Minimal Python Package
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What does it take to create an installable python package that can be hosted on pypi?

Date: January 10, 2021

What does it take to create an installable python package that can be hosted on pypi?

What is the minimal python package
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- setup.py
- my_module.py

This post is somewhat inspired by the bottle framework, which is famously created as a single python module. Yes, a whole web framework is written in one file.

Directory structure
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[code]
  .
  ├── setup.py
  └── my_pipeline.py

setup.py
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[code]
  from setuptools import setup
  
  setup(
      name="",
      version="0.1.0",
      py_modules=["my_pipeline", ],
      install_requires=["kedro"],
  )

name
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The name of the package can contain any letters, numbers, “_”, or “-”. Even if it’s for internal/personal consumption only I usually check for discrepancy with pypi so that you don’t run into conflicts.

│ Note that pypi treats “-” and “_” as the same thing, beware of name clashes

version
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This is the version number of your package. Most packages follow semver <https://semver.org>. At a high level its three numbers separated by a . that follow the format major.minor.patch. It’s a common courtesy to only break APIs on major changes, new releases on minor, and fixes on patch. This can become much more blurry in practice so checkout semver.org <https://semver.org/>.

py_modules
──────────

Typically most packages use the packages argument combined with find_packages, but for this minimal package, we are only creating one .py file.

Using packages instead
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[code]
  from setuptools import setup, find_packages
  
  setup(
      name="",
      version="0.1.0",
      packages=find_packages(),
      install_requires=["kedro"],
  )

install_requires
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These are your external dependencies that come from pypi. They go in this list but are often pulled in from a file called requirements.txt. Other developers may look for this file and want to do a pip install -r requirements.txt.

Clean?
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One thing to be careful of here is that everything sits at the top level API, when you users import your module and hit tab they are going to see a lot of stuff unless you hide all of your internal functions behind an _.

Minimal
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Can you create a python package with less than two files and less than 8 lines? Should you? I really like a minimal point to get started from for quick and simple prototypes. You can always pull a more complicated cookiecutter template later if the project is successful.