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fix(metrics): prevent thread leak by ensuring singleton initialization #1492

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49 changes: 30 additions & 19 deletions google/cloud/spanner_v1/client.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@
import os
import logging
import warnings
import threading

from google.api_core.gapic_v1 import client_info
from google.auth.credentials import AnonymousCredentials
Expand Down Expand Up @@ -99,6 +100,9 @@ def _get_spanner_optimizer_statistics_package():

log = logging.getLogger(__name__)

_metrics_monitor_initialized = False
_metrics_monitor_lock = threading.Lock()


def _get_spanner_enable_builtin_metrics_env():
return os.getenv(SPANNER_DISABLE_BUILTIN_METRICS_ENV_VAR) != "true"
Expand Down Expand Up @@ -252,30 +256,37 @@ def __init__(
):
warnings.warn(_EMULATOR_HOST_HTTP_SCHEME)
# Check flag to enable Spanner builtin metrics
global _metrics_monitor_initialized
if (
_get_spanner_enable_builtin_metrics_env()
and not disable_builtin_metrics
and HAS_GOOGLE_CLOUD_MONITORING_INSTALLED
):
meter_provider = metrics.NoOpMeterProvider()
try:
if not _get_spanner_emulator_host():
meter_provider = MeterProvider(
metric_readers=[
PeriodicExportingMetricReader(
CloudMonitoringMetricsExporter(
project_id=project, credentials=credentials
),
export_interval_millis=METRIC_EXPORT_INTERVAL_MS,
),
]
)
metrics.set_meter_provider(meter_provider)
SpannerMetricsTracerFactory()
except Exception as e:
log.warning(
"Failed to initialize Spanner built-in metrics. Error: %s", e
)
if not _metrics_monitor_initialized:
with _metrics_monitor_lock:
if not _metrics_monitor_initialized:
meter_provider = metrics.NoOpMeterProvider()
try:
if not _get_spanner_emulator_host():
meter_provider = MeterProvider(
metric_readers=[
PeriodicExportingMetricReader(
CloudMonitoringMetricsExporter(
project_id=project,
credentials=credentials,
),
export_interval_millis=METRIC_EXPORT_INTERVAL_MS,
),
]
)
metrics.set_meter_provider(meter_provider)
SpannerMetricsTracerFactory()
_metrics_monitor_initialized = True
except Exception as e:
log.warning(
"Failed to initialize Spanner built-in metrics. Error: %s",
e,
)
else:
SpannerMetricsTracerFactory(enabled=False)

Expand Down
88 changes: 78 additions & 10 deletions tests/unit/test_client.py
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Original file line number Diff line number Diff line change
Expand Up @@ -255,28 +255,44 @@ def test_constructor_w_directed_read_options(self):
expected_scopes, creds, directed_read_options=self.DIRECTED_READ_OPTIONS
)

@mock.patch("google.cloud.spanner_v1.client.metrics")
@mock.patch("google.cloud.spanner_v1.client.CloudMonitoringMetricsExporter")
@mock.patch("google.cloud.spanner_v1.client.PeriodicExportingMetricReader")
@mock.patch("google.cloud.spanner_v1.client.MeterProvider")
@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
self,
mock_spanner_metrics_factory,
mock_meter_provider,
mock_periodic_reader,
mock_exporter,
mock_metrics,
):
"""
Test that Client constructor handles exceptions during metrics
initialization and logs a warning.
"""
from google.cloud.spanner_v1.client import Client
from google.cloud.spanner_v1 import client as MUT

MUT._metrics_monitor_initialized = False
mock_spanner_metrics_factory.side_effect = Exception("Metrics init failed")
creds = build_scoped_credentials()

with self.assertLogs("google.cloud.spanner_v1.client", level="WARNING") as log:
client = Client(project=self.PROJECT, credentials=creds)
self.assertIsNotNone(client)
self.assertIn(
"Failed to initialize Spanner built-in metrics. Error: Metrics init failed",
log.output[0],
)
mock_spanner_metrics_factory.assert_called_once()
try:
with self.assertLogs(
"google.cloud.spanner_v1.client", level="WARNING"
) as log:
client = Client(project=self.PROJECT, credentials=creds)
self.assertIsNotNone(client)
self.assertIn(
"Failed to initialize Spanner built-in metrics. Error: Metrics init failed",
log.output[0],
)
mock_spanner_metrics_factory.assert_called_once()
mock_metrics.set_meter_provider.assert_called_once()
finally:
MUT._metrics_monitor_initialized = False

