluster
+    @gcp_cluster = ::Clusters::Cluster.new.tap do |cluster|
+      cluster.build_provider_gcp
+    end
+  end
+
+  def user_cluster
+    @user_cluster = ::Clusters::Cluster.new.tap do |cluster|
+      cluster.build_platform_kubernetes
+    end
+  end
+
+  def validate_gcp_token
+    @valid_gcp_token = GoogleApi::CloudPlatform::Client.new(token_in_session, nil)
+      .validate_token(expires_at_in_session)
+  end
+
+  def token_in_session
+    session[GoogleApi::CloudPlatform::Client.session_key_for_token]
+  end
+
+  def expires_at_in_session
+    @expires_at_in_session ||=
+      session[GoogleApi::CloudPlatform::Client.session_key_for_expires_at]
+  end
+
+  def generate_session_key_redirect(uri)
+    GoogleApi::CloudPlatform::Client.new_session_key_for_redirect_uri do |key|
+      session[key] = uri
+    end
+  end
+
+  def update_applications_status
+    @cluster.applications.each(&:schedule_status_update)
+  end
+end
diff --git a/app/controllers/concerns/project_unauthorized.rb b/app/controllers/concerns/project_unauthorized.rb
new file mode 100644
index 00000000000..f59440dbc59
--- /dev/null
+++ b/app/controllers/concerns/project_unauthorized.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+module ProjectUnauthorized
+  extend ActiveSupport::Concern
+
+  # EE would override this
+  def project_unauthorized_proc
+    # no-op
+  end
+end
diff --git a/app/controllers/concerns/routable_actions.rb b/app/controllers/concerns/routable_actions.rb
index 88939b002b2..5624eb3aa45 100644
--- a/app/controllers/concerns/routable_actions.rb
+++ b/app/controllers/concerns/routable_actions.rb
@@ -3,23 +3,25 @@
 module RoutableActions
   extend ActiveSupport::Concern
 
-  def find_routable!(routable_klass, requested_full_path, extra_authorization_proc: nil)
+  def find_routable!(routable_klass, requested_full_path, extra_authorization_proc: nil, not_found_or_authorized_proc: nil)
     routable = routable_klass.find_by_full_path(requested_full_path, follow_redirects: request.get?)
     if routable_authorized?(routable, extra_authorization_proc)
       ensure_canonical_path(routable, requested_full_path)
       routable
     else
-      handle_not_found_or_authorized(routable)
+      if not_found_or_authorized_proc
+        not_found_or_authorized_proc.call(routable)
+      end
+
+      route_not_found unless performed?
+
       nil
     end
   end
 
-  # This is overridden in gitlab-ee.
-  def handle_not_found_or_authorized(_routable)
-    route_not_found
-  end
-
   def routable_authorized?(routable, extra_authorization_proc)
+    return false unless routable
+
     action = :"read_#{routable.class.to_s.underscore}"
     return false unless can?(current_user, action, routable)
 
diff --git a/app/controllers/projects/application_controller.rb b/app/controllers/projects/application_controller.rb
index a2bdcaefa9b..e0677ce3fbc 100644
--- a/app/controllers/projects/application_controller.rb
+++ b/app/controllers/projects/application_controller.rb
@@ -3,6 +3,7 @@
 class Projects::ApplicationController < ApplicationController
   include CookiesHelper
   include RoutableActions
+  include ProjectUnauthorized
   include ChecksCollaboration
 
   skip_before_action :authenticate_user!
@@ -21,7 +22,7 @@ class Projects::ApplicationController < ApplicationController
     path = File.join(params[:namespace_id], params[:project_id] || params[:id])
     auth_proc = ->(project) { !project.pending_delete? }
 
-    @project = find_routable!(Project, path, extra_authorization_proc: auth_proc)
+    @project = find_routable!(Project, path, extra_authorization_proc: auth_proc, not_found_or_authorized_proc: project_unauthorized_proc)
   end
 
   def build_canonical_path(project)
diff --git a/app/controllers/projects/clusters/applications_controller.rb b/app/controllers/projects/clusters/applications_controller.rb
index bcea96bce94..c7b6218d007 100644
--- a/app/controllers/projects/clusters/applications_controller.rb
+++ b/app/controllers/projects/clusters/applications_controller.rb
@@ -1,29 +1,17 @@
 # frozen_string_literal: true
 
