kedro.extras.datasets.dask.ParquetDataSet¶
- class kedro.extras.datasets.dask.ParquetDataSet(filepath, load_args=None, save_args=None, credentials=None, fs_args=None)[source]¶
ParquetDataSet
loads and saves data to parquet file(s). It uses Dask remote data services to handle the corresponding load and save operations: https://docs.dask.org/en/latest/how-to/connect-to-remote-data.htmlExample usage for the YAML API:
cars: type: dask.ParquetDataSet filepath: s3://bucket_name/path/to/folder save_args: compression: GZIP credentials: client_kwargs: aws_access_key_id: YOUR_KEY aws_secret_access_key: YOUR_SECRET
Example usage for the Python API:
from kedro.extras.datasets.dask import ParquetDataSet import pandas as pd import dask.dataframe as dd data = pd.DataFrame({'col1': [1, 2], 'col2': [4, 5], 'col3': [[5, 6], [7, 8]]}) ddf = dd.from_pandas(data, npartitions=2) data_set = ParquetDataSet( filepath="s3://bucket_name/path/to/folder", credentials={ 'client_kwargs':{ 'aws_access_key_id': 'YOUR_KEY', 'aws_secret_access_key': 'YOUR SECRET', } }, save_args={"compression": "GZIP"} ) data_set.save(ddf) reloaded = data_set.load() assert ddf.compute().equals(reloaded.compute())
The output schema can also be explicitly specified using Triad. This is processed to map specific columns to PyArrow field types or schema. For instance:
parquet_dataset: type: dask.ParquetDataSet filepath: "s3://bucket_name/path/to/folder" credentials: client_kwargs: aws_access_key_id: YOUR_KEY aws_secret_access_key: "YOUR SECRET" save_args: compression: GZIP schema: col1: [int32] col2: [int32] col3: [[int32]]
Attributes
Property of optional file system parameters.
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.
save
(data)Saves data by delegation to the provided save method.
- DEFAULT_LOAD_ARGS: Dict[str, Any] = {}¶
- DEFAULT_SAVE_ARGS: Dict[str, Any] = {'write_index': False}¶
- __init__(filepath, load_args=None, save_args=None, credentials=None, fs_args=None)[source]¶
Creates a new instance of
ParquetDataSet
pointing to concrete parquet files.- Parameters
filepath (
str
) – Filepath in POSIX format to a parquet file parquet collection or the directory of a multipart parquet.load_args (
Optional
[Dict
[str
,Any
]]) – Additional loading options dask.dataframe.read_parquet: https://docs.dask.org/en/latest/generated/dask.dataframe.read_parquet.htmlsave_args (
Optional
[Dict
[str
,Any
]]) – Additional saving options for dask.dataframe.to_parquet: https://docs.dask.org/en/latest/generated/dask.dataframe.to_parquet.htmlcredentials (
Optional
[Dict
[str
,Any
]]) – Credentials required to get access to the underlying filesystem. E.g. forGCSFileSystem
it should look like {“token”: None}.fs_args (
Optional
[Dict
[str
,Any
]]) – Optional parameters to the backend file system driver: https://docs.dask.org/en/latest/how-to/connect-to-remote-data.html#optional-parameters
- 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 – Data set name.
config – Data set config dictionary.
load_version – 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 – 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.
- Returns
An instance of an
AbstractDataset
subclass.- Raises
DatasetError – When the function fails to create the data set from its config.
- property fs_args: Dict[str, Any]¶
Property of optional file system parameters.
- Return type
Dict
[str
,Any
]- Returns
A dictionary of backend file system parameters, including credentials.
- load()¶
Loads data by delegation to the provided load method.
- Return type
TypeVar
(_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
- save(data)¶
Saves data by delegation to the provided save method.
- Parameters
data (
TypeVar
(_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