root: fix prometheus path in ServiceMonitor, return WWW-Authenticate header so basic auth is sent

passbook/root/monitoring.py

@@ -2,7 +2,7 @@
 from base64 import b64encode
 
 from django.conf import settings
-from django.http import Http404, HttpRequest, HttpResponse
+from django.http import HttpRequest, HttpResponse
 from django.views import View
 from django_prometheus.exports import ExportToDjangoView
 
@@ -18,6 +18,8 @@ class MetricsView(View):
         expected = b64encode(str.encode(credentials)).decode()
 
         if auth_type != "Basic" or credentials != expected:
-            raise Http404
+            response = HttpResponse(status=401)
+            response['WWW-Authenticate'] = 'Basic realm="passbook-monitoring"'
+            return response
 
         return ExportToDjangoView(request)