refactor(metrics): Make MetricUtils.registry non-nullable

- Make MetricUtils.registry non-nullable with default no-op implementation. This allows us to remove boilerplate for handling the null case
- Rename request context metric names to follow convention

datahub-graphql-core/src/main/java/com/linkedin/datahub/graphql/GraphQLEngine.java

@@ -87,13 +87,9 @@ public class GraphQLEngine {
             graphQLQueryComplexityLimit, new DataHubFieldComplexityCalculator()));
 
     if (metricUtils != null && graphQLConfiguration.getMetrics().isEnabled()) {
-      metricUtils
+      instrumentations.add(
-          .getRegistry()
+          new GraphQLTimingInstrumentation(
-          .ifPresent(
+              metricUtils.getRegistry(), graphQLConfiguration.getMetrics()));
-              meterRegistry ->
-                  instrumentations.add(
-                      new GraphQLTimingInstrumentation(
-                          meterRegistry, graphQLConfiguration.getMetrics())));
     }
 
     ChainedInstrumentation chainedInstrumentation = new ChainedInstrumentation(instrumentations);

datahub-graphql-core/src/test/java/com/linkedin/datahub/graphql/GraphQLEngineTest.java

@@ -284,7 +284,7 @@ public class GraphQLEngineTest {
   public void testMetricsEnabled() {
     // Setup metrics
     MeterRegistry meterRegistry = new SimpleMeterRegistry();
-    when(mockMetricUtils.getRegistry()).thenReturn(Optional.of(meterRegistry));
+    when(mockMetricUtils.getRegistry()).thenReturn(meterRegistry);
 
     // Enable metrics in configuration
     GraphQLConfiguration metricsEnabledConfig = createDefaultConfiguration();
@@ -405,7 +405,7 @@ public class GraphQLEngineTest {
     metrics.setTrivialDataFetchersEnabled(true);
 
     MeterRegistry meterRegistry = new SimpleMeterRegistry();
-    when(mockMetricUtils.getRegistry()).thenReturn(Optional.of(meterRegistry));
+    when(mockMetricUtils.getRegistry()).thenReturn(meterRegistry);
 
     graphQLEngine =
         GraphQLEngine.builder()
@@ -457,7 +457,7 @@ public class GraphQLEngineTest {
   @Test
   public void testMetricsWithEmptyRegistry() {
     // Setup metrics with empty registry
-    when(mockMetricUtils.getRegistry()).thenReturn(Optional.empty());
+    when(mockMetricUtils.getRegistry()).thenReturn(new SimpleMeterRegistry());
 
     GraphQLConfiguration metricsEnabledConfig = createDefaultConfiguration();
     metricsEnabledConfig.getMetrics().setEnabled(true);

metadata-io/src/main/java/com/linkedin/metadata/timeseries/elastic/ElasticSearchTimeseriesAspectService.java

@@ -124,7 +124,7 @@ public class ElasticSearchTimeseriesAspectService
             new ThreadPoolExecutor.CallerRunsPolicy());
     if (metricUtils != null) {
       MicrometerMetricsRegistry.registerExecutorMetrics(
-          "timeseries", this.queryPool, metricUtils.getRegistry().orElse(null));
+          "timeseries", this.queryPool, metricUtils.getRegistry());
     }
 
     this.entityRegistry = entityRegistry;

metadata-io/src/test/java/com/linkedin/metadata/system_telemetry/GraphQLTimingInstrumentationTest.java

@@ -30,7 +30,6 @@ import io.micrometer.core.instrument.Timer;
 import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
 import java.util.Collections;
 import java.util.Map;
-import java.util.Optional;
 import java.util.concurrent.CompletableFuture;
 import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
@@ -97,7 +96,7 @@ public class GraphQLTimingInstrumentationTest {
 
     // Setup real GraphQL configuration for GraphQLEngine
     graphQLConfiguration = createDefaultConfiguration();
-    when(mockMetricUtils.getRegistry()).thenReturn(Optional.of(meterRegistry));
+    when(mockMetricUtils.getRegistry()).thenReturn(meterRegistry);
   }
 
   @Test

metadata-jobs/common/src/main/java/com/linkedin/metadata/kafka/listener/AbstractKafkaListener.java

@@ -69,17 +69,13 @@ public abstract class AbstractKafkaListener<E, H extends EventHook<E>, R>
                 // TODO: include priority level when available
                 metricUtils
                     .getRegistry()
-                    .ifPresent(
+                    .timer(
-                        meterRegistry -> {
+                        MetricUtils.KAFKA_MESSAGE_QUEUE_TIME,
-                          meterRegistry
+                        "topic",
-                              .timer(
+                        consumerRecord.topic(),
-                                  MetricUtils.KAFKA_MESSAGE_QUEUE_TIME,
+                        "consumer.group",
-                                  "topic",
+                        consumerGroupId)
-                                  consumerRecord.topic(),
+                    .record(Duration.ofMillis(queueTimeMs));
-                                  "consumer.group",
-                                  consumerGroupId)
-                              .record(Duration.ofMillis(queueTimeMs));
-                        });
               });
       final R record = consumerRecord.value();
       log.debug(

metadata-jobs/mae-consumer/src/main/java/com/linkedin/metadata/kafka/DataHubUsageEventsProcessor.java

@@ -76,17 +76,13 @@ public class DataHubUsageEventsProcessor {
                     // TODO: include priority level when available
                     metricUtils
                         .getRegistry()
-                        .ifPresent(
+                        .timer(
-                            meterRegistry -> {
+                            MetricUtils.KAFKA_MESSAGE_QUEUE_TIME,
-                              meterRegistry
+                            "topic",
-                                  .timer(
+                            consumerRecord.topic(),
-                                      MetricUtils.KAFKA_MESSAGE_QUEUE_TIME,
+                            "consumer.group",
-                                      "topic",
+                            datahubUsageEventConsumerGroupId)
-                                      consumerRecord.topic(),
+                        .record(Duration.ofMillis(queueTimeMs));
-                                      "consumer.group",
-                                      datahubUsageEventConsumerGroupId)
-                                  .record(Duration.ofMillis(queueTimeMs));
-                            });
                   });
           final String record = consumerRecord.value();
 

metadata-jobs/mae-consumer/src/main/java/com/linkedin/metadata/kafka/listener/mcl/MCLKafkaListener.java

@@ -118,12 +118,8 @@ public class MCLKafkaListener
                 // request
                 metricUtils
                     .getRegistry()
-                    .ifPresent(
+                    .timer(MetricUtils.DATAHUB_REQUEST_HOOK_QUEUE_TIME, "hook", hookName)
-                        meterRegistry -> {
+                    .record(Duration.ofMillis(queueTimeMs));
-                          meterRegistry
-                              .timer(MetricUtils.DATAHUB_REQUEST_HOOK_QUEUE_TIME, "hook", hookName)
-                              .record(Duration.ofMillis(queueTimeMs));
-                        });
               }
             });
   }

metadata-jobs/mae-consumer/src/test/java/com/linkedin/metadata/kafka/DataHubUsageEventsProcessorTest.java

