xarrera 0.0.5

Schema validation for Xarray objects

Xarrera

Schema validation for Xarray

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About the project

Xarrera is an open source project that provides an API for performing data-format validation on Xarray objects.

Getting Started

Prerequisites

• Python >= 3.9

Installation

Install Xarrera from PyPI:

pip install xarrera

Conda:

conda install -c conda-forge xarrera

Or install it from source:

pip install git+https://github.com/javgat/xarrera

Another option is cloning the repository and installing the python package and its dependencies by using:

git clone https://github.com/javgat/xarrera.git
cd xarrera
pip install -e .

Usage

Xarrera's API is modeled after Pandera. The DataArraySchema and DatasetSchema objects both have .validate() methods.

The basic usage is as follows:

import numpy as np
import xarray as xr
from xarrera import DataArraySchema, DatasetSchema, CoordsSchema

da = xr.DataArray(np.ones(4, dtype='i4'), dims=['x'], name='foo')

schema = DataArraySchema(dtype=np.integer, name='foo', shape=(4, ), dims=['x'])

schema.validate(da)

You can also use it to validate a Dataset like so:

schema_ds = DatasetSchema({'foo': schema})

schema_ds.validate(da.to_dataset())

Each component of the Xarray data model is implemented as a stand alone class:

from xarrera.components import (
    DTypeSchema,
    DimsSchema,
    ShapeSchema,
    NameSchema,
    ChunksSchema,
    ArrayTypeSchema,
    AttrSchema,
    AttrsSchema
)

# example constructions
dtype_schema = DTypeSchema('i4')
dims_schema = DimsSchema(('x', 'y', None))  # None is used as a wildcard
shape_schema = ShapeSchema((5, 10, None))  # None is used as a wildcard
name_schema = NameSchema('foo')
chunk_schema = ChunksSchema({'x': None, 'y': -1})  # None is used as a wildcard, -1 is used as
ArrayTypeSchema = ArrayTypeSchema(np.ndarray)

# Example usage
dtype_schema.validate(da.dtype)

# Each object schema can be exported to JSON format
dtype_json = dtype_schema.to_json()

Roadmap

This is a very early prototype of a library, based on a library with multiple forks with small additions. The following key things to do are:

• Contact former xarray-schema developers, forkers, and issue writers about xarrera.
• ...
• String comparison using regex xarray-schema~#9
• Accumulate schema exceptions and report them all at once. Currently, we are a eagerly raising SchemaErrors when the are found.
• Improve SchemaError reported information.
• Extract schema from xarray objects xarray-schema~#45

Versioning

Version changes and descriptions are stored in the CHANGELOG. This file is updated each time a new version is released.

Contributing

Development Guide

1. Install npm (required for pre-commit hooks)

   Some pre-commit hooks (e.g., for formatting or linting) depend on Node.js and npm. You can install them via your system package manager, or download from nodejs.org (npm is included).

   For example, on Debian/Ubuntu:

   sudo apt update
   sudo apt install nodejs npm
   

   If you use conda, you can also install it with:

   conda install -c conda-forge nodejs
   

2. Install Pre-commit Hooks

   Install the pre-commit hooks to automatically check code styling:

   pre-commit install
   

3. Install Python Dependencies

   Install the python package dependencies listed in the requirements.txt file, preferably in a python virtual enironment:

   pip install -r requirements.txt
   # or
   pip install -e .
   

Testing

1. Install test dependencies

   Install de development dependencies with:

   pip install -r dev-requirements.txt
   # or
   pip install -e ".[dev]"
   

2. Run the style check

   Run the mypy style check with:

   mypy xarrera tests
   

3. Run the tests

   Run the tests with:

   pytest
   

   Generate the coverage with

   pytest --cov=./ --cov-report=xml --verbose
   

License

All the code in this repository is MIT licensed.

History

This project was originally developed at CarbonPlan. It was transferred to the xarray-contrib organization in August 2022.

Due to the inactivity in xarray-contrib, it was forked to Xarrera in March 2026.

Authors

• Javier Gatón Herguedas - Maintainer - :octocat: @javgat - [e-mail]
• Callan Gray - Contributor - :octocat: @calgray
• Joe Hamman - CarbonPlan - Initial Work - :octocat: @jhamman
• Anderson Banihirwe - CarbonPlan - Initial Work - :octocat @andersy005 - [e-mail]
• Peter A. I. Forsyth - Initial Work - :octocat: @paiforsyth
• Oriana Chegwidden - CarbonPlan - Initial Work - :octocat: @orianac
• Raphael Hagen - CarbonPlan - Initial Work - [e-mail]