Python packaging

Creating a `setup.py`

Example of a setup.py file:

from setuptools import find_packages, setup

with open("README.md", "r", encoding="utf-8") as f:
    long_description = f.read()

setup(
    name="marc",
    version="22.5.0",
    url="https://github.com/maxhumber/marc",
    description="Markov chain generator",
    long_description=long_description,
    long_description_content_type="text/markdown",
    author="Max Humber",
    author_email="max.humber@gmail.com",
    license="MIT",
    classifiers=[
        "Development Status :: 5 - Production/Stable",
        "License :: OSI Approved :: MIT License",
        "Programming Language :: Python :: 3",
    ],
    packages=[""],
    package_dir={"": "python/src"},
    extras_require={
        "dev": [
            "black>=22.3.0",
        ],
    },
    python_requires=">=3.9",
    setup_requires=["setuptools>=62.1.0"],
)

Structure of package with CLI scripts

Example structure:

my_package/
    my_package/
        __init__.py
        cli_scripts.py
    setup.py

Let's assume your __init__.py looks like this (as a side note, I'd recommend moving the classes defined in there to a separate file, and then simply importing that file in the __init__):

class Test(object):

    def __init__(self, a)
        self.a = a

    def __call__(self):
        print(self.a)

Now there is an additional file inside the package that utilizes the stuff you implemented in the package, let's call it cli_scripts.py:

import argparse

from my_package import Test

def parse_args():
    parser = argparse.ArgumentParser()
    parser.add_argument("a", type=int, help="Just an example argument")
    return parser.parse_args()

def demonstration():
    args = parse_args()
    t = Test(a=args.a)
    t()

My suggestion now is to utilize the console_scripts entry point inside setup.py, which could now look something like this:

from setuptools import setup

setup(
    name='testpy',
    version='0.1',
    description='Just an example',
    author='RunOrVeith',
    author_email='xyz@mailinator.com',
    packages=["my_package"],
    entry_points={
        "console_scripts": ["mypkg=my_package.cli_scripts:demonstration"]},
    install_requires=[],
)

Now when you run pip install . inside the top-level my_package folder, your package will be installed. The entry_points automatically generate an executable for you, that you can now call with the name you gave it inside setup.py, in this example mypkg. This means you can now run mypkg 5 and this will call demonstration().

This way:

you do not need to handle any __main__ files
you can give your script a meaningful name
you don't need to care whether your script is executable, or specify to run the script with python
you can have as many of these as you want inside the list entry_points
it forces you to write functions that you could also call from other modules, instead of the __main__

Python packaging

Creating a setup.py

Structure of package with CLI scripts

Creating a `setup.py`