@@ -49,6 +49,8 @@ public class DataHubUsageEventsProcessorTest {
   public void setUp() {
     MockitoAnnotations.openMocks(this);
 
+    when(metricUtils.getRegistry()).thenReturn(new SimpleMeterRegistry());
+
     systemOperationContext =
         TestOperationContexts.Builder.builder()
             .systemTelemetryContextSupplier(
@@ -65,6 +67,8 @@ public class DataHubUsageEventsProcessorTest {
             dataHubUsageEventTransformer,
             systemOperationContext.getSearchContext().getIndexConvention(),
             systemOperationContext);
+    // Set the consumer group ID
+    setConsumerGroupId(processor, "datahub-usage-event-consumer-job-client");
   }
 
   @Test
@@ -346,10 +350,7 @@ public class DataHubUsageEventsProcessorTest {
     SimpleMeterRegistry meterRegistry = new SimpleMeterRegistry();
 
     // Configure the mock metricUtils to return the registry
-    when(metricUtils.getRegistry()).thenReturn(Optional.of(meterRegistry));
+    when(metricUtils.getRegistry()).thenReturn(meterRegistry);
-
-    // Set the consumer group ID via reflection
-    setConsumerGroupId(processor, "datahub-usage-event-consumer-job-client");
 
     // Setup test data
     String eventJson = "{\"type\":\"PageViewEvent\",\"timestamp\":1234567890}";
@@ -397,10 +398,7 @@ public class DataHubUsageEventsProcessorTest {
     SimpleMeterRegistry meterRegistry = new SimpleMeterRegistry();
 
     // Configure the mock metricUtils to return the registry
-    when(metricUtils.getRegistry()).thenReturn(Optional.of(meterRegistry));
+    when(metricUtils.getRegistry()).thenReturn(meterRegistry);
-
-    // Set the consumer group ID
-    setConsumerGroupId(processor, "datahub-usage-event-consumer-job-client");
 
     // Setup test data
     String eventJson = "{\"type\":\"SearchEvent\"}";
@@ -466,10 +464,7 @@ public class DataHubUsageEventsProcessorTest {
     SimpleMeterRegistry meterRegistry = new SimpleMeterRegistry();
 
     // Configure the mock metricUtils to return the registry
-    when(metricUtils.getRegistry()).thenReturn(Optional.of(meterRegistry));
+    when(metricUtils.getRegistry()).thenReturn(meterRegistry);
-
-    // Set the consumer group ID
-    setConsumerGroupId(processor, "datahub-usage-event-consumer-job-client");
 
     // Setup test data
     String eventJson = "{\"invalid\":\"event\"}";
@@ -504,89 +499,13 @@ public class DataHubUsageEventsProcessorTest {
     verify(elasticsearchConnector, never()).feedElasticEvent(any());
   }
 
-  @Test
-  public void testMicrometerMetricsAbsentWhenRegistryNotPresent() {
-    // Configure the mock metricUtils to return empty Optional (no registry)
-    when(metricUtils.getRegistry()).thenReturn(Optional.empty());
-
-    // Set the consumer group ID
-    setConsumerGroupId(processor, "datahub-usage-event-consumer-job-client");
-
-    // Setup test data
-    String eventJson = "{\"type\":\"ViewEvent\"}";
-    String transformedDocument = "{\"view\":\"data\"}";
-
-    when(mockRecord.timestamp()).thenReturn(System.currentTimeMillis() - 1000);
-    when(mockRecord.value()).thenReturn(eventJson);
-
-    DataHubUsageEventTransformer.TransformedDocument transformedDoc =
-        new DataHubUsageEventTransformer.TransformedDocument(TEST_EVENT_ID, transformedDocument);
-
-    when(dataHubUsageEventTransformer.transformDataHubUsageEvent(eventJson))
-        .thenReturn(Optional.of(transformedDoc));
-
-    // Execute - should not throw exception
-    processor.consume(mockRecord);
-
-    // Verify the histogram method was still called (for dropwizard metrics)
-    verify(metricUtils).histogram(eq(DataHubUsageEventsProcessor.class), eq("kafkaLag"), anyLong());
-
-    // Verify processing completed successfully despite no registry
-    verify(elasticsearchConnector).feedElasticEvent(any());
-  }
-
-  @Test
-  public void testMicrometerKafkaQueueTimeWithCustomConsumerGroup() {
-    // Setup a real MeterRegistry
-    SimpleMeterRegistry meterRegistry = new SimpleMeterRegistry();
-
-    // Configure the mock metricUtils to return the registry
-    when(metricUtils.getRegistry()).thenReturn(Optional.of(meterRegistry));
-
-    // Set a custom consumer group ID
-    String customConsumerGroup = "custom-usage-event-consumer";
-    setConsumerGroupId(processor, customConsumerGroup);
-
-    // Setup test data
-    String eventJson = "{\"type\":\"Event\"}";
-    String transformedDocument = "{\"data\":\"value\"}";
-
-    when(mockRecord.timestamp()).thenReturn(System.currentTimeMillis() - 1500);
-    when(mockRecord.topic()).thenReturn("DataHubUsageEvent_v1");
-    when(mockRecord.value()).thenReturn(eventJson);
-
-    DataHubUsageEventTransformer.TransformedDocument transformedDoc =
-        new DataHubUsageEventTransformer.TransformedDocument(TEST_EVENT_ID, transformedDocument);
-
-    when(dataHubUsageEventTransformer.transformDataHubUsageEvent(eventJson))
-        .thenReturn(Optional.of(transformedDoc));
-
-    // Execute
-    processor.consume(mockRecord);
-
-    // Verify timer was recorded with custom consumer group
-    Timer timer =
-        meterRegistry.timer(
-            MetricUtils.KAFKA_MESSAGE_QUEUE_TIME,
-            "topic",
-            "DataHubUsageEvent_v1",
-            "consumer.group",
-            customConsumerGroup);
-
-    assertNotNull(timer);
-    assertEquals(timer.count(), 1);
-  }
-
   @Test
   public void testMicrometerKafkaQueueTimeAccuracy() {
     // Setup a real MeterRegistry
     SimpleMeterRegistry meterRegistry = new SimpleMeterRegistry();
 
     // Configure the mock metricUtils to return the registry
-    when(metricUtils.getRegistry()).thenReturn(Optional.of(meterRegistry));
+    when(metricUtils.getRegistry()).thenReturn(meterRegistry);
-
-    // Set the consumer group ID
-    setConsumerGroupId(processor, "datahub-usage-event-consumer-job-client");
 
     // Setup test data
     String eventJson = "{\"type\":\"Event\"}";

metadata-jobs/mae-consumer/src/test/java/com/linkedin/metadata/kafka/listener/mcl/MCLKafkaListenerTest.java

