fix crash when monit is disabled

Signed-off-by: huanggze <loganhuang@yunify.com>

pkg/models/metrics/namespaces.go

@@ -40,6 +40,9 @@ func GetNamespacesWithMetrics(namespaces []*v1.Namespace) []*v1.Namespace {
 	}
 
 	rawMetrics := GetNamespaceMetrics(params)
+	if rawMetrics == nil {
+		return namespaces
+	}
 
 	for _, result := range rawMetrics.Results {
 		for _, data := range result.Data.Result {

pkg/models/metrics/util.go

@@ -68,7 +68,7 @@ func (rawMetrics *Response) SortBy(sortMetricName string, sortType string) (*Res
 		}
 	}()
 
-	if sortMetricName == "" {
+	if sortMetricName == "" || rawMetrics == nil {
 		return rawMetrics, -1
 	}