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Poetry

What is Poetry?​

Poetry is a modern Python package and dependency management tool that streamlines creating, building, and sharing Python projects. It helps:

  • Manage dependencies
  • Handle virtual environments
  • Build and publish Python packages

Unlike traditional tools like pip and virtualenv, Poetry integrates dependency resolution and project management in a single tool.

Why Use Poetry?​

  • Dependency Resolution: Automatically resolves dependencies to ensure package compatibility
  • Simplified Configuration: Uses a pyproject.toml file for centralized configuration
  • Built-in Virtual Environment Management: Creates and manages virtual environments automatically
  • Cross-Platform Support: Works seamlessly across different operating systems

Installing Poetry​

1. Install Poetry​

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

Or on macOS with Homebrew:

brew install poetry

Verify installation:

poetry --version

Setting Up a New Project​

1. Create a New Project​

poetry new my_project

Creates this directory structure:

my_project/
├── my_project/
│   └── __init__.py
├── tests/
│   └── __init__.py
├── pyproject.toml
└── README.rst

2. Understand pyproject.toml​

Includes:

  • Project Metadata: name, version, description, authors, etc.
  • Dependencies: required packages
  • Dev Dependencies: development-only packages

Adding Dependencies​

1. Add a Dependency​

poetry add requests

2. Add Development Dependencies​

poetry add --group dev pytest

Install all with dev dependencies:

poetry install --with dev

Managing Virtual Environments​

Poetry creates a virtual environment for your project automatically.

1. Check the Environment​

poetry env info

2. Activate the Environment​

Linux/macOS:

source $(poetry env info --path)/bin/activate

Windows:

. $(poetry env info --path)\Scripts\activate

Or start a new shell:

poetry shell

Exit with:

exit

Running Scripts​

To run a Python script within the Poetry environment:

poetry run python script.py

Building and Publishing a Package​

1. Build the Package​

poetry build

Creates files in the dist/ directory.

2. Publish to PyPI​

poetry publish --username <your-username> --password <your-password>

Or using a token (recommended):

poetry publish --username __token__ --password <your-token>

Bonus Tips​

1. Lock File​

Poetry creates a poetry.lock file to lock exact versions for reproducibility.

2. Upgrade Dependencies​

Upgrade all:

poetry update

Upgrade one:

poetry update requests

Conclusion​

Poetry 2.x is a powerful tool for modern Python development. It simplifies dependency resolution, environment setup, and package publishing, letting you focus on writing great code.

Reference​