file_writer.py

# Copyright (c) 2022 ING Wholesale Banking Advanced Analytics
#
# Permission is hereby granted, free of charge, to any person obtaining a copy of
# this software and associated documentation files (the "Software"), to deal in
# the Software without restriction, including without limitation the rights to
# use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
# the Software, and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
# FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
# COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.


import copy
from pathlib import Path
from typing import Callable, Optional, Union

from ..base import Module


class FileWriter(Module):
    """Module transforms specific datastore content and writes it to a file."""

    _input_keys = ("read_key",)
    _output_keys = ("store_key",)

    def __init__(
        self,
        read_key: str,
        store_key: Optional[str] = None,
        file_path: Optional[Union[str, Path]] = None,
        apply_func: Optional[Callable] = None,
        **kwargs,
    ):
        """Initialize an instance.

        :param str read_key: key of input histogram-dict to read from data store
        :param str store_key: key of output data to store in data store (optional)
        :param str file_path: the file path where to output the report (optional)
        :param callable apply_func: function to be used for the transformation of data (optional)
        :param dict kwargs: additional keyword arguments which would be passed to `apply_func`
        """
        super().__init__()
        if file_path is not None and not isinstance(file_path, (str, Path)):
            raise TypeError("file_path should be of type `str` or `pathlib.Path`")
        if apply_func is not None and not callable(apply_func):
            raise TypeError("transformation function must be a callable object")
        self.read_key = read_key
        self.store_key = store_key or read_key

        self.file_path = file_path
        self.apply_func = apply_func
        self.kwargs = kwargs

    def get_description(self):
        return self.file_path

    def transform(self, data):
        data = copy.deepcopy(data)

        # if a transformation function is provided, transform the data
        if self.apply_func is not None:
            data = self.apply_func(data, **self.kwargs)

        # if file path is provided, write data to a file. Otherwise, write data into the datastore
        if self.file_path is None:
            return data

        with open(self.file_path, "w+") as file:
            file.write(data)
        self.logger.info(
            f'Object "{self.read_key}" written to file "{self.file_path}".'
        )
        return None