[#884] cli: Fix error message for undefined endpoint

Signed-off-by: Alexander Chuprov <a.chuprov@yadro.com>

cmd/frostfs-cli/internal/client/sdk.go

@@ -34,6 +34,10 @@ func GetSDKClientByFlag(cmd *cobra.Command, key *ecdsa.PrivateKey, endpointFlag
 func getSDKClientByFlag(cmd *cobra.Command, key *ecdsa.PrivateKey, endpointFlag string) (*client.Client, error) {
 	var addr network.Address
 
+	if len(viper.GetString(endpointFlag)) == 0 {
+		return nil, fmt.Errorf("%s is not defined", endpointFlag)
+	}
+
 	err := addr.FromString(viper.GetString(endpointFlag))
 	if err != nil {
 		return nil, fmt.Errorf("%v: %w", errInvalidEndpoint, err)

pkg/network/address.go

@@ -88,6 +88,10 @@ func (a *Address) FromString(s string) error {
 
 // multiaddrStringFromHostAddr converts "localhost:8080" to "/dns4/localhost/tcp/8080".
 func multiaddrStringFromHostAddr(host string) (string, error) {
+	if len(host) == 0 {
+		return "", fmt.Errorf("host is empty")
+	}
+
 	endpoint, port, err := net.SplitHostPort(host)
 	if err != nil {
 		return "", err