@@ -64,7 +64,7 @@ public class MCLKafkaListenerTest {
 
     mockSystemMetadata = spy(SystemMetadataUtils.createDefaultSystemMetadata());
     meterRegistry = new SimpleMeterRegistry();
-    when(metricUtils.getRegistry()).thenReturn(Optional.of(meterRegistry));
+    when(metricUtils.getRegistry()).thenReturn(meterRegistry);
 
     systemOperationContext =
         TestOperationContexts.Builder.builder()

metadata-jobs/mce-consumer/src/main/java/com/linkedin/metadata/kafka/MetadataChangeProposalsProcessor.java

@@ -93,17 +93,13 @@ public class MetadataChangeProposalsProcessor {
                 // TODO: include priority level when available
                 metricUtils
                     .getRegistry()
-                    .ifPresent(
+                    .timer(
-                        meterRegistry -> {
+                        MetricUtils.KAFKA_MESSAGE_QUEUE_TIME,
-                          meterRegistry
+                        "topic",
-                              .timer(
+                        consumerRecord.topic(),
-                                  MetricUtils.KAFKA_MESSAGE_QUEUE_TIME,
+                        "consumer.group",
-                                  "topic",
+                        mceConsumerGroupId)
-                                  consumerRecord.topic(),
+                    .record(Duration.ofMillis(queueTimeMs));
-                                  "consumer.group",
-                                  mceConsumerGroupId)
-                              .record(Duration.ofMillis(queueTimeMs));
-                        });
               });
       final GenericRecord record = consumerRecord.value();
 

metadata-jobs/mce-consumer/src/main/java/com/linkedin/metadata/kafka/batch/BatchMetadataChangeProposalsProcessor.java

@@ -95,17 +95,13 @@ public class BatchMetadataChangeProposalsProcessor {
                 // TODO: include priority level when available
                 metricUtils
                     .getRegistry()
-                    .ifPresent(
+                    .timer(
-                        meterRegistry -> {
+                        MetricUtils.KAFKA_MESSAGE_QUEUE_TIME,
-                          meterRegistry
+                        "topic",
-                              .timer(
+                        consumerRecord.topic(),
-                                  MetricUtils.KAFKA_MESSAGE_QUEUE_TIME,
+                        "consumer.group",
-                                  "topic",
+                        mceConsumerGroupId)
-                                  consumerRecord.topic(),
+                    .record(Duration.ofMillis(queueTimeMs));
-                                  "consumer.group",
-                                  mceConsumerGroupId)
-                              .record(Duration.ofMillis(queueTimeMs));
-                        });
               });
       final GenericRecord record = consumerRecord.value();
 

metadata-jobs/mce-consumer/src/test/java/com/linkedin/metadata/kafka/MetadataChangeProposalsProcessorTest.java

@@ -1,7 +1,6 @@
 package com.linkedin.metadata.kafka;
 
 import static org.mockito.ArgumentMatchers.any;
-import static org.mockito.ArgumentMatchers.anyLong;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.mockStatic;
@@ -41,6 +40,7 @@ import com.linkedin.mxe.Topics;
 import io.datahubproject.metadata.context.OperationContext;
 import io.datahubproject.metadata.context.SystemTelemetryContext;
 import io.datahubproject.test.metadata.context.TestOperationContexts;
+import io.micrometer.core.instrument.MeterRegistry;
 import io.micrometer.core.instrument.Timer;
 import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
 import io.opentelemetry.api.trace.Span;
@@ -48,7 +48,6 @@ import io.opentelemetry.api.trace.StatusCode;
 import io.opentelemetry.api.trace.Tracer;
 import java.io.IOException;
 import java.util.List;
-import java.util.Optional;
 import java.util.concurrent.TimeUnit;
 import org.apache.avro.generic.GenericRecord;
 import org.apache.kafka.clients.consumer.ConsumerRecord;
@@ -100,18 +99,18 @@ public class MetadataChangeProposalsProcessorTest {
 
   @Mock private Span mockSpan;
 
-  @Mock private MetricUtils metricUtils;
+  private MetricUtils metricUtils;
 
   private AutoCloseable mocks;
 
   private MockedStatic<Span> spanMock;
-  private MockedStatic<MetricUtils> metricUtilsMock;
   private MockedStatic<EventUtils> eventUtilsMock;
 
   @BeforeMethod
   public void setup() {
     mocks = MockitoAnnotations.openMocks(this);
 
+    metricUtils = MetricUtils.builder().registry(new SimpleMeterRegistry()).build();
     opContext =
         opContext.toBuilder()
             .systemTelemetryContext(
@@ -160,11 +159,6 @@ public class MetadataChangeProposalsProcessorTest {
     spanMock = mockStatic(Span.class);
     spanMock.when(Span::current).thenReturn(mockSpan);
 
-    metricUtilsMock = mockStatic(MetricUtils.class);
-    metricUtilsMock
-        .when(() -> MetricUtils.name(eq(MetadataChangeProposalsProcessor.class), any()))
-        .thenReturn("metricName");
-
     eventUtilsMock = mockStatic(EventUtils.class);
 
     // Setup consumer record mock
@@ -185,11 +179,6 @@ public class MetadataChangeProposalsProcessorTest {
       spanMock = null; // Set to null after closing
     }
 
-    if (metricUtilsMock != null) {
-      metricUtilsMock.close();
-      metricUtilsMock = null; // Set to null after closing
-    }
-
     if (eventUtilsMock != null) {
       eventUtilsMock.close();
       eventUtilsMock = null; // Set to null after closing
@@ -344,11 +333,7 @@ public class MetadataChangeProposalsProcessorTest {
 
   @Test
   public void testMicrometerKafkaQueueTimeMetric() throws Exception {
-    // Setup a real MeterRegistry
+    MeterRegistry meterRegistry = metricUtils.getRegistry();
-    SimpleMeterRegistry meterRegistry = new SimpleMeterRegistry();
-
-    // Configure the mock metricUtils to return the registry
-    when(metricUtils.getRegistry()).thenReturn(Optional.of(meterRegistry));
 
     // Set timestamp to simulate queue time
     long messageTimestamp = System.currentTimeMillis() - 3000; // 3 seconds ago
@@ -376,21 +361,13 @@ public class MetadataChangeProposalsProcessorTest {
     assertTrue(timer.totalTime(TimeUnit.MILLISECONDS) >= 2500); // At least 2.5 seconds
     assertTrue(timer.totalTime(TimeUnit.MILLISECONDS) <= 3500); // At most 3.5 seconds
 
-    // Verify the histogram method was called
-    verify(metricUtils)
-        .histogram(eq(MetadataChangeProposalsProcessor.class), eq("kafkaLag"), anyLong());
-
     // Verify successful processing
     verify(mockEntityService).ingestProposal(eq(opContext), any(), eq(false));
   }
 
   @Test
   public void testMicrometerKafkaQueueTimeWithDifferentTopics() throws Exception {
-    // Setup a real MeterRegistry
+    MeterRegistry meterRegistry = metricUtils.getRegistry();
-    SimpleMeterRegistry meterRegistry = new SimpleMeterRegistry();
-
-    // Configure the mock metricUtils to return the registry
-    when(metricUtils.getRegistry()).thenReturn(Optional.of(meterRegistry));
 
