Implement Helm ResetCommand for removing Tiller

Also creates specs

Only allow Helm to be uninstalled if it's the only app

- Remove Tiller leftovers after reser command
- Fixes specs and offenses

Adds changelog file

Fix reset_command specs

2 files changed, 54 insertions, 11 deletions

diff --git a/lib/gitlab/kubernetes/helm/delete_command.rb b/lib/gitlab/kubernetes/helm/delete_command.rb
index aeba4a54b6d..dcf22e7abb6 100644
--- a/lib/gitlab/kubernetes/helm/delete_command.rb
+++ b/lib/gitlab/kubernetes/helm/delete_command.rb
@@ -43,17 +43,6 @@ module Gitlab
 
           command.shelljoin
         end
-
-        def optional_tls_flags
-          return [] unless files.key?(:'ca.pem')
-
-          [
-            '--tls',
-            '--tls-ca-cert', "#{files_dir}/ca.pem",
-            '--tls-cert', "#{files_dir}/cert.pem",
-            '--tls-key', "#{files_dir}/key.pem"
-          ]
-        end
       end
     end
   end
diff --git a/lib/gitlab/kubernetes/helm/reset_command.rb b/lib/gitlab/kubernetes/helm/reset_command.rb
new file mode 100644
index 00000000000..37e1d8573ab
--- /dev/null
+++ b/lib/gitlab/kubernetes/helm/reset_command.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Kubernetes
+    module Helm
+      class ResetCommand
+        include BaseCommand
+        include ClientCommand
+
+        attr_reader :name, :files
+
+        def initialize(name:, rbac:, files:)
+          @name = name
+          @files = files
+          @rbac = rbac
+        end
+
+        def generate_script
+          super + [
+            reset_helm_command,
+            delete_tiller_replicaset
+          ].join("\n")
+        end
+
+        def rbac?
+          @rbac
+        end
+
+        def pod_name
+          "uninstall-#{name}"
+        end
+
+        private
+
+        # This method can be delete once we upgrade Helm to > 12.13.0
+        # https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/27096#note_159695900
+        #
+        # Tracking this method to be removed here:
+        # https://gitlab.com/gitlab-org/gitlab-ce/issues/52791#note_199374155
+        def delete_tiller_replicaset
+          command = %w[kubectl delete replicaset -n gitlab-managed-apps -l name=tiller]
+
+          command.shelljoin
+        end
+
+        def reset_helm_command
+          command = %w[helm reset] + optional_tls_flags
+
+          command.shelljoin
+        end
+      end
+    end
+  end
+end