def event_id(event):
    """
    Gets a unique identifier for an event retrieved from Pilatus files (or HiDRA).

    Returns a label that unambiguosly identifies, within an experiment, the event
    currently being processed. For the Pilatus detector, an event corresponds to a
    single CBF file, and the full path to the file is used as identifier.

    Arguments:

        event (:class:`~onda.utils.data_event.DataEvent`): an object storing the event
            data.

    Returns:

        str: a unique event identifier.
    """
    return event.framework_info['full_path']
