re-add a name fallback

This was removed in open-telemetry#1759.

Author: muncus

instrumentation/opentelemetry-instrumentation-django/src/opentelemetry/instrumentation/django/middleware/otel_middleware.py

@@ -174,6 +174,9 @@ def _get_span_name(request):
 
             if hasattr(match, "route") and match.route:
                 return f"{request.method} {match.route}"
+            
+            if hasattr(match, "url_name") and match.url_name:
+                return f"{request.method} {match.url_name}"
 
             return request.method
 

instrumentation/opentelemetry-instrumentation-django/tests/test_middleware.py

@@ -78,8 +78,10 @@
     from django.urls import path
 else:
     from django.conf.urls import url as re_path
+
     def path(p, *args, **kwargs):
-      return re_path(r"^%s$" % p, *args, **kwargs)
+        return re_path(r"^%s$" % p, *args, **kwargs)
+
 
 urlpatterns = [
     re_path(r"^traced/", traced),
@@ -217,7 +219,7 @@ def test_empty_path(self):
 
         span = spans[0]
 
-        self.assertEqual(span.name, "empty")
+        self.assertEqual(span.name, "GET empty")
 
     def test_traced_post(self):
         Client().post("/traced/")