Structure settings in modules

[niklasmohrin]

Since we are shipping EvaP via PyPI, using the evap.localsettings module doesn't really cut it anymore. We want to ship the majority of settings as default, but overwrite some of them in the deployment. Furthermore, we may want to have default config values that depend on values overwritten later, and we may want to mix in settings that add to previously defined values. Clearly, we need to implement the nix module system for our settings.

On production (with the current naming, which I want to still change later) it would be used like this:

from evap.settings import default, dev, local_services, open_id, test
from evap.settings_resolver import resolve_settings


class LocalSettings:
    DEBUG = False
    SECRET_KEY = "xxx"  # nosec
    # ... some more required fields


globals().update(resolve_settings([default, open_id, LocalSettings]))

Alternatively, one can also make two Python files, one containing what I put in the LocalSettings class namespace here, and the other just containing globals().update(...) which then also includes the other file.

[niklasmohrin]

One can confirm that the same settings are generated by comparing the output of ./manage.py diffsettings before and after. For our local development setup, the settings are identical (up to some module renamings). For CI, the new evap.settings.cisettings have some more values set compared to our previous cp evap/settings_test.py evap/localsettings.py approach, but it does not seem significant and tests still pass, so I don't think we need to change anything.

[niklasmohrin]

You don't all have to review, but would be good to have more eyes on this :)

[richardebeling]

Surprisingly unpainful to read, given the mental complexity that I felt our discussions about this required. Nice, I like it!

I'll have to play around with it a bit locally when the first round of discussions is through, particularly it's super hard on github to check whether stuff was forgotten when moving code around.

[richardebeling]

Next level: Can we make these required() iff ACTIVE_OPEN_ID_LOGIN is true? (If not, that's fine with me, just wondering, seems not too hard from my simple mind)

[niklasmohrin]

yup, sounds good

[richardebeling]

I feel like the ones you would need to change should be part of localsettings.py, I think they don't really make sense in here. Any argument I'm missing for keeping them here?

[fekoch]

Suggested change

	git submodule update --init
	./manage.py compilemessages --locale de
	git submodule update --init
	export DJANGO_SETTINGS_MODULE=localsettings
	./manage.py compilemessages --locale de