Reduce Prometheus requests for modify_query calls

Each call to modify_query will send a request to Prometheus to
determine all metric names saved in Prometheus unless we
provide the list with the modify_query call. We use the modify_query
in two places in Aetos, one is the query controller, the other one
is the process_matches function. In the query controller, we call
modify_query just once, so the code can stay as is. In process_matches
we call modify_query in a loop, so we send a request to Prometheus
to retrieve a list of metrics before the loop and provide the list
to modify_query to to avoid sending a request to Prometheus with each
iteration of the loop.

Change-Id: I5f5c82ce25033748c321dd836256094fbcf305ef
Signed-off-by: Jaromir Wysoglad <jwysogla@redhat.com>

aetos/controllers/api/v1/base.py

@@ -94,9 +94,11 @@ class Base(rest.RestController):
             return promQLRbac.append_rbac_labels('')
 
         # Apply RBAC modification to each match
+        metric_names = self.prometheus_client.label_values("__name__")
         modified_matches = []
         for match in matches:
-            modified_matches.append(promQLRbac.modify_query(match))
+            modified_matches.append(
+                promQLRbac.modify_query(match, metric_names=metric_names))
 
         return modified_matches
 

aetos/tests/functional/test_core_endpoints.py

@@ -166,11 +166,13 @@ class TestCoreEndpointsAsUser(base.TestCase):
         expected_params = {'match[]': expected_matches}
 
         with (
+            mock.patch.object(prometheus_client.PrometheusAPIClient,
+                              'label_values', return_value=['metric_name']),
             mock.patch.object(prometheus_client.PrometheusAPIClient, '_get',
                               return_value=returned_from_prometheus
                               ) as get_mock,
             mock.patch.object(rbac.PromQLRbac, 'modify_query',
-                              side_effect=lambda x:
+                              side_effect=lambda x, metric_names:
                               expected_matches[matches.index(x)]
                               ) as rbac_mock
             ):
@@ -184,7 +186,7 @@ class TestCoreEndpointsAsUser(base.TestCase):
             f'label/{label_name}/values', expected_params
         )
         for match in matches:
-            rbac_mock.assert_any_call(match)
+            rbac_mock.assert_any_call(match, metric_names=['metric_name'])
 
     def test_labels(self):
         expected_status_code = 200
@@ -240,11 +242,13 @@ class TestCoreEndpointsAsUser(base.TestCase):
         expected_params = {'match[]': expected_matches}
 
         with (
+            mock.patch.object(prometheus_client.PrometheusAPIClient,
+                              'label_values', return_value=['metric_name']),
             mock.patch.object(prometheus_client.PrometheusAPIClient, '_get',
                               return_value=returned_from_prometheus
                               ) as get_mock,
             mock.patch.object(rbac.PromQLRbac, 'modify_query',
-                              side_effect=lambda x:
+                              side_effect=lambda x, metric_names:
                               expected_matches[matches.index(x)]
                               ) as rbac_mock
             ):
@@ -258,7 +262,7 @@ class TestCoreEndpointsAsUser(base.TestCase):
             'labels', expected_params
         )
         for match in matches:
-            rbac_mock.assert_any_call(match)
+            rbac_mock.assert_any_call(match, metric_names=['metric_name'])
 
     def test_query(self):
         expected_status_code = 200
@@ -342,11 +346,13 @@ class TestCoreEndpointsAsUser(base.TestCase):
         modified_params = {'match[]': modified_matches}
 
         with (
+            mock.patch.object(prometheus_client.PrometheusAPIClient,
+                              'label_values', return_value=['metric_name']),
             mock.patch.object(prometheus_client.PrometheusAPIClient, '_get',
                               return_value=returned_from_prometheus
                               ) as get_mock,
             mock.patch.object(rbac.PromQLRbac, 'modify_query',
-                              side_effect=lambda x:
+                              side_effect=lambda x, metric_names:
                               modified_matches[matches.index(x)]
                               ) as rbac_mock
             ):
@@ -358,7 +364,7 @@ class TestCoreEndpointsAsUser(base.TestCase):
         self.assertEqual(expected_status_code, result.status_code)
         get_mock.assert_called_once_with('series', modified_params)
         for match in matches:
-            rbac_mock.assert_any_call(match)
+            rbac_mock.assert_any_call(match, metric_names=['metric_name'])
 
     def test_status(self):
         expected_status_code = 403

requirements.txt

@@ -15,4 +15,4 @@ pecan>=0.8.0 # BSD
 oslo.middleware>=3.22.0 # Apache-2.0
 oslo.utils>=4.7.0 # Apache-2.0
 WSME>=0.12.1 # MIT
-python-observabilityclient>=0.0.4 # Apache-2.0
+python-observabilityclient>=1.1.0 # Apache-2.0