test(datastore): update test case to expect 1 NoOp recorder

Author: lqiu96

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

@@ -120,29 +120,38 @@ private static String hashClientUId(String uuid) {
    */
   @Nullable
   public OpenTelemetry createOpenTelemetry(@Nonnull DatastoreOptions options) {
-    Credentials credentials = options.getCredentials();
+    Credentials credentials =
+        Preconditions.checkNotNull(
+            options.getCredentials(), "Credentials cannot be null for built in metrics");
     String projectId = options.getProjectId();
     String databaseId = options.getDatabaseId();
-    Preconditions.checkNotNull(credentials, "Credentials cannot be null for built in metrics");
-    SdkMeterProviderBuilder sdkMeterProviderBuilder = SdkMeterProvider.builder();
 
-    Map<String, String> clientAttributes = buildClientAttributes();
+    // No need to send metrics when using an emulator
+    String emulatorHost =
+        System.getProperty(
+            DatastoreOptions.LOCAL_HOST_ENV_VAR,
+            System.getenv(DatastoreOptions.LOCAL_HOST_ENV_VAR));
+    boolean emulatorEnabled = emulatorHost != null && !emulatorHost.isEmpty();
 
+    if (emulatorEnabled) {
+      logger.log(Level.FINE, "Emulator detected in Datastore. Metrics are not being recorded.");
+      return OpenTelemetry.noop();
+    }
     if (credentials instanceof NoCredentials) {
-      logger.log(
-          Level.WARNING,
-          "Built-in metrics exporting is disabled when using NoCredentials (emulator).");
-      return null;
+      logger.log(Level.WARNING, "Built-in metrics exporting is disabled when using NoCredentials.");
+      return OpenTelemetry.noop();
     }
 
+    SdkMeterProviderBuilder sdkMeterProviderBuilder = SdkMeterProvider.builder();
+    Map<String, String> clientAttributes = buildClientAttributes();
     DatastoreCloudMonitoringExporter exporter =
         DatastoreCloudMonitoringExporter.create(
             projectId, databaseId, credentials, clientAttributes);
     if (exporter == null) {
       logger.log(
           Level.WARNING,
           "Built-in metrics exporting is disabled as the exporter could not be created.");
-      return null;
+      return OpenTelemetry.noop();
     }
 
     // Register Datastore-specific views and the PeriodicMetricReader.

java-datastore/google-cloud-datastore/src/test/java/com/google/cloud/datastore/DatastoreImplMetricsTest.java

@@ -25,6 +25,8 @@
 import com.google.cloud.datastore.spi.v1.DatastoreRpc;
 import com.google.cloud.datastore.telemetry.DatastoreMetricsRecorder;
 import com.google.cloud.datastore.telemetry.TelemetryConstants;
+import com.google.cloud.grpc.GrpcTransportOptions;
+import com.google.cloud.http.HttpTransportOptions;
 import com.google.datastore.v1.BeginTransactionRequest;
 import com.google.datastore.v1.BeginTransactionResponse;
 import com.google.datastore.v1.CommitRequest;
@@ -113,9 +115,9 @@ public void setUp() {
                     .build());
 
     if (TelemetryConstants.Transport.GRPC.equals(transport)) {
-      builder.setTransportOptions(com.google.cloud.grpc.GrpcTransportOptions.newBuilder().build());
+      builder.setTransportOptions(GrpcTransportOptions.newBuilder().build());
     } else {
-      builder.setTransportOptions(com.google.cloud.http.HttpTransportOptions.newBuilder().build());
+      builder.setTransportOptions(HttpTransportOptions.newBuilder().build());
     }
 
     DatastoreOptions datastoreOptions = builder.build();

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

@@ -46,15 +46,15 @@ public void testBuildClientAttributes() {
   }
 
   @Test
-  public void testCreateOpenTelemetry_returnsNull() {
+  public void testCreateOpenTelemetry_returnsNoOp() {
     DatastoreOptions options =
         DatastoreOptions.newBuilder()
             .setProjectId(PROJECT_ID)
             .setDatabaseId("test-db")
             .setCredentials(NoCredentials.getInstance())
             .build();
     OpenTelemetry otel = BuiltInDatastoreMetricsProvider.INSTANCE.createOpenTelemetry(options);
-    assertThat(otel).isNull();
+    assertThat(otel).isInstanceOf(OpenTelemetry.noop().getClass());
   }
 
   @Test
@@ -120,4 +120,17 @@ public void testCreateOpenTelemetry_eachCallReturnsDistinctInstance() {
       }
     }
   }
+
+  @Test
+  public void testCreateOpenTelemetry_withEmulatorHostProperty_returnsNoOp() {
+    System.setProperty(DatastoreOptions.LOCAL_HOST_ENV_VAR, "localhost:8081");
+    try {
+      DatastoreOptions options =
+          DatastoreOptions.newBuilder().setProjectId(PROJECT_ID).setDatabaseId("test-db").build();
+      OpenTelemetry otel = BuiltInDatastoreMetricsProvider.INSTANCE.createOpenTelemetry(options);
+      assertThat(otel).isInstanceOf(OpenTelemetry.noop().getClass());
+    } finally {
+      System.clearProperty(DatastoreOptions.LOCAL_HOST_ENV_VAR);
+    }
+  }
 }

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

@@ -88,14 +88,16 @@ public void defaultOptionsWithBuiltInMetricsEnabled_butNoCredentials_returnsNoRe
                     .setExportBuiltinMetricsToGoogleCloudMonitoring(true)
                     .build())
             .build();
-    DatastoreMetricsRecorder recorder = DatastoreMetricsRecorder.getInstance(options, null);
+    DatastoreMetricsRecorder recorder =
+        DatastoreMetricsRecorder.getInstance(options, OpenTelemetry.noop());
 
-    // Since baseOptions() uses NoCredentials, it should not have any recorders
-    // as we don't want to send metrics for local emulator logic.
+    // Since baseOptions() uses NoCredentials, the provider returns OpenTelemetry.noop().
+    // This NoOp instance is passed to getInstance, which adds it to the recorders list.
+    // So we have 1 recorder (the NoOp one).
     assertThat(recorder).isInstanceOf(CompositeDatastoreMetricsRecorder.class);
     CompositeDatastoreMetricsRecorder compositeRecorder =
         (CompositeDatastoreMetricsRecorder) recorder;
-    assertThat(compositeRecorder.getMetricRecorders().size()).isEqualTo(0);
+    assertThat(compositeRecorder.getMetricRecorders().size()).isEqualTo(1);
   }
 
   @Test