core.py 文件源码

def _backup_current_release(self):
        """

        [advanced]\t

        dpkg likes to blow away your old files when
        you make new ones. this is a hack to keep them
        around
        """
        current_release = self._rpath('releases', self._get_current_release()).rstrip('/')

        should_backup = \
                '.old' not in current_release and \
                not files.exists(current_release + '.old')

        if should_backup:
            sudo('mv %(dir)s %(dir)s.old' % {'dir': current_release}, user=self._user, group=self._group)
            self._change_symlink_to("%s.old" % current_release)