Packaging with Python

This is a quick article I had for quite a while as a draft. It might not be finished or have other problems, but I still want to share it. I wrote this when I did not know much about packaging.

The following article is a wrap-up of the talk Python Packages from Daniel Hepper given at a German PyCon 2013.

distutils have very limited functionality. This is the reason why you should use setuptools. But 'distribute' is compatible to setuptools.

PyPi is the Python Package Index. They distribute packages in form of "eggs". You can install them with easy_install or with pip.

virtualenv / virtualenvwrapper

Package Management Tools

Distutils

Distutils is part of the standard library. When you run

python setup.py install

then distutils is running.

Major disadvantages of distutils are:

No Meta-data:
no deinstallation
no dependencies
No Package listing (so you can't automatically search pypi)

Setuptools

Setuptools are startet when you install a package with easy_install:

easy_install package

Setuptools are an extension for distutils. Setuptools offers dependency management. With setuptools, so called 'egg files' were introduced. Those files are comparable to jar files in Java.

Distribute

Distribute was a fork of setuptools that got merged back to setuptools. So don't use distribute, but use setuptools.

Installer

PIP

PIP is short for 'PIP installs Python'. It can only install files from sources; so it does not support egg files.

PIP commands are

install
uninstall
freeze
search
bundle
unzip
zip
wheel
help

Environments

It might be the case that you have to have a Django 1.4 and a Django 1.5 project. In that case, you need different environments.

Virtualenv

$ pip freeze
$ virtualenv my_env
$ source my_env/bin/activate

Virtualenvwrapper

Creating packages

A project could have this structure:

$ tree
.
├── LICENSE
├── MANIFEST
├── pyconde2013news
│   └── __init__.py
├── README
└── setup.py

With this setup.py:

from distutils.core import setup
setup(name="pycon2013news", version="0.1", py_modules=["pycon2013news"],)

This can directly be registered on PyPi:

python setup.py register

But a problem of this code is that it does not show the dependencies. So you should rather use setuptools for your setup.py:

from setuptools import setup
setup(name="pycon2013news",
      version="0.1",
      py_modules=["pycon2013news"],
      description="Reads latest news headlines from the PyCon.DE 2013 website")
      author="Daniel Hepper",
      author_email="[email protected]",
      url="https://github.com/dhepper/pyconde2013news",
      install_requires=[
          "beautifulsoup4==4.3.2",
          "requests==2.0.0"
      ]

When you add scripts argument to setup, you can later execute those. Entry points are also interesting.

Additional information

http://guide.python-distribute.org/contributing.html