     // Create MCP
     MetadataChangeProposal mcp = createSimpleMCP();
@@ -448,11 +425,7 @@ public class MetadataChangeProposalsProcessorTest {
 
   @Test
   public void testMicrometerMetricsWithProcessingFailure() throws Exception {
-    // Setup a real MeterRegistry
+    MeterRegistry meterRegistry = metricUtils.getRegistry();
-    SimpleMeterRegistry meterRegistry = new SimpleMeterRegistry();
-
-    // Configure the mock metricUtils to return the registry
-    when(metricUtils.getRegistry()).thenReturn(Optional.of(meterRegistry));
 
     // Create MCP that will fail
     MetadataChangeProposal mcp = new MetadataChangeProposal();
@@ -492,9 +465,6 @@ public class MetadataChangeProposalsProcessorTest {
 
   @Test
   public void testMicrometerMetricsAbsentWhenRegistryNotPresent() throws Exception {
-    // Configure the mock metricUtils to return empty Optional (no registry)
-    when(metricUtils.getRegistry()).thenReturn(Optional.empty());
-
     // Create MCP
     MetadataChangeProposal mcp = createSimpleMCP();
     eventUtilsMock.when(() -> EventUtils.avroToPegasusMCP(mockRecord)).thenReturn(mcp);
@@ -504,21 +474,13 @@ public class MetadataChangeProposalsProcessorTest {
     // Execute - should not throw exception
     processor.consume(mockConsumerRecord);
 
-    // Verify the histogram method was still called (for dropwizard metrics)
-    verify(metricUtils)
-        .histogram(eq(MetadataChangeProposalsProcessor.class), eq("kafkaLag"), anyLong());
-
     // Verify processing completed successfully despite no registry
     verify(mockEntityService).ingestProposal(eq(opContext), any(), eq(false));
   }
 
   @Test
   public void testMicrometerKafkaQueueTimeAccuracy() throws Exception {
-    // Setup a real MeterRegistry
+    MeterRegistry meterRegistry = metricUtils.getRegistry();
-    SimpleMeterRegistry meterRegistry = new SimpleMeterRegistry();
-
-    // Configure the mock metricUtils to return the registry
-    when(metricUtils.getRegistry()).thenReturn(Optional.of(meterRegistry));
 
     // Create MCP
     MetadataChangeProposal mcp = createSimpleMCP();
@@ -562,10 +524,6 @@ public class MetadataChangeProposalsProcessorTest {
     // Verify max recorded time
     assertTrue(timer.max(TimeUnit.MILLISECONDS) >= 4500);
     assertTrue(timer.max(TimeUnit.MILLISECONDS) <= 5500);
-
-    // Verify histogram was called for each record
-    verify(metricUtils, times(queueTimes.length))
-        .histogram(eq(MetadataChangeProposalsProcessor.class), eq("kafkaLag"), anyLong());
   }
 
   @Test
@@ -598,10 +556,6 @@ public class MetadataChangeProposalsProcessorTest {
 
     // Verify processing completed successfully
     verify(mockEntityService).ingestProposal(eq(opContextNoMetrics), any(), eq(false));
-
-    // Verify metricUtils methods were never called since it's not present in context
-    verify(metricUtils, never()).histogram(any(), any(), anyLong());
-    verify(metricUtils, never()).getRegistry();
   }
 
   // Helper method

metadata-jobs/mce-consumer/src/test/java/com/linkedin/metadata/kafka/batch/BatchMetadataChangeProposalsProcessorTest.java

@@ -557,6 +557,7 @@ public class BatchMetadataChangeProposalsProcessorTest {
   public void testConsumeWithTelemetryMetrics() throws Exception {
     // Mock the metric utils
     MetricUtils mockMetricUtils = mock(MetricUtils.class);
+    when(mockMetricUtils.getRegistry()).thenReturn(new SimpleMeterRegistry());
 
     // Create a mock operation context
     OperationContext opContextWithMetrics = spy(opContext);
@@ -856,12 +857,12 @@ public class BatchMetadataChangeProposalsProcessorTest {
 
   @Test
   public void testMicrometerMetricsAbsentWhenRegistryNotPresent() throws Exception {
-    // Create MetricUtils without a registry
+    // With the new non-null contract, we can't create MetricUtils with null registry
-    MetricUtils metricUtilsNoRegistry = MetricUtils.builder().registry(null).build();
+    // Instead, test the case where MetricUtils is absent from OperationContext
 
-    // Create operation context with metric utils that has no registry
+    // Create operation context without metric utils
     OperationContext opContextNoRegistry = mock(OperationContext.class);
-    when(opContextNoRegistry.getMetricUtils()).thenReturn(Optional.of(metricUtilsNoRegistry));
+    when(opContextNoRegistry.getMetricUtils()).thenReturn(Optional.empty());
 
     // Mock withQueueSpan
     doAnswer(

metadata-jobs/pe-consumer/src/main/java/com/datahub/event/PlatformEventProcessor.java

@@ -82,17 +82,13 @@ public class PlatformEventProcessor {
                     // TODO: include priority level when available
                     metricUtils
                         .getRegistry()
-                        .ifPresent(
+                        .timer(
-                            meterRegistry -> {
+                            MetricUtils.KAFKA_MESSAGE_QUEUE_TIME,
-                              meterRegistry
+                            "topic",
-                                  .timer(
+                            consumerRecord.topic(),
-                                      MetricUtils.KAFKA_MESSAGE_QUEUE_TIME,
+                            "consumer.group",
-                                      "topic",
+                            datahubPlatformEventConsumerGroupId)
-                                      consumerRecord.topic(),
+                        .record(Duration.ofMillis(queueTimeMs));
-                                      "consumer.group",
-                                      datahubPlatformEventConsumerGroupId)
-                                  .record(Duration.ofMillis(queueTimeMs));
-                            });
                   });
           final GenericRecord record = consumerRecord.value();
           log.info(

metadata-jobs/pe-consumer/src/test/java/com/datahub/event/PlatformEventProcessorTest.java

@@ -62,6 +62,7 @@ public class PlatformEventProcessorTest {
 
     // Create mock MetricUtils
     mockMetricUtils = mock(MetricUtils.class);
+    when(mockMetricUtils.getRegistry()).thenReturn(new SimpleMeterRegistry());
     when(mockOperationContext.getMetricUtils()).thenReturn(Optional.of(mockMetricUtils));
 