-class Projects::Clusters::ApplicationsController < Projects::ApplicationController
-  before_action :cluster
-  before_action :authorize_read_cluster!
-  before_action :authorize_create_cluster!, only: [:create]
+class Projects::Clusters::ApplicationsController < Clusters::ApplicationsController
+  include ProjectUnauthorized
 
-  def create
-    Clusters::Applications::CreateService
-      .new(@cluster, current_user, create_cluster_application_params)
-      .execute(request)
-
-    head :no_content
-  rescue Clusters::Applications::CreateService::InvalidApplicationError
-    render_404
-  rescue StandardError
-    head :bad_request
-  end
+  prepend_before_action :project
 
   private
 
-  def cluster
-    @cluster ||= project.clusters.find(params[:id]) || render_404
+  def clusterable
+    @clusterable ||= ClusterablePresenter.fabricate(project, current_user: current_user)
   end
 
-  def create_cluster_application_params
-    params.permit(:application, :hostname)
+  def project
+    @project ||= find_routable!(Project, File.join(params[:namespace_id], params[:project_id]), not_found_or_authorized_proc: project_unauthorized_proc)
   end
 end
diff --git a/app/controllers/projects/clusters_controller.rb b/app/controllers/projects/clusters_controller.rb
index 62adc66fb09..feda6deeaa6 100644
--- a/app/controllers/projects/clusters_controller.rb
+++ b/app/controllers/projects/clusters_controller.rb
@@ -1,224 +1,24 @@
 # frozen_string_literal: true
 
-class Projects::ClustersController < Projects::ApplicationController
-  before_action :cluster, except: [:index, :new, :create_gcp, :create_user]
-  before_action :authorize_read_cluster!
-  before_action :generate_gcp_authorize_url, only: [:new]
-  before_action :validate_gcp_token, only: [:new]
-  before_action :gcp_cluster, only: [:new]
-  before_action :user_cluster, only: [:new]
-  before_action :authorize_create_cluster!, only: [:new]
-  before_action :authorize_update_cluster!, only: [:update]
-  before_action :authorize_admin_cluster!, only: [:destroy]
-  before_action :update_applications_status, only: [:status]
-  helper_method :token_in_session
+class Projects::ClustersController < Clusters::ClustersController
+  include ProjectUnauthorized
 
-  STATUS_POLLING_INTERVAL = 10_000
+  prepend_before_action :project
+  before_action :repository
 
-  def index
-    clusters = ClustersFinder.new(project, current_user, :all).execute
-    @clusters = clusters.page(params[:page]).per(20)
-  end
-
-  def new
-  end
-
-  def status
-    respond_to do |format|
-      format.json do
-        Gitlab::PollingInterval.set_header(response, interval: STATUS_POLLING_INTERVAL)
-
-        render json: ClusterSerializer
-          .new(project: @project, current_user: @current_user)
-          .represent_status(@cluster)
-      end
-    end
-  end
-
-  def show
-  end
-
-  def update
-    Clusters::UpdateService
-      .new(current_user, update_params)
-      .execute(cluster)
-
-    if cluster.valid?
-      respond_to do |format|
-        format.json do
-          head :no_content
-        end
-        format.html do
-          flash[:notice] = _('Kubernetes cluster was successfully updated.')
-          redirect_to project_cluster_path(project, cluster)
-        end
-      end
-    else
-      respond_to do |format|
-        format.json { head :bad_request }
-        format.html { render :show }
-      end
-    end
-  end
-
-  def destroy
-    if cluster.destroy
-      flash[:notice] = _('Kubernetes cluster integration was successfully removed.')
-      redirect_to project_clusters_path(project), status: :found
-    else
-      flash[:notice] = _('Kubernetes cluster integration was not removed.')
-      render :show
-    end
-  end
-
-  def create_gcp
-    @gcp_cluster = ::Clusters::CreateService
-      .new(current_user, create_gcp_cluster_params)
-      .execute(project: project, access_token: token_in_session)
-
-    if @gcp_cluster.persisted?
-      redirect_to project_cluster_path(project, @gcp_cluster)
-    else
-      generate_gcp_authorize_url
-      validate_gcp_token
-      user_cluster
-
-      render :new, locals: { active_tab: 'gcp' }
-    end
-  end
-
-  def create_user
-    @user_cluster = ::Clusters::CreateService
-      .new(current_user, create_user_cluster_params)
-      .execute(project: project, access_token: token_in_session)
-
-    if @user_cluster.persisted?
-      redirect_to project_cluster_path(project, @user_cluster)
-    else
-      generate_gcp_authorize_url
-      validate_gcp_token
-      gcp_cluster
-
-      render :new, locals: { active_tab: 'user' }
-    end
-  end
+  layout 'project'
 
