Question: call signature for validator

[tcompa]

Validating a zarr group takes place at least at two levels:

1. Validate attributes of specific groups (e.g. as currently available in https://github.com/ome/ngff/blob/main/0.4/schemas/image.schema for an image group)
2. Validate a whol zarr container (e.g. as in https://github.com/ome/ome-ngff-validator)

A relevant example for case 2 is the following: image metadata includes multiscales, that include datasets, that have path properties. Do these match to some actually-existing zarr subgroups? How can we check?

Option A

• Spec define models for validation 1
• Implementation adds validation 2

Option B

• Specs define models for entire hierarchies
• Validator call signature takes metadata of the whole hierarchy

[tcompa]

Note: ome-zarr-py already does something more than just type 1 validation, see e.g. https://github.com/ome/ome-zarr-py/blob/master/ome_zarr/format.py#L220

    def validate_well_dict(
        self, well: dict, rows: List[str], columns: List[str]
    ) -> None:
        super().validate_well_dict(well, rows, columns)
        if len(well["path"].split("/")) != 2:
            raise ValueError("%s path must exactly be composed of 2 groups", well)
        row, column = well["path"].split("/")
        if row not in rows:
            raise ValueError("%s is not defined in the plate rows", row)
        if well["rowIndex"] != rows.index(row):
            raise ValueError("Mismatching row index for %s", well)
        if column not in columns:
            raise ValueError("%s is not defined in the plate columns", column)
        if well["columnIndex"] != columns.index(column):
            raise ValueError("Mismatching column index for %s", well)

[d-v-b]

A relevant example for case 2 is the following: image metadata includes multiscales, that include datasets, that have path properties. Do these match to some actually-existing zarr subgroups? How can we check?

Definitely! see https://github.com/JaneliaSciComp/pydantic-ome-ngff/commit/90507a970b4f9264a212eb24792fe6143c1e6e17 for for an example of this kind of check