Assuming you are running the program inside the cluster use InClusterConfig as below and call clientset.CoreV1().Pods("").List(context.TODO(), metav1.ListOptions{}). Since we are not passing any value for namespace it will list all pods in all namespaces.

func main() {
	// creates the in-cluster config
	config, err := rest.InClusterConfig()
	if err != nil {
		panic(err.Error())
	}
	// creates the clientset
	clientset, err := kubernetes.NewForConfig(config)
	if err != nil {
		panic(err.Error())
	}
	for {
		// get pods in all the namespaces by omitting namespace
		// Or specify namespace to get pods in particular namespace
		pods, err := clientset.CoreV1().Pods("").List(context.TODO(), metav1.ListOptions{})
		if err != nil {
			panic(err.Error())
		}
		fmt.Printf("There are %d pods in the cluster\n", len(pods.Items))

		// Examples for error handling:
		// - Use helper functions e.g. errors.IsNotFound()
		// - And/or cast to StatusError and use its properties like e.g. ErrStatus.Message
		_, err = clientset.CoreV1().Pods("default").Get(context.TODO(), "example-xxxxx", metav1.GetOptions{})
		if errors.IsNotFound(err) {
			fmt.Printf("Pod example-xxxxx not found in default namespace\n")
		} else if statusError, isStatus := err.(*errors.StatusError); isStatus {
			fmt.Printf("Error getting pod %v\n", statusError.ErrStatus.Message)
		} else if err != nil {
			panic(err.Error())
		} else {
			fmt.Printf("Found example-xxxxx pod in default namespace\n")
		}

		time.Sleep(10 * time.Second)
	}
}