django: Replace gunicorn-prometheus-exporter with django-prometheus

Remove the dedicated metrics port (9091) and gunicorn-prometheus-exporter
support. With Uvicorn ASGI workers, the gunicorn exporter's hooks could
not populate any metrics (system gauges were empty). Additionally, both
exporters shared the same prometheus_client registry, causing django-
prometheus metrics to be duplicated on port 9091.

django-prometheus serves metrics at /metrics on the application port
(8000), so no extra container or service port is needed. The
ServiceMonitor now scrapes the django port directly.

Author: bbliem

charts/django/Chart.yaml

@@ -15,7 +15,7 @@ type: application
 # This is the chart version. This version number should be incremented each time you make changes
 # to the chart and its templates, including the app version.
 # Versions are expected to follow Semantic Versioning (https://semver.org/)
-version: 0.8.2
+version: 0.8.3
 
 # This is the version number of the application being deployed. This version number should be
 # incremented each time you make changes to the application. Versions are not expected to

charts/django/templates/deployment.yaml

@@ -78,11 +78,6 @@ spec:
             - name: django
               containerPort: {{ .Values.image.containerPort }}
               protocol: TCP
-            {{- if .Values.metrics.enabled }}
-            - name: metrics
-              containerPort: {{ .Values.metrics.port | default 9091 }}
-              protocol: TCP
-            {{- end }}
           {{- with .Values.probes }}
           {{- if .liveness.enabled }}
           livenessProbe:

charts/django/templates/service.yaml

@@ -17,12 +17,6 @@ spec:
       protocol: TCP
       name: caddy
     {{- end }}
-    {{- if .Values.metrics.enabled }}
-    - name: metrics
-      port: {{ .Values.metrics.port | default 9091 }}
-      targetPort: metrics
-      protocol: TCP
-    {{- end }}
   selector:
     {{- include "django.labels" . | nindent 4 }}
     app.kubernetes.io/component: {{ include "django.fullname" . }}

charts/django/templates/servicemonitor.yaml

@@ -10,12 +10,7 @@ spec:
     matchLabels:
       {{- include "django.selectorLabels" . | nindent 6 }}
   endpoints:
-    - port: metrics
-      path: /metrics
-      interval: {{ .Values.metrics.serviceMonitor.interval | default "30s" }}
-    {{- if .Values.metrics.djangoMetrics.enabled }}
     - port: django
       path: /metrics
       interval: {{ .Values.metrics.serviceMonitor.interval | default "30s" }}
-    {{- end }}
 {{- end }}

charts/django/values.yaml

@@ -62,15 +62,12 @@ service:
   type: ClusterIP
   port: 8000
 
-# Prometheus metrics (e.g. gunicorn-prometheus-exporter)
+# Prometheus metrics (django-prometheus)
 metrics:
   enabled: false
-  port: 9091
   serviceMonitor:
     enabled: false
     interval: 30s
-  djangoMetrics:
-    enabled: false
 
 # Caddy Settings (static + media files serving)
 proxy: