Python Eggs and how to create one

Python Eggs is a distribution format that packages and distributes Python modules and applications. They are similar to Python Wheels, but Eggs have been around longer and support a broader range of use cases. Eggs can be used to distribute both pure Python code and code that contains compiled extensions.

In this article, we will walk you through creating a Python Egg. We will cover the following topics:

1. Overview of Python Eggs
2. Creating a Python package
3. Adding metadata to your package
4. Building the Egg file
5. Installing the Egg

1. Overview of Python Eggs

Python Eggs are essentially zip files containing your Python package and some metadata. The metadata includes information such as the package’s name, its version number, and any dependencies the package has. Eggs can be uploaded to a package index or hosted on a web server, making it easy for others to download and install your package.

2. Creating a Python package

The first step in creating a Python Egg is to create a Python package. A package is a collection of Python modules organized in a directory structure. Each package must contain an init.py file executed when the package is imported. Here is an example package structure:

my_package/
    __init__.py
    my_module.py

In this example, my_package is the package name, and my_module is a module within the package. You can add as many modules as you need to your package.

3. Adding metadata to your package

The next step is to add metadata to your package. This metadata is stored in setup.py, which is used to build the Egg file. Here is an example setup.py file:

from setuptools import setup

setup(
    name='my_package',
    version='1.0.0',
    author='Your Name',
    author_email='your.email@example.com',
    description='A short description of my package',
    packages=['my_package'],
    install_requires=[
        'numpy>=1.0.0',
        'pandas>=1.0.0',
    ],
)

In this example, we are using the setuptools library to define the metadata for our package. The name and version fields are self-explanatory. At the same time, the author and author_email fields should contain your name and email address. The description field should include a short description of your package.

The packages field should contain a list of all the packages you want to include in the Egg file. In our example, we only have one package (my_package). If you have more packages, you can include them in the list.

The install_requires field should contain a list of all the packages that your package depends on. In our example, we rely on numpy and pandas. If your package has no dependencies, you can omit this field.

4. Building the Egg file

Once you have created your package and added the metadata, you can build the Egg file. To do this, you will need to use the setuptools library. Here is the command to build the Egg file:

python setup.py bdist_egg

This command will create a file called dist/my_package-1.0.0-py3.7.egg (the filename will vary depending on the name and version of your package). When executed, this is the Egg file you can distribute to others.

5. Installing the Egg

To install the Egg file, you can use pip. Here is the command to install the Egg:

pip install dist/my_package-1.0.0-py3.7.egg

This command will install your package and any dependencies that it has. Once the installation is complete, you can use your package just like any other Python package.

It’s worth noting that Python Eggs are no longer the preferred distribution format for Python packages. Python Wheels have largely replaced Eggs and are the recommended way to distribute Python packages. However, if you need to create an Egg for a specific use case, the steps outlined in this article should help you get started.

In conclusion, creating a Python Egg is a straightforward process. It would be best to create a Python package, add metadata to your package, build the Egg file, and distribute it. Once you have completed the Egg, you can distribute it to others, making it easy for them to install and use your Python package.