   private
 
-  def cluster
-    @cluster ||= project.clusters.find(params[:id])
-                                 .present(current_user: current_user)
-  end
-
-  def update_params
-    if cluster.managed?
-      params.require(:cluster).permit(
-        :enabled,
-        :environment_scope,
-        platform_kubernetes_attributes: [
-          :namespace
-        ]
-      )
-    else
-      params.require(:cluster).permit(
-        :enabled,
-        :name,
-        :environment_scope,
-        platform_kubernetes_attributes: [
-          :api_url,
-          :token,
-          :ca_cert,
-          :namespace
-        ]
-      )
-    end
-  end
-
-  def create_gcp_cluster_params
-    params.require(:cluster).permit(
-      :enabled,
-      :name,
-      :environment_scope,
-      provider_gcp_attributes: [
-        :gcp_project_id,
-        :zone,
-        :num_nodes,
-        :machine_type,
-        :legacy_abac
-      ]).merge(
-        provider_type: :gcp,
-        platform_type: :kubernetes
-      )
-  end
-
-  def create_user_cluster_params
-    params.require(:cluster).permit(
-      :enabled,
-      :name,
-      :environment_scope,
-      platform_kubernetes_attributes: [
-        :namespace,
-        :api_url,
-        :token,
-        :ca_cert,
-        :authorization_type
-      ]).merge(
-        provider_type: :user,
-        platform_type: :kubernetes
-      )
-  end
-
-  def generate_gcp_authorize_url
-    state = generate_session_key_redirect(new_project_cluster_path(@project).to_s)
-
-    @authorize_url = GoogleApi::CloudPlatform::Client.new(
-      nil, callback_google_api_auth_url,
-      state: state).authorize_url
-  rescue GoogleApi::Auth::ConfigMissingError
-    # no-op
-  end
-
-  def gcp_cluster
-    @gcp_cluster = ::Clusters::Cluster.new.tap do |cluster|
-      cluster.build_provider_gcp
-    end
-  end
-
-  def user_cluster
-    @user_cluster = ::Clusters::Cluster.new.tap do |cluster|
-      cluster.build_platform_kubernetes
-    end
-  end
-
-  def validate_gcp_token
-    @valid_gcp_token = GoogleApi::CloudPlatform::Client.new(token_in_session, nil)
-      .validate_token(expires_at_in_session)
-  end
-
-  def token_in_session
-    session[GoogleApi::CloudPlatform::Client.session_key_for_token]
-  end
-
-  def expires_at_in_session
-    @expires_at_in_session ||=
-      session[GoogleApi::CloudPlatform::Client.session_key_for_expires_at]
-  end
-
-  def generate_session_key_redirect(uri)
-    GoogleApi::CloudPlatform::Client.new_session_key_for_redirect_uri do |key|
-      session[key] = uri
-    end
-  end
-
-  def authorize_update_cluster!
-    access_denied! unless can?(current_user, :update_cluster, cluster)
+  def clusterable
+    @clusterable ||= ClusterablePresenter.fabricate(project, current_user: current_user)
   end
 
-  def authorize_admin_cluster!
-    access_denied! unless can?(current_user, :admin_cluster, cluster)
+  def project
+    @project ||= find_routable!(Project, File.join(params[:namespace_id], params[:project_id]), not_found_or_authorized_proc: project_unauthorized_proc)
   end
 
-  def update_applications_status
-    @cluster.applications.each(&:schedule_status_update)
+  def repository
+    @repository ||= project.repository
   end
 end
diff --git a/app/finders/clusters_finder.rb b/app/finders/clusters_finder.rb
index b40d6c41b71..0cce493b73e 100644
--- a/app/finders/clusters_finder.rb
+++ b/app/finders/clusters_finder.rb
@@ -1,20 +1,20 @@
 # frozen_string_literal: true
 
 class ClustersFinder
-  def initialize(project, user, scope)
-    @project = project
+  def initialize(clusterable, user, scope)
+    @clusterable = clusterable
     @user = user
     @scope = scope || :active
   end
 
   def execute
-    clusters = project.clusters
+    clusters = clusterable.clusters
     filter_by_scope(clusters)
   end
 
   private
 
-  attr_reader :project, :user, :scope
+  attr_reader :clusterable, :user, :scope
 
   def filter_by_scope(clusters)
     case scope.to_sym
diff --git a/app/helpers/clusters_helper.rb b/app/helpers/clusters_helper.rb
index 19eb763e1de..916dcb1a308 100644
--- a/app/helpers/clusters_helper.rb
+++ b/app/helpers/clusters_helper.rb
@@ -1,7 +1,8 @@
 # frozen_string_literal: true
 
 module ClustersHelper
-  def has_multiple_clusters?(project)
+  # EE overrides this
+  def has_multiple_clusters?
     false
   end
 
