Add google-cloud-monitoring client library support (#22)

- Include `google-cloud-monitoring~=2.18` into the requirements
- Add cached `GcpApiManager.monitoring_metric_service` method returning
self-closing `google.cloud.monitoring_v3.MetricServiceClient`
- Add a placeholder subtest
`gamma.csm_observability_test.4_check_monitoring_metric_client` that
checks the monitoring API connection by making an RPC with intentionally
incorrect server-validated argument, and expecting an `InvalidArgument`
response from the server.

framework/infrastructure/gcp/api.py

@@ -20,6 +20,7 @@
 
 from absl import flags
 from google.cloud import secretmanager_v1
+import google.cloud.monitoring_v3
 from google.longrunning import operations_pb2
 from google.protobuf import json_format
 from google.rpc import code_pb2
@@ -175,6 +176,26 @@ def secrets(version: str):
 
         raise NotImplementedError(f"Secret Manager {version} not supported")
 
+    @functools.lru_cache(None)
+    def monitoring_metric_service(self, version: str):
+        """Monitoring API Metric Service.
+
+        Manages metric descriptors, monitored resource descriptors,
+        and time series data.
+
+        https://cloud.google.com/python/docs/reference/monitoring/latest/google.cloud.monitoring_v3.services.metric_service.MetricServiceClient
+        """
+        client = None
+        if version == "v3":
+            # TODO(sergiitk): set client_options arg if staging api is needed.
+            client = google.cloud.monitoring_v3.MetricServiceClient()
+
+        if not client:
+            raise NotImplementedError(f"Metric Service {version} not supported")
+
+        self._exit_stack.enter_context(client)
+        return client
+
     @functools.lru_cache(None)
     def iam(self, version: str) -> discovery.Resource:
         """Identity and Access Management (IAM) API.

requirements.lock

@@ -3,6 +3,7 @@ PyYAML==6.0
 absl-py==0.15.0
 google-api-python-client==1.12.11
 google-cloud-secret-manager==2.15.1
+google-cloud-monitoring==2.18.0
 grpcio==1.57.0
 grpcio-health-checking==1.57.0
 grpcio-tools==1.57.0

requirements.txt

@@ -3,6 +3,7 @@ PyYAML~=6.0
 absl-py~=0.11
 google-api-python-client~=1.12
 google-cloud-secret-manager~=2.1
+google-cloud-monitoring~=2.18
 grpcio~=1.57
 grpcio-health-checking~=1.57
 grpcio-tools~=1.57

tests/gamma/csm_observability_test.py

@@ -15,6 +15,8 @@
 
 from absl import flags
 from absl.testing import absltest
+from google.api_core import exceptions as gapi_errors
+from google.cloud import monitoring_v3
 
 from framework import xds_gamma_testcase
 from framework import xds_k8s_testcase
@@ -29,13 +31,20 @@
 
 
 class CsmObservabilityTest(xds_gamma_testcase.GammaXdsKubernetesTestCase):
+    metric_client: monitoring_v3.MetricServiceClient
+
     @staticmethod
     def is_supported(config: skips.TestConfig) -> bool:
         if config.client_lang == _Lang.CPP and config.server_lang == _Lang.CPP:
             # CSM Observability Test is only supported for CPP for now.
             return config.version_gte("v1.61.x")
         return False
 
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        cls.metric_client = cls.gcp_api_manager.monitoring_metric_service("v3")
+
     def test_csm_observability(self):
         # TODO(sergiitk): [GAMMA] Consider moving out custom gamma
         #   resource creation out of self.startTestServers()
@@ -52,6 +61,21 @@ def test_csm_observability(self):
         with self.subTest("3_test_server_received_rpcs_from_test_client"):
             self.assertSuccessfulRpcs(test_client)
 
+        # For now, this just makes a bogus call to ensure metrics client
+        # connected to the remote API service.
+        with self.subTest("4_check_monitoring_metric_client"):
+            with self.assertRaises(gapi_errors.GoogleAPICallError) as cm:
+                self.metric_client.list_metric_descriptors(
+                    request=monitoring_v3.ListMetricDescriptorsRequest(
+                        name="whatever",
+                    )
+                )
+            err = cm.exception
+            self.assertIsInstance(err, gapi_errors.InvalidArgument)
+            self.assertIsNotNone(err.grpc_status_code)
+            self.assertStartsWith(err.message, "Name must begin with")
+            self.assertEndsWith(err.message, " got: whatever")
+
 
 if __name__ == "__main__":
     absltest.main()