)

const (
	// Location to read istioctl defaults from
	defaultIstioctlConfig = "$HOME/.istioctl/config.yaml"
)

var (
	// IstioConfig is the name of the istioctl config file (if any)
	IstioConfig = env.Register("ISTIOCONFIG", defaultIstioctlConfig,
		"Default values for istioctl flags").Get()

	LoggingOptions = defaultLogOptions()

// RawExtension is used to hold extensions in external versions.
//
// To use this, make a field which has RawExtension as its type in your external, versioned
// struct, and Object in your internal struct. You also need to register your
// various plugin types.
//
// // Internal package:
//
// 	type MyAPIObject struct {
// 		runtime.TypeMeta `json:",inline"`
// 		MyPlugin runtime.Object `json:"myPlugin"`
// 	}
//

    cs-->pc
    sd-->ep
```

### Config Translation

With a few exceptions, Istio controllers typically are split in two phases: construction and running.

Construction should create informers (via `kclient.New`), setup a queue (via `controllers.NewQueue`), and register event handlers on the informers.
Often, these handlers are adding something to the queue like `client.AddEventHandler(controllers.ObjectHandler(queue.AddObject))`.

	// Note: we do not rely on istio env package to retrieve configuration. We relies on viper.
	// This is just to make sure the reference doc tool can generate doc with these vars as env variable at istio.io.
	env.Register(envName, defaultValue, usage)
	bindViper(name)
}

func bindViper(name string) {
	if err := viper.BindPFlag(name, rootCmd.Flags().Lookup(name)); err != nil {
		log.Error(err)
		os.Exit(1)
	}
}

	if dnsCapture {
		md["ISTIO_META_DNS_CAPTURE"] = strconv.FormatBool(dnsCapture)
	}
	if autoRegister {
		md["ISTIO_META_AUTO_REGISTER_GROUP"] = wg.Name
	}

	proxyConfig, err := protomarshal.ToJSONMap(meshConfig.DefaultConfig)
	if err != nil {
		return nil, err
	}