How to regenerate the ER diagram

In the docs there is an autogenerated ER diagram showing the Django models as SQL tables, relations and fields. Whenever tables, fields and relations are added, changed or removed this diagram should be regenerated.

Get dependencies

You need to have installed the development dependencies to regenerate the diagram:

pip install argus-server[dev]

This will install django_extensions which has the diagram generator we use.

Test by making a .dot-file

To test if everything is installed correctly, run:

python manage.py graph_models argus_auth argus_incident argus_notificationprofile \
--group-models -X Permission,AbstractBaseUser,PermissionsMixin

This will dump a .dot-file, the textual representation of the graph, to standard out.

Generate PNG

In order to generate a PNG there are two methods:

  1. Generate via the graph_models command and one more dependency

  2. Use graphviz directly on a .dot-file

Generate via the graph_models command

We need to have one more dependency installed: one of pygraphviz or pydotplus. If one cannot be installed via pip, try the other.

To generate the final PNG in the correct location, run:

python manage.py graph_models argus_auth argus_incident argus_notificationprofile \
--group-models -X Permission,AbstractBaseUser,PermissionsMixin \
-o docs/reference/img/ER_model.png

Use graphviz directly on a .dot-file

  1. Make sure you have graphviz installed, how is OS/distro dependent

  2. Generate the dot-file with:

    python manage.py graph_models argus_auth argus_incident argus_notificationprofile \
--group-models -X Permission,AbstractBaseUser,PermissionsMixin \
-o ER_model.dot

  3. Generate the PNG with dot:

    dot -T png -o docs/reference/img/ER_model.png ER_model.dot

  4. You can now delete ER_model.dot

Commit!

Commit the new image with a message like “Sync the ER diagram to current database schema”.