feat(spanner): make built-in metrics enabled by default

Author: sinhasubham

google/cloud/spanner_v1/client.py

@@ -52,7 +52,6 @@
 from google.cloud.spanner_v1._helpers import _metadata_with_prefix
 from google.cloud.spanner_v1.instance import Instance
 from google.cloud.spanner_v1.metrics.constants import (
-    ENABLE_SPANNER_METRICS_ENV_VAR,
     METRIC_EXPORT_INTERVAL_MS,
 )
 from google.cloud.spanner_v1.metrics.spanner_metrics_tracer_factory import (
@@ -75,7 +74,7 @@
 
 _CLIENT_INFO = client_info.ClientInfo(client_library_version=__version__)
 EMULATOR_ENV_VAR = "SPANNER_EMULATOR_HOST"
-ENABLE_BUILTIN_METRICS_ENV_VAR = "SPANNER_ENABLE_BUILTIN_METRICS"
+SPANNER_DISABLE_BUILTIN_METRICS_ENV_VAR = "SPANNER_DISABLE_BUILTIN_METRICS"
 _EMULATOR_HOST_HTTP_SCHEME = (
     "%s contains a http scheme. When used with a scheme it may cause gRPC's "
     "DNS resolver to endlessly attempt to resolve. %s is intended to be used "
@@ -102,7 +101,7 @@ def _get_spanner_optimizer_statistics_package():
 
 
 def _get_spanner_enable_builtin_metrics():
-    return os.getenv(ENABLE_SPANNER_METRICS_ENV_VAR) == "true"
+    return os.getenv(SPANNER_DISABLE_BUILTIN_METRICS_ENV_VAR) != "true"
 
 
 class Client(ClientWithProject):

tests/unit/test_client.py

@@ -22,6 +22,7 @@
 from tests._builders import build_scoped_credentials
 
 
+@mock.patch.dict(os.environ, {"SPANNER_DISABLE_BUILTIN_METRICS": "true"})
 class TestClient(unittest.TestCase):
     PROJECT = "PROJECT"
     PATH = "projects/%s" % (PROJECT,)
@@ -161,8 +162,7 @@ def test_constructor_custom_client_info(self):
         creds = build_scoped_credentials()
         self._constructor_test_helper(expected_scopes, creds, client_info=client_info)
 
-    # Disable metrics to avoid google.auth.default calls from Metric Exporter
-    @mock.patch.dict(os.environ, {"SPANNER_ENABLE_BUILTIN_METRICS": ""})
+    # Metrics are disabled by default for tests in this class
     def test_constructor_implicit_credentials(self):
         from google.cloud.spanner_v1 import client as MUT
 
@@ -255,8 +255,8 @@ def test_constructor_w_directed_read_options(self):
             expected_scopes, creds, directed_read_options=self.DIRECTED_READ_OPTIONS
         )
 
-    @mock.patch.dict(os.environ, {"SPANNER_ENABLE_BUILTIN_METRICS": "true"})
     @mock.patch("google.cloud.spanner_v1.client.SpannerMetricsTracerFactory")
+    @mock.patch.dict(os.environ, {"SPANNER_DISABLE_BUILTIN_METRICS": "false"})
     def test_constructor_w_metrics_initialization_error(
         self, mock_spanner_metrics_factory
     ):