     // Create mock hooks
@@ -133,6 +134,8 @@ public class PlatformEventProcessorTest {
     // Setup
     List<PlatformEventHook> hooks = Arrays.asList(mockHook1, mockHook2);
     processor = new PlatformEventProcessor(mockOperationContext, hooks);
+    // Set the consumer group ID
+    setConsumerGroupId(processor, "generic-platform-event-job-client");
 
     try (MockedStatic<EventUtils> mockedEventUtils = Mockito.mockStatic(EventUtils.class)) {
       mockedEventUtils
@@ -161,6 +164,8 @@ public class PlatformEventProcessorTest {
     // Setup
     List<PlatformEventHook> hooks = Arrays.asList(mockHook1);
     processor = new PlatformEventProcessor(mockOperationContext, hooks);
+    // Set the consumer group ID
+    setConsumerGroupId(processor, "generic-platform-event-job-client");
 
     try (MockedStatic<EventUtils> mockedEventUtils = Mockito.mockStatic(EventUtils.class)) {
       mockedEventUtils
@@ -189,6 +194,8 @@ public class PlatformEventProcessorTest {
     // Setup
     List<PlatformEventHook> hooks = Arrays.asList(mockHook1, mockHook2);
     processor = new PlatformEventProcessor(mockOperationContext, hooks);
+    // Set the consumer group ID
+    setConsumerGroupId(processor, "generic-platform-event-job-client");
 
     // Make first hook throw exception
     doThrow(new RuntimeException("Hook 1 failed"))
@@ -224,6 +231,8 @@ public class PlatformEventProcessorTest {
     // Setup
     List<PlatformEventHook> hooks = Arrays.asList(mockHook1, mockHook2);
     processor = new PlatformEventProcessor(mockOperationContext, hooks);
+    // Set the consumer group ID
+    setConsumerGroupId(processor, "generic-platform-event-job-client");
 
     // Make both hooks throw exceptions
     doThrow(new RuntimeException("Hook 1 failed"))
@@ -283,6 +292,8 @@ public class PlatformEventProcessorTest {
     // Setup
     List<PlatformEventHook> hooks = Arrays.asList(mockHook1);
     processor = new PlatformEventProcessor(mockOperationContext, hooks);
+    // Set the consumer group ID
+    setConsumerGroupId(processor, "generic-platform-event-job-client");
 
     // Set up specific consumer record values
     String expectedKey = "test-key-123";
@@ -321,7 +332,8 @@ public class PlatformEventProcessorTest {
       // Verify that the consumer record methods were called
       // Note: some methods may be called multiple times (e.g., for logging and metrics)
       verify(specificMockRecord, times(1)).key();
-      verify(specificMockRecord, times(1)).topic();
+      verify(specificMockRecord, times(2))
+          .topic(); // Called twice: once for metrics, once for logging
       verify(specificMockRecord, times(1)).partition();
       verify(specificMockRecord, times(1)).offset();
       verify(specificMockRecord, times(2))
@@ -336,6 +348,8 @@ public class PlatformEventProcessorTest {
     // Setup
     List<PlatformEventHook> hooks = Arrays.asList(mockHook1);
     processor = new PlatformEventProcessor(mockOperationContext, hooks);
+    // Set the consumer group ID
+    setConsumerGroupId(processor, "generic-platform-event-job-client");
 
     PlatformEvent event1 = mock(PlatformEvent.class);
     when(event1.getName()).thenReturn("Event1");
@@ -389,6 +403,8 @@ public class PlatformEventProcessorTest {
     // Setup
     List<PlatformEventHook> hooks = Arrays.asList(mockHook1);
     processor = new PlatformEventProcessor(mockOperationContext, hooks);
+    // Set the consumer group ID
+    setConsumerGroupId(processor, "generic-platform-event-job-client");
 
     ConsumerRecord<String, GenericRecord> nullValueRecord = mock(ConsumerRecord.class);
     when(nullValueRecord.value()).thenReturn(null);
@@ -422,7 +438,7 @@ public class PlatformEventProcessorTest {
     SimpleMeterRegistry meterRegistry = new SimpleMeterRegistry();
 
     // Configure the mock metricUtils to return the registry
-    when(mockMetricUtils.getRegistry()).thenReturn(Optional.of(meterRegistry));
+    when(mockMetricUtils.getRegistry()).thenReturn(meterRegistry);
 
     // Set the consumer group ID via reflection
     setConsumerGroupId(processor, "generic-platform-event-job-client");
@@ -469,7 +485,7 @@ public class PlatformEventProcessorTest {
     SimpleMeterRegistry meterRegistry = new SimpleMeterRegistry();
 
     // Configure the mock metricUtils to return the registry
-    when(mockMetricUtils.getRegistry()).thenReturn(Optional.of(meterRegistry));
+    when(mockMetricUtils.getRegistry()).thenReturn(meterRegistry);
 
     // Set the consumer group ID
     setConsumerGroupId(processor, "generic-platform-event-job-client");
@@ -534,7 +550,7 @@ public class PlatformEventProcessorTest {
     SimpleMeterRegistry meterRegistry = new SimpleMeterRegistry();
 
     // Configure the mock metricUtils to return the registry
-    when(mockMetricUtils.getRegistry()).thenReturn(Optional.of(meterRegistry));
+    when(mockMetricUtils.getRegistry()).thenReturn(meterRegistry);
 
     // Set the consumer group ID
     setConsumerGroupId(processor, "generic-platform-event-job-client");
@@ -578,7 +594,7 @@ public class PlatformEventProcessorTest {
   @Test
   public void testMicrometerMetricsAbsentWhenRegistryNotPresent() throws Exception {
     // Configure the mock metricUtils to return empty Optional (no registry)
-    when(mockMetricUtils.getRegistry()).thenReturn(Optional.empty());
+    when(mockMetricUtils.getRegistry()).thenReturn(new SimpleMeterRegistry());
 
     // Set the consumer group ID
     setConsumerGroupId(processor, "generic-platform-event-job-client");
@@ -608,7 +624,7 @@ public class PlatformEventProcessorTest {
     SimpleMeterRegistry meterRegistry = new SimpleMeterRegistry();
 
     // Configure the mock metricUtils to return the registry
-    when(mockMetricUtils.getRegistry()).thenReturn(Optional.of(meterRegistry));
+    when(mockMetricUtils.getRegistry()).thenReturn(meterRegistry);
 
     // Set a custom consumer group ID
     String customConsumerGroup = "custom-platform-event-consumer";
@@ -645,7 +661,7 @@ public class PlatformEventProcessorTest {
     SimpleMeterRegistry meterRegistry = new SimpleMeterRegistry();
 
     // Configure the mock metricUtils to return the registry
-    when(mockMetricUtils.getRegistry()).thenReturn(Optional.of(meterRegistry));
+    when(mockMetricUtils.getRegistry()).thenReturn(meterRegistry);
 
     // Set the consumer group ID
     setConsumerGroupId(processor, "generic-platform-event-job-client");
@@ -705,7 +721,7 @@ public class PlatformEventProcessorTest {
     SimpleMeterRegistry meterRegistry = new SimpleMeterRegistry();
 
     // Configure the mock metricUtils to return the registry
-    when(mockMetricUtils.getRegistry()).thenReturn(Optional.of(meterRegistry));
+    when(mockMetricUtils.getRegistry()).thenReturn(meterRegistry);
 
     // Set the consumer group ID
     setConsumerGroupId(processor, "generic-platform-event-job-client");

metadata-operation-context/src/main/java/io/datahubproject/metadata/context/RequestContext.java

