How to Write a Python Script to Create and Update a Changelog

No more generators, logs, or dependencies-now for Python!

Photo by Javier Allegue Barros on Unsplash

If you read my previous post about how to write a bash script to create and update a changelog, you might find this post interesting as well. I was working on some python scripts for work when it occurred to me that some Python devs might appreciate having a changelog script in Python.

Now they do!

I’ve added Python support to extend my original changelog script to engineers with a preference for Python. You can now use the same script logic with Python code. If you’re a python developer and want to add more customizations to your changelog creation/generation, you can do so more easily now with this added support.

Since it’s the same logic as my previous script, I won’t go too in depth in terms of functionality. Instead, I’ll highlight some syntactic differences. Let’s jump right in!

First, create a changelog.py file to run the script’s logic. You can make this file executable by running chmod 755 changelog.py. With this you will be able to run ./changelog.py from your command line or include it in another script if that’s preferred by appending ./changelog.py to it.

Next, we need our project’s version to be synced with our changelog. Here is how we get the version in Bash.

version="$(git describe --long)"

In Python, you can achieve the same result with the below code.

version=subprocess.check_output([“git”, “describe”, “ — long”]).strip()

In other parts of the code, you will need to use string interpolation. This is done a little differently in Python than it is in Bash. See below for Bash string interpolation.

name="Matthew Croak"
introduction="My name is $name"
echo $introduction
> "My name is Matthew"

Now here is string interpolation for Python.

name="Matthew Croak"
introduction="My name is {}".format(name)
print(introduction)
> "My name is Matthew"