Minimal Python Package
======================

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

* 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

``` bash

.
├── setup.py
└── my_pipeline.py
```

## setup.py

``` python
from setuptools import setup

setup(
 name="",
 version="0.1.0",
 py_modules=["my_pipeline", ],
 install_requires=["kedro"],
)
```

## name

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

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

``` python
from setuptools import setup, find_packages

setup(
 name="",
 version="0.1.0",
 packages=find_packages(),
 install_requires=["kedro"],
)
```

## install_requires
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?

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

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.