LogFormat  = "log"
	JSONFormat = "json"
	YAMLFormat = "yaml"
)

var (
	MsgOutputFormatKeys = []string{LogFormat, JSONFormat, YAMLFormat}
	MsgOutputFormats    = make(map[string]bool)
	termEnvVar          = env.Register("TERM", "", "Specifies terminal type.  Use 'dumb' to suppress color output")
)

func init() {
	for _, key := range MsgOutputFormatKeys {
		MsgOutputFormats[key] = true
	}
}

)

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()

	"istioNamespace":      env.Register("ISTIOCTL_ISTIONAMESPACE", constants.IstioSystemNamespace, "The istioctl --istioNamespace override"),
	"xds-address":         env.Register("ISTIOCTL_XDS_ADDRESS", "", "The istioctl --xds-address override"),
	"xds-port":            env.Register("ISTIOCTL_XDS_PORT", 15012, "The istioctl --xds-port override"),
	"authority":           env.Register("ISTIOCTL_AUTHORITY", "", "The istioctl --authority override"),

	// 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
	}