Somepackage
Show how to structure a Python project.
Inspired by https://github.com/kennethreitz/samplemod.
Great resources
- https://manikos.github.io/a-tour-on-python-packaging
- https://docs.python-guide.org/writing/structure/
- http://veekaybee.github.io/2017/09/26/python-packaging/
- https://github.com/audreyr/cookiecutter-pypackage
- https://medium.com/@jonas.r.kemper/understanding-best-practice-python-tooling-by-comparing-popular-project-templates-6eba49229106
Recommendations
Please browse this blog post for a good summary of recommendatios and templates: https://medium.com/@jonas.r.kemper/understanding-best-practice-python-tooling-by-comparing-popular-project-templates-6eba49229106
Python 2 or 3?
- Develop your code under Python 3, test it for both Python 2 and Python 3 but consider Python 3 to be the default today.
Split your code into packages, modules, and functions
- All code should be inside some function (except perhaps
if __name__ == '__main__':). - Split long functions into smaller functions.
- If you need to scroll through a function over several screens, it is probably too long.
- Functions should do one thing and one thing only.
- Hide internals with underscores.
- Organize related functions into modules.
- If modules grow too large, split them.
- Import from other modules under
somepackage/usingfrom .somemodule import something. - Do file I/O on the "outside" of your code, not deep inside.
Classes vs. functions
- Do not overuse classes.
- Prefer immutable data structures.
- Prefer pure functions.
Naming
- Give the subdirectory the same name as your package.
- Before you name your package, check that the name is not taken on https://pypi.org (you may want to upload your package to PyPI one day).
Interfaces
- In
somepackage/__init__.pydefine what should be visible to the outside. - Use https://semver.org.
Testing
- Test all non-trivial code. I recommend to use https://pytest.org.
- Use Travis CI: https://docs.travis-ci.com/user/languages/python/.
Dependency management
- Package dependencies for developers should be listed in
requirements.txt. - Alternatively, consider using http://pipenv.readthedocs.io.
- Package dependencies for users of your code (who will probably install via pip) should be listed in
setup.py.
Code style
- Follow PEP8: https://www.python.org/dev/peps/pep-0008/
- Use
pycodestyleto automatically check for PEP8.
Type checking
- Consider using type hints: https://docs.python.org/3/library/typing.html
- Consider using http://mypy-lang.org.
- Consider verifying type annotations at runtime: https://github.com/RussBaz/enforce
Share your package
- Choose a license and add a LICENSE file.
- Share your package on PyPI. For this you can follow https://github.com/bast/pypi-howto.
Documentation
I used to recommend reStructuredText for READMEs in contrast to Markdown but PyPI no longer requires reStructuredText. You can use Markdown as noted on https://pypi.org/help/ under "How can I upload a project description in a different format?".
Example shown here: https://packaging.python.org/tutorials/packaging-projects/#creating-setup-py
Suggestions? Corrections? Pull requests?
Yes please!