Metadata

class lsst.verify.Metadata(measurement_set, data=None)

Bases: JsonSerializationMixin

Container for verification framework job metadata.

Metadata are key-value terms. Both keys and values should be JSON-serializable.

Parameters:

measurement_setlsst.verify.MeasurementSet, optional

When provided, metadata with keys prefixed by metric names are deferred to Metadata instances attached to measurements (lsst.verify.Measurement.notes).

datadict, optional

Dictionary to seed metadata.

Attributes Summary

json	A dict that can be serialized as semantic SQUASH JSON.

Methods Summary

items()	Iterate over key-value metadata pairs.
jsonify_dict(d)	Recursively build JSON-renderable objects on all values in a dict.
keys()	Get a list of metadata keys.
update(data)	Update metadata with key-value pairs from a dict-like object.
write_json(filepath)	Write JSON to a file.

Attributes Documentation

json

A dict that can be serialized as semantic SQUASH JSON.

Keys in the dict are metadata keys (see Metadata.keys). Values are the associated metadata values as JSON-serializable objects.

Methods Documentation

items()

Iterate over key-value metadata pairs.

Yields:

itemtuple

A metadata item is a tuple of:

• Key (str).

• Value (object).

static jsonify_dict(d)

Recursively build JSON-renderable objects on all values in a dict.

Parameters:

ddict

Dictionary to convert into a JSON-serializable object. Values are recursively JSON-ified.

Returns:

json_dictdict

Dictionary that can be serialized to JSON.

Examples

Subclasses can use this method to prepare output in their json-method implementation. For example:

def json(self):
    return JsonSerializationMixin.jsonify_dict({
        'value': self.value,
    })

keys()

Get a list of metadata keys.

Returns:

keyslist of str

These keys keys can be used to access metadata values (like a dict).

update(data)

Update metadata with key-value pairs from a dict-like object.

Parameters:

datadict-like

The data object needs to provide an items method to iterate over its key-value pairs. If this Metadata instance already has a key, the value will be overwritten with the value from data.

write_json(filepath)

Write JSON to a file.

Parameters:

filepathstr

Destination file name for JSON output.