kedro_datasets.redis.PickleDataset

class kedro_datasets.redis.PickleDataset(*, key, backend='pickle', load_args=None, save_args=None, credentials=None, redis_args=None, metadata=None)

PickleDataset loads/saves data from/to a Redis database. The underlying functionality is supported by the redis library, so it supports all allowed options for instantiating the redis app from_url and setting a value.

Example usage for the YAML API:

my_python_object: # simple example
  type: redis.PickleDataset
  key: my_object
  from_url_args:
    url: redis://127.0.0.1:6379

final_python_object: # example with save args
  type: redis.PickleDataset
  key: my_final_object
  from_url_args:
    url: redis://127.0.0.1:6379
    db: 1
  save_args:
    ex: 10

Example usage for the Python API:

from kedro_datasets.redis import PickleDataset
import pandas as pd

data = pd.DataFrame({"col1": [1, 2], "col2": [4, 5], "col3": [5, 6]})

my_data = PickleDataset(key="my_data")
my_data.save(data)
reloaded = my_data.load()
assert data.equals(reloaded)

Attributes

DEFAULT_LOAD_ARGS
DEFAULT_REDIS_URL
DEFAULT_SAVE_ARGS

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_REDIS_URL = 'redis://127.0.0.1:6379'

DEFAULT_SAVE_ARGS: dict[str, Any] = {}

__init__(*, key, backend='pickle', load_args=None, save_args=None, credentials=None, redis_args=None, metadata=None)

Creates a new instance of PickleDataset. This loads/saves data from/to a Redis database while deserialising/serialising. Supports custom backends to serialise/deserialise objects.

Example backends that are compatible (non-exhaustive):

• pickle

• dill

• compress_pickle

• cloudpickle

Example backends that are incompatible:

• torch

Parameters:

• key (str) – The key to use for saving/loading object to Redis.

• backend (str) – Backend to use, must be an import path to a module which satisfies the pickle interface. That is, contains a loads and dumps function. Defaults to ‘pickle’.

• load_args (Optional[dict[str, Any]]) – Pickle options for loading pickle files. You can pass in arguments that the backend load function specified accepts, e.g: pickle.loads: https://docs.python.org/3/library/pickle.html#pickle.loads dill.loads: https://dill.readthedocs.io/en/latest/index.html#dill.loads compress_pickle.loads: https://lucianopaz.github.io/compress_pickle/html/api/compress_pickle.html#compress_pickle.compress_pickle.loads cloudpickle.loads: https://github.com/cloudpipe/cloudpickle/blob/master/tests/cloudpickle_test.py All defaults are preserved.

• save_args (Optional[dict[str, Any]]) – Pickle options for saving pickle files. You can pass in arguments that the backend dump function specified accepts, e.g: pickle.dumps: https://docs.python.org/3/library/pickle.html#pickle.dump dill.dumps: https://dill.readthedocs.io/en/latest/index.html#dill.dumps compress_pickle.dumps: https://lucianopaz.github.io/compress_pickle/html/api/compress_pickle.html#compress_pickle.compress_pickle.dumps cloudpickle.dumps: https://github.com/cloudpipe/cloudpickle/blob/master/tests/cloudpickle_test.py All defaults are preserved.

• credentials (Optional[dict[str, Any]]) – Credentials required to get access to the redis server. E.g. {“password”: None}.

• redis_args (Optional[dict[str, Any]]) – Extra arguments to pass into the redis client constructor redis.StrictRedis.from_url. (e.g. {“socket_timeout”: 10}), as well as to pass to the redis.StrictRedis.set through nested keys from_url_args and set_args. Here you can find all available arguments for from_url: https://redis-py.readthedocs.io/en/stable/connections.html?highlight=from_url#redis.Redis.from_url All defaults are preserved, except url, which is set to redis://127.0.0.1:6379. You could also specify the url through the env variable REDIS_URL.

• metadata (Optional[dict[str, Any]]) – Any arbitrary metadata. This is ignored by Kedro, but may be consumed by users or external plugins.

Raises:

• ValueError – If backend does not satisfy the pickle interface.

• ImportError – If the backend module could not be imported.

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 (str | None) – 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 (str | None) – 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:

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