add CACHES to settings, defaulting to locmem

[joshuadavidthomas]

No description provided.

[jefftriplett]

I'm waffling on what the default should be. I think it's fine/safe to start with this, but if something comes up, we might want to make default to Django's default https://docs.djangoproject.com/en/5.1/topics/cache/#local-memory-caching

Also, we probably need to make sure our test settings have dummycache or keep that in mind in case we see anything weird pop up.

[joshuadavidthomas]

@jefftriplett Re: the dummycache, that's already in place

django-twc-project/src/django_twc_project/tests/settings.py.jinja

Lines 9 to 13 in 59edc06

	CACHES = {
	"default": {
	"BACKEND": "django.core.cache.backends.dummy.DummyCache",
	}
	}

What about checking for the presence of the CACHE_URL env var, and if it's not present falling back to the in memory?

[joshuadavidthomas]

Ah, you can set the localmem via the cache url https://github.com/epicserve/django-cache-url#supported-caches

locmem (default): 'locmem://[NAME]'

I'm not opposed to that, but like I mentioned in one of our most recent meetings my only worry would be memory usage and how our applications are currently deployed. I've never done any benchmarking around this, so I do not know how much memory the caching would take and whether it would make a measurable difference where we would have to bump the specs up on the app machines. If you have some experience in this area, I'm all ears.

[joshuadavidthomas]

On the other hand, I probably run those machines a little too close to the edge in terms of allocated memory, so maybe they could all stand to be bumped a bit. 🤷

[jefftriplett]

I'm not opposed to that, but like I mentioned in one of our most recent meetings my only worry would be memory usage and how our applications are currently deployed.

Yes, but this is the default, and we aren't seeing any apps run out of memory. I think the change is fine, but there might be a non-zero impact if we were to set it to one of fly's persistent volumes. (which we aren't using)

[joshuadavidthomas]

Ok, you've convinced me. I'm probably being a bit overly worried about it anyway.