"""``CSVDataset`` loads/saves data from/to a CSV file using an underlying
filesystem (e.g.: local, S3, GCS). It uses polars to handle the CSV file.
"""
import logging
import warnings
from copy import deepcopy
from io import BytesIO
from pathlib import PurePosixPath
from typing import Any, Dict
import fsspec
import polars as pl
from kedro.io.core import (
PROTOCOL_DELIMITER,
Version,
get_filepath_str,
get_protocol_and_path,
)
from kedro_datasets import KedroDeprecationWarning
from kedro_datasets._io import AbstractVersionedDataset, DatasetError
logger = logging.getLogger(__name__)
[docs]class CSVDataset(AbstractVersionedDataset[pl.DataFrame, pl.DataFrame]):
"""``CSVDataset`` loads/saves data from/to a CSV file using an underlying
filesystem (e.g.: local, S3, GCS). It uses polars to handle the CSV file.
Example usage for the `YAML API <https://kedro.readthedocs.io/en/stable/data/\
data_catalog_yaml_examples.html>`_:
.. code-block:: yaml
cars:
type: polars.CSVDataset
filepath: data/01_raw/company/cars.csv
load_args:
sep: ","
parse_dates: False
save_args:
has_header: False
null_value: "somenullstring"
motorbikes:
type: polars.CSVDataset
filepath: s3://your_bucket/data/02_intermediate/company/motorbikes.csv
credentials: dev_s3
Example usage for the
`Python API <https://kedro.readthedocs.io/en/stable/data/\
advanced_data_catalog_usage.html>`_:
::
>>> from kedro_datasets.polars import CSVDataset
>>> import polars as pl
>>>
>>> data = pl.DataFrame({'col1': [1, 2], 'col2': [4, 5],
... 'col3': [5, 6]})
>>>
>>> dataset = CSVDataset(filepath='test.csv')
>>> dataset.save(data)
>>> reloaded = dataset.load()
>>> assert data.frame_equal(reloaded)
"""
DEFAULT_LOAD_ARGS: Dict[str, Any] = {"rechunk": True}
DEFAULT_SAVE_ARGS: Dict[str, Any] = {}
[docs] def __init__( # noqa: PLR0913
self,
filepath: str,
load_args: Dict[str, Any] = None,
save_args: Dict[str, Any] = None,
version: Version = None,
credentials: Dict[str, Any] = None,
fs_args: Dict[str, Any] = None,
metadata: Dict[str, Any] = None,
) -> None:
"""Creates a new instance of ``CSVDataset`` pointing to a concrete CSV file
on a specific filesystem.
Args:
filepath: Filepath in POSIX format to a CSV file prefixed with a protocol
`s3://`.
If prefix is not provided, `file` protocol (local filesystem)
will be used.
The prefix should be any protocol supported by ``fsspec``.
Note: `http(s)` doesn't support versioning.
load_args: Polars options for loading CSV files.
Here you can find all available arguments:
https://pola-rs.github.io/polars/py-polars/html/reference/api/polars.read_csv.html#polars.read_csv
All defaults are preserved, but we explicity use `rechunk=True` for `seaborn`
compability.
save_args: Polars options for saving CSV files.
Here you can find all available arguments:
https://pola-rs.github.io/polars/py-polars/html/reference/api/polars.DataFrame.write_csv.html
All defaults are preserved.
version: If specified, should be an instance of
``kedro.io.core.Version``. If its ``load`` attribute is
None, the latest version will be loaded. If its ``save``
attribute is None, save version will be autogenerated.
credentials: Credentials required to get access to the underlying filesystem.
E.g. for ``GCSFileSystem`` it should look like `{"token": None}`.
fs_args: Extra arguments to pass into underlying filesystem class constructor
(e.g. `{"project": "my-project"}` for ``GCSFileSystem``).
metadata: Any arbitrary metadata.
This is ignored by Kedro, but may be consumed by users or external plugins.
"""
_fs_args = deepcopy(fs_args) or {}
_credentials = deepcopy(credentials) or {}
protocol, path = get_protocol_and_path(filepath, version)
if protocol == "file":
_fs_args.setdefault("auto_mkdir", True)
self._protocol = protocol
self._storage_options = {**_credentials, **_fs_args}
self._fs = fsspec.filesystem(self._protocol, **self._storage_options)
self.metadata = metadata
super().__init__(
filepath=PurePosixPath(path),
version=version,
exists_function=self._fs.exists,
glob_function=self._fs.glob,
)
# Handle default load and save arguments
self._load_args = deepcopy(self.DEFAULT_LOAD_ARGS)
if load_args is not None:
self._load_args.update(load_args)
self._save_args = deepcopy(self.DEFAULT_SAVE_ARGS)
if save_args is not None:
self._save_args.update(save_args)
if "storage_options" in self._save_args or "storage_options" in self._load_args:
logger.warning(
"Dropping 'storage_options' for %s, "
"please specify them under 'fs_args' or 'credentials'.",
self._filepath,
)
self._save_args.pop("storage_options", None)
self._load_args.pop("storage_options", None)
def _describe(self) -> Dict[str, Any]:
return {
"filepath": self._filepath,
"protocol": self._protocol,
"load_args": self._load_args,
"save_args": self._save_args,
"version": self._version,
}
def _load(self) -> pl.DataFrame:
load_path = str(self._get_load_path())
if self._protocol == "file":
# file:// protocol seems to misbehave on Windows
# (<urlopen error file not on local host>),
# so we don't join that back to the filepath;
# storage_options also don't work with local paths
return pl.read_csv(load_path, **self._load_args)
load_path = f"{self._protocol}{PROTOCOL_DELIMITER}{load_path}"
return pl.read_csv(
load_path, storage_options=self._storage_options, **self._load_args
)
def _save(self, data: pl.DataFrame) -> None:
save_path = get_filepath_str(self._get_save_path(), self._protocol)
buf = BytesIO()
data.write_csv(file=buf, **self._save_args)
with self._fs.open(save_path, mode="wb") as fs_file:
fs_file.write(buf.getvalue())
self._invalidate_cache()
def _exists(self) -> bool:
try:
load_path = get_filepath_str(self._get_load_path(), self._protocol)
except DatasetError:
return False
return self._fs.exists(load_path)
def _release(self) -> None:
super()._release()
self._invalidate_cache()
def _invalidate_cache(self) -> None:
"""Invalidate underlying filesystem caches."""
filepath = get_filepath_str(self._filepath, self._protocol)
self._fs.invalidate_cache(filepath)
_DEPRECATED_CLASSES = {
"CSVDataSet": CSVDataset,
}
def __getattr__(name):
if name in _DEPRECATED_CLASSES:
alias = _DEPRECATED_CLASSES[name]
warnings.warn(
f"{repr(name)} has been renamed to {repr(alias.__name__)}, "
f"and the alias will be removed in Kedro-Datasets 2.0.0",
KedroDeprecationWarning,
stacklevel=2,
)
return alias
raise AttributeError(f"module {repr(__name__)} has no attribute {repr(name)}")