metrics: Make metrics actually usable

core/core/metrics.py

@@ -1,36 +1,16 @@
 from django.apps import apps
 from prometheus_client.core import CounterMetricFamily, REGISTRY
-from django.db.models import Case, Value, When, BooleanField, Count
-from inventory.models import Item
-import logging
 
-class ItemCountCollector(object):
+class ModelCountCollector(object):
 
     def collect(self):
-        counter = CounterMetricFamily("item_count", "Current number of items", labels=['event', 'state'])
-
+        counter = CounterMetricFamily('model_count', 'Number of objects per model', labels=['model', 'app'])
         yield counter
-
         if not apps.models_ready or not apps.apps_ready:
             return
-
-        queryset = (
-            Item.all_objects
-                .annotate(
-                    returned=Case(
-                        When(returned_at__isnull=False, then=Value(False)),
-                        default=Value(True),
-                        output_field=BooleanField()
-                    )
-                )
-                .values('event__slug', 'returned', 'event_id')
-                .annotate(amount=Count('id'))
-                .order_by('event__slug', 'returned')  # Optional: order by slug and returned
-        )
-
-        for e in queryset:
-            counter.add_metric([e["event__slug"].lower(), str(e["returned"])], e["amount"])
-
+        for app_name, app_config in apps.app_configs.items():
+            for model in app_config.get_models():
+                counter.add_metric([model.__name__, app_name], model.objects.count())
         yield counter
 
-REGISTRY.register(ItemCountCollector())
+REGISTRY.register(ModelCountCollector())