Python Package Demo

This is a simple example of creating and consuming a distributable Python package. While I find the Python language to be intuitive and useful, for some reason I often struggle with pip & packages - both creating them and consuming them. So this is to just be a simple example of how to create and consume a package as a reference for myself.

This is not intended to be a replacement for the Python Packaging User Guide (PyPUG) and its corresponding sample project. I've used that as my primary reference, and I encourage others to do the same. This has a slightly simplified example and a FAQ and Troubleshooting section with some questions and problems I've encountered while exploring Python. Happy to accept PRs for suggested improvements.

Contents

• package-project contains a project directory for a Python package. Note that its only content is the package-project/src directory for now. If you wanted to add tests or something you could put those in package-project/tests or something.
• package-project/src/boopackage is the actual "package". In accordance with Python's documented behavior, the directory is a package because it contains an __init__.py file.
• package-consumer-project is a project directory containing a Python module/script/app that consumes the package in package-project/src/boopackage.

FAQ

How do I install and use a package in Development Mode?

Development Mode installs the package in "editable" mode so that you can change the source for your package in the actual source directory and consuming Python scripts/applications will see your edits the next time they run. To install your package in Development Mode run install-package-devmode.sh. Note that this script also runs pip show boopackage to confirm that the package boopackage is installed.

How do I Package/Bundle/Zip/Prepare my source code into a distributable package that I can distribute to others to use in their own Python apps?

Run build-package.sh to prepare your package source code for distribution. This will deploy a distributable Python package into package-project/src/dist/boopackage-1.0.tar.gz.

How do other users install the package once it's built?

Other users can run pip install boopackage-1.0.tar.gz to install your package. See install-built-package.sh as an example. To use the package once it's installed see test-consume-package.sh which simply runs the Python script/app in package-consumer-project/consumepackage.py that uses the package boopackage.

Alternatively, you can upload your built package to PyPI and then they can install it by running pip install boopackage.

What are the differences between "Python Packages" and eggs?

I've been trying to figure that out myself. I can tell you that eggs appear to essentially be deprecated and as noted on the previously linked python.org site Wheel is currently considered the standard for built and binary packaging for Python. Therefore I no longer maintain an example of building eggs, but some docs you might find interesting are as follows: "Python Packages" are documented at https://packaging.python.org/distributing/ and Eggs are documented at http://peak.telecommunity.com/DevCenter/PythonEggs

Troubleshooting

After installing the package I still see the error 'ImportError: No module named ' when trying to use it in a script/app.

It is important that the setup.py is in the parent of the actual root package folder. If you don't do this you won't get any errors, and pip will show you're package as installed (e.g. with pip show <mypackage>) but consuming scripts of the package won't ever find the package and will always get the ImportError.

So this also implies that the "package" isn't what you specify as the name of your package in setup.py. Although pip uses the name in setup.py to determine whether it is installed, Python itself only cares about the directory that contains the __init__.py file.