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

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):

google/cloud/spanner_v1/metrics/constants.py

@@ -20,7 +20,6 @@
 GOOGLE_CLOUD_REGION_KEY = "cloud.region"
 GOOGLE_CLOUD_REGION_GLOBAL = "global"
 SPANNER_METHOD_PREFIX = "/google.spanner.v1."
-ENABLE_SPANNER_METRICS_ENV_VAR = "SPANNER_ENABLE_BUILTIN_METRICS"
 
 # Monitored resource labels
 MONITORED_RES_LABEL_KEY_PROJECT = "project_id"

tests/system/test_metrics.py

@@ -0,0 +1,92 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os
+import mock
+import pytest
+
+from opentelemetry.sdk.metrics import MeterProvider
+from opentelemetry.sdk.metrics.export import InMemoryMetricReader
+
+from google.cloud.spanner_v1 import Client
+
+# System tests are skipped if the environment variables are not set.
+PROJECT = os.environ.get("GOOGLE_CLOUD_PROJECT")
+INSTANCE_ID = os.environ.get("SPANNER_TEST_INSTANCE")
+DATABASE_ID = "test_metrics_db_system"
+
+
+pytestmark = pytest.mark.skipif(
+    not all([PROJECT, INSTANCE_ID]), reason="System test environment variables not set."
+)
+
+
+@pytest.fixture(scope="module")
+def metrics_database():
+    """Create a database for the test."""
+    client = Client(project=PROJECT)
+    instance = client.instance(INSTANCE_ID)
+    database = instance.database(DATABASE_ID)
+    if database.exists():  # Clean up from previous failed run
+        database.drop()
+    op = database.create()
+    op.result(timeout=300)  # Wait for creation to complete
+    yield database
+    if database.exists():
+        database.drop()
+
+
+def test_builtin_metrics_with_default_otel(metrics_database):
+    """
+    Verifies that built-in metrics are collected by default when a
+    transaction is executed.
+    """
+    reader = InMemoryMetricReader()
+    meter_provider = MeterProvider(metric_readers=[reader])
+
+    # Patch the client's metric setup to use our in-memory reader.
+    with mock.patch(
+        "google.cloud.spanner_v1.client.MeterProvider",
+        return_value=meter_provider,
+    ):
+        with mock.patch.dict(os.environ, {"SPANNER_DISABLE_BUILTIN_METRICS": "false"}):
+            with metrics_database.snapshot() as snapshot:
+                list(snapshot.execute_sql("SELECT 1"))
+
+    metric_data = reader.get_metrics_data()
+
+    assert len(metric_data.resource_metrics) >= 1
+    assert len(metric_data.resource_metrics[0].scope_metrics) >= 1
+
+    collected_metrics = {
+        metric.name
+        for metric in metric_data.resource_metrics[0].scope_metrics[0].metrics
+    }
+    expected_metrics = {
+        "spanner/operation_latencies",
+        "spanner/attempt_latencies",
+        "spanner/operation_count",
+        "spanner/attempt_count",
+        "spanner/gfe_latencies",
+    }
+    assert expected_metrics.issubset(collected_metrics)
+
+    for metric in metric_data.resource_metrics[0].scope_metrics[0].metrics:
+        if metric.name == "spanner/operation_count":
+            point = next(iter(metric.data.data_points))
+            assert point.value == 1
+            assert point.attributes["method"] == "ExecuteSql"
+            return
+
+    pytest.fail("Metric 'spanner/operation_count' not found.")

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
     ):