"""``EmailMessageDataset`` loads/saves an email message from/to a file
using an underlying filesystem (e.g.: local, S3, GCS). It uses the
``email`` package in the standard library to manage email messages.
"""
from __future__ import annotations
from copy import deepcopy
from email.generator import Generator
from email.message import Message
from email.parser import Parser
from email.policy import default
from pathlib import PurePosixPath
from typing import Any
import fsspec
from kedro.io.core import (
AbstractVersionedDataset,
DatasetError,
Version,
get_filepath_str,
get_protocol_and_path,
)
[docs]
class EmailMessageDataset(AbstractVersionedDataset[Message, Message]):
"""``EmailMessageDataset`` loads/saves an email message from/to a file
using an underlying filesystem (e.g.: local, S3, GCS). It uses the
``email`` package in the standard library to manage email messages.
Note that ``EmailMessageDataset`` doesn't handle sending email messages.
Example:
.. code-block:: pycon
>>> from email.message import EmailMessage
>>>
>>> from kedro_datasets.email import EmailMessageDataset
>>>
>>> string_to_write = "what would you do if you were invisable for one day????"
>>>
>>> # Create a text/plain message
>>> msg = EmailMessage()
>>> msg.set_content(string_to_write)
>>> msg["Subject"] = "invisibility"
>>> msg["From"] = '"sin studly17"'
>>> msg["To"] = '"strong bad"'
>>>
>>> dataset = EmailMessageDataset(filepath=tmp_path / "test")
>>> dataset.save(msg)
>>> reloaded = dataset.load()
>>> assert msg.__dict__ == reloaded.__dict__
"""
DEFAULT_LOAD_ARGS: dict[str, Any] = {}
DEFAULT_SAVE_ARGS: dict[str, Any] = {}
DEFAULT_FS_ARGS: dict[str, Any] = {
"open_args_save": {"mode": "w"},
"open_args_load": {"mode": "r"},
}
[docs]
def __init__( # noqa: PLR0913
self,
*,
filepath: str,
load_args: dict[str, Any] | None = None,
save_args: dict[str, Any] | None = None,
version: Version | None = None,
credentials: dict[str, Any] | None = None,
fs_args: dict[str, Any] | None = None,
metadata: dict[str, Any] | None = None,
) -> None:
"""Creates a new instance of ``EmailMessageDataset`` pointing to a concrete text file
on a specific filesystem.
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.
load_args: ``email`` options for parsing email messages (arguments passed
into ``email.parser.Parser.parse``). Here you can find all available arguments:
https://docs.python.org/3/library/email.parser.html#email.parser.Parser.parse
If you would like to specify options for the `Parser`,
you can include them under the "parser" key. Here you can
find all available arguments:
https://docs.python.org/3/library/email.parser.html#email.parser.Parser
All defaults are preserved, but "policy", which is set to ``email.policy.default``.
save_args: ``email`` options for generating MIME documents (arguments passed into
``email.generator.Generator.flatten``). Here you can find all available arguments:
https://docs.python.org/3/library/email.generator.html#email.generator.Generator.flatten
If you would like to specify options for the `Generator`,
you can include them under the "generator" key. Here you can
find all available arguments:
https://docs.python.org/3/library/email.generator.html#email.generator.Generator
All defaults are preserved.
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.
credentials: Credentials required to get access to the underlying filesystem.
E.g. for ``GCSFileSystem`` it should look like `{"token": None}`.
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 keys
`open_args_load` and `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 `r` when loading
and to `w` when saving.
metadata: Any arbitrary metadata.
This is ignored by Kedro, but may be consumed by users or external plugins.
"""
_fs_args = deepcopy(fs_args) or {}
_fs_open_args_load = _fs_args.pop("open_args_load", {})
_fs_open_args_save = _fs_args.pop("open_args_save", {})
_credentials = deepcopy(credentials) or {}
protocol, path = get_protocol_and_path(filepath, version)
self._protocol = protocol
if protocol == "file":
_fs_args.setdefault("auto_mkdir", True)
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,
)
# Handle default load and save and fs arguments
self._load_args = {**self.DEFAULT_LOAD_ARGS, **(load_args or {})}
self._parser_args = self._load_args.pop("parser", {"policy": default})
self._save_args = {**self.DEFAULT_SAVE_ARGS, **(save_args or {})}
self._generator_args = self._save_args.pop("generator", {})
self._fs_open_args_load = {
**self.DEFAULT_FS_ARGS.get("open_args_load", {}),
**(_fs_open_args_load or {}),
}
self._fs_open_args_save = {
**self.DEFAULT_FS_ARGS.get("open_args_save", {}),
**(_fs_open_args_save or {}),
}
def _describe(self) -> dict[str, Any]:
return {
"filepath": self._filepath,
"protocol": self._protocol,
"load_args": self._load_args,
"parser_args": self._parser_args,
"save_args": self._save_args,
"generator_args": self._generator_args,
"version": self._version,
}
[docs]
def load(self) -> Message:
load_path = get_filepath_str(self._get_load_path(), self._protocol)
with self._fs.open(load_path, **self._fs_open_args_load) as fs_file:
return Parser(**self._parser_args).parse(fs_file, **self._load_args)
[docs]
def save(self, data: Message) -> None:
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:
Generator(fs_file, **self._generator_args).flatten(data, **self._save_args)
self._invalidate_cache()
def _exists(self) -> bool:
try:
load_path = get_filepath_str(self._get_load_path(), self._protocol)
except DatasetError:
return False
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)
