Enable GitLabb runner to be uninstalled from cluster

- Set as uninstallable app
- Update docs
- Adjust specs

3 files changed, 32 insertions, 17 deletions

diff --git a/app/models/clusters/applications/runner.rb b/app/models/clusters/applications/runner.rb
index f0256ff4d41..6ae8c3bd7f3 100644
--- a/app/models/clusters/applications/runner.rb
+++ b/app/models/clusters/applications/runner.rb
@@ -29,13 +29,6 @@ module Clusters
         content_values.to_yaml
       end
 
-      # Need to investigate if pipelines run by this runner will stop upon the
-      # executor pod stopping
-      # I.e.run a pipeline, and uninstall runner while pipeline is running
-      def allowed_to_uninstall?
-        false
-      end
-
       def install_command
         Gitlab::Kubernetes::Helm::InstallCommand.new(
           name: name,
@@ -47,6 +40,14 @@ module Clusters
         )
       end
 
+      def prepare_uninstall
+        runner&.update!(active: false)
+      end
+
+      def post_uninstall
+        runner.destroy!
+      end
+
       private
 
       def ensure_runner
diff --git a/app/models/clusters/concerns/application_core.rb b/app/models/clusters/concerns/application_core.rb
index 4514498b84b..803a65726d3 100644
--- a/app/models/clusters/concerns/application_core.rb
+++ b/app/models/clusters/concerns/application_core.rb
@@ -46,6 +46,16 @@ module Clusters
             command.version = version
           end
         end
+
+        def prepare_uninstall
+          # Override if your application needs any action before
+          # being uninstalled by Helm
+        end
+
+        def post_uninstall
+          # Override if your application needs any action after
+          # being uninstalled by Helm
+        end
       end
     end
   end
diff --git a/app/models/clusters/concerns/application_status.rb b/app/models/clusters/concerns/application_status.rb
index 54a3dda6d75..342d766f723 100644
--- a/app/models/clusters/concerns/application_status.rb
+++ b/app/models/clusters/concerns/application_status.rb
@@ -59,29 +59,33 @@ module Clusters
             transition [:scheduled] => :uninstalling
           end
 
-          before_transition any => [:scheduled] do |app_status, _|
-            app_status.status_reason = nil
+          before_transition any => [:scheduled] do |application, _|
+            application.status_reason = nil
           end
 
-          before_transition any => [:errored] do |app_status, transition|
+          before_transition any => [:errored] do |application, transition|
             status_reason = transition.args.first
-            app_status.status_reason = status_reason if status_reason
+            application.status_reason = status_reason if status_reason
           end
 
-          before_transition any => [:updating] do |app_status, _|
-            app_status.status_reason = nil
+          before_transition any => [:updating] do |application, _|
+            application.status_reason = nil
           end
 
-          before_transition any => [:update_errored, :uninstall_errored] do |app_status, transition|
+          before_transition any => [:update_errored, :uninstall_errored] do |application, transition|
             status_reason = transition.args.first
-            app_status.status_reason = status_reason if status_reason
+            application.status_reason = status_reason if status_reason
           end
 
-          before_transition any => [:installed, :updated] do |app_status, _|
+          before_transition any => [:installed, :updated] do |application, _|
             # When installing any application we are also performing an update
             # of tiller (see Gitlab::Kubernetes::Helm::ClientCommand) so
             # therefore we need to reflect that in the database.
-            app_status.cluster.application_helm.update!(version: Gitlab::Kubernetes::Helm::HELM_VERSION)
+            application.cluster.application_helm.update!(version: Gitlab::Kubernetes::Helm::HELM_VERSION)
+          end
+
+          after_transition any => [:uninstalling], :use_transactions => false do |application, _|
+            application.prepare_uninstall
           end
         end
       end