Publish technique metadata in Bliss#

Use the scan metadata mechanism in BLISS to add metadata automatically to any scan and dataset based on the content of the scan. For example any scan that has an “energy” counter is an “XAS” scan:

from bliss import current_session
from bliss.scanning.scan_meta import get_user_scan_meta, META_TIMING
from esrf_ontologies import technique

def add_xas_technique(scan):
    channels = scan.scan_info.get("channels", dict())
    if "energy" in channels:
        technique_metadata = technique.get_technique_metadata("XAS")

        # For ICAT:
        technique_metadata.fill_dataset_metadata(current_session.scan_saving.dataset)

        # For HDF5:
        return technique_metadata.get_scan_metadata()

scan_meta = get_user_scan_meta()
scan_meta.add_categories({"techniques"})
scan_meta.techniques.timing = META_TIMING.START
scan_meta.techniques.set("add_xas_technique", add_xas_technique)

Note that get_technique_metadata accepts one or more technique names or acronyms.

When the beamline has technique specific commands instead of the generic BLISS scan command it can be done like this

from bliss import setup_globals
from bliss import current_session
from esrf_ontologies import technique

def xas_scan(start, stop, intervals, count_time, scan_info=None):
    technique_metadata = technique.get_technique_metadata("XAS")

    # For ICAT:
    technique_metadata.fill_dataset_metadata(current_session.scan_saving.dataset)

    # For HDF5:
    if scan_info is None:
        scan_info = technique_metadata.get_scan_info()
    else:
        technique_metadata.fill_scan_info(scan_info)

    setup_globals.ascan(setup_globals.energy, start, stop, intervals, count_time, scan_info=scan_info)

Adding the same technique to a dataset several times is not a problem; a unique list of techniques is maintained, preventing duplicates.

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