configparser-override 0.1.0

Configparser with environment variable and direct override

ConfigParser Override

This library provides a utility class ConfigParserOverride that extends the functionality of configparser.ConfigParser to allow overriding configuration values with environment variables and directly assigned key-value arguments.

NOTE: This library only depends on the Python standard library!

Features

• Read configuration from one or more files.
• Override configuration values with environment variables.
• Override configuration values with directly assigned arguments.
• Support for optional environment variable prefix.

Install

pip install configparser-override

Usage

Example of how to use ConfigParserOverride:

Example config.ini File

[DEFAULT]
default_key1 = default_value1
default_key2 = default_value2

[section1]
key1 = value1
key2 = value2

[section2]
key3 = value3
key4 = value4

Python Code

import os
from configparser_override import ConfigParserOverride

# Optionally set environment variables for overriding
os.environ['MYAPP_KEY1'] = 'overridden_default_value1'
os.environ['MYAPP__SECTION1_KEY1'] = 'overridden_value1'
os.environ['MYAPP__SECTION2_KEY3'] = 'overridden_value3'

# Initialize the parser with an optional environment variable prefix
parser = ConfigParserOverride(env_prefix='MYAPP', section2__key4="direct_override_value4")

# Read configuration from a file
config = parser.read(filenames='config.ini')

# Access the configuration
print(config.defaults()['default_key1'])  # Output: overridden_default_value1
print(config.defaults()['default_key2'])  # Output: default_value2
print(config['section1']['key1'])  # Output: overridden_value1
print(config['section1']['key2'])  # Output: value2
print(config['section2']['key3'])  # Output: overridden_value3
print(config['section2']['key4'])  # Output: direct_override_value4

Note

Configuration values can be overridden in three ways, in order of precedence:

1. Directly passed arguments during initialization of the class.
2. Environment variables.
3. Configuration files.

The format for environment variable names is as follows:

• When no prefix is set: The format is [KEY].
• When a prefix is set: The format is [PREFIX]_[KEY].
• Sections are denoted with double underscores (__).
  • The format is [PREFIX]__[SECTION]_[KEY] or [SECTION]_[KEY] if no prefix is set.

For example, to override key1 in section1 with a prefix MYAPP, the environment variable would be MYAPP__SECTION1_KEY1.

Development

To list available commands for your convenience:

make help

Local environment setup

python3 -m venv ./venv
source ./venv/bin/activate # Linux and MacOS
venv\Scripts\activate # Windows

pip install --editable .[dev]

Run tests

make pytest # Run pytest
make style # Run lint formatting and type check
make test-all # Run all tests with tox

make auto-fix # Auto-fix possible style issues

Pre-commit hooks

To install optional pre-commit hooks; after environment set-up run:

pre-commit install

Project maintenance

Intended for project maintainers

Release

Bump my version is used to bump the semantic version of the project.

For details see:

bump-my-version bump --help

Bump my version is configured to create a new commit and tag it with the new version when a version is bumped.

When a new tag is pushed to github the publish-pypi workflow is triggered and will build and publish the new version to PyPi.

Documentation

Sphinx is used to create documentation for the project. To generate:

cd docs
make apidocs # Generates API reference documentation for the code of the project
make html # Generates HTML that can be viwed in the browser