@@ -10,7 +11,7 @@ module ClustersHelper
     return unless show_gcp_signup_offer?
 
     content_tag :section, class: 'no-animate expanded' do
-      render 'projects/clusters/gcp_signup_offer_banner'
+      render 'clusters/clusters/gcp_signup_offer_banner'
     end
   end
 end
diff --git a/app/presenters/clusterable_presenter.rb b/app/presenters/clusterable_presenter.rb
new file mode 100644
index 00000000000..cff0e74d6ea
--- /dev/null
+++ b/app/presenters/clusterable_presenter.rb
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+class ClusterablePresenter < Gitlab::View::Presenter::Delegated
+  presents :clusterable
+
+  def self.fabricate(clusterable, **attributes)
+    presenter_class = "#{clusterable.class.name}ClusterablePresenter".constantize
+    attributes_with_presenter_class = attributes.merge(presenter_class: presenter_class)
+
+    Gitlab::View::Presenter::Factory
+      .new(clusterable, attributes_with_presenter_class)
+      .fabricate!
+  end
+
+  def can_create_cluster?
+    can?(current_user, :create_cluster, clusterable)
+  end
+
+  def index_path
+    polymorphic_path([clusterable, :clusters])
+  end
+
+  def new_path
+    new_polymorphic_path([clusterable, :cluster])
+  end
+
+  def create_user_clusters_path
+    polymorphic_path([clusterable, :clusters], action: :create_user)
+  end
+
+  def create_gcp_clusters_path
+    polymorphic_path([clusterable, :clusters], action: :create_gcp)
+  end
+
+  def cluster_status_cluster_path(cluster, params = {})
+    raise NotImplementedError
+  end
+
+  def install_applications_cluster_path(cluster, application)
+    raise NotImplementedError
+  end
+
+  def cluster_path(cluster, params = {})
+    raise NotImplementedError
+  end
+end
diff --git a/app/presenters/clusters/cluster_presenter.rb b/app/presenters/clusters/cluster_presenter.rb
index dfdd8e82f97..78d632eb77c 100644
--- a/app/presenters/clusters/cluster_presenter.rb
+++ b/app/presenters/clusters/cluster_presenter.rb
@@ -11,5 +11,13 @@ module Clusters
     def can_toggle_cluster?
       can?(current_user, :update_cluster, cluster) && created?
     end
+
+    def show_path
+      if cluster.project_type?
+        project_cluster_path(project, cluster)
+      else
+        raise NotImplementedError
+      end
+    end
   end
 end
diff --git a/app/presenters/project_clusterable_presenter.rb b/app/presenters/project_clusterable_presenter.rb
new file mode 100644
index 00000000000..12077b2e735
--- /dev/null
+++ b/app/presenters/project_clusterable_presenter.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+class ProjectClusterablePresenter < ClusterablePresenter
+  def cluster_status_cluster_path(cluster, params = {})
+    cluster_status_project_cluster_path(clusterable, cluster, params)
+  end
+
+  def install_applications_cluster_path(cluster, application)
+    install_applications_project_cluster_path(clusterable, cluster, application)
+  end
+
+  def cluster_path(cluster, params = {})
+    project_cluster_path(clusterable, cluster, params)
+  end
+end
diff --git a/app/services/clusters/create_service.rb b/app/services/clusters/create_service.rb
index cd843b8ffa8..270db4a52fd 100644
--- a/app/services/clusters/create_service.rb
+++ b/app/services/clusters/create_service.rb
@@ -8,10 +8,11 @@ module Clusters
       @current_user, @params = user, params.dup
     end
 
-    def execute(project:, access_token: nil)
-      raise ArgumentError, _('Instance does not support multiple Kubernetes clusters') unless can_create_cluster?(project)
+    def execute(access_token: nil)
+      raise ArgumentError, 'Unknown clusterable provided' unless clusterable
+      raise ArgumentError, _('Instance does not support multiple Kubernetes clusters') unless can_create_cluster?
 
