replica.py 文件源码

def touch_replica(replica, session=None):
    """
    Update the accessed_at timestamp of the given file replica/did but don't wait if row is locked.

    :param replica: a dictionary with the information of the affected replica.
    :param session: The database session in use.

    :returns: True, if successful, False otherwise.
    """
    if 'rse_id' not in replica:
        replica['rse_id'] = get_rse_id(rse=replica['rse'], session=session)

    try:
        accessed_at, none_value = replica.get('accessed_at') or datetime.utcnow(), None

        session.query(models.RSEFileAssociation).\
            filter_by(rse_id=replica['rse_id'], scope=replica['scope'], name=replica['name']).\
            with_hint(models.RSEFileAssociation, "index(REPLICAS REPLICAS_PK)", 'oracle').\
            with_for_update(nowait=True).one()

        session.query(models.RSEFileAssociation).filter_by(rse_id=replica['rse_id'], scope=replica['scope'], name=replica['name']).\
            with_hint(models.RSEFileAssociation, "index(REPLICAS REPLICAS_PK)", 'oracle').\
            update({'accessed_at': accessed_at,
                    'tombstone': case([(and_(models.RSEFileAssociation.tombstone != none_value,
                                             models.RSEFileAssociation.tombstone != OBSOLETE),
                                        accessed_at)],
                                      else_=models.RSEFileAssociation.tombstone)},
                   synchronize_session=False)

        session.query(models.DataIdentifier).\
            filter_by(scope=replica['scope'], name=replica['name'], did_type=DIDType.FILE).\
            with_hint(models.DataIdentifier, "INDEX(DIDS DIDS_PK)", 'oracle').\
            with_for_update(nowait=True).one()

        session.query(models.DataIdentifier).\
            filter_by(scope=replica['scope'], name=replica['name'], did_type=DIDType.FILE).\
            with_hint(models.DataIdentifier, "INDEX(DIDS DIDS_PK)", 'oracle').\
            update({'accessed_at': accessed_at}, synchronize_session=False)

    except DatabaseError:
        return False
    except NoResultFound:
        return True

    return True