Folder API: optionally force deleting Grafana 8 alerts when deleting a folder (or error) (#36427)

* Folder API: Add an optional query parameter for allowing deleting a  folder containing rules

* Update frontend

- Set forceDeleteRules=true when frontend deletes a folder
- Improve modal text

* Update docs

* Apply suggestions from code review

Co-authored-by: gotjosh <josue@grafana.com>
Co-authored-by: Nathan Rodman <nathanrodman@gmail.com>
Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>

pkg/api/folder.go

@@ -96,7 +96,7 @@ func (hs *HTTPServer) DeleteFolder(c *models.ReqContext) response.Response { //
 		return ToFolderErrorResponse(err)
 	}
 
-	f, err := s.DeleteFolder(c.Params(":uid"))
+	f, err := s.DeleteFolder(c.Params(":uid"), c.QueryBool("forceDeleteRules"))
 	if err != nil {
 		return ToFolderErrorResponse(err)
 	}
@@ -149,7 +149,8 @@ func ToFolderErrorResponse(err error) response.Response {
 	if errors.Is(err, models.ErrFolderTitleEmpty) ||
 		errors.Is(err, models.ErrDashboardTypeMismatch) ||
 		errors.Is(err, models.ErrDashboardInvalidUid) ||
-		errors.Is(err, models.ErrDashboardUidTooLong) {
+		errors.Is(err, models.ErrDashboardUidTooLong) ||
+		errors.Is(err, models.ErrFolderContainsAlertRules) {
 		return response.Error(400, err.Error(), nil)
 	}
 

pkg/api/folder_test.go

@@ -238,7 +238,7 @@ func (s *fakeFolderService) UpdateFolder(existingUID string, cmd *models.UpdateF
 	return s.UpdateFolderError
 }
 
-func (s *fakeFolderService) DeleteFolder(uid string) (*models.Folder, error) {
+func (s *fakeFolderService) DeleteFolder(uid string, forceDeleteRules bool) (*models.Folder, error) {
 	s.DeletedFolderUids = append(s.DeletedFolderUids, uid)
 	return s.DeleteFolderResult, s.DeleteFolderError
 }