metrics: Add the first (simple) custom metrics

core/core/management/commands/update_metrics.py

@@ -0,0 +1,8 @@
+from django.core.management.base import BaseCommand, CommandError
+from core.metrics import update_item_count
+
+class Command(BaseCommand):
+    help = "Refresh the metrics"
+    
+    def handle(self, *args, **options):
+        update_item_count()

core/core/metrics.py

@@ -0,0 +1,11 @@
+from prometheus_client import Gauge
+from django_prometheus import exports
+from inventory.models import *
+
+g_items_total = Gauge('c3lf_items_total', 'Current Total items')
+
+def update_item_count():
+    # Get the count of MyModel objects
+    count = Item.objects.count()
+    # Set the gauge to the current count
+    g_items_total.set(count)

core/core/settings.py

@@ -70,6 +70,7 @@ INSTALLED_APPS = [
     'inventory',
     'mail',
     'notify_sessions',
+    'core'
 ]
 
 REST_FRAMEWORK = {

core/core/urls.py

@@ -19,6 +19,8 @@ from django.urls import path, include
 
 from .version import get_info
 
+from .metrics import *
+
 urlpatterns = [
     path('djangoadmin/', admin.site.urls),
     path('api/2/', include('inventory.api_v2')),

deploy/ansible/playbooks/deploy-c3lf-sys3.yml

@@ -311,6 +311,16 @@
       notify:
         - restart c3lf-sys3
 
+    - name: add c3lf-sys3-cron service
+      template:
+        src: templates/c3lf-sys3-cron.service.j2
+        dest: /etc/systemd/system/c3lf-sys3-cron.service
+
+    - name: add c3lf-sys3-cron timer
+      template:
+        src: templates/c3lf-sys3-cron.timer.j2
+        dest: /etc/systemd/system/c3lf-sys3-cron.timer
+
     - name: reload systemd
       systemd:
         daemon_reload: yes
@@ -321,6 +331,12 @@
         state: started
         enabled: yes
 
+    - name: start c3lf-sys3 timer
+      service:
+        name: c3lf-sys3-cron.timer
+        state: started
+        enabled: yes
+
     - name: add postfix to www-data group
       user:
         name: postfix

deploy/ansible/playbooks/templates/c3lf-sys3-cron.service.j2

@@ -0,0 +1,13 @@
+[Unit]
+Description=c3lf sys3 background service
+After=network.target
+
+[Service]
+User=www-data
+Group=www-data
+WorkingDirectory=/var/www/c3lf-sys3
+ExecStart=/var/www/c3lf-sys3/venv/bin/python3 /var/www/c3lf-sys3/repo/core/manage.py update_metrics
+Environment=DJANGO_SETTINGS_MODULE=core.settings
+
+[Install]
+WantedBy=multi-user.target

deploy/ansible/playbooks/templates/c3lf-sys3-cron.timer.j2

@@ -0,0 +1,9 @@
+[Unit]
+Description=Run Nextcloud cron.php every 5 minutes
+
+[Timer]
+OnCalendar=minutely
+Unit=c3lf-sys3-cron.service
+
+[Install]
+WantedBy=timers.target