"""``MatplotlibWriter`` saves one or more Matplotlib objects as image
files to an underlying filesystem (e.g. local, S3, GCS)."""
from __future__ import annotations
import base64
import io
from copy import deepcopy
from pathlib import PurePosixPath
from typing import Any, NoReturn, Union
from warnings import warn
import fsspec
import matplotlib.pyplot as plt
from kedro.io.core import (
AbstractVersionedDataset,
DatasetError,
Version,
get_filepath_str,
get_protocol_and_path,
)
from matplotlib.figure import Figure
from kedro_datasets._typing import ImagePreview
[docs]
class MatplotlibWriter(
AbstractVersionedDataset[Union[Figure, list[Figure], dict[str, Figure]], NoReturn]
):
"""``MatplotlibWriter`` saves one or more Matplotlib objects as
image files to an underlying filesystem (e.g. local, S3, GCS).
Example usage for the
`YAML API <https://kedro.readthedocs.io/en/stable/data/\
data_catalog_yaml_examples.html>`_:
.. code-block:: yaml
output_plot:
type: matplotlib.MatplotlibWriter
filepath: data/08_reporting/output_plot.png
save_args:
format: png
Example usage for the
`Python API <https://kedro.readthedocs.io/en/stable/data/\
advanced_data_catalog_usage.html>`_:
.. code-block:: pycon
>>> import matplotlib.pyplot as plt
>>> from kedro_datasets.matplotlib import MatplotlibWriter
>>>
>>> fig = plt.figure()
>>> plt.plot([1, 2, 3]) # doctest: +ELLIPSIS
[<matplotlib.lines.Line2D object at 0x...>]
>>> plot_writer = MatplotlibWriter(filepath=tmp_path / "data/08_reporting/output_plot.png")
>>> plt.close()
>>> plot_writer.save(fig)
Example saving a plot as a PDF file:
.. code-block:: pycon
>>> import matplotlib.pyplot as plt
>>> from kedro_datasets.matplotlib import MatplotlibWriter
>>>
>>> fig = plt.figure()
>>> plt.plot([1, 2, 3]) # doctest: +ELLIPSIS
[<matplotlib.lines.Line2D object at 0x...>]
>>> pdf_plot_writer = MatplotlibWriter(
... filepath=tmp_path / "data/08_reporting/output_plot.pdf", save_args={"format": "pdf"}
... )
>>> plt.close()
>>> pdf_plot_writer.save(fig)
Example saving multiple plots in a folder, using a dictionary:
.. code-block:: pycon
>>> import matplotlib.pyplot as plt
>>> from kedro_datasets.matplotlib import MatplotlibWriter
>>>
>>> plots_dict = {}
>>> for colour in ["blue", "green", "red"]:
... plots_dict[f"{colour}.png"] = plt.figure()
... plt.plot([1, 2, 3], color=colour)
...
[<matplotlib.lines.Line2D object at 0x...>]
[<matplotlib.lines.Line2D object at 0x...>]
[<matplotlib.lines.Line2D object at 0x...>]
>>> plt.close("all")
>>> dict_plot_writer = MatplotlibWriter(filepath=tmp_path / "data/08_reporting/plots")
>>> dict_plot_writer.save(plots_dict)
Example saving multiple plots in a folder, using a list:
.. code-block:: pycon
>>> import matplotlib.pyplot as plt
>>> from kedro_datasets.matplotlib import MatplotlibWriter
>>>
>>> plots_list = []
>>> for i in range(5): # doctest: +ELLIPSIS
... plots_list.append(plt.figure())
... plt.plot([i, i + 1, i + 2])
...
[<matplotlib.lines.Line2D object at 0x...>]
[<matplotlib.lines.Line2D object at 0x...>]
[<matplotlib.lines.Line2D object at 0x...>]
[<matplotlib.lines.Line2D object at 0x...>]
[<matplotlib.lines.Line2D object at 0x...>]
>>> plt.close("all")
>>> list_plot_writer = MatplotlibWriter(filepath=tmp_path / "data/08_reporting/plots")
>>> list_plot_writer.save(plots_list)
"""
DEFAULT_SAVE_ARGS: dict[str, Any] = {}
[docs]
def __init__( # noqa: PLR0913
self,
*,
filepath: str,
fs_args: dict[str, Any] | None = None,
credentials: dict[str, Any] | None = None,
save_args: dict[str, Any] | None = None,
version: Version | None = None,
overwrite: bool = False,
metadata: dict[str, Any] | None = None,
) -> None:
"""Creates a new instance of ``MatplotlibWriter``.
