effortless-config 0.2.0

Globally scoped configuration with argparse integration

Effortless Config

Globally scoped configuration with argparse integration.

Installation

pip install effortless-config

Rationale

1. When building machine learning models, I often find myself with a file named config.py that has a bunch of global variables that I reference throughout the codebase.
2. As the work progresses, I end up with groups of specific configuration settings that correspond to specific experiments.
3. I want to be able to select configuration group on the command line when I start an experiment.
4. And I want to be able to override certain settings within that experiment, from the command line.

Usage

Defining configuration

Inside some file in your project, for example example/config.py:

from effortless_config import Config, setting

class config(Config):  # notice lowercase c

    groups = ['experiment1', 'experiment2']

    SOME_INTEGER_SETTING = setting(10, experiment1=20, experiment2=30)
    FLOAT_SETTING = 0.5
    A_BOOLEAN = setting(False, experiment1=True)
    MY_STRING_SETTING = setting('foo', experiment2='bar')
    SOME_OTHER_INTEGER = 100

First we create a class that extends effortless_config.Config. Inside it we add configurable parameters, either simply by value, or by using the effortless_config.setting method. setting has the signature:

def setting(default: T, **kwargs: T) -> T

...where T is Union[int, float, str, bool, NoneType] and kwargs is a map from group names to values. Specifying parameters by value is shorthand for a setting with no groups, i.e. SOME_KEY = 'value' is equivalent to SOME_KEY = setting('value').

Using the configuration

Then in your code you can use these settings, for example inexample/main.py:

from .config import config

if __name__ == '__main__':
    config.parse_args()
    print(f'SOME_INTEGER_SETTING is {config.SOME_INTEGER_SETTING}')
    print(f'FLOAT_SETTING is {config.FLOAT_SETTING}')
    print(f'A_BOOLEAN is {config.A_BOOLEAN}')
    print(f'MY_STRING_SETTING is {config.MY_STRING_SETTING}')
    print(f'SOME_OTHER_INTEGER is {config.SOME_OTHER_INTEGER}')

When we invoke main.py without any arguments, we get the default settings:

$ python -m example.main
SOME_INTEGER_SETTING is 10
FLOAT_SETTING is 0.5
A_BOOLEAN is False
MY_STRING_SETTING is foo
SOME_OTHER_INTEGER is 100

When we pass an configuration group using the --configuration parameter, we get different values:

$ python -m example.main --configuration experiment1
SOME_INTEGER_SETTING is 20
FLOAT_SETTING is 0.5
A_BOOLEAN is True
MY_STRING_SETTING is foo
SOME_OTHER_INTEGER is 100

We can also override individual settings:

$ python -m example.main --some-integer-setting 40 --float-setting -5
SOME_INTEGER_SETTING is 40
FLOAT_SETTING is -5.0
A_BOOLEAN is False
MY_STRING_SETTING is foo
SOME_OTHER_INTEGER is 100

As well as combining groups with individual settings:

$ python -m example.main --configuration experiment1 --some-integer-setting 40
SOME_INTEGER_SETTING is 40
FLOAT_SETTING is 0.5
A_BOOLEAN is True
MY_STRING_SETTING is foo
SOME_OTHER_INTEGER is 100

You can see all available settings using the -h flag:

$ python -m example.main -h
usage: main.py [-h] [--configuration {experiment1,experiment2}]
               [--some-integer-setting SOME_INTEGER_SETTING]
               [--float-setting FLOAT_SETTING] [--a-boolean {true,false}]
               [--my-string-setting MY_STRING_SETTING]
               [--some-other-integer SOME_OTHER_INTEGER]

optional arguments:
  -h, --help            show this help message and exit
  --configuration {experiment1,experiment2}, -c {experiment1,experiment2}
  --some-integer-setting SOME_INTEGER_SETTING
  --float-setting FLOAT_SETTING
  --a-boolean {true,false}
  --my-string-setting MY_STRING_SETTING
  --some-other-integer SOME_OTHER_INTEGER

Testing

When writing tests, you can use the config.override context manager to override individual settings:

import pytest
from .config import config

def test_with_context_manager():
    with config.override(FLOAT_SETTING=0.8, A_BOOLEAN=True):
        assert config.FLOAT_SETTING * config.SOME_INTEGER_SETTING == 8
        assert config.A_BOOLEAN is True

The config.override method can also be used without context management in conjunction with config.reset_to_defaults:

def test_with_manual_reset():
    config.override(FLOAT_SETTING=0.8, A_BOOLEAN=True)
    assert config.FLOAT_SETTING * config.SOME_INTEGER_SETTING == 8
    assert config.A_BOOLEAN is True
    config.reset_to_defaults()