Enables ingress for uninstallation

- JupyterHub must not be available (installed or updated)

app/models/clusters/applications/ingress.rb

@@ -35,11 +35,8 @@ module Clusters
         'stable/nginx-ingress'
       end
 
-      # We will implement this in future MRs.
-      # Basically we need to check all dependent applications are not installed
-      # first.
       def allowed_to_uninstall?
-        false
+        external_ip_or_hostname? && application_jupyter_nil_or_installable?
       end
 
       def install_command
@@ -52,6 +49,10 @@ module Clusters
         )
       end
 
+      def external_ip_or_hostname?
+        external_ip.present? || external_hostname.present?
+      end
+
       def schedule_status_update
         return unless installed?
         return if external_ip
@@ -63,6 +64,12 @@ module Clusters
       def ingress_service
         cluster.kubeclient.get_service('ingress-nginx-ingress-controller', Gitlab::Kubernetes::Helm::NAMESPACE)
       end
+
+      private
+
+      def application_jupyter_nil_or_installable?
+        cluster.application_jupyter.nil? || cluster.application_jupyter&.installable?
+      end
     end
   end
 end

app/models/clusters/applications/jupyter.rb

@@ -23,9 +23,7 @@ module Clusters
         return unless cluster&.application_ingress_available?
 
         ingress = cluster.application_ingress
-        if ingress.external_ip || ingress.external_hostname
-          self.status = 'installable'
-        end
+        self.status = 'installable' if ingress.external_ip_or_hostname?
       end
 
       def chart

app/models/clusters/applications/prometheus.rb

@@ -49,14 +49,6 @@ module Clusters
         )
       end
 
-      def uninstall_command
-        Gitlab::Kubernetes::Helm::DeleteCommand.new(
-          name: name,
-          rbac: cluster.platform_kubernetes_rbac?,
-          files: files
-        )
-      end
-
       def upgrade_command(values)
         ::Gitlab::Kubernetes::Helm::InstallCommand.new(
           name: name,

changelogs/unreleased/feature-uninstall_cluster_ingress.yml

+---
+title: Allow Ingress to be uninstalled from the UI
+merge_request: 29977
+author:
+type: added

doc/user/clusters/applications.md

@@ -251,6 +251,7 @@ The applications below can be uninstalled.
 
 | Application | GitLab version | Notes |
 | ----------- | -------------- | ----- |
+| Ingress  | 12.1+         | The associated load balancer and IP will be deleted and cannot be restored. Furthermore, it can only be uninstalled if JupyterHub is not installed. |
 | JupyterHub  | 12.1+         | All data not committed to GitLab will be deleted and cannot be restored. |
 | Prometheus  | 11.11+         | All data will be deleted and cannot be restored. |
 

spec/features/projects/clusters/applications_spec.rb

@@ -21,8 +21,7 @@ describe 'Clusters Applications', :js do
 
       it 'user is unable to install applications' do
         page.within('.js-cluster-application-row-helm') do
-          expect(page.find(:css, '.js-cluster-application-install-button')['disabled']).to eq('true')
-          expect(page).to have_css('.js-cluster-application-install-button', exact_text: 'Install')
+          expect(page).to have_css('.js-cluster-application-install-button[disabled]', exact_text: 'Install')
         end
       end
     end
@@ -53,19 +52,16 @@ describe 'Clusters Applications', :js do
         it 'they see status transition' do
           page.within('.js-cluster-application-row-helm') do
             # FE sends request and gets the response, then the buttons is "Installing"
-            expect(page.find(:css, '.js-cluster-application-install-button')['disabled']).to eq('true')
-            expect(page).to have_css('.js-cluster-application-install-button', exact_text: 'Installing')
+            expect(page).to have_css('.js-cluster-application-install-button[disabled]', exact_text: 'Installing')
 
             Clusters::Cluster.last.application_helm.make_installing!
 
             # FE starts polling and update the buttons to "Installing"
-            expect(page.find(:css, '.js-cluster-application-install-button')['disabled']).to eq('true')
-            expect(page).to have_css('.js-cluster-application-install-button', exact_text: 'Installing')
+            expect(page).to have_css('.js-cluster-application-install-button[disabled]', exact_text: 'Installing')
 
             Clusters::Cluster.last.application_helm.make_installed!
 
-            expect(page.find(:css, '.js-cluster-application-install-button')['disabled']).to eq('true')
-            expect(page).to have_css('.js-cluster-application-install-button', exact_text: 'Installed')
+            expect(page).to have_css('.js-cluster-application-install-button[disabled]', exact_text: 'Installed')
           end
 
           expect(page).to have_content('Helm Tiller was successfully installed on your Kubernetes cluster')
@@ -212,26 +208,25 @@ describe 'Clusters Applications', :js do
           it 'they see status transition' do
             page.within('.js-cluster-application-row-ingress') do
               # FE sends request and gets the response, then the buttons is "Installing"
-              expect(page).to have_css('.js-cluster-application-install-button[disabled]')
-              expect(page).to have_css('.js-cluster-application-install-button', exact_text: 'Installing')
+              expect(page).to have_css('.js-cluster-application-install-button[disabled]', exact_text: 'Installing')
 
               Clusters::Cluster.last.application_ingress.make_installing!
 
               # FE starts polling and update the buttons to "Installing"
-              expect(page).to have_css('.js-cluster-application-install-button', exact_text: 'Installing')
-              expect(page).to have_css('.js-cluster-application-install-button[disabled]')
+              expect(page).to have_css('.js-cluster-application-install-button[disabled]', exact_text: 'Installing')
 
               # The application becomes installed but we keep waiting for external IP address
               Clusters::Cluster.last.application_ingress.make_installed!
 
-              expect(page).to have_css('.js-cluster-application-install-button', exact_text: 'Installed')
-              expect(page).to have_css('.js-cluster-application-install-button[disabled]')
+              expect(page).to have_css('.js-cluster-application-install-button[disabled]', exact_text: 'Installed')
               expect(page).to have_selector('.js-no-endpoint-message')
               expect(page).to have_selector('.js-ingress-ip-loading-icon')
 
               # We receive the external IP address and display
               Clusters::Cluster.last.application_ingress.update!(external_ip: '192.168.1.100')
 
+              expect(page).not_to have_css('.js-cluster-application-install-button')
+              expect(page).to have_css('.js-cluster-application-uninstall-button:not([disabled])', exact_text: 'Uninstall')
               expect(page).not_to have_selector('.js-no-endpoint-message')
               expect(page.find('.js-endpoint').value).to eq('192.168.1.100')
             end

spec/models/clusters/applications/ingress_spec.rb

@@ -21,7 +21,21 @@ describe Clusters::Applications::Ingress do
   describe '#can_uninstall?' do
     subject { ingress.can_uninstall? }
 
-    it { is_expected.to be_falsey }
+    it 'returns true if application_jupyter_nil_or_installable? AND external_ip_or_hostname? are true' do
+      ingress.external_ip = 'IP'
+
+      is_expected.to be_truthy
+    end
+
+    it 'returns false if application_jupyter_nil_or_installable? is false' do
+      create(:clusters_applications_jupyter, :installed, cluster: ingress.cluster)
+
+      is_expected.to be_falsey
+    end
+
+    it 'returns false if external_ip_or_hostname? is false' do
+      is_expected.to be_falsey
+    end
   end
 
   describe '#make_installed!' do