easyconf 1.3.1
Easy file-based and environment configuration.
License: MIT
Keywords: configuration

========
EasyConf
========

Easy file-based and environment configuration.

Usage
=====

First create a ``Config`` object:

.. code:: python

    config = easyconf.Config('config.yaml')

Then reference a configuration variable as an attribute of this object:

.. code:: python

    some_variable = config.SOME_VARIABLE()

At runtime, EasyConf will try to each variable from the following sources
in order:

1. A matching environment variable

2. A matching variable within the configuration file

3. The ``default`` attribute (if no attribute is provided, an
   ``easyconf.config.RequiredConfigVarMissing`` exception will be raised)

Config file generation
----------------------

If the ``Config`` file doesn't exist yet and the file location is writable,
EasyConf will generate it using the ``initial`` values and commented
``default`` values defined in each configuration variable.

If the configuration file is within a git repository it will also be added to
the ``.gitignore`` file.

Don't hide configuration variables within conditional statements, load them at
the top of a module so they can be generated regardless.

If you don't want file generation for non-existant configuration, use
``generate=False`` when instantiating the ``Config`` object.


Example Django configuration
============================

.. code:: python

    import easyconf

    config = easyconf.Config('myproject.yaml')

    DEBUG = config.DEBUG(default=False)
    DATABASES = {'default': config.DATABASE(
        default='postgres:///myproject',
        cast=easyconf.dict_or_url,
    )}
    SECRET_KEY = config.SECRET_KEY(initial=easyconf.random_text_generator(60))


Configuration Variable options
==============================

``default``
    The default value for the variable if it is not provided in the environment
    or in the configuration file.

``initial``
    A value or callable used to set the initial value of a variable in the
    configuration file.

``help``
    Help text to use in the configuration file for this variable.

``cast``
    A callable to convert an incoming value (from the environment or default
    value) to the correct Python type.

    Set the ``cast_from_config`` attribute of this callable to ``True`` if it
    is safe to cast from the configuration file as well.


``Config`` Object options
=========================

``default_files``
    A file or list of files to attempt to read configuration variables from. If
    multiple files are provided, only the first one found will be used.

    If none of the provided files are found, the first one in a writable
    location will be created and populated automatically.

``file_env_var``
    An environment variable which could be used to specify the configuration
    file path.

    If provided and an environment variable matches, this overrides any
    ``default_files`` specified.

``generate``
    Whether to generate a new config file if none of the default_files can be
    loaded. Defaults to ``True``.


Helper Modules
==============

``easyconf.dict_or_url``
------------------------

Expand url strings defined in django-environ_ into dictionaries. For example:

.. code:: pycon

    >>> import easyconf
    >>> easyconf.dict_or_url('mysql:///abc')
    {'NAME': 'abc', 'USER': '', 'PASSWORD': '', 'HOST': '', 'PORT': '', 'ENGINE': 'django.db.backends.mysql'}

.. _django-environ: https://pypi.org/project/django-environ/

This will also cast url strings coming from the configuration file.


``easyconf.random_text_generator``
----------------------------------

Creates a function that can be called to securely generate a random text string
of a predefined length (containing base64 characters).

Useful for the ``initial`` configuration variable option.

.. code:: pycon

    >>> import easyconf
    >>> gen = easyconf.random_text_generator(20)
    >>> gen()
    'sYw0D/7xjXqxfCyUdHqr'
    >>> gen()
    'ig1Z1n+mFLt+qYNOmD6I'

==========
Change Log
==========

1.3.1 (2019-08-26)
==================

- Don't require git executable to be installed.


1.3 (2019-08-02)
================

- Use environment values for automatic configuration generation.


1.2.2 (2019-08-02)
==================

- Correctly lock down ``ruamel.yaml`` this time (it's v0.16, not v16).


1.2.1 (2019-08-01)
==================

- Avoid new version of ``ruamel.yaml`` which changed loading format.


1.2 (2019-05-21)
================

- When generating a config that is within a git repository, add it to
  ``.gitignore``.

- If a cast callable has a ``cast_from_config`` attribute set to ``True``, cast
  values coming from the configuration file. This is set to ``True`` for the
  ``dict_or_url`` helper method.


1.1.1 (2019-05-16)
==================

- Fix issue with generating multiple comments (for multiple default values) at
  the end of the YAML config.

- Cast default values when writing to config.


1.1 (2019-05-15)
================

- Allow explicit disabling of automatic config generation.

- Cast default values if a ``cast`` argument is provided.


1.0 (2019-05-15)
================

- Initial Release