gamma-config 0.5.0

Opinionated config handling for BCG Gamma projects

Gamma Config

An opinionated way of setting up configuration for data science projects.

Overview

Gamma config provides a standard and flexible way of implementing application configuration primarily based on YAML files. It promotes best practices by:

• simplify separation of code and config data;
• breaking large, complex configuration into multiple files;
• providing a way to write environment-aware config files;
• facilitating security best-practices, like proper secrets management;
• providing a immutable central global object storing all contextual data.

Another benefit of a standard config mechanism is allowing Gamma extension libraries to provide configuration in a common way.

New in 0.5

• We're now in PyPI!
• Options for installing extra dependencies (eg. jinja2, pydantic)

Breaking changes in 0.5

• When using the dot (.) syntax, missing values raise AttributeError instead of returning a false-y object.
• Dropped support for Python 3.7

Features

• Configuration expressed as a set of YAML files (by defaul) inside a config folder in the root of the project.
• Multiple YAML files merged following simple rules. Simple file ordering convention using two digit prefixes.
• Builtin support for environment specific parameters (production, development, etc.)
• Support for .env files via python-dotenv, including .local.env that can be added to .gitignore
• Dynamic evaluation via YAML tags. For instance, the !ref tag allow you to reference other parameters in any config file.
• Custom tag support via simple and cool multiple dispatch mechanism.
• Round-trip dump of config back into YAML. Support for hiding sensitive data on dump.
• Simplified key access via dot (.). Eg. for config: {foo: {bar: 100}}, this is True: config.foo.bar == 100

Click here to view the full documentation

Getting started

Using pip:

pip install gamma-config

In most cases, you'll want to use the !j2 tag to interpolate values using Jinja2. This requires manually installing the jinja2 package or using the jinja2 extras.

pip install gamma-config[jinja2]

You must install pydantic if using the structured configuration feature.

pip install gamma-config[pydantic]

Basic Usage

The package comes with "scaffolding" to help you get started. In your project folder:

   python -m gamma.config.scaffold

Remove the sample files, then create yourself a config/20-myconfig.yaml file with the contents:

foo: 1
user: !env USER

To access the config from within your Python program:

import os
from gamma.config import get_config

def run():

    # it's safe and efficient to call this multiple times
    config = get_config()

    # get static value using the dict keys or attribute access
    assert config["foo"] == 1
    assert config.foo == 1

    # get dynamic variables
    assert config["user"] == os.getenv("USER")
    assert config.user == os.getenv("USER")

Most of the magic happen via tags. Look at the documentation for info on the built-in tags available.

Copyright

Copyright 2021 Boston Consulting Group, all rights reserved.