# The MIT License (MIT)
# Copyright (c) 2019 by the xcube development team and contributors
#
# Permission is hereby granted, free of charge, to any person obtaining a copy of
# this software and associated documentation files (the "Software"), to deal in
# the Software without restriction, including without limitation the rights to
# use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
# of the Software, and to permit persons to whom the Software is furnished to do
# so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
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#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# SOFTWARE.
import json
import os.path
from typing import List, Sequence
import numpy as np
import xarray as xr
import zarr
[docs]def unchunk_dataset(dataset_path: str, var_names: Sequence[str] = None, coords_only: bool = False):
"""
Unchunk dataset variables in-place.
:param dataset_path: Path to ZARR dataset directory.
:param var_names: Optional list of variable names.
:param coords_only: Un-chunk coordinate variables only.
"""
is_zarr = os.path.isfile(os.path.join(dataset_path, '.zgroup'))
if not is_zarr:
raise ValueError(f'{dataset_path!r} is not a valid Zarr directory')
with xr.open_zarr(dataset_path) as dataset:
if var_names is None:
if coords_only:
var_names = list(dataset.coords)
else:
var_names = list(dataset.variables)
else:
for var_name in var_names:
if coords_only:
if var_name not in dataset.coords:
raise ValueError(f'variable {var_name!r} is not a coordinate variable in {dataset_path!r}')
else:
if var_name not in dataset.variables:
raise ValueError(f'variable {var_name!r} is not a variable in {dataset_path!r}')
_unchunk_vars(dataset_path, var_names)
def _unchunk_vars(dataset_path: str, var_names: List[str]):
for var_name in var_names:
var_path = os.path.join(dataset_path, var_name)
# Optimization: if "shape" and "chunks" are equal in ${var}/.zarray, we are done
var_array_info_path = os.path.join(var_path, '.zarray')
with open(var_array_info_path, 'r') as fp:
var_array_info = json.load(fp)
if var_array_info.get('shape') == var_array_info.get('chunks'):
continue
# Open array and remove chunks from the data
var_array = zarr.convenience.open_array(var_path, 'r+')
if var_array.shape != var_array.chunks:
# TODO (forman): Fully loading data is inefficient and dangerous for large arrays.
# Instead save unchunked to temp and replace existing chunked array dir with temp.
# Fully load data and attrs so we no longer depend on files
data = np.array(var_array)
attributes = var_array.attrs.asdict()
# Save array data
zarr.convenience.save_array(var_path, data, chunks=False, fill_value=var_array.fill_value)
# zarr.convenience.save_array() does not seem save user attributes (file ".zattrs" not written),
# therefore we must modify attrs explicitly:
var_array = zarr.convenience.open_array(var_path, 'r+')
var_array.attrs.update(attributes)