Lasso
Core controller framework used by Wrangler and Norman.
This framework is a bit raw, but can be used directly. The intention is try to standardize some boilerplate of building controllers.
Basic components
Package cache
This is a generic form of the generated SharedIndexFactory.
Package client
Generic form of the generated clientsets.
Package controller
The Controller is a simple approach that wraps the standard pattern of worker goroutines and workqueue. The package
depends on the cache and client removing the need for generated clientsets, informers, and listers.
The SharedController type is an extension of Controller that adds the ability to register multiple handlers on a
shared controller instance.
Simple Example
import (
"context"
"github.com/rancher/lasso/pkg/controller"
appsv1 "k8s.io/api/apps/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/client-go/rest"
)
func MyController(ctx context.Context, config *rest.Config) error {
// Setup types you want to work with
scheme := runtime.NewScheme()
appsv1.AddToScheme(scheme)
controllerFactory, err := controller.NewSharedControllerFactoryFromConfig(config, scheme)
if err != nil {
return err
}
sharedController, err := controllerFactory.ForObject(&appsv1.Deployment{})
if err != nil {
return err
}
// Register a handler on a shared controller. If you a dedicated queue then use controller.New()
sharedController.RegisterHandler(ctx, "my-handler", controller.SharedControllerHandlerFunc(func(key string, obj runtime.Object) (runtime.Object, error) {
// obj is the latest version of this obj in the cache and MAY BE NIL when an object is finally deleted
dep, ok := obj.(*appsv1.Deployment)
if !ok {
return obj, nil
}
// Do some stuff ...
// Get stuff from the cache
sharedController.Informer().GetStore().Get(key)
result := &appsv1.Deployment{}
err := sharedController.Client().Update(ctx, dep.Namespace, dep, result, metav1.UpdateOptions{})
// return the latest version of the object
return result, err
}))
return controllerFactory.Start(ctx, 5)
}