arcon

0.4.0 verified Mon Apr 27 auth: no python

arcon is a Python library (v0.4.0) for persistent runtime configuration. It provides a CLI argument parser that can load defaults from a pyproject.toml file, reducing boilerplate. It requires Python >=3.8, <4.0 and is released on an irregular cadence.

pip install arcon

Common errors

error AttributeError: module 'arcon' has no attribute 'ArgumentParser' ↓

cause Incorrect import: from arcon import arcon or import arcon.ArgumentParser

fix

Use: from arcon import ArgumentParser

error TypeError: __init__() got an unexpected keyword argument 'config' ↓

cause Trying to pass a config path directly to ArgumentParser (not supported) or using an older version.

fix

Check version; from arcon import ArgumentParser; parser = ArgumentParser() — config is handled automatically via pyproject.toml.

error arcon.exceptions.ArconConfigError: No pyproject.toml found ↓

cause No pyproject.toml in the project tree, or the file is not readable.

fix

Create a pyproject.toml at the project root, or use parser = ArgumentParser(pyproject=False) to disable config loading.

Warnings

gotcha Dashes in argument names are not supported; use underscores instead. ↓

fix Use underscores: --my-arg → my_arg

gotcha pyproject.toml must be in the current or parent directory; arcon walks up to the root. ↓

fix Ensure pyproject.toml is in the project root (the directory containing your script's parent).

gotcha Only simple types (str, int, float, bool) are supported for pyproject.toml defaults; complex types may cause silent failures. ↓

fix Use only simple types or override via command-line.

Imports

ArgumentParser
```
from arcon import ArgumentParser
```
Arcon's ArgumentParser subclass with config loading

Quickstart

Basic CLI with pyproject.toml support – if a pyproject.toml exists with [tool.arcon] keys, they serve as defaults.

from arcon import ArgumentParser

parser = ArgumentParser()
parser.add_argument('--name', type=str, default='world')
args = parser.parse_args()
print(f"Hello, {args.name}!")