K8s/Folders: Fix folder status error message (#95464)

* Fix folder status error message
* Add test for folder creation response message
* Add TestFoldersCreateAPIEndpointK8S fixes
* Fix message returned when user has no permissions

pkg/api/apierrors/folder.go

@@ -1,6 +1,7 @@
 package apierrors
 
 import (
+	"encoding/json"
 	"errors"
 	"net/http"
 
@@ -48,20 +49,36 @@ func ToFolderErrorResponse(err error) response.Response {
 
 func ToFolderStatusError(err error) k8sErrors.StatusError {
 	resp := ToFolderErrorResponse(err)
+	defaultErr := k8sErrors.StatusError{
+		ErrStatus: metav1.Status{
+			Message: "Folder API error",
+			Code:    http.StatusInternalServerError,
+		},
+	}
 
 	normResp, ok := resp.(*response.NormalResponse)
 	if !ok {
-		return k8sErrors.StatusError{
-			ErrStatus: metav1.Status{
-				Message: "Folder API error",
-				Code:    http.StatusInternalServerError,
-			},
-		}
+		return defaultErr
+	}
+
+	var dat map[string]interface{}
+	if err := json.Unmarshal(normResp.Body(), &dat); err != nil {
+		return defaultErr
+	}
+
+	m, ok := dat["message"]
+	if !ok {
+		return defaultErr
+	}
+
+	message, ok := m.(string)
+	if !ok {
+		return defaultErr
 	}
 
 	return k8sErrors.StatusError{
 		ErrStatus: metav1.Status{
-			Message: normResp.ErrMessage(),
+			Message: message,
 			Code:    int32(normResp.Status()),
 		},
 	}

pkg/api/folder.go

@@ -807,7 +807,14 @@ func (fk8s *folderK8sHandler) writeError(c *contextmodel.ReqContext, err error)
 	//nolint:errorlint
 	statusError, ok := err.(*k8sErrors.StatusError)
 	if ok {
-		c.JsonApiErr(int(statusError.Status().Code), statusError.Status().Message, err)
+		message := statusError.Status().Message
+		// #TODO: Is there a better way to set the correct meesage? Instead of "access denied to folder", currently we are
+		// returning something like `folders.folder.grafana.app is forbidden: User "" cannot create resource "folders" in
+		// API group "folder.grafana.app" in the namespace "default": folder``
+		if statusError.Status().Code == http.StatusForbidden {
+			message = dashboards.ErrFolderAccessDenied.Error()
+		}
+		c.JsonApiErr(int(statusError.Status().Code), message, err)
 		return
 	}
 	errhttp.Write(c.Req.Context(), err, c.Resp)