Args:
filepath: Filepath in POSIX format to save Matplotlib objects to, prefixed with a
protocol like `s3://`. If prefix is not provided, `file` protocol (local filesystem)
will be used. The prefix should be any protocol supported by ``fsspec``.
fs_args: Extra arguments to pass into underlying filesystem class constructor
(e.g. `{"project": "my-project"}` for ``GCSFileSystem``), as well as
to pass to the filesystem's `open` method through nested key `open_args_save`.
Here you can find all available arguments for `open`:
https://filesystem-spec.readthedocs.io/en/latest/api.html#fsspec.spec.AbstractFileSystem.open
All defaults are preserved, except `mode`, which is set to `wb` when saving.
credentials: Credentials required to get access to the underlying filesystem.
E.g. for ``S3FileSystem`` it should look like:
`{'key': '<id>', 'secret': '<key>'}}`
save_args: Save args passed to `plt.savefig`. See
https://matplotlib.org/api/_as_gen/matplotlib.pyplot.savefig.html
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.
overwrite: If True, any existing image files will be removed.
Only relevant when saving multiple Matplotlib objects at
once.
metadata: Any arbitrary Any arbitrary metadata.
This is ignored by Kedro, but may be consumed by users or external plugins.
"""
_credentials = deepcopy(credentials) or {}
_fs_args = deepcopy(fs_args) or {}
_fs_open_args_save = _fs_args.pop("open_args_save", {})
_fs_open_args_save.setdefault("mode", "wb")
protocol, path = get_protocol_and_path(filepath, version)
if protocol == "file":
_fs_args.setdefault("auto_mkdir", True)
self._protocol = protocol
self._fs = fsspec.filesystem(self._protocol, **_credentials, **_fs_args)
self.metadata = metadata
super().__init__(
filepath=PurePosixPath(path),
version=version,
exists_function=self._fs.exists,
glob_function=self._fs.glob,
)
self._fs_open_args_save = _fs_open_args_save
# Handle default save arguments
self._save_args = deepcopy(self.DEFAULT_SAVE_ARGS)
if save_args is not None:
self._save_args.update(save_args)
if overwrite and version is not None:
warn(
"Setting 'overwrite=True' is ineffective if versioning "
"is enabled, since the versioned path must not already "
"exist; overriding flag with 'overwrite=False' instead."
)
overwrite = False
self._overwrite = overwrite
def _describe(self) -> dict[str, Any]:
return {
"filepath": self._filepath,
"protocol": self._protocol,
"save_args": self._save_args,
"version": self._version,
}
def _load(self) -> NoReturn:
raise DatasetError(f"Loading not supported for '{self.__class__.__name__}'")
def _save(self, data: Figure | (list[Figure] | dict[str, Figure])) -> None:
save_path = self._get_save_path()
if isinstance(data, (list, dict)) and self._overwrite and self._exists():
self._fs.rm(get_filepath_str(save_path, self._protocol), recursive=True)
if isinstance(data, list):
for index, plot in enumerate(data):
full_key_path = get_filepath_str(
save_path / f"{index}.png", self._protocol
)
self._save_to_fs(full_key_path=full_key_path, plot=plot)
elif isinstance(data, dict):
for plot_name, plot in data.items():
full_key_path = get_filepath_str(save_path / plot_name, self._protocol)
self._save_to_fs(full_key_path=full_key_path, plot=plot)
else:
full_key_path = get_filepath_str(save_path, self._protocol)
self._save_to_fs(full_key_path=full_key_path, plot=data)
plt.close("all")
self._invalidate_cache()
def _save_to_fs(self, full_key_path: str, plot: Figure):
bytes_buffer = io.BytesIO()
plot.savefig(bytes_buffer, **self._save_args)
with self._fs.open(full_key_path, **self._fs_open_args_save) as fs_file:
fs_file.write(bytes_buffer.getvalue())
def _exists(self) -> bool:
load_path = get_filepath_str(self._get_load_path(), self._protocol)
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)
[docs]
def preview(self) -> ImagePreview:
"""
Generates a preview of the matplotlib dataset as a base64 encoded image.
Returns:
str: A base64 encoded string representing the matplotlib plot image.
"""
load_path = get_filepath_str(self._get_load_path(), self._protocol)
with self._fs.open(load_path, mode="rb") as img_file:
base64_bytes = base64.b64encode(img_file.read())
return ImagePreview(base64_bytes.decode("utf-8"))
