Poetry Packaging

Overview

Master modern Python dependency management and packaging with Poetry. Learn to create, manage, and publish professional Python packages with reproducible builds and clean dependency resolution.

Learning Objectives

• Manage project dependencies with Poetry
• Create and publish Python packages
• Handle version constraints and dependency resolution
• Structure projects following best practices
• Implement semantic versioning
• Automate packaging workflows

Core Topics

1. Poetry Basics

• Installing Poetry
• Creating new projects
• Managing dependencies
• Virtual environment management
• Lock files and reproducibility
• Poetry commands and workflow

Code Example:

# Install Poetry
curl -sSL https://install.python-poetry.org | python3 -

# Create new project
poetry new my-awesome-package
cd my-awesome-package

# Project structure created:
# my-awesome-package/
# ├── my_awesome_package/
# │   └── __init__.py
# ├── tests/
# │   └── __init__.py
# ├── pyproject.toml
# └── README.md

# Add dependencies
poetry add requests
poetry add pandas numpy
poetry add --group dev pytest black mypy

# Install dependencies
poetry install

# Run commands in virtual environment
poetry run python main.py
poetry run pytest

# Update dependencies
poetry update

# Show dependency tree
poetry show --tree

# Export to requirements.txt
poetry export -f requirements.txt --output requirements.txt

2. pyproject.toml Configuration

• Project metadata
• Dependency specification
• Version constraints
• Development dependencies
• Build system configuration
• Scripts and entry points

Code Example:

# pyproject.toml
[tool.poetry]
name = "my-awesome-package"
version = "0.1.0"
description = "An awesome Python package"
authors = ["Your Name <you@example.com>"]
license = "MIT"
readme = "README.md"
homepage = "https://github.com/username/my-awesome-package"
repository = "https://github.com/username/my-awesome-package"
documentation = "https://my-awesome-package.readthedocs.io"
keywords = ["awesome", "package", "python"]
classifiers = [
    "Development Status :: 3 - Alpha",
    "Intended Audience :: Developers",
    "License :: OSI Approved :: MIT License",
    "Programming Language :: Python :: 3",
    "Programming Language :: Python :: 3.9",
    "Programming Language :: Python :: 3.10",
    "Programming Language :: Python :: 3.11",
]

[tool.poetry.dependencies]
python = "^3.9"
requests = "^2.28.0"
pandas = "^2.0.0"
click = "^8.1.0"

[tool.poetry.group.dev.dependencies]
pytest = "^7.0.0"
pytest-cov = "^4.0.0"
black = "^23.0.0"
mypy = "^1.0.0"
ruff = "^0.1.0"

[tool.poetry.scripts]
my-cli = "my_awesome_package.cli:main"

[build-system]
requires = ["poetry-core>=1.0.0"]
build-backend = "poetry.core.masonry.api"

# Version constraints examples:
# ^2.0.0  = >=2.0.0 <3.0.0  (caret)
# ~2.0.0  = >=2.0.0 <2.1.0  (tilde)
# 2.0.*   = >=2.0.0 <2.1.0  (wildcard)
# >=2.0.0 = 2.0.0 or higher (range)

3. Package Structure & Publishing

• Package layout best practices
• Versioning with semantic versioning
• Building distributions (sdist, wheel)
• Publishing to PyPI/TestPyPI
• Package metadata
• Documentation generation

Code Example:

# Recommended package structure
my-awesome-package/
├── my_awesome_package/
│   ├── __init__.py           # Package initialization
│   ├── core.py               # Core functionality
│   ├── utils.py              # Utility functions
│   ├── cli.py                # Command-line interface
│   └── py.typed              # Type hints marker
├── tests/
│   ├── __init__.py
│   ├── test_core.py
│   └── test_utils.py
├── docs/
│   ├── index.md
│   └── api.md
├── examples/
│   └── basic_usage.py
├── pyproject.toml
├── README.md
├── LICENSE
├── CHANGELOG.md
└── .gitignore

# my_awesome_package/__init__.py
"""
My Awesome Package

A comprehensive package for doing awesome things.
"""

__version__ = "0.1.0"
__author__ = "Your Name"
__email__ = "you@example.com"

from .core import main_function
from .utils import helper_function

__all__ = ["main_function", "helper_function"]

# Publishing workflow
# 1. Update version in pyproject.toml
poetry version patch  # 0.1.0 -> 0.1.1
poetry version minor  # 0.1.1 -> 0.2.0
poetry version major  # 0.2.0 -> 1.0.0

