Week 9 — Packaging & Distribution

Turn your Python code into a distributable package. Learn pyproject.toml, build tools (hatch/setuptools), create CLI entry points, and publish to PyPI (or TestPyPI).

packagingpyproject.tomlwheelPyPICLIhatch

Duration

⏱ 2.5 hours

Level

📊 Advanced

Prerequisite

🎯 Week 3

OUTCOME

Publish a Python package with a CLI entry point to TestPyPI

What you'll learn

1Structure a Python package with src/ layout
2Write pyproject.toml with metadata and dependencies
3Build wheel and sdist distributions
4Create CLI commands with entry_points.scripts
5Publish to TestPyPI and install with pip

1. Package Structure

text

mypackage/
├── src/
│   └── mypackage/
│       ├── __init__.py
│       ├── core.py
│       └── cli.py
├── tests/
│   └── test_core.py
├── pyproject.toml
└── README.md

2. pyproject.toml

toml

[build-system]
requires = ["hatchling"]
build-backend = "hatchling.build"

[project]
name = "mypackage"
version = "0.1.0"
description = "My first Python package"
requires-python = ">=3.10"
dependencies = ["requests>=2.28"]

[project.scripts]
mypkg = "mypackage.cli:main"

[tool.hatch.build.targets.wheel]
packages = ["src/mypackage"]

3. Build & Publish

bash

pip install hatch
hatch build          # creates dist/*.whl and dist/*.tar.gz

# Publish to TestPyPI
pip install twine
twine upload --repository testpypi dist/*

# Install from TestPyPI
pip install --index-url https://test.pypi.org/simple/ mypackage

💻 Examples

Run these examples and check the output yourself.

cli.py— CLI entry point using argparse

CODE

import argparse
from .core import process

def main():
    parser = argparse.ArgumentParser(description="MyPackage CLI")
    parser.add_argument("input", help="Input file")
    parser.add_argument("-o", "--output", default="output.txt")
    parser.add_argument("-v", "--verbose", action="store_true")
    args = parser.parse_args()

    result = process(args.input, verbose=args.verbose)
    with open(args.output, "w") as f:
        f.write(result)
    print(f"Wrote {args.output}")

if __name__ == "__main__":
    main()

📝 Exercises

Try them yourself first, then open the solution to compare.

Exercise 1

Build your own package

Goal: Package and distribute the text analyzer from Week 10 capstone.

Requirements

src/ layout with pyproject.toml
CLI entry point: analyze <file> [--top N] [--format text|csv]
Unit tests with pytest
Build a wheel with hatch build

Grading

· Package installs with pip — 30%
· CLI entry point works — 30%
· Tests pass — 30%
· Wheel file created — 10%

Example code / lecture materials

All lecture materials and example code are openly available on GitHub.

View on GitHub ↗