Defining Python dependencies at the top of the file

Earlier in the year, I wrote about updating Flickr metadata using Python. For this script to work, I needed to install the flickrapi package first.

I recently came across PEP 723 – Inline script metadata that makes this much easier for single file scripts like my sync-flickr-dates script.

Essentially, we can now put a special comment block at the top of the file, before our import statements like this:

# /// script
# requires-python = ">=3.11"
# dependencies = [
#   "flickrapi",
# ]
# ///

The Python version is optional and we could specify a specific version constraint on each package should we wish to.

Now, when we run with uv, uv will ensure that the flickrapi package is installed for us.

$ uv run sync-flickr-dates.py 
Reading inline script metadata from: sync-flickr-dates.py
Installed 10 packages in 13ms
usage: sync-flickr-dates.py [-h] photo_ids

In this case, uv will create a Python 3.12 venv for us. For me this is in ~/.cache/uv (which you can find via uv cache dir).

Such a nice way to run a Python script and saves faffing with a venv manually, so I expect to be learning more about uv over time as it looks promising.

It’s also motivating me to consider using Python for more one-off scripts where I would usually use bash.