@@ -275,11 +275,11 @@ public class RequestContext implements ContextInterface {
       metricUtils.incrementMicrometer(
           MetricUtils.DATAHUB_REQUEST_COUNT,
           1,
-          "user.category",
+          "user_category",
           userCategory,
-          "agent.class",
+          "agent_class",
           agentClass,
-          "request.api",
+          "request_api",
           requestAPI);
     }
   }

metadata-operation-context/src/test/java/io/datahubproject/metadata/context/RequestContextTest.java

@@ -278,13 +278,13 @@ public class RequestContextTest {
 
     verify(mockMetricUtils, atLeastOnce())
         .incrementMicrometer(
-            eq("datahub.request.count"),
+            eq(MetricUtils.DATAHUB_REQUEST_COUNT),
             eq(1.0d),
-            eq("user.category"),
+            eq("user_category"),
             eq("system"),
-            eq("agent.class"),
+            eq("agent_class"),
             eq("unknown"),
-            eq("request.api"),
+            eq("request_api"),
             eq("restli"));
   }
 
@@ -303,13 +303,13 @@ public class RequestContextTest {
 
     verify(mockMetricUtils, atLeastOnce())
         .incrementMicrometer(
-            eq("datahub.request.count"),
+            eq(MetricUtils.DATAHUB_REQUEST_COUNT),
             eq(1.0d),
-            eq("user.category"),
+            eq("user_category"),
             eq("admin"),
-            eq("agent.class"),
+            eq("agent_class"),
             eq("unknown"),
-            eq("request.api"),
+            eq("request_api"),
             eq("restli"));
   }
 
@@ -328,13 +328,13 @@ public class RequestContextTest {
 
     verify(mockMetricUtils, atLeastOnce())
         .incrementMicrometer(
-            eq("datahub.request.count"),
+            eq(MetricUtils.DATAHUB_REQUEST_COUNT),
             eq(1.0d),
-            eq("user.category"),
+            eq("user_category"),
             eq("regular"),
-            eq("agent.class"),
+            eq("agent_class"),
             eq("unknown"),
-            eq("request.api"),
+            eq("request_api"),
             eq("restli"));
   }
 

metadata-service/factories/src/main/java/com/linkedin/gms/factory/graphql/GraphQLEngineFactory.java

@@ -317,7 +317,7 @@ public class GraphQLEngineFactory {
         GraphQLConcurrencyUtils.setExecutorService(graphQLWorkerPool);
     if (metricUtils != null) {
       MicrometerMetricsRegistry.registerExecutorMetrics(
-          "graphql", graphqlExecutorService, metricUtils.getRegistry().orElse(null));
+          "graphql", graphqlExecutorService, metricUtils.getRegistry());
     }
 
     return graphQLWorkerPool;

metadata-service/factories/src/main/java/com/linkedin/gms/factory/kafka/trace/KafkaTraceReaderFactory.java

@@ -86,7 +86,7 @@ public class KafkaTraceReaderFactory {
     traceExecutorService = Executors.newFixedThreadPool(threadPoolSize);
     if (metricUtils != null) {
       MicrometerMetricsRegistry.registerExecutorMetrics(
-          "api-trace", this.traceExecutorService, metricUtils.getRegistry().orElse(null));
+          "api-trace", this.traceExecutorService, metricUtils.getRegistry());
     }
     return traceExecutorService;
   }

metadata-service/factories/src/test/java/com/linkedin/gms/factory/graphql/GraphQLEngineFactoryTest.java

@@ -41,6 +41,7 @@ import io.datahubproject.metadata.context.SystemTelemetryContext;
 import io.datahubproject.metadata.services.RestrictedService;
 import io.datahubproject.metadata.services.SecretService;
 import io.datahubproject.test.metadata.context.TestOperationContexts;
+import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
 import io.opentelemetry.api.trace.Tracer;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.ThreadPoolExecutor;
@@ -261,7 +262,7 @@ public class GraphQLEngineFactoryTest extends AbstractTestNGSpringContextTests {
   public void setUp() {
     // Set up default mock behaviors
     when(graphService.supportsMultiHop()).thenReturn(true);
-    when(metricUtils.getRegistry()).thenReturn(java.util.Optional.empty());
+    when(metricUtils.getRegistry()).thenReturn(new SimpleMeterRegistry());
   }
 
   @Test

metadata-service/restli-client-api/src/main/java/com/linkedin/common/client/ClientCache.java

@@ -109,7 +109,7 @@ public class ClientCache<K, V, C extends ClientCacheConfig> {
 
       if (config.isStatsEnabled() && metricUtils != null) {
         MicrometerMetricsRegistry.registerCacheMetrics(
-            config.getName(), cache, metricUtils.getRegistry().orElse(null));
+            config.getName(), cache, metricUtils.getRegistry());
       }
 
       return new ClientCache<>(config, cache, loadFunction, weigher, ttlSecondsFunction);

metadata-service/restli-client/src/main/java/com/linkedin/entity/client/RestliEntityClient.java

@@ -145,7 +145,7 @@ public class RestliEntityClient extends BaseClient implements EntityClient {
             new ThreadPoolExecutor.CallerRunsPolicy());
     if (metricUtils != null) {
       MicrometerMetricsRegistry.registerExecutorMetrics(
-          "entity-client-get", this.batchGetV2Pool, metricUtils.getRegistry().orElse(null));
+          "entity-client-get", this.batchGetV2Pool, metricUtils.getRegistry());
     }
     this.batchIngestPool =
         new ThreadPoolExecutor(
@@ -158,7 +158,7 @@ public class RestliEntityClient extends BaseClient implements EntityClient {
             new ThreadPoolExecutor.CallerRunsPolicy());
     if (metricUtils != null) {
       MicrometerMetricsRegistry.registerExecutorMetrics(
-          "entity-client-ingest", this.batchIngestPool, metricUtils.getRegistry().orElse(null));
+          "entity-client-ingest", this.batchIngestPool, metricUtils.getRegistry());
     }
   }
 

metadata-service/restli-client/src/test/java/com/linkedin/common/client/BaseClientTest.java

@@ -63,6 +63,7 @@ import com.linkedin.restli.client.RestLiResponseException;
 import com.linkedin.restli.client.response.BatchKVResponse;
 import io.datahubproject.metadata.context.OperationContext;
 import io.datahubproject.test.metadata.context.TestOperationContexts;
+import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
 import java.net.URISyntaxException;
 import java.util.Arrays;
 import java.util.Collections;
@@ -98,7 +99,7 @@ public class BaseClientTest {
 
     // Setup MetricUtils mock
     mockMetricUtils = mock(MetricUtils.class);
-    when(mockMetricUtils.getRegistry()).thenReturn(Optional.empty());
+    when(mockMetricUtils.getRegistry()).thenReturn(new SimpleMeterRegistry());
   }
 
   @Test

metadata-utils/src/main/java/com/linkedin/metadata/utils/metrics/MetricUtils.java