-      cluster_params = params.merge(user: current_user, cluster_type: :project_type, projects: [project])
+      cluster_params = params.merge(user: current_user).merge(clusterable_params)
       cluster_params[:provider_gcp_attributes].try do |provider|
         provider[:access_token] = access_token
       end
@@ -27,9 +28,20 @@ module Clusters
       Clusters::Cluster.create(cluster_params)
     end
 
+    def clusterable
+      @clusterable ||= params.delete(:clusterable)
+    end
+
+    def clusterable_params
+      case clusterable
+      when ::Project
+        { cluster_type: :project_type, projects: [clusterable] }
+      end
+    end
+
     # EE would override this method
-    def can_create_cluster?(project)
-      project.clusters.empty?
+    def can_create_cluster?
+      clusterable.clusters.empty?
     end
   end
 end
diff --git a/app/views/projects/clusters/_advanced_settings.html.haml b/app/views/clusters/clusters/_advanced_settings.html.haml
index 243e8cd9ba0..7037c80aa6b 100644
--- a/app/views/projects/clusters/_advanced_settings.html.haml
+++ b/app/views/clusters/clusters/_advanced_settings.html.haml
@@ -12,4 +12,4 @@
       = s_('ClusterIntegration|Remove Kubernetes cluster integration')
     %p
       = s_("ClusterIntegration|Remove this Kubernetes cluster's configuration from this project. This will not delete your actual Kubernetes cluster.")
-    = link_to(s_('ClusterIntegration|Remove integration'), namespace_project_cluster_path(@project.namespace, @project, @cluster.id), method: :delete, class: 'btn btn-danger', data: { confirm: s_("ClusterIntegration|Are you sure you want to remove this Kubernetes cluster's integration? This will not delete your actual Kubernetes cluster.")})
+    = link_to(s_('ClusterIntegration|Remove integration'), clusterable.cluster_path(@cluster), method: :delete, class: 'btn btn-danger', data: { confirm: s_("ClusterIntegration|Are you sure you want to remove this Kubernetes cluster's integration? This will not delete your actual Kubernetes cluster.")})
diff --git a/app/views/projects/clusters/_banner.html.haml b/app/views/clusters/clusters/_banner.html.haml
index 73cfea0ef92..73cfea0ef92 100644
--- a/app/views/projects/clusters/_banner.html.haml
+++ b/app/views/clusters/clusters/_banner.html.haml
diff --git a/app/views/projects/clusters/_cluster.html.haml b/app/views/clusters/clusters/_cluster.html.haml
index 2d7f7c6b1fb..facbcb7fc59 100644
--- a/app/views/projects/clusters/_cluster.html.haml
+++ b/app/views/clusters/clusters/_cluster.html.haml
@@ -2,7 +2,7 @@
   .table-section.section-30
     .table-mobile-header{ role: "rowheader" }= s_("ClusterIntegration|Kubernetes cluster")
     .table-mobile-content
-      = link_to cluster.name, namespace_project_cluster_path(@project.namespace, @project, cluster)
+      = link_to cluster.name, cluster.show_path
   .table-section.section-30
     .table-mobile-header{ role: "rowheader" }= s_("ClusterIntegration|Environment scope")
     .table-mobile-content= cluster.environment_scope
@@ -16,7 +16,7 @@
         class: "#{'is-checked' if cluster.enabled?} #{'is-disabled' if !cluster.can_toggle_cluster?}",
         "aria-label": s_("ClusterIntegration|Toggle Kubernetes Cluster"),
         disabled: !cluster.can_toggle_cluster?,
-        data: { endpoint: namespace_project_cluster_path(@project.namespace, @project, cluster, format: :json) } }
+        data: { endpoint: clusterable.cluster_path(cluster, format: :json) } }
         %input.js-project-feature-toggle-input{ type: "hidden", value: cluster.enabled? }
         = icon("spinner spin", class: "loading-icon")
         %span.toggle-icon
diff --git a/app/views/projects/clusters/_empty_state.html.haml b/app/views/clusters/clusters/_empty_state.html.haml
index b8a3556a206..800e76d92ef 100644
--- a/app/views/projects/clusters/_empty_state.html.haml
+++ b/app/views/clusters/clusters/_empty_state.html.haml
@@ -7,6 +7,6 @@
       - link_to_help_page = link_to(_('Learn more about Kubernetes'), help_page_path('user/project/clusters/index'), target: '_blank', rel: 'noopener noreferrer')
       %p= s_('ClusterIntegration|Kubernetes clusters allow you to use review apps, deploy your applications, run your pipelines, and much more in an easy way. %{link_to_help_page}').html_safe % { link_to_help_page: link_to_help_page}
 
