python-packaging

name	python-packaging
description	Create distributable Python packages with proper project structure, pyproject.toml, and publishing to PyPI.
when_to_use	Packaging Python libraries, creating CLI tools, or distributing Python code.

Python Packaging

Comprehensive guide to creating, structuring, and distributing Python packages using modern packaging tools, pyproject.toml, and publishing to PyPI.

Core Concepts

1. Package Structure

• Source layout: src/package_name/ (recommended)
• Flat layout: package_name/ (simpler but less flexible)
• Package metadata: pyproject.toml, setup.py, or setup.cfg
• Distribution formats: wheel (.whl) and source distribution (.tar.gz)

2. Modern Packaging Standards

• PEP 517/518: Build system requirements
• PEP 621: Metadata in pyproject.toml
• PEP 660: Editable installs
• pyproject.toml: Single source of configuration

3. Build Backends

• setuptools: Traditional, widely used
• hatchling: Modern, opinionated
• flit: Lightweight, for pure Python
• poetry: Dependency management + packaging

4. Distribution

• PyPI: Python Package Index (public)
• TestPyPI: Testing before production
• Private repositories: JFrog, AWS CodeArtifact, etc.

Quick Start

Minimal Package Structure

my-package/
|-- pyproject.toml
|-- README.md
|-- LICENSE
|-- src/
|   `-- my_package/
|       |-- __init__.py
|       `-- module.py
`-- tests/
    `-- test_module.py

Minimal pyproject.toml

[build-system]
requires = ["setuptools>=61.0"]
build-backend = "setuptools.build_meta"

[project]
name = "my-package"
version = "0.1.0"
description = "A short description"
authors = [{name = "Your Name", email = "[e-mail]"}]
readme = "README.md"
requires-python = ">=3.8"
dependencies = [
    "requests>=2.28.0",
]

[project.optional-dependencies]
dev = [
    "pytest>=7.0",
    "black>=22.0",
]

Package Structure Patterns

Pattern 1: Source Layout (Recommended)

my-package/
|-- pyproject.toml
|-- README.md
|-- LICENSE
|-- .gitignore
|-- src/
|   `-- my_package/
|       |-- __init__.py
|       |-- core.py
|       |-- utils.py
|       `-- py.typed          # For type hints
|-- tests/
|   |-- __init__.py
|   |-- test_core.py
|   `-- test_utils.py
`-- docs/
    `-- index.md

Advantages:

• Prevents accidentally importing from source
• Cleaner test imports
• Better isolation

pyproject.toml for source layout:

[tool.setuptools.packages.find]
where = ["src"]

Pattern 2: Flat Layout

my-package/
|-- pyproject.toml
|-- README.md
|-- my_package/
|   |-- __init__.py
|   `-- module.py
`-- tests/
    `-- test_module.py

Simpler but:

• Can import package without installing
• Less professional for libraries

Pattern 3: Multi-Package Project

project/
|-- pyproject.toml
|-- packages/
|   |-- package-a/
|   |   `-- src/
|   |       `-- package_a/
|   `-- package-b/
|       `-- src/
|           `-- package_b/
`-- tests/

Detailed patterns and worked examples

Detailed pattern documentation lives in references/details.md. Read that file when the navigation tier above is insufficient. For advanced patterns, see references/advanced-patterns.md.