pyproject.toml - Automating Book Availability Checks

A pyproject.toml file is not just for code destined to be distributed or packaged and published (PyPI). It has a much wider scope. It is a central config file. It can store settings for tools like formatters and linters, it can list dependencies instead of requirements.txt (or pointing to it), it can store metadata…

Here’s the official guide: https://packaging.python.org/en/latest/guides/writing-pyproject-toml/

And here are my changes: https://github.com/k-candidate/selenium-book-search-slack-alerts/pull/2

Now once I clone the repo, here’s what I have to do:

# The .python-version file takes care of the Python version
python -m venv .venv
source .venv/bin/activate
pip install .

I used a pip install . because I am not touching the source code this time.
But usually I’d use pip install -e . to have an editable install so that I am able to modify the source code and have changes visible immediately without reinstalling. However, changes to project metadata or dependencies would still require rerunning pip install -e . to update packages or scripts.

One thing we notice in the pyproject.toml is:

[project.scripts]
book-search = "main:main"

The syntax is command-name = "module:function"

It allows me to use book-search from the command line without explicitly calling python main.py:

That obviously is available only in the venv. But let’s look into how it works:

We can see that book-search is just a tiny executable wrapper script placed in the .venv/bin/.