@mock.patch("google.cloud.spanner_v1.client.SpannerMetricsTracerFactory")
@mock.patch.dict(os.environ, {"SPANNER_DISABLE_BUILTIN_METRICS": "true"})
Expand All @@ -293,6 +309,58 @@ def test_constructor_w_disable_builtin_metrics_using_env(
self.assertIsNotNone(client)
mock_spanner_metrics_factory.assert_called_once_with(enabled=False)

@mock.patch("google.cloud.spanner_v1.client.metrics")
@mock.patch("google.cloud.spanner_v1.client.CloudMonitoringMetricsExporter")
@mock.patch("google.cloud.spanner_v1.client.PeriodicExportingMetricReader")
@mock.patch("google.cloud.spanner_v1.client.MeterProvider")
@mock.patch("google.cloud.spanner_v1.client.SpannerMetricsTracerFactory")
@mock.patch.dict(os.environ, {"SPANNER_DISABLE_BUILTIN_METRICS": "false"})
def test_constructor_metrics_singleton_behavior(
self,
mock_spanner_metrics_factory,
mock_meter_provider,
mock_periodic_reader,
mock_exporter,
mock_metrics,
):
"""
Test that metrics are only initialized once.
"""
from google.cloud.spanner_v1 import client as MUT

# Reset global state for this test
MUT._metrics_monitor_initialized = False
try:
creds = build_scoped_credentials()

# First client initialization
client1 = MUT.Client(project=self.PROJECT, credentials=creds)
self.assertIsNotNone(client1)
mock_metrics.set_meter_provider.assert_called_once()
mock_spanner_metrics_factory.assert_called_once()

# Verify MeterProvider chain was created
mock_meter_provider.assert_called_once()
mock_periodic_reader.assert_called_once()
mock_exporter.assert_called_once()

self.assertTrue(MUT._metrics_monitor_initialized)

# Reset mocks to verify they are NOT called again
mock_metrics.set_meter_provider.reset_mock()
mock_spanner_metrics_factory.reset_mock()
mock_meter_provider.reset_mock()

# Second client initialization
client2 = MUT.Client(project=self.PROJECT, credentials=creds)
self.assertIsNotNone(client2)
mock_metrics.set_meter_provider.assert_not_called()
mock_spanner_metrics_factory.assert_not_called()
mock_meter_provider.assert_not_called()
self.assertTrue(MUT._metrics_monitor_initialized)
finally:
MUT._metrics_monitor_initialized = False

@mock.patch("google.cloud.spanner_v1.client.SpannerMetricsTracerFactory")
def test_constructor_w_disable_builtin_metrics_using_option(
self, mock_spanner_metrics_factory
Expand Down
19 changes: 13 additions & 6 deletions tests/unit/test_metrics.py
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Original file line number Diff line number Diff line change
Expand Up @@ -60,17 +60,24 @@ def patched_client(monkeypatch):
if SpannerMetricsTracerFactory._metrics_tracer_factory is not None:
SpannerMetricsTracerFactory._metrics_tracer_factory = None

client = Client(
project="test",
credentials=TestCredentials(),
# client_options={"api_endpoint": "none"}
)
yield client
# Reset the global flag to ensure metrics initialization runs
from google.cloud.spanner_v1 import client as client_module

client_module._metrics_monitor_initialized = False

with patch("google.cloud.spanner_v1.client.CloudMonitoringMetricsExporter"):
client = Client(
project="test",
credentials=TestCredentials(),
# client_options={"api_endpoint": "none"}
)
yield client

# Resetting
metrics.set_meter_provider(metrics.NoOpMeterProvider())
SpannerMetricsTracerFactory._metrics_tracer_factory = None
SpannerMetricsTracerFactory.current_metrics_tracer = None
client_module._metrics_monitor_initialized = False


def test_metrics_emission_with_failure_attempt(patched_client):
Expand Down
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