pyshipper: A Python repository from retospect

Shipping pip packages — the automated way

ITNEXT: Create, build and ship a Python3 pip module in 5 minutes

Prerequisites

PyPi account. Register here and save your credentials in a safe place.
Docker. Install instructions: Ubuntu or Mac.

You also need the ability to run make, have a POSIX compliant shell and a code editor — nearly every Linux-, Unix- or Mac system will work.

PyShipper

PyShipper is an automation part, doing the grunt-work of setting up a module structure, adds some boilerplate code, and provides a pipeline to build, test and ship a module — saving time when you update or create a module.

The relevant code is mostly in Makefile, complemented with some Docker configuration and a slightly modified setup.py. For the curious readers, this previous Docker & Makefile article explains the base. PyShipper is a version that does the job of Python module delivery.

Steps

Think of a name
Create a new module directory
Configure variables
Run and edit code
Make module
Publish

I will go through each step, and explain where and how PyShipper kicks in to automate a few things along the way.

1. Think of a name

If you find it difficult to come up with a good name, you are not alone:

There are only two hard things in Computer Science: cache invalidation and naming things. — Phil Karlton

I always struggle with naming things. After hours in slow thinking mode, I usually end up with a name that describes what problem is solved — hence the name PyShipper. If a name is taken, pre- or postfixing the name with “Py”, “Script”, “Tool”, or something similar usually works out.

Naming is one of these things I have not yet figured out how to automate. If there are any machine learning related ideas, please share!

2. Create a new module structure

This documentation on Python packages describes the required package structure. Even as we automated this step, it goes without saying the documentation is still essential reading material — useful for debugging.

Let’s go to the one-liners.

# get a copy of PyShipper and change into it
git clone [https://github.com/LINKIT-Group/pyshipper.git](https://github.com/LINKIT-Group/pyshipper.git)
cd pyshipper

# fork (copy/ paste) the contents to a new directory
make fork dest=~/${YOUR_NEW_MODULE_NAME}

This forks a stripped version of PyShipper to a new directory called ~/${YOUR_NEW_MODULE_NAME}. Files like LICENSE and README.md are not copied. After all, you own the new module, and thus need to add a license and documentation to it — no license strings attached.

3. Configure variables

Our next step is to change to the new directory and edit the /variables file.

# switch to the new module
cd ~/${YOUR_NEW_MODULE_NAME}

# edit the /variables file
{replace_with_your_editor} variables

The NAME variable in /variables is picked up by Makefile, and all variables are exported to the environment of a Docker container, used by setup.py during container execution.

4. Run and edit code

PyShipper ships with a /module directory containing boilerplate code for a module. There is also a coding pattern, with a minimal “hello-world”-like function, that can be called both CLI- and import-style.

Of course all Python3 — as Python2 goes EOL Januari 2020!

# enter the container runtime
make shell

# test run the module in CLI
python3 -m module --name "PyShipper"

# start Python3, import the module and test
python3

>>> import module
>>> module.main(name="PyShipper")

This runs the code under /module. Instead of using the name “module”, you can also replace it with the name of your own module. A symlink is created to make both work — in the shipped version, only your own name can be used to reference the module.

If you are a Python Developer, I am sure you need to know what do next. All module code to edit is in the /module — have fun tinkering!

5. Make module

When you have a minimal working version it is time to build the package. One thing you may want to do if check the VERSION in /variables first and ensure it’s updated — I just made a note to myself to automate that in a next version, who likes keeping track of versions? ;).

# build the module -- this runs setup.py in the container
make module

# better practice version of the former
# includes pylint code quality testing
make pylint module

6. Publish

The output of the build process is a gzipped tar archive, present in the /dist directory. By uploading this file to PyPi —Python Package Index — the module is published, and install-able through Python pip by everyone.

# upload the module
make upload

The command above prompts for a username and password. You need to insert your PyPi credentials—see Prerequisites at the beginning of this chapter.

After you created the module, published it on PyPi, you can install it on any capable system and use it like any other Python3 pip module.

# install the module
sudo python3 -m pip install ${YOUR_NEW_MODULE_NAME}

Final thoughts

I already use this automation myself and I am quite happy with it. I regularly create small Python modules for specific tasks; it’s incredibly easy to import them in containers or server-less environments afterwards.

Now with this piece of automation more repetitive work is cut — that means more time to spend on other innovations.

I hope you find this equally useful. I’d be delighted if this helps, at least to some of you, to contribute to the Python eco-system.

Happy Python module writing!

retospect/pyshipper