python-lib cookiecutter template

Opinionated cookiecutter template for creating a new Python library

Use this template on your own machine with cookiecutter, or create a brand new repository based on this template entirely through the GitHub web interface using python-lib-template-repository.

Installation

You'll need to have cookiecutter installed. I recommend pipx for this:

pipx install cookiecutter

Regular pip will work OK too.

Usage

Run cookiecutter gh:simonw/python-lib and then answer the prompts. Here's an example run:

cookiecutter gh:simonw/python-lib

lib_name []: python lib template demo
description []: Demonstrating https://github.com/simonw/python-lib
hyphenated [python-lib-template-demo]: 
underscored [python_lib_template_demo]: 
github_username []: simonw
author_name []: Simon Willison

I strongly recommend accepting the suggested value for "hyphenated" and "underscored" by hitting enter on those prompts.

This will create a directory called python-lib-template-demo - the name you enter is converted to lowercase and uses hyphens instead of spaces.

See https://github.com/simonw/python-lib-template-demo for the output of this example.

Developing your library

Having created the new structure from the template, here's how to start working on the library.

If your library is called my-new-library, you can start working on it like so:

cd my-new-library
# Create and activate a virtual environment:
python -m venv venv
source venv/bin/activate
# Install dependencies so you can edit the project:
python -m pip install -e '.[test]'
# With zsh you have to run this again for some reason:
source venv/bin/activate

You can run the default test for your library like so:

python -m pytest

This will execute the test in tests/test_my_new_library.py.

Creating a Git repository for your library

You can initialize a Git repository for your library like this:

cd my-new-library
git init
git add .
git commit -m "Initial structure from template"
# Rename the 'master' branch to 'main':
git branch -m master main

Publishing your library to GitHub

Use https://github.com/new to create a new GitHub repository sharing the same name as your library, which should be something like my-new-library.

Push your main branch to GitHub like this:

git remote add origin git@github.com:YOURNAME/my-new-library.git
git push -u origin main

The template will have created a GitHub Action which runs your library's test suite against every commit.

Publishing your library as a package to PyPI

The template also includes a publish.yml GitHub Actions workflow for publishing packages to PyPI, using pypa/gh-action-pypi-publish.

To use this action, you need to create a PyPI account and configure a Trusted Publisher for this package.

Once you have created your account, navigate to https://pypi.org/manage/account/publishing/ and create a "pending publisher" for the package. Use the following values:

• PyPI Project Name: The name of your package
• Owner: Your GitHub username or organization - the "foo" in github.com/foo/bar
• Repsitory name: The name of your repository - the "bar" in github.com/foo/bar
• Workflow name: publish.yml
• Environment name: release

Now, any time you create a new "Release" on GitHub the Action will build your package and push it to PyPI.

The tag for your release needs to match the VERSION string at the top of your pyproject.toml file. You should bump this version any time you release a new version of your package.

Notes on updating this cookiecutter template

Updating this cookiecutter template while keeping the python-lib-template-repository template repository working is a little bit complicated. Detailed notes in issue #6, but the short version is:

1. Any changes to the {{cookiecutter.hyphenated}}/.github/workflows/*.yml files need to be manually pushed to the python-lib-template-demo repository, because GitHub Actions cannot update their own workflows.
2. Generated final versions of those workflows then need to be copied to python-lib-template-repository .github/workflows for the same reason.