# 2. Build package
poetry build
# Creates dist/my_awesome_package-0.1.0.tar.gz
# Creates dist/my_awesome_package-0.1.0-py3-none-any.whl

# 3. Publish to TestPyPI first
poetry config repositories.testpypi https://test.pypi.org/legacy/
poetry publish -r testpypi

# 4. Test installation
pip install --index-url https://test.pypi.org/simple/ my-awesome-package

# 5. Publish to PyPI
poetry publish

# 6. Create git tag
git tag v0.1.0
git push origin v0.1.0

4. Advanced Features

• Monorepo management
• Plugin systems
• Custom build scripts
• Private package repositories
• CI/CD integration
• Dependency groups

Code Example:

# Advanced pyproject.toml configuration

[tool.poetry]
name = "advanced-package"
version = "1.0.0"
description = "Advanced packaging example"

# Include/exclude files
include = ["my_package/data/*.json"]
exclude = ["my_package/tests/*"]

[tool.poetry.dependencies]
python = "^3.9"

# Optional dependencies (extras)
psycopg2 = { version = "^2.9", optional = true }
mysqlclient = { version = "^2.1", optional = true }

[tool.poetry.extras]
postgresql = ["psycopg2"]
mysql = ["mysqlclient"]
all = ["psycopg2", "mysqlclient"]

# Multiple dependency groups
[tool.poetry.group.test.dependencies]
pytest = "^7.0.0"
pytest-cov = "^4.0.0"

[tool.poetry.group.docs.dependencies]
sphinx = "^5.0.0"
sphinx-rtd-theme = "^1.0.0"

[tool.poetry.group.lint.dependencies]
black = "^23.0.0"
ruff = "^0.1.0"
mypy = "^1.0.0"

# Platform-specific dependencies
[tool.poetry.dependencies.pywin32]
version = "^305"
platform = "win32"

# Plugins
[tool.poetry.plugins."my_package.plugins"]
plugin1 = "my_package.plugins:plugin1"

# CI/CD with GitHub Actions
# .github/workflows/publish.yml
name: Publish to PyPI

on:
  release:
    types: [published]

jobs:
  publish:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - name: Set up Python
        uses: actions/setup-python@v4
        with:
          python-version: '3.11'
      - name: Install Poetry
        run: curl -sSL https://install.python-poetry.org | python3 -
      - name: Build and publish
        env:
          POETRY_PYPI_TOKEN_PYPI: ${{ secrets.PYPI_TOKEN }}
        run: |
          poetry build
          poetry publish

Hands-On Practice

Project 1: CLI Tool Package

Create a command-line tool and publish to PyPI.

Requirements:

• Build CLI with Click/Typer
• Add multiple subcommands
• Include configuration file support
• Write comprehensive tests
• Generate documentation
• Publish to PyPI

Key Skills: Poetry, CLI development, packaging

Project 2: Library Package

Develop a reusable library with clean API.

Requirements:

• Design public API
• Type hints throughout
• Comprehensive docstrings
• Unit and integration tests
• API documentation
• Versioning strategy

Key Skills: API design, documentation, testing

Project 3: Plugin System

Create package with plugin architecture.

Requirements:

• Plugin discovery mechanism
• Entry points configuration
• Plugin API specification
• Example plugins
• Plugin documentation
• Distribution strategy

Key Skills: Advanced packaging, architecture

Assessment Criteria

• [ ] Create projects with Poetry
• [ ] Manage dependencies effectively
• [ ] Understand version constraints
• [ ] Build and publish packages
• [ ] Structure projects professionally
• [ ] Write clear package metadata
• [ ] Implement semantic versioning

Resources

Official Documentation

• Poetry Docs - Official documentation
• PyPI - Python Package Index
• Packaging Guide - Python packaging authority

Learning Platforms

• Python Packaging - Real Python guide
• Modern Python Packaging - Video tutorial
• Poetry Tutorial - Comprehensive guide

Tools

• Poetry - Dependency management
• Twine - PyPI upload tool
• bump2version - Version bumping
• setuptools - Alternative packaging

Next Steps

After mastering Poetry, explore:

• Docker - Containerized packaging
• GitHub Actions - Automated publishing
• Read the Docs - Documentation hosting
• Pre-commit - Code quality automation