This repository contains a simple library to make reconciling Kubernetes resources a bit less tedious. It wraps the typical get-update-else-create loop in a convenient interface and relies on code generation. A set of default reconciler functions are shipped with this library.

For common resources like Deployments, ConfigMaps or Secrets you can use the reconcilers that ship with this library directly.

func myNamedConfigMapReconcilerFactory() (name string, reconciler reconciling.ConfigMapReconciler) {
   return "my-configmap", func myConfigMapReconciler(cm *corev1.ConfigMap) (*corev1.ConfigMap, error) {
      cm.Data["field"] = "new-value"

      return cm, nil
   }
}

reconcilers := []reconciling.NamedConfigMapReconcilerFactory{
   myNamedConfigMapReconcilerFactory(),
}

if err := reconciling.ReconcileConfigMaps(ctx, client, "namespace", reconcilers); err != nil {
   log.Fatalf("Failed to reconcile ConfigMap: %v", err)
}

For non-standard APIs you can use reconciler-gen to generate your own reconciler code. Create a YAML config file like so:

package: reconciling
boilerplate: boilerplate.go.txt
resourceTypes:
  - { package: k8s.io/kube-aggregator/pkg/apis/apiregistration/v1, resourceName: APIService }
  - { package: kubevirt.io/api/instancetype/v1alpha1, resourceName: VirtualMachineInstancetype }

Then run reconciler-gen:

go run k8c.io/reconciler/cmd/reconciler-gen --config reconciling.yaml > zz_generated_reconcile.go