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Add new default metric: inflight gauge #481

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Add new default metric: inflight gauge #481

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ed743ef
add two more default metrics
john-wd Aug 11, 2025
477552a
remove dupe metric
john-wd Aug 12, 2025
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18 changes: 17 additions & 1 deletion django_prometheus/middleware.py
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
from django.utils.deprecation import MiddlewareMixin
from prometheus_client import Counter, Histogram
from prometheus_client import Counter, Histogram, Gauge

from django_prometheus.conf import NAMESPACE, PROMETHEUS_LATENCY_BUCKETS
from django_prometheus.utils import PowersOf, Time, TimeSince
Expand All @@ -21,6 +21,19 @@ def __init__(self, *args, **kwargs):
self.register()

def register(self):
self.inflight_requests = self.register_metric(
Gauge,
"django_http_inflight_requests",
"Current number of inflight requests.",
namespace=NAMESPACE,
)
self.requests_total_by_view = self.register_metric(
Counter,
"django_http_requests_total_by_view",
"Total count of requests by view.",
["view"],
namespace=NAMESPACE,
)
self.requests_total = self.register_metric(
Counter,
"django_http_requests_before_middlewares_total",
Expand Down Expand Up @@ -217,6 +230,7 @@ def process_request(self, request):
method = self._method(request)
self.label_metric(self.metrics.requests_by_method, request, method=method).inc()
self.label_metric(self.metrics.requests_by_transport, request, transport=transport).inc()
self.label_metric(self.metrics.inflight_requests, request).inc()

# Mimic the behaviour of the deprecated "Request.is_ajax()" method.
if request.headers.get("x-requested-with") == "XMLHttpRequest":
Expand Down Expand Up @@ -261,6 +275,8 @@ def process_response(self, request, response):
method = self._method(request)
name = self._get_view_name(request)
status = str(response.status_code)
self.label_metric(self.metrics.inflight_requests, request).dec()
self.label_metric(self.metrics.requests_total_by_view, request, view=name).inc()
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I don't think we need this additional metric. As it can be easily constructed from the responses_by_status_view_method metric by sum(...) by (view). Is there a reason this doesn't work for your use case?

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Yeah, I think you are right, this should suffice for this usecase. Thanks.

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Remove this dupe from my latest commit, kept the inflights one.

self.label_metric(self.metrics.responses_by_status, request, response, status=status).inc()
self.label_metric(
self.metrics.responses_by_status_view_method,
Expand Down