kedro.io.AbstractVersionedDataSet

class kedro.io.AbstractVersionedDataSet(filepath, version, exists_function=None, glob_function=None)

AbstractVersionedDataSet is the base class for all versioned data set implementations. All data sets that implement versioning should extend this abstract class and implement the methods marked as abstract.

Example:

from pathlib import Path, PurePosixPath
import pandas as pd
from kedro.io import AbstractVersionedDataSet


class MyOwnDataSet(AbstractVersionedDataSet):
    def __init__(self, filepath, version, param1, param2=True):
        super().__init__(PurePosixPath(filepath), version)
        self._param1 = param1
        self._param2 = param2

    def _load(self) -> pd.DataFrame:
        load_path = self._get_load_path()
        return pd.read_csv(load_path)

    def _save(self, df: pd.DataFrame) -> None:
        save_path = self._get_save_path()
        df.to_csv(str(save_path))

    def _exists(self) -> bool:
        path = self._get_load_path()
        return Path(path.as_posix()).exists()

    def _describe(self):
        return dict(version=self._version, param1=self._param1, param2=self._param2)

Example catalog.yml specification:

my_dataset:
    type: <path-to-my-own-dataset>.MyOwnDataSet
    filepath: data/01_raw/my_data.csv
    versioned: true
    param1: <param1-value> # param1 is a required argument
    # param2 will be True by default

Methods

exists()	Checks whether a data set’s output already exists by calling the provided _exists() method.
from_config(name, config[, load_version, …])	Create a data set instance using the configuration provided.
load()	Loads data by delegation to the provided load method.
release()	Release any cached data.
resolve_load_version()	Compute the version the dataset should be loaded with.
resolve_save_version()	Compute the version the dataset should be saved with.
save(data)	Saves data by delegation to the provided save method.

__init__(filepath, version, exists_function=None, glob_function=None)

Creates a new instance of AbstractVersionedDataSet.

Parameters

• filepath (PurePosixPath) – Filepath in POSIX format to a file.

• version (Optional[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.

• exists_function (Optional[Callable[[str], bool]]) – Function that is used for determining whether a path exists in a filesystem.

• glob_function (Optional[Callable[[str], List[str]]]) – Function that is used for finding all paths in a filesystem, which match a given pattern.

exists()

Checks whether a data set’s output already exists by calling the provided _exists() method.

Return type

bool

Returns

Flag indicating whether the output already exists.

Raises

DataSetError – when underlying exists method raises error.

classmethod from_config(name, config, load_version=None, save_version=None)

Create a data set instance using the configuration provided.

Parameters

• name (str) – Data set name.

• config (Dict[str, Any]) – Data set config dictionary.

• load_version (Optional[str]) – Version string to be used for load operation if the data set is versioned. Has no effect on the data set if versioning was not enabled.

• save_version (Optional[str]) – Version string to be used for save operation if the data set is versioned. Has no effect on the data set if versioning was not enabled.

Return type

AbstractDataSet

Returns

An instance of an AbstractDataSet subclass.

Raises

DataSetError – When the function fails to create the data set from its config.

load()

Loads data by delegation to the provided load method.

Return type

~_DO

Returns

Data returned by the provided load method.

Raises

DataSetError – When underlying load method raises error.

release()

Release any cached data.

Raises

DataSetError – when underlying release method raises error.

Return type

None

resolve_load_version()

Compute the version the dataset should be loaded with.

Return type

Optional[str]

resolve_save_version()

Compute the version the dataset should be saved with.

Return type

Optional[str]

save(data)

Saves data by delegation to the provided save method.

Parameters

data (~_DI) – the value to be saved by provided save method.

Raises

• DataSetError – when underlying save method raises error.

• FileNotFoundError – when save method got file instead of dir, on Windows.

• NotADirectoryError – when save method got file instead of dir, on Unix.

Return type

None