"""``HoloviewsWriter`` saves Holoviews objects as image file(s) to an underlying
filesystem (e.g. local, S3, GCS)."""
from __future__ import annotations
import io
from copy import deepcopy
from pathlib import PurePosixPath
from typing import Any, NoReturn, TypeVar
import fsspec
import holoviews as hv
from kedro.io.core import (
AbstractVersionedDataset,
DatasetError,
Version,
get_filepath_str,
get_protocol_and_path,
)
# HoloViews to be passed in `hv.save()`
HoloViews = TypeVar("HoloViews")
[docs]
class HoloviewsWriter(AbstractVersionedDataset[HoloViews, NoReturn]):
"""``HoloviewsWriter`` saves Holoviews objects to image file(s) in an underlying
filesystem (e.g. local, S3, GCS).
Example:
.. code-block:: pycon
>>> import holoviews as hv
>>> from kedro_datasets.holoviews import HoloviewsWriter
>>>
>>> curve = hv.Curve(range(10))
>>> holoviews_writer = HoloviewsWriter(filepath=tmp_path / "holoviews")
>>>
>>> holoviews_writer.save(curve)
"""
DEFAULT_SAVE_ARGS: dict[str, Any] = {"fmt": "png"}
[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,
metadata: dict[str, Any] | None = None,
) -> None:
"""Creates a new instance of ``HoloviewsWriter``.
Args:
filepath: Filepath in POSIX format to a text file 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``.
Note: `http(s)` doesn't support versioning.
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: Extra save args passed to `holoviews.save()`. See
https://holoviews.org/reference_manual/holoviews.util.html#holoviews.util.save
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.
metadata: 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 = {**self.DEFAULT_SAVE_ARGS, **(save_args or {})}
def _describe(self) -> dict[str, Any]:
return {
"filepath": self._filepath,
"protocol": self._protocol,
"save_args": self._save_args,
"version": self._version,
}
[docs]
def load(self) -> NoReturn:
raise DatasetError(f"Loading not supported for '{self.__class__.__name__}'")
[docs]
def save(self, data: HoloViews) -> None:
bytes_buffer = io.BytesIO()
hv.save(data, bytes_buffer, **self._save_args)
save_path = get_filepath_str(self._get_save_path(), self._protocol)
with self._fs.open(save_path, **self._fs_open_args_save) as fs_file:
fs_file.write(bytes_buffer.getvalue())
self._invalidate_cache()
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)
