let example generate

examples/alertmanager-config-template-external.jsonnet

 local configmap(name, namespace, data) = {
-    apiVersion: "v1",
-    kind: "ConfigMap",
+  apiVersion: 'v1',
+  kind: 'ConfigMap',
   metadata: {
     name: name,
     namespace: namespace,
@@ -11,18 +11,25 @@ local configmap(name, namespace, data) = {
 local kp =
   // different libsonnet imported
   {
-      configmap+:: {
-          'alert-templates': configmap(
-          'alertmanager-alert-template.tmpl',
-          $._config.namespace,
-          {"data": importstr 'alertmanager-alert-template.tmpl'},
-          )
+    values+:: {
+      common+: {
+        namespace: 'monitoring',
       },
+    },
+    alertmanager+:: {
       alertmanager+: {
         spec+: {
-                # the important field configmaps:
-                configMaps: ['alert-templates',], # goes to etc/alermanager/configmaps
+          // the important field configmaps:
+          configMaps: ['alert-templates'],  // goes to etc/alermanager/configmaps
+        },
       },
     },
+    configmap+:: {
+      'alert-templates': configmap(
+        'alertmanager-alert-template.tmpl',
+        $.values.common.namespace,  // could be $._config.namespace to assign namespace once
+        { data: importstr 'alertmanager-alert-template.tmpl' },
+      ),
+    },
   };
 { [name + '-configmap']: kp.configmap[name] for name in std.objectFields(kp.configmap) }