Follow signature contract

docs/generate-metrics.py

@@ -22,14 +22,8 @@ class Generator:
         for name in dir(jupyterhub.metrics):
             obj = getattr(jupyterhub.metrics, name)
             if obj.__class__.__module__.startswith('prometheus_client.'):
-                description = obj.describe()[0]
-                table_rows.append(
-                    [
-                        description.type,
-                        description.name,
-                        description.documentation,
-                    ]
-                )
+                for metric in obj.describe():
+                    table_rows.append([metric.type, metric.name, metric.documentation])
         return table_rows
 
     def prometheus_metrics(self):

jupyterhub/tests/test_metrics.py

@@ -11,15 +11,15 @@ from .utils import add_user, api_request, get_page
 
 
 @pytest.mark.parametrize(
-    "metric, expected_name",
+    "metric_object, expected_names",
     [
-        (metrics.TOTAL_USERS, 'jupyterhub_total_users'),
-        (metrics.REQUEST_DURATION_SECONDS, 'jupyterhub_request_duration_seconds'),
+        (metrics.TOTAL_USERS, ['jupyterhub_total_users']),
+        (metrics.REQUEST_DURATION_SECONDS, ['jupyterhub_request_duration_seconds']),
     ],
 )
-def test_metrics_prefix(metric, expected_name):
-    description = metric.describe()[0]
-    assert description.name == expected_name
+def test_metrics_prefix(metric_object, expected_names):
+    for metric, expected_name in zip(metric_obj.describe(), expected_names):
+        assert metric.name == expected_name
 
 
 async def test_total_users(app):