fix(datastore): filter out non-datastore metrics in Cloud Monitoring exporter

Author: lqiu96

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

@@ -235,6 +235,10 @@ public CompletableResultCode export(@Nonnull Collection<MetricData> collection)
       return CompletableResultCode.ofFailure();
     }
 
+    if (datastoreTimeSeries.isEmpty()) {
+      return CompletableResultCode.ofSuccess();
+    }
+
     ProjectName projectName = ProjectName.of(projectId);
 
     // Perform the actual network call to Cloud Monitoring.

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

@@ -84,6 +84,9 @@ static List<TimeSeries> convertToDatastoreTimeSeries(
 
     // Metrics should already been filtered for Gax and Datastore related ones
     for (MetricData metricData : collection) {
+      if (!metricData.getName().startsWith(TelemetryConstants.METRIC_PREFIX)) {
+        continue;
+      }
       // TODO(b/405457573): The monitored resource is currently written to `global` because the
       // Firestore namespace in Cloud Monitoring has not been deployed yet. Once the namespace
       // is available, database_id and location labels should be added here using

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

@@ -42,6 +42,7 @@
 import com.google.monitoring.v3.TimeSeries;
 import com.google.protobuf.Empty;
 import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.sdk.common.CompletableResultCode;
 import io.opentelemetry.sdk.common.InstrumentationScopeInfo;
 import io.opentelemetry.sdk.metrics.data.AggregationTemporality;
 import io.opentelemetry.sdk.metrics.data.LongPointData;
@@ -190,6 +191,35 @@ public void testClientCacheReferenceCounting() {
     verify(mockClient);
   }
 
+  @Test
+  public void testExportingIgnoredMetrics() {
+    // No expectations on mockMetricServiceStub means we expect NO calls to it.
+    replay(mockMetricServiceStub);
+
+    long fakeValue = 11L;
+    long startEpoch = 10;
+    long endEpoch = 15;
+    LongPointData longPointData =
+        ImmutableLongPointData.create(startEpoch, endEpoch, attributes, fakeValue);
+
+    String ignoredMetricName = "otel.sdk.metric_reader.collection.duration";
+    MetricData ignoredData =
+        ImmutableMetricData.createLongSum(
+            resource,
+            scope,
+            ignoredMetricName,
+            "description",
+            "1",
+            ImmutableSumData.create(
+                true, AggregationTemporality.CUMULATIVE, ImmutableList.of(longPointData)));
+
+    CompletableResultCode result = exporter.export(Collections.singletonList(ignoredData));
+
+    assertThat(result.isSuccess()).isTrue();
+
+    verify(mockMetricServiceStub);
+  }
+
   private static class FakeMetricServiceClient extends MetricServiceClient {
     protected FakeMetricServiceClient(MetricServiceStub stub) {
       super(stub);