One does not simply migrate a primary key

This is the demo app for a talk at the PyCon Austria 2025. The slides for the talk are here: https://tantemalkah.at/2025/pycon

To run this app you need docker to run the Postgres database, as well as the python packages listed in requirements.txt. This is tested with a Python 3.12 virtual environment created with uv.

Once your environment is up, install the requirements, e.g. with (if you use a classical venv and pip just leave out the uv):

uv pip sync src/requirements.txt

You then need to copy the env-skel file to .env, and adapt it accordingly:

cp env-skel .env
vi .env   # or use nano, or some other text editor

you don't actually need to change anything if you run it once locally and throw it away again, but i strongly recommend setting a long random database password

Now you are theoretically ready to run the app. But for it to really work, you need to spin up the database, run the initial migrations, and probably you also want to set up some demo data. And THEN start the dev server. All of that is done with the following commands:

docker compose up -d
cd src
python manage.py migrate
python manage.py loaddata artworks/fixtures/demo_data.json
python manage.py manage.py changepassword demo
python manage.py runserver

Now you can visit the demo app on http://127.0.0.1:8000/

The admin interface is at http://127.0.0.1:8000/admin/

Stopping & cleaning up

While the Django dev server (the thing started with the last runserver) command is running, you can hit Ctrl + C to quit. In order to clean up the container, go up to the root directory again and use docker compose to stop and remove the containers:

cd ..
docker compose down

Next time to start up everything you can just do:

docker compose up -d
cd src
python manage.py runserver

If you want to start with a fresh database, you need to remove the postgres folder inside the dockerdata folder (when the container is currently not running). And then you need the whole startup sequence from the section before, including the migrate, loaddata, and changepassword commands.

How to set up a virtual environment

If you are already using a plain Python installation, the quickest way to set up a new virtual environment is with:

python -m virtualenv .venv

Then you can start the virtual environment with:

# On Linux and MacOS
source .venv/bin/activate

# On Windows
.venv\Scripts\activate.bat

If you want to get out of your virtual environment without just closing your terminal window, you can use the deactivate command.

Generally I can recommend using uv for handling python versions as well as virtual environments. Once it is set up properly (which is not very complicated), it provides convenient and fast ways to install different python versions and set up virtual environments. And the uv pip commands are just soooo much faster than the classical pip commands.