Use default VS and TS templates when CfgMap obj is deleted

Author: jjngx

internal/configs/configmaps.go

@@ -359,10 +359,14 @@ func ParseConfigMap(ctx context.Context, cfgm *v1.ConfigMap, nginxPlus bool, has
 
 	if virtualServerTemplate, exists := cfgm.Data["virtualserver-template"]; exists {
 		cfgParams.VirtualServerTemplate = &virtualServerTemplate
+	} else {
+		cfgParams.VirtualServerTemplate = nil
 	}
 
 	if transportServerTemplate, exists := cfgm.Data["transportserver-template"]; exists {
 		cfgParams.TransportServerTemplate = &transportServerTemplate
+	} else {
+		cfgParams.TransportServerTemplate = nil
 	}
 
 	if mainStreamSnippets, exists := GetMapKeyAsStringSlice(cfgm.Data, "stream-snippets", cfgm, "\n"); exists {

internal/configs/configurator.go

@@ -1327,20 +1327,29 @@ func (cnf *Configurator) UpdateConfig(cfgParams *ConfigParams, resources Extende
 		if err != nil {
 			return allWarnings, fmt.Errorf("error when parsing the ingress template: %w", err)
 		}
+	} else {
+		// reverse to default ingress template parsed at NIC startup.
+		cnf.templateExecutor.UseOriginalIngressTemplate()
 	}
 
 	if cfgParams.VirtualServerTemplate != nil {
 		err := cnf.templateExecutorV2.UpdateVirtualServerTemplate(cfgParams.VirtualServerTemplate)
 		if err != nil {
 			return allWarnings, fmt.Errorf("error when parsing the VirtualServer template: %w", err)
 		}
+	} else {
+		// Reverse to default TransportServer template
+		cnf.templateExecutorV2.UseOriginalVStemplate()
 	}
 
 	if cfgParams.TransportServerTemplate != nil {
 		err := cnf.templateExecutorV2.UpdateTransportServerTemplate(cfgParams.TransportServerTemplate)
 		if err != nil {
 			return allWarnings, fmt.Errorf("error when parsing the TransportServer template: %w", err)
 		}
+	} else {
+		// Reverse to defualt TransportServer template
+		cnf.templateExecutorV2.UseOriginalTStemplate()
 	}
 
 	mainCfg := GenerateNginxMainConfig(cnf.staticCfgParams, cfgParams)