From f3155973f6f9620f8147243f53917a08e9bfd369 Mon Sep 17 00:00:00 2001
From: Jeremy Stretch <jstretch@netboxlabs.com>
Date: Mon, 28 Jul 2025 15:26:16 -0400
Subject: [PATCH] Subclass django_prometheus middleware to capture REST API
 metrics

---
 netbox/netbox/metrics.py    | 32 ++++++++++++++++++++++++++++++++
 netbox/netbox/middleware.py | 24 ++++++++++++++++++++++++
 netbox/netbox/settings.py   |  4 ++--
 3 files changed, 58 insertions(+), 2 deletions(-)
 create mode 100644 netbox/netbox/metrics.py

diff --git a/netbox/netbox/metrics.py b/netbox/netbox/metrics.py
new file mode 100644
index 000000000..43b549d7c
--- /dev/null
+++ b/netbox/netbox/metrics.py
@@ -0,0 +1,32 @@
+from django_prometheus.conf import NAMESPACE
+from django_prometheus import middleware
+from prometheus_client import Counter
+
+__all__ = (
+    'Metrics',
+)
+
+
+class Metrics(middleware.Metrics):
+    """
+    Expand the stock Metrics class from django_prometheus to add our own counters.
+    """
+
+    def register(self):
+        super().register()
+
+        # REST API metrics
+        self.rest_api_requests = self.register_metric(
+            Counter,
+            "rest_api_requests_total_by_method",
+            "Count of total REST API requests by method",
+            ["method"],
+            namespace=NAMESPACE,
+        )
+        self.rest_api_requests_by_view_method = self.register_metric(
+            Counter,
+            "django_http_requests_total_by_view_method",
+            "Count of REST API requests by view & method",
+            ["view", "method"],
+            namespace=NAMESPACE,
+        )
diff --git a/netbox/netbox/middleware.py b/netbox/netbox/middleware.py
index 145141615..e4c57d4c1 100644
--- a/netbox/netbox/middleware.py
+++ b/netbox/netbox/middleware.py
@@ -8,8 +8,10 @@ from django.core.exceptions import ImproperlyConfigured
 from django.db import connection, ProgrammingError
 from django.db.utils import InternalError
 from django.http import Http404, HttpResponseRedirect
+from django_prometheus import middleware
 
 from netbox.config import clear_config, get_config
+from netbox.metrics import Metrics
 from netbox.views import handler_500
 from utilities.api import is_api_request
 from utilities.error_handlers import handle_rest_api_exception
@@ -18,6 +20,8 @@ from utilities.request import apply_request_processors
 __all__ = (
     'CoreMiddleware',
     'MaintenanceModeMiddleware',
+    'PrometheusAfterMiddleware',
+    'PrometheusBeforeMiddleware',
     'RemoteUserMiddleware',
 )
 
@@ -180,6 +184,26 @@ class RemoteUserMiddleware(RemoteUserMiddleware_):
         return groups
 
 
+class PrometheusBeforeMiddleware(middleware.PrometheusBeforeMiddleware):
+    metrics_cls = Metrics
+
+
+class PrometheusAfterMiddleware(middleware.PrometheusAfterMiddleware):
+    metrics_cls = Metrics
+
+    def process_response(self, request, response):
+        response = super().process_response(request, response)
+
+        # Increment REST API request counters
+        if is_api_request(request):
+            method = self._method(request)
+            name = self._get_view_name(request)
+            self.label_metric(self.metrics.rest_api_requests, request, method=method).inc()
+            self.label_metric(self.metrics.rest_api_requests_by_view_method, request, method=method, view=name).inc()
+
+        return response
+
+
 class MaintenanceModeMiddleware:
     """
     Middleware that checks if the application is in maintenance mode
diff --git a/netbox/netbox/settings.py b/netbox/netbox/settings.py
index d293a9979..909a67f60 100644
--- a/netbox/netbox/settings.py
+++ b/netbox/netbox/settings.py
@@ -471,9 +471,9 @@ if DEBUG:
 if METRICS_ENABLED:
     # If metrics are enabled, add the before & after Prometheus middleware
     MIDDLEWARE = [
-        'django_prometheus.middleware.PrometheusBeforeMiddleware',
+        'netbox.middleware.PrometheusBeforeMiddleware',
         *MIDDLEWARE,
-        'django_prometheus.middleware.PrometheusAfterMiddleware',
+        'netbox.middleware.PrometheusAfterMiddleware',
     ]
 
 # URLs