DMR++

The DMRPP parser reads DMR++ (Data Model Response Protocol Plus) XML files, which contain metadata describing datasets and their chunk locations. It creates virtual Zarr arrays backed by the original data files.

virtualizarr.parsers.DMRPPParser

__call__

__call__(url: str, registry: ObjectStoreRegistry) -> ManifestStore

Parse the metadata and byte offsets from a given DMR++ file to product a VirtualiZarr ManifestStore.

Parameters:

• url (str) –

  The URL of the input DMR++ file (e.g., "s3://bucket/file.dmrpp").

• registry (ObjectStoreRegistry) –

  An ObjectStoreRegistry for resolving urls and reading data.

Returns:

• ManifestStore –

  A ManifestStore that provides a Zarr representation of the data source referenced by the DMR++ file.

__init__

__init__(group: str | None = None, skip_variables: Iterable[str] | None = None)

Instantiate a parser with parser-specific parameters that can be used in the call method.

Parameters:

• group (str | None, default: None ) –

  The group within the file to be used as the Zarr root group for the ManifestStore.

• skip_variables (Iterable[str] | None, default: None ) –

  Variables in the file that will be ignored when creating the ManifestStore.

Usage

import virtualizarr
from virtualizarr.parsers import DMRPPParser

# Open a DMR++ file as a virtual dataset
ds = virtualizarr.open_virtual_dataset(
    "file:///path/to/dataset.dmrpp",
    parser=DMRPPParser(),
)

Validation

The DMRPP parser includes validation for missing attributes in the DMR++ XML. When required attributes are missing, the parser raises a ValueError. When optional attributes are missing, validation issues are accumulated and can be accessed via the _validation_issues attribute of the parser instance.