-      - if can?(current_user, :create_cluster, @project)
+      - if clusterable.can_create_cluster?
         .text-center
-          = link_to s_('ClusterIntegration|Add Kubernetes cluster'), new_project_cluster_path(@project), class: 'btn btn-success'
+          = link_to s_('ClusterIntegration|Add Kubernetes cluster'), clusterable.new_path, class: 'btn btn-success'
diff --git a/app/views/projects/clusters/_gcp_signup_offer_banner.html.haml b/app/views/clusters/clusters/_gcp_signup_offer_banner.html.haml
index 73b11d509d3..73b11d509d3 100644
--- a/app/views/projects/clusters/_gcp_signup_offer_banner.html.haml
+++ b/app/views/clusters/clusters/_gcp_signup_offer_banner.html.haml
diff --git a/app/views/projects/clusters/_integration_form.html.haml b/app/views/clusters/clusters/_integration_form.html.haml
index d0a553e3414..5e451f60c9d 100644
--- a/app/views/projects/clusters/_integration_form.html.haml
+++ b/app/views/clusters/clusters/_integration_form.html.haml
@@ -1,4 +1,4 @@
-= form_for @cluster, url: namespace_project_cluster_path(@project.namespace, @project, @cluster), as: :cluster do |field|
+= form_for @cluster, url: clusterable.cluster_path(@cluster), as: :cluster do |field|
   = form_errors(@cluster)
   .form-group
     %h5= s_('ClusterIntegration|Integration status')
@@ -13,7 +13,7 @@
           = sprite_icon('status_failed_borderless', size: 16, css_class: 'toggle-icon-svg toggle-status-unchecked')
       .form-text.text-muted= s_('ClusterIntegration|Enable or disable GitLab\'s connection to your Kubernetes cluster.')
 
-  - if has_multiple_clusters?(@project)
+  - if has_multiple_clusters?
     .form-group
       %h5= s_('ClusterIntegration|Environment scope')
       = field.text_field :environment_scope, class: 'col-md-6 form-control js-select-on-focus', placeholder: s_('ClusterIntegration|Environment scope')
@@ -23,7 +23,7 @@
     .form-group
       = field.submit _('Save changes'), class: 'btn btn-success'
 
-  - unless has_multiple_clusters?(@project)
+  - unless has_multiple_clusters?
     %h5= s_('ClusterIntegration|Environment scope')
     %p
       %code *
diff --git a/app/views/projects/clusters/_sidebar.html.haml b/app/views/clusters/clusters/_sidebar.html.haml
index 3d10348212f..3d10348212f 100644
--- a/app/views/projects/clusters/_sidebar.html.haml
+++ b/app/views/clusters/clusters/_sidebar.html.haml
diff --git a/app/views/projects/clusters/gcp/_form.html.haml b/app/views/clusters/clusters/gcp/_form.html.haml
index 171ceeceb68..ad842036a62 100644
--- a/app/views/projects/clusters/gcp/_form.html.haml
+++ b/app/views/clusters/clusters/gcp/_form.html.haml
@@ -12,14 +12,14 @@
 
 %p= link_to('Select a different Google account', @authorize_url)
 
-= form_for @gcp_cluster, html: { class: 'js-gke-cluster-creation prepend-top-20', data: { token: token_in_session } }, url:  create_gcp_namespace_project_clusters_path(@project.namespace, @project), as: :cluster do |field|
+= form_for @gcp_cluster, html: { class: 'js-gke-cluster-creation prepend-top-20', data: { token: token_in_session } }, url: clusterable.create_gcp_clusters_path, as: :cluster do |field|
   = form_errors(@gcp_cluster)
   .form-group
     = field.label :name, s_('ClusterIntegration|Kubernetes cluster name'), class: 'label-bold'
     = field.text_field :name, class: 'form-control', placeholder: s_('ClusterIntegration|Kubernetes cluster name')
   .form-group
     = field.label :environment_scope, s_('ClusterIntegration|Environment scope'), class: 'label-bold'
-    = field.text_field :environment_scope, class: 'form-control', readonly: !has_multiple_clusters?(@project), placeholder: s_('ClusterIntegration|Environment scope')
+    = field.text_field :environment_scope, class: 'form-control', readonly: !has_multiple_clusters?, placeholder: s_('ClusterIntegration|Environment scope')
 
