etcdctl/ctlv3/command/role_command.go
func roleAddCommandFunc(cmd *cobra.Command, args []string) {
	if len(args) != 1 {
		ExitWithError(ExitBadArgs, fmt.Errorf("role add command requires role name as its argument"))
	}

	resp, err := mustClientFromCmd(cmd).Auth.RoleAdd(context.TODO(), args[0])
	if err != nil {
		ExitWithError(ExitError, err)
	}

	display.RoleAdd(args[0], *resp)
}
func roleAddCommandFunc(cmd *cobra.Command, args []string) {
	if len(args) != 1 {
		ExitWithError(ExitBadArgs, fmt.Errorf("role add command requires role name as its argument"))
	}

	resp, err := mustClientFromCmd(cmd).Auth.RoleAdd(context.TODO(), args[0])
	if err != nil {
		ExitWithError(ExitError, err)
	}

	display.RoleAdd(args[0], *resp)
}
// roleAddCommandFunc executes the "role add" command.