b.WriteString("KubeconfigFilename: " + c.KubeconfigFilename + "\n")
	b.WriteString("KubeconfigMode: " + fmt.Sprintf("%#o", c.KubeconfigMode) + "\n")
	b.WriteString("KubeCAFile: " + c.KubeCAFile + "\n")
	b.WriteString("SkipTLSVerify: " + fmt.Sprint(c.SkipTLSVerify) + "\n")

	b.WriteString("K8sServiceProtocol: " + c.K8sServiceProtocol + "\n")
	b.WriteString("K8sServiceHost: " + c.K8sServiceHost + "\n")

		return r.Filter.Tag.String()
	}
	if len(r.Filter.And.Tags) != 0 {
		var buf bytes.Buffer
		for _, t := range r.Filter.And.Tags {
			if buf.Len() > 0 {
				buf.WriteString("&")
			}
			buf.WriteString(t.String())
		}
		return buf.String()
	}
	return ""
}

// Validate - validates the rule element
func (r Rule) Validate() error {
	if err := r.validateID(); err != nil {

		// readability.
		w.Header().Set("Content-Type", "text/plain")
		var b strings.Builder
		b.WriteString("| Name | Type | Help | Labels |\n")
		b.WriteString("| ---- | ---- | ---- | ------ |\n")
		for _, metric := range metrics {
			b.WriteString(metric.TableRow())
		}
		w.Write([]byte(b.String()))
	})
}