fix(datastore): disable built-in OpenTelemetry SDK when metrics export is disabled

java-datastore/google-cloud-datastore/src/main/java/com/google/cloud/datastore/telemetry/BuiltInDatastoreMetricsProvider.java

@@ -120,6 +120,12 @@ private static String hashClientUId(String uuid) {
    */
   @Nullable
   public OpenTelemetry createOpenTelemetry(@Nonnull DatastoreOptions options) {
+    // If built-in metrics export is disabled, return no-op OpenTelemetry to avoid instantiating
+    // a real SdkMeterProvider. Otherwise, the SDK-internal PeriodicMetricReader will start
+    // and attempt to export diagnostic metrics, leading to log spam if the exporter fails.
+    if (!options.getOpenTelemetryOptions().isExportBuiltinMetricsToGoogleCloudMonitoring()) {
+      return OpenTelemetry.noop();
+    }
     Credentials credentials =
         Preconditions.checkNotNull(
             options.getCredentials(), "Credentials cannot be null for built in metrics");

java-datastore/google-cloud-datastore/src/test/java/com/google/cloud/datastore/telemetry/BuiltInDatastoreMetricsProviderTest.java

@@ -21,6 +21,7 @@
 import com.google.auth.CredentialTypeForMetrics;
 import com.google.auth.Credentials;
 import com.google.cloud.NoCredentials;
+import com.google.cloud.datastore.DatastoreOpenTelemetryOptions;
 import com.google.cloud.datastore.DatastoreOptions;
 import io.opentelemetry.api.OpenTelemetry;
 import io.opentelemetry.sdk.OpenTelemetrySdk;
@@ -69,6 +70,10 @@ public void testCreateOpenTelemetry_returnsNonNull() {
             .setProjectId(PROJECT_ID)
             .setDatabaseId("test-db")
             .setCredentials(credentials)
+            .setOpenTelemetryOptions(
+                DatastoreOpenTelemetryOptions.newBuilder()
+                    .setExportBuiltinMetricsToGoogleCloudMonitoring(true)
+                    .build())
             .build();
 
     OpenTelemetry otel = BuiltInDatastoreMetricsProvider.INSTANCE.createOpenTelemetry(options);
@@ -96,13 +101,21 @@ public void testCreateOpenTelemetry_eachCallReturnsDistinctInstance() {
             .setProjectId(PROJECT_ID)
             .setDatabaseId("test-db")
             .setCredentials(credentials1)
+            .setOpenTelemetryOptions(
+                DatastoreOpenTelemetryOptions.newBuilder()
+                    .setExportBuiltinMetricsToGoogleCloudMonitoring(true)
+                    .build())
             .build();
 
     DatastoreOptions options2 =
         DatastoreOptions.newBuilder()
             .setProjectId(PROJECT_ID)
             .setDatabaseId("test-db")
             .setCredentials(credentials2)
+            .setOpenTelemetryOptions(
+                DatastoreOpenTelemetryOptions.newBuilder()
+                    .setExportBuiltinMetricsToGoogleCloudMonitoring(true)
+                    .build())
             .build();
 
     OpenTelemetry otel1 = BuiltInDatastoreMetricsProvider.INSTANCE.createOpenTelemetry(options1);
@@ -137,4 +150,21 @@ public void testCreateOpenTelemetry_withEmulatorHostProperty_returnsNoOp() {
       System.clearProperty(DatastoreOptions.LOCAL_HOST_ENV_VAR);
     }
   }
+
+  @Test
+  public void testCreateOpenTelemetry_exportDisabled_returnsNoOp() {
+    Credentials credentials = EasyMock.mock(Credentials.class);
+    EasyMock.replay(credentials);
+
+    DatastoreOptions options =
+        DatastoreOptions.newBuilder()
+            .setProjectId(PROJECT_ID)
+            .setDatabaseId("test-db")
+            .setCredentials(credentials)
+            // export is disabled by default
+            .build();
+
+    OpenTelemetry otel = BuiltInDatastoreMetricsProvider.INSTANCE.createOpenTelemetry(options);
+    assertThat(otel).isInstanceOf(OpenTelemetry.noop().getClass());
+  }
 }