@@ -7,11 +7,12 @@ import io.micrometer.core.instrument.DistributionSummary;
 import io.micrometer.core.instrument.Gauge;
 import io.micrometer.core.instrument.MeterRegistry;
 import io.micrometer.core.instrument.Timer;
+import io.micrometer.core.instrument.composite.CompositeMeterRegistry;
 import java.util.Map;
-import java.util.Optional;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.TimeUnit;
 import lombok.Builder;
+import lombok.NonNull;
 import lombok.extern.slf4j.Slf4j;
 
 @Slf4j
@@ -21,10 +22,10 @@ public class MetricUtils {
   public static final String DROPWIZARD_METRIC = "dwizMetric";
   public static final String DROPWIZARD_NAME = "dwizName";
 
-  /* Micrometer */
+  /* Micrometer. See https://prometheus.io/docs/practices/naming/ */
   public static final String KAFKA_MESSAGE_QUEUE_TIME = "kafka.message.queue.time";
   public static final String DATAHUB_REQUEST_HOOK_QUEUE_TIME = "datahub.request.hook.queue.time";
-  public static final String DATAHUB_REQUEST_COUNT = "datahub.request.count";
+  public static final String DATAHUB_REQUEST_COUNT = "datahub_request_count";
 
   /* OpenTelemetry */
   public static final String CACHE_HIT_ATTR = "cache.hit";
@@ -42,7 +43,7 @@ public class MetricUtils {
 
   @Deprecated public static final String DELIMITER = "_";
 
-  private final MeterRegistry registry;
+  @Builder.Default @NonNull private final MeterRegistry registry = new CompositeMeterRegistry();
   private static final Map<String, Timer> legacyTimeCache = new ConcurrentHashMap<>();
   private static final Map<String, Counter> legacyCounterCache = new ConcurrentHashMap<>();
   private static final Map<String, DistributionSummary> legacyHistogramCache =
@@ -52,24 +53,17 @@ public class MetricUtils {
   // For state-based gauges (like throttled state)
   private static final Map<String, AtomicDouble> gaugeStates = new ConcurrentHashMap<>();
 
-  public Optional<MeterRegistry> getRegistry() {
+  public MeterRegistry getRegistry() {
-    return Optional.ofNullable(registry);
+    return registry;
   }
 
   @Deprecated
   public void time(String dropWizardMetricName, long durationNanos) {
-    getRegistry()
+    Timer timer =
-        .ifPresent(
+        legacyTimeCache.computeIfAbsent(
-            meterRegistry -> {
+            dropWizardMetricName,
-              Timer timer =
+            name -> Timer.builder(name).tags(DROPWIZARD_METRIC, "true").register(registry));
-                  legacyTimeCache.computeIfAbsent(
+    timer.record(durationNanos, TimeUnit.NANOSECONDS);
-                      dropWizardMetricName,
-                      name ->
-                          Timer.builder(name)
-                              .tags(DROPWIZARD_METRIC, "true")
-                              .register(meterRegistry));
-              timer.record(durationNanos, TimeUnit.NANOSECONDS);
-            });
   }
 
   @Deprecated
@@ -90,18 +84,14 @@ public class MetricUtils {
 
   @Deprecated
   public void increment(String metricName, double increment) {
-    getRegistry()
+    Counter counter =
-        .ifPresent(
+        legacyCounterCache.computeIfAbsent(
-            meterRegistry -> {
+            metricName,
-              Counter counter =
+            name ->
-                  legacyCounterCache.computeIfAbsent(
+                Counter.builder(MetricRegistry.name(name))
-                      metricName,
+                    .tag(DROPWIZARD_METRIC, "true")
-                      name ->
+                    .register(registry));
-                          Counter.builder(MetricRegistry.name(name))
+    counter.increment(increment);
-                              .tag(DROPWIZARD_METRIC, "true")
-                              .register(meterRegistry));
-              counter.increment(increment);
-            });
   }
 
   /**
@@ -112,16 +102,11 @@ public class MetricUtils {
    * @param tags The tags to associate with the metric (can be empty)
    */
   public void incrementMicrometer(String metricName, double increment, String... tags) {
-    getRegistry()
+    // Create a cache key that includes both metric name and tags
-        .ifPresent(
+    String cacheKey = createCacheKey(metricName, tags);
-            meterRegistry -> {
+    Counter counter =
-              // Create a cache key that includes both metric name and tags
+        micrometerCounterCache.computeIfAbsent(cacheKey, key -> registry.counter(metricName, tags));
-              String cacheKey = createCacheKey(metricName, tags);
+    counter.increment(increment);
-              Counter counter =
-                  micrometerCounterCache.computeIfAbsent(
-                      cacheKey, key -> meterRegistry.counter(metricName, tags));
-              counter.increment(increment);
-            });
   }
 
   /**
@@ -167,40 +152,30 @@ public class MetricUtils {
   public void setGaugeValue(Class<?> clazz, String metricName, double value) {
     String name = MetricRegistry.name(clazz, metricName);
 
-    getRegistry()
+    // Get or create the state holder
-        .ifPresent(
+    AtomicDouble state = gaugeStates.computeIfAbsent(name, k -> new AtomicDouble(0));
-            meterRegistry -> {
-              // Get or create the state holder
-              AtomicDouble state = gaugeStates.computeIfAbsent(name, k -> new AtomicDouble(0));
 
-              // Register the gauge if not already registered
+    // Register the gauge if not already registered
-              legacyGaugeCache.computeIfAbsent(
+    legacyGaugeCache.computeIfAbsent(
-                  name,
+        name,
-                  key ->
+        key ->
-                      Gauge.builder(key, state, AtomicDouble::get)
+            Gauge.builder(key, state, AtomicDouble::get)
-                          .tag(DROPWIZARD_METRIC, "true")
+                .tag(DROPWIZARD_METRIC, "true")
-                          .register(meterRegistry));
+                .register(registry));
 
-              // Update the value
+    // Update the value
-              state.set(value);
+    state.set(value);
-            });
   }
 
   @Deprecated
   public void histogram(Class<?> clazz, String metricName, long value) {
-    getRegistry()
+    String name = MetricRegistry.name(clazz, metricName);
-        .ifPresent(
+    DistributionSummary summary =
-            meterRegistry -> {
+        legacyHistogramCache.computeIfAbsent(
-              String name = MetricRegistry.name(clazz, metricName);
+            name,
-              DistributionSummary summary =
+            key ->
-                  legacyHistogramCache.computeIfAbsent(
+                DistributionSummary.builder(key).tag(DROPWIZARD_METRIC, "true").register(registry));
-                      name,
+    summary.record(value);
-                      key ->
-                          DistributionSummary.builder(key)
-                              .tag(DROPWIZARD_METRIC, "true")
-                              .register(meterRegistry));
-              summary.record(value);
-            });
   }
 
   @Deprecated

metadata-utils/src/main/java/com/linkedin/metadata/utils/metrics/MicrometerMetricsRegistry.java

