A common meta thing that I need in python is to find the version of a package. Most of the time I reach for package_name.__version__, but that does not always work.

but not all projects have a __version__

In searching the internet for an answer nearly every one of them pointed me to __version__. This works for most projects, but is simply a convention, its not required. Not all projects implement a __version__, but most do. I've never seen it lie to me, but there is nothing stopping someone from shipping mismatched versions.

If you maintain a project ship a __version__

I appreciate it

While its not required its super handy and easy for anyone to remember off the top of their head. It makes it easy to start debugging differences between what you have vs what you see somewhere else. You can do this by dropping a __version__ variable inside your __init__.py file.

## __init__.py
__version__ = 1.0.0


stack overflow saves the day

Special thanks to this Stack Overflow post for answering this question for me.

So what do you do...


Your next option is to reach into the package metadata of the package that you are interested in, and this has changed over time as highlighted in the stack overflow post.

for Python >= 3.8:

from importlib.metadata import version

# `0.3.0.b4`

I only really use python >= 3.8 these days, but if you need to implement it for an older version check out the stack overflow post.

Another option..

use the command line

Another common option uses pip at the command line.

โฏ pip show markata
Name: markata
Version: 0.3.0b4
Summary: Static site generator plugins all the way down.
Home-page: https://markata.dev
Author: Waylon Walker
Author-email: [email protected]
License: MIT
Location: /home/waylon/git/waylonwalker.com/.venv/lib/python3.11/site-packages
Requires: anyconfig, beautifulsoup4, checksumdir, diskcache, feedgen, jinja2, more-itertools, pathspec, pillow, pluggy, pymdown-extensions, python-frontmatter, pytz, rich, textual, toml, typer

And if the package implements a command line its common to ship a version command such as --version or -V.

โฏ markata --version
Markata CLI Version: 0.3.0.b4

Why did I need to do this?

Well we have a cli tool that wraps around piptools and we wanted to include the version of piptools in the comments that it produces dynamically. This is why I wanted to dynamically grab the version inside python without shelling out to pip show. Now along with the version of our internal tool you will get the version of piptools even though piptools does not ship a __version__ variable.


In the end, I am glad I learned that its so easy to use the more accurate package metadata, but still appreciate packages shipping __version__ for all of us n00b's out here.