def get_basebackup(self, arg):
        """Download a basebackup from an object store"""
        if not arg.tablespace_dir:
            tablespace_mapping = {}
        else:
            try:
                tablespace_mapping = dict(v.split("=", 1) for v in arg.tablespace_dir)
            except ValueError:
                raise RestoreError("Invalid tablespace mapping {!r}".format(arg.tablespace_dir))

        self.config = config.read_json_config_file(arg.config, check_commands=False, check_pgdata=False)
        site = config.get_site_from_config(self.config, arg.site)
        try:
            self.storage = self._get_object_storage(site, arg.target_dir)
            self._get_basebackup(
                pgdata=arg.target_dir,
                basebackup=arg.basebackup,
                site=site,
                debug=arg.debug,
                status_output_file=arg.status_output_file,
                primary_conninfo=arg.primary_conninfo,
                recovery_end_command=arg.recovery_end_command,
                recovery_target_action=arg.recovery_target_action,
                recovery_target_name=arg.recovery_target_name,
                recovery_target_time=arg.recovery_target_time,
                recovery_target_xid=arg.recovery_target_xid,
                restore_to_master=arg.restore_to_master,
                overwrite=arg.overwrite,
                tablespace_mapping=tablespace_mapping,
                tablespace_base_dir=arg.tablespace_base_dir,
            )
        except RestoreError:  # pylint: disable=try-except-raise
            # Pass RestoreErrors thru
            raise
        except Exception as ex:
            if self.log_tracebacks:
                self.log.exception("Unexpected _get_basebackup failure")
            raise RestoreError("{}: {}".format(ex.__class__.__name__, ex))
Download a basebackup from an object store