Cfg-Loader 0.1.1

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Cfg-Loader
==========

Cfg-Loader is a library that allows to easily load configuration settings.
It uses `marshmallow`_ to deserialize input data into a target format configuration data.

Main features
~~~~~~~~~~~~~

- input data validation and automatic processing using `marshmallow`_
- substitution of environment variables in input data (following `docker compose variable substitution syntax`_)
- configuration loading from .yaml file

.. _`marshmallow`: https://github.com/marshmallow-code/marshmallow
.. _`docker compose variable substitution syntax`: https://docs.docker.com/compose/compose-file/#variable-substitution

Requirements
------------

- Python>=3.5

A simple example
----------------

.. code-block:: python

>>> from cfg_loader import ConfigSchema, BaseConfigLoader
>>> from marshmallow import fields

# Declare your configuration schema
>>> class MyConfigSchema(ConfigSchema):
... setting1 = fields.Str()
... setting2 = fields.Int(required=True)
... setting3 = fields.Float(missing=13.2)

# Declare mapping to substitute environment variable
>>> substitution_mapping = {'FILE_PATH': 'file'}

# Initialize config loader
>>> my_config_loader = BaseConfigLoader(MyConfigSchema, substitution_mapping=substitution_mapping)

# Load configuration
>>> config = my_config_loader.load({'setting1': '/home/folder/${FILE_PATH?:file path required}', 'setting2': '4'})
>>> config == {'setting1': '/home/folder/file', 'setting2': 4, 'setting3': 13.2}
True

# Invalid input data
>>> my_config_loader.load({'setting1': '/home/folder/${FILE_PATH?:file path required}', 'setting3': 13.4})
Traceback (most recent call last):
...
cfg_loader.exceptions.ValidationError: {'setting2': ['Missing data for required field.']}

>>> my_config_loader.load({'setting2': 12, 'setting3': 'string'})
Traceback (most recent call last):
...
cfg_loader.exceptions.ValidationError: {'setting3': ['Not a valid number.']}

# Variable substitution invalid
>>> my_config_loader.load({'setting2': '${UNSET_VARIABLE?Variable "UNSET_VARIABLE" required}'})
Traceback (most recent call last):
...
cfg_loader.exceptions.UnsetRequiredSubstitution: Variable "UNSET_VARIABLE" required

Platform: any
Classifier: Development Status :: 5 - Production/Stable
Classifier: Environment :: Web Environment
Classifier: Intended Audience :: Developers
Classifier: License :: OSI Approved :: BSD License
Classifier: Operating System :: OS Independent
Classifier: Programming Language :: Python
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.5
Classifier: Programming Language :: Python :: 3.6
Provides-Extra: dev
Provides-Extra: doc