def prep_jid(nocache=False, passed_jid=None):
    '''
    Return a job id and prepare the job id directory
    This is the function responsible for making sure jids don't collide
    (unless its passed a jid). So do what you have to do to make sure that
    stays the case
    '''
    conn = _get_conn()
    if conn is None:
        return None
    cur = conn.cursor()
    if passed_jid is None:
        jid = _gen_jid(cur)
    else:
        jid = passed_jid
    while not jid:
        log.info("jid clash, generating a new one")
        jid = _gen_jid(cur)

    cur.close()
    conn.close()
    return jid