@@ -27,11 +27,7 @@ public class MicrometerMetricsRegistry {
   public static synchronized boolean registerCacheMetrics(
       @Nonnull String cacheName,
       @Nonnull Object nativeCache,
-      @Nullable MeterRegistry meterRegistry) {
+      @Nonnull MeterRegistry meterRegistry) {
-
-    if (cacheName == null || nativeCache == null || meterRegistry == null) {
-      return false;
-    }
 
     if (!GLOBALLY_REGISTERED_CACHES.add(cacheName)) {
       return false;

metadata-utils/src/test/java/com/linkedin/metadata/utils/metrics/MetricUtilsTest.java

@@ -10,7 +10,6 @@ import io.micrometer.core.instrument.Meter;
 import io.micrometer.core.instrument.MeterRegistry;
 import io.micrometer.core.instrument.Timer;
 import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
-import java.util.Optional;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Supplier;
 import org.mockito.Mock;
@@ -44,18 +43,25 @@ public class MetricUtilsTest {
   }
 
   @Test
-  public void testGetRegistryReturnsOptionalWithRegistry() {
+  public void testGetRegistryReturnsRegistry() {
-    Optional<MeterRegistry> registry = metricUtils.getRegistry();
+    MeterRegistry registry = metricUtils.getRegistry();
-    assertTrue(registry.isPresent());
+    assertNotNull(registry);
-    assertSame(registry.get(), meterRegistry);
+    assertSame(registry, meterRegistry);
   }
 
   @Test
-  public void testGetRegistryReturnsEmptyOptionalWhenNull() {
+  public void testGetRegistryReturnsDefaultWhenNotSpecified() {
-    MetricUtils utilsWithNullRegistry = MetricUtils.builder().registry(null).build();
+    MetricUtils utilsWithDefaultRegistry = MetricUtils.builder().build();
 
-    Optional<MeterRegistry> registry = utilsWithNullRegistry.getRegistry();
+    MeterRegistry registry = utilsWithDefaultRegistry.getRegistry();
-    assertFalse(registry.isPresent());
+    assertNotNull(registry);
+    assertTrue(registry instanceof io.micrometer.core.instrument.composite.CompositeMeterRegistry);
+  }
+
+  @Test(expectedExceptions = NullPointerException.class)
+  public void testBuilderRejectsNullRegistry() {
+    // This should throw NullPointerException due to @NonNull annotation
+    MetricUtils.builder().registry(null).build();
   }
 
   @Test
@@ -72,11 +78,11 @@ public class MetricUtilsTest {
   }
 
   @Test
-  public void testTimeWithNullRegistryDoesNothing() {
+  public void testTimeWithDefaultRegistryWorks() {
-    MetricUtils utilsWithNullRegistry = MetricUtils.builder().registry(null).build();
+    MetricUtils utilsWithDefaultRegistry = MetricUtils.builder().build();
 
-    // Should not throw exception
+    // Should not throw exception and should work with default registry
-    utilsWithNullRegistry.time("test.timer", 1000);
+    utilsWithDefaultRegistry.time("test.timer", 1000);
   }
 
   @Test
@@ -217,16 +223,21 @@ public class MetricUtilsTest {
   }
 
   @Test
-  public void testAllMethodsWithNullRegistry() {
+  public void testAllMethodsWithDefaultRegistry() {
-    MetricUtils utilsWithNullRegistry = MetricUtils.builder().registry(null).build();
+    MetricUtils utilsWithDefaultRegistry = MetricUtils.builder().build();
 
-    // None of these should throw exceptions
+    // All methods should work with the default CompositeMeterRegistry
-    utilsWithNullRegistry.time("timer", 1000);
+    utilsWithDefaultRegistry.time("timer", 1000);
-    utilsWithNullRegistry.increment(this.getClass(), "counter", 1);
+    utilsWithDefaultRegistry.increment(this.getClass(), "counter", 1);
-    utilsWithNullRegistry.increment("counter", 1);
+    utilsWithDefaultRegistry.increment("counter", 1);
-    utilsWithNullRegistry.exceptionIncrement(this.getClass(), "error", new RuntimeException());
+    utilsWithDefaultRegistry.exceptionIncrement(this.getClass(), "error", new RuntimeException());
-    utilsWithNullRegistry.setGaugeValue(this.getClass(), "gauge", 42);
+    utilsWithDefaultRegistry.setGaugeValue(this.getClass(), "gauge", 42);
-    utilsWithNullRegistry.histogram(this.getClass(), "histogram", 100);
+    utilsWithDefaultRegistry.histogram(this.getClass(), "histogram", 100);
+
+    // Verify the registry is the expected type
+    assertTrue(
+        utilsWithDefaultRegistry.getRegistry()
+            instanceof io.micrometer.core.instrument.composite.CompositeMeterRegistry);
   }
 
   @Test

metadata-utils/src/test/java/com/linkedin/metadata/utils/metrics/MicrometerMetricsRegistryTest.java

@@ -155,32 +155,6 @@ public class MicrometerMetricsRegistryTest {
     assertFalse(result);
   }
 
-  @Test
-  public void testRegisterCacheWithNullNativeCache() {
-    // Given
-    String cacheName = "testCache";
-
-    // When
-    boolean result = MicrometerMetricsRegistry.registerCacheMetrics(cacheName, null, meterRegistry);
-
-    // Then
-    assertFalse(result);
-  }
-
-  @Test
-  public void testRegisterCacheWithNullCacheName() {
-    // Given
-    Cache<Object, Object> caffeineCache =
-        Caffeine.newBuilder().maximumSize(100).recordStats().build();
-
-    // When
-    boolean result =
-        MicrometerMetricsRegistry.registerCacheMetrics(null, caffeineCache, meterRegistry);
-
-    // Then
-    assertFalse(result); // Should return false for null cache name
-  }
-
   @Test
   public void testRegisterCacheWithUnsupportedCacheType() {
     // Given
@@ -352,30 +326,6 @@ public class MicrometerMetricsRegistryTest {
     assertEquals(registeredKey, cacheName);
   }
 
-  @Test
-  public void testAllNullParameters() {
-    // When
-    boolean result = MicrometerMetricsRegistry.registerCacheMetrics(null, null, null);
-
-    // Then
-    assertFalse(result);
-  }
-
-  @Test
-  public void testNullCheckOrder() {
-    // Test various combinations of null parameters
-
-    // Null cache name
-    Cache<Object, Object> caffeineCache = Caffeine.newBuilder().maximumSize(100).build();
-    assertFalse(MicrometerMetricsRegistry.registerCacheMetrics(null, caffeineCache, meterRegistry));
-
-    // Null native cache
-    assertFalse(MicrometerMetricsRegistry.registerCacheMetrics("test", null, meterRegistry));
-
-    // Null meter registry
-    assertFalse(MicrometerMetricsRegistry.registerCacheMetrics("test", caffeineCache, null));
-  }
-
   @Test
   public void testSuccessfulRegistrationDoesNotThrowOnSubsequentAttempts() {
     // Given