HOWTO actually use the kubernetes generic client

generic-client.go

package main

import (
	"context"
	"fmt"
	"os"
	"path"

	corev1 "k8s.io/api/core/v1"
	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/runtime"
	cacheddiscovery "k8s.io/client-go/discovery/cached/memory"
	"k8s.io/client-go/dynamic"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/rest"
	"k8s.io/client-go/restmapper"
	"k8s.io/client-go/tools/clientcmd"
	"k8s.io/kubectl/pkg/scheme"
)

func GetObject[T runtime.Object](cfg *rest.Config, dest T, namespace, name string) error {
	// in reality, you would only construct these once
	clientset, err := kubernetes.NewForConfig(cfg)
	if err != nil {
		return err
	}
	dynamicClientset, err := dynamic.NewForConfig(cfg)
	if err != nil {
		return err
	}
	discoveryClient := cacheddiscovery.NewMemCacheClient(clientset.Discovery())
	mapper := restmapper.NewDeferredDiscoveryRESTMapper(discoveryClient)
	// end one-time construction

	// Map object to GroupVersionKind
	kinds, _, _ := scheme.Scheme.ObjectKinds(dest)
  // But bail if the object doesn't have exactly one GVK
	if len(kinds) != 1 {
		return fmt.Errorf("bad kinds")
	}
	gvk := kinds[0]

  // Map GVK to server resource
	restMapping, err := mapper.RESTMapping(gvk.GroupKind(), gvk.Version)
	if err != nil {
		return err
	}

  // Finally, we can get what we were looking for
	uns, err := dynamicClientset.Resource(restMapping.Resource).Namespace(namespace).Get(context.TODO(), name, v1.GetOptions{})
	if err != nil {
		return nil
	}

	if err := scheme.Scheme.Convert(uns, dest, nil); err != nil {
		return err
	}

	return nil
}

func main() {
	home, err := os.UserHomeDir()
	if err != nil {
		panic(err)
	}
	// note: better to use genericclioptions + LoadingRules
	cfg, err := clientcmd.BuildConfigFromFlags("", path.Join(home, ".kube", "config"))
	if err != nil {
		panic(err)
	}
	p := &corev1.Pod{}

	if err := GetObject(cfg, p, "kube-system", "kube-apiserver-kind-control-plane"); err != nil {
		panic(err)
	}
	fmt.Printf("%+v\n", p)
}