   = field.fields_for :provider_gcp, @gcp_cluster.provider_gcp do |provider_gcp_field|
     .form-group
diff --git a/app/views/projects/clusters/gcp/_header.html.haml b/app/views/clusters/clusters/gcp/_header.html.haml
index a2ad3cd64df..a2ad3cd64df 100644
--- a/app/views/projects/clusters/gcp/_header.html.haml
+++ b/app/views/clusters/clusters/gcp/_header.html.haml
diff --git a/app/views/projects/clusters/gcp/_show.html.haml b/app/views/clusters/clusters/gcp/_show.html.haml
index 779c9c245c1..6021b220285 100644
--- a/app/views/projects/clusters/gcp/_show.html.haml
+++ b/app/views/clusters/clusters/gcp/_show.html.haml
@@ -6,7 +6,7 @@
     %span.input-group-append
       = clipboard_button(text: @cluster.name, title: s_('ClusterIntegration|Copy Kubernetes cluster name'), class: 'input-group-text btn-default')
 
-= form_for @cluster, url: namespace_project_cluster_path(@project.namespace, @project, @cluster), as: :cluster do |field|
+= form_for @cluster, url: clusterable.cluster_path(@cluster), as: :cluster do |field|
   = form_errors(@cluster)
 
   = field.fields_for :platform_kubernetes, @cluster.platform_kubernetes do |platform_kubernetes_field|
diff --git a/app/views/projects/clusters/index.html.haml b/app/views/clusters/clusters/index.html.haml
index a55de84b5cd..a55de84b5cd 100644
--- a/app/views/projects/clusters/index.html.haml
+++ b/app/views/clusters/clusters/index.html.haml
diff --git a/app/views/projects/clusters/new.html.haml b/app/views/clusters/clusters/new.html.haml
index a38003f5750..eeeef6bd824 100644
--- a/app/views/projects/clusters/new.html.haml
+++ b/app/views/clusters/clusters/new.html.haml
@@ -19,9 +19,9 @@
 
     .tab-content.gitlab-tab-content
       .tab-pane{ id: 'create-gcp-cluster-pane', class: active_when(active_tab == 'gcp'), role: 'tabpanel' }
-        = render 'projects/clusters/gcp/header'
+        = render 'clusters/clusters/gcp/header'
         - if @valid_gcp_token
-          = render 'projects/clusters/gcp/form'
+          = render 'clusters/clusters/gcp/form'
         - elsif @authorize_url
           .signin-with-google
             = link_to(image_tag('auth_buttons/signin_with_google.png', width: '191px'), @authorize_url)
@@ -32,5 +32,5 @@
           = s_('Google authentication is not %{link_to_documentation}. Ask your GitLab administrator if you want to use this service.').html_safe % { link_to_documentation: link }
 
       .tab-pane{ id: 'add-user-cluster-pane', class: active_when(active_tab == 'user'), role: 'tabpanel' }
-        = render 'projects/clusters/user/header'
-        = render 'projects/clusters/user/form'
+        = render 'clusters/clusters/user/header'
+        = render 'clusters/clusters/user/form'
diff --git a/app/views/projects/clusters/show.html.haml b/app/views/clusters/clusters/show.html.haml
index eddd3613c5f..1e1157c34bd 100644
--- a/app/views/projects/clusters/show.html.haml
+++ b/app/views/clusters/clusters/show.html.haml
@@ -1,24 +1,25 @@
 - @content_class = "limit-container-width" unless fluid_layout
-- add_to_breadcrumbs "Kubernetes Clusters", project_clusters_path(@project)
+- add_to_breadcrumbs "Kubernetes Clusters", clusterable.index_path
 - breadcrumb_title @cluster.name
 - page_title _("Kubernetes Cluster")
+- manage_prometheus_path = edit_project_service_path(@cluster.project, 'prometheus') if @project
 
 - expanded = Rails.env.test?
 
