Observe request duration

kinto/core/initialization.py

@@ -491,6 +491,18 @@ def on_new_response(event):
             ],
         )
 
+        try:
+            current = utils.msec_time()
+            duration = current - request._received_at
+            metrics_service.observe(
+                "request_duration",
+                duration,
+                labels=[("endpoint", utils.strip_uri_prefix(request.path))],
+            )
+        except AttributeError:  # pragma: no cover
+            # Logging was not setup in this Kinto app (unlikely but possible)
+            pass
+
         # Observe response size.
         metrics_service.observe(
             "request_size",

tests/core/test_initialization.py

@@ -423,6 +423,16 @@ def test_statsd_observe_request_size(self):
             labels=[("endpoint", "/__heartbeat__")],
         )
 
+    def test_statsd_observe_request_duration(self):
+        kinto.core.initialize(self.config, "0.0.1", "settings_prefix")
+        app = webtest.TestApp(self.config.make_wsgi_app())
+        app.get("/v0/__heartbeat__")
+        self.mocked().observe.assert_any_call(
+            "request_duration",
+            mock.ANY,
+            labels=[("endpoint", "/__heartbeat__")],
+        )
+
     def test_statsd_counts_views_and_methods(self):
         kinto.core.initialize(self.config, "0.0.1", "settings_prefix")
         app = webtest.TestApp(self.config.make_wsgi_app())