(feat) add more template functions

controllers/template_instantiation.go

@@ -154,7 +154,7 @@ func fecthClusterObjects(ctx context.Context, config *rest.Config, c client.Clie
 	return result, nil
 }
 
-func instantiateTemplateValues(ctx context.Context, config *rest.Config, c client.Client,
+func instantiateTemplateValues(ctx context.Context, config *rest.Config, c client.Client, //nolint: funlen // adding few closures
 	clusterType libsveltosv1beta1.ClusterType, clusterNamespace, clusterName, requestorName, values string,
 	mgmtResources map[string]*unstructured.Unstructured, logger logr.Logger) (string, error) {
 
@@ -182,20 +182,90 @@ func instantiateTemplateValues(ctx context.Context, config *rest.Config, c clien
 			return ""
 		}
 
-		var uObject unstructured.Unstructured
-		uObject.SetUnstructuredContent(u)
-		uObject.SetManagedFields(nil)
-		uObject.SetResourceVersion("")
-		uObject.SetUID("")
+		uObject := resetFields(u)
 
 		data, err := yaml.Marshal(uObject.UnstructuredContent())
 		if err != nil {
 			// Swallow errors inside of a template.
+			logger.V(logs.LogInfo).Info(fmt.Sprintf("failed with err %v", err))
 			return ""
 		}
 
 		return strings.TrimSuffix(string(data), "\n")
 	}
+	funcMap["getField"] = func(id string, fields string) interface{} {
+		u, ok := objects.MgmtResources[id]
+		if !ok {
+			// Swallow errors inside of a template.
+			return ""
+		}
+
+		v, isPresent, err := unstructured.NestedFieldCopy(u, strings.Split(fields, ".")...)
+		if err != nil || !isPresent {
+			return ""
+		}
+
+		return v
+	}
+	funcMap["removeField"] = func(id, fields string) string {
+		u, ok := objects.MgmtResources[id]
+		if !ok {
+			// Swallow errors inside of a template.
+			return ""
+		}
+
+		unstructured.RemoveNestedField(u, strings.Split(fields, ".")...)
+		uObject := resetFields(u)
+
+		data, err := yaml.Marshal(uObject)
+		if err != nil {
+			// Swallow errors inside of a template.
+			logger.V(logs.LogInfo).Info(fmt.Sprintf("failed with err %v", err))
+			return ""
+		}
+
+		return strings.TrimSuffix(string(data), "\n")
+	}
+	funcMap["setField"] = func(id, fields string, value any) string {
+		u, ok := objects.MgmtResources[id]
+		if !ok {
+			// Swallow errors inside of a template.
+			return ""
+		}
+
+		err := unstructured.SetNestedField(u, value, strings.Split(fields, ".")...)
+		if err != nil {
+			// Swallow errors inside of a template.
+			logger.V(logs.LogInfo).Info(fmt.Sprintf("failed with err %v", err))
+			return ""
+		}
+
+		uObject := resetFields(u)
+
+		data, err := yaml.Marshal(uObject.UnstructuredContent())
+		if err != nil {
+			// Swallow errors inside of a template.
+			logger.V(logs.LogInfo).Info(fmt.Sprintf("failed with err %v", err))
+			return ""
+		}
+
+		return strings.TrimSuffix(string(data), "\n")
+	}
+	funcMap["chainRemoveField"] = func(u map[string]interface{}, fields string) map[string]interface{} {
+		unstructured.RemoveNestedField(u, strings.Split(fields, ".")...)
+
+		return u
+	}
+	funcMap["chainSetField"] = func(u map[string]interface{}, fields string, value any) map[string]interface{} {
+		err := unstructured.SetNestedField(u, value, strings.Split(fields, ".")...)
+		if err != nil {
+			// Swallow errors inside of a template.
+			logger.V(logs.LogInfo).Info(fmt.Sprintf("failed with err %v", err))
+			return nil
+		}
+
+		return u
+	}
 
 	templateName := getTemplateName(clusterNamespace, clusterName, requestorName)
 	tmpl, err := template.New(templateName).Option("missingkey=error").Funcs(funcMap).Parse(values)
@@ -217,3 +287,13 @@ func instantiateTemplateValues(ctx context.Context, config *rest.Config, c clien
 func getTemplateName(clusterNamespace, clusterName, requestorName string) string {
 	return fmt.Sprintf("%s-%s-%s", clusterNamespace, clusterName, requestorName)
 }
+
+func resetFields(u map[string]interface{}) unstructured.Unstructured {
+	var uObject unstructured.Unstructured
+	uObject.SetUnstructuredContent(u)
+	uObject.SetManagedFields(nil)
+	uObject.SetResourceVersion("")
+	uObject.SetUID("")
+
+	return uObject
+}