-- status_path = status_namespace_project_cluster_path(@cluster.project.namespace, @cluster.project, @cluster.id, format: :json) if can?(current_user, :admin_cluster, @cluster)
+- status_path = clusterable.cluster_status_cluster_path(@cluster.id, format: :json) if can?(current_user, :admin_cluster, @cluster)
 .edit-cluster-form.js-edit-cluster-form{ data: { status_path: status_path,
-  install_helm_path: install_applications_namespace_project_cluster_path(@cluster.project.namespace, @cluster.project, @cluster, :helm),
-  install_ingress_path: install_applications_namespace_project_cluster_path(@cluster.project.namespace, @cluster.project, @cluster, :ingress),
-  install_prometheus_path: install_applications_namespace_project_cluster_path(@cluster.project.namespace, @cluster.project, @cluster, :prometheus),
-  install_runner_path: install_applications_namespace_project_cluster_path(@cluster.project.namespace, @cluster.project, @cluster, :runner),
-  install_jupyter_path: install_applications_namespace_project_cluster_path(@cluster.project.namespace, @cluster.project, @cluster, :jupyter),
+  install_helm_path: clusterable.install_applications_cluster_path(@cluster, :helm),
+  install_ingress_path: clusterable.install_applications_cluster_path(@cluster, :ingress),
+  install_prometheus_path: clusterable.install_applications_cluster_path(@cluster, :prometheus),
+  install_runner_path: clusterable.install_applications_cluster_path(@cluster, :runner),
+  install_jupyter_path: clusterable.install_applications_cluster_path(@cluster, :jupyter),
   toggle_status: @cluster.enabled? ? 'true': 'false',
   cluster_status: @cluster.status_name,
   cluster_status_reason: @cluster.status_reason,
   help_path: help_page_path('user/project/clusters/index.md', anchor: 'installing-applications'),
   ingress_help_path: help_page_path('user/project/clusters/index.md', anchor: 'getting-the-external-ip-address'),
   ingress_dns_help_path: help_page_path('topics/autodevops/quick_start_guide.md', anchor: 'point-dns-at-cluster-ip'),
-  manage_prometheus_path: edit_project_service_path(@cluster.project, 'prometheus') } }
+  manage_prometheus_path: manage_prometheus_path } }
 
   .js-cluster-application-notice
     .flash-container
@@ -38,9 +39,9 @@
       %p= s_('ClusterIntegration|See and edit the details for your Kubernetes cluster')
     .settings-content
       - if @cluster.managed?
-        = render 'projects/clusters/gcp/show'
+        = render 'clusters/clusters/gcp/show'
       - else
-        = render 'projects/clusters/user/show'
+        = render 'clusters/clusters/user/show'
 
   %section.settings.no-animate#js-cluster-advanced-settings{ class: ('expanded' if expanded) }
     .settings-header
diff --git a/app/views/projects/clusters/user/_form.html.haml b/app/views/clusters/clusters/user/_form.html.haml
index 54a6e685bb0..4e6232b69de 100644
--- a/app/views/projects/clusters/user/_form.html.haml
+++ b/app/views/clusters/clusters/user/_form.html.haml
@@ -1,9 +1,9 @@
-= form_for @user_cluster, url: create_user_namespace_project_clusters_path(@project.namespace, @project), as: :cluster do |field|
+= form_for @user_cluster, url: clusterable.create_user_clusters_path, as: :cluster do |field|
   = form_errors(@user_cluster)
   .form-group
     = field.label :name, s_('ClusterIntegration|Kubernetes cluster name'), class: 'label-bold'
     = field.text_field :name, class: 'form-control', placeholder: s_('ClusterIntegration|Kubernetes cluster name')
-  - if has_multiple_clusters?(@project)
+  - if has_multiple_clusters?
     .form-group
       = field.label :environment_scope, s_('ClusterIntegration|Environment scope'), class: 'label-bold'
       = field.text_field :environment_scope, class: 'form-control', placeholder: s_('ClusterIntegration|Environment scope')
diff --git a/app/views/projects/clusters/user/_header.html.haml b/app/views/clusters/clusters/user/_header.html.haml
index 749177fa6c1..749177fa6c1 100644
--- a/app/views/projects/clusters/user/_header.html.haml
+++ b/app/views/clusters/clusters/user/_header.html.haml
diff --git a/app/views/projects/clusters/user/_show.html.haml b/app/views/clusters/clusters/user/_show.html.haml
index 5b57f7ceb7d..a871fef0240 100644
--- a/app/views/projects/clusters/user/_show.html.haml
+++ b/app/views/clusters/clusters/user/_show.html.haml
@@ -1,4 +1,4 @@
-= form_for @cluster, url: namespace_project_cluster_path(@project.namespace, @project, @cluster), as: :cluster do |field|
+= form_for @cluster, url: clusterable.cluster_path(@cluster), as: :cluster do |field|
   = form_errors(@cluster)
   .form-group
     = field.label :name, s_('ClusterIntegration|Kubernetes cluster name'), class: 'label-bold'