Bump version to 1.54.1

The problem was one hedge was committed before another had drained
start(). This was not testable because HedgingRunnable checks whether
scheduledHedgingRef is cancelled, which is racy, but there's no way to
deterministically trigger either race.

The same problem couldn't be triggered with retries because only one
attempt will be draining at a time. Retries with cancellation also
couldn't trigger it, for the surprising reason that the noop stream used
in cancel() wasn't considered drained.

This commit marks the noop stream as drained with cancel(), which allows
memory to be garbage collected sooner and exposes the race for tests.
That then showed the stream as hanging, because inFlightSubStreams
wasn't being decremented.

Fixes #9185

README.md

@@ -44,8 +44,8 @@ For a guided tour, take a look at the [quick start
 guide](https://grpc.io/docs/languages/java/quickstart) or the more explanatory [gRPC
 basics](https://grpc.io/docs/languages/java/basics).
 
-The [examples](https://github.com/grpc/grpc-java/tree/v1.52.1/examples) and the
-[Android example](https://github.com/grpc/grpc-java/tree/v1.52.1/examples/android)
+The [examples](https://github.com/grpc/grpc-java/tree/v1.54.1/examples) and the
+[Android example](https://github.com/grpc/grpc-java/tree/v1.54.1/examples/android)
 are standalone projects that showcase the usage of gRPC.
 
 Download
@@ -56,18 +56,18 @@ Download [the JARs][]. Or for Maven with non-Android, add to your `pom.xml`:
 <dependency>
   <groupId>io.grpc</groupId>
   <artifactId>grpc-netty-shaded</artifactId>
-  <version>1.52.1</version>
+  <version>1.54.1</version>
   <scope>runtime</scope>
 </dependency>
 <dependency>
   <groupId>io.grpc</groupId>
   <artifactId>grpc-protobuf</artifactId>
-  <version>1.52.1</version>
+  <version>1.54.1</version>
 </dependency>
 <dependency>
   <groupId>io.grpc</groupId>
   <artifactId>grpc-stub</artifactId>
-  <version>1.52.1</version>
+  <version>1.54.1</version>
 </dependency>
 <dependency> <!-- necessary for Java 9+ -->
   <groupId>org.apache.tomcat</groupId>
@@ -79,23 +79,23 @@ Download [the JARs][]. Or for Maven with non-Android, add to your `pom.xml`:
 
 Or for Gradle with non-Android, add to your dependencies:
 ```gradle
-runtimeOnly 'io.grpc:grpc-netty-shaded:1.52.1'
-implementation 'io.grpc:grpc-protobuf:1.52.1'
-implementation 'io.grpc:grpc-stub:1.52.1'
+runtimeOnly 'io.grpc:grpc-netty-shaded:1.54.1'
+implementation 'io.grpc:grpc-protobuf:1.54.1'
+implementation 'io.grpc:grpc-stub:1.54.1'
 compileOnly 'org.apache.tomcat:annotations-api:6.0.53' // necessary for Java 9+
 ```
 
 For Android client, use `grpc-okhttp` instead of `grpc-netty-shaded` and
 `grpc-protobuf-lite` instead of `grpc-protobuf`:
 ```gradle
-implementation 'io.grpc:grpc-okhttp:1.52.1'
-implementation 'io.grpc:grpc-protobuf-lite:1.52.1'
-implementation 'io.grpc:grpc-stub:1.52.1'
+implementation 'io.grpc:grpc-okhttp:1.54.1'
+implementation 'io.grpc:grpc-protobuf-lite:1.54.1'
+implementation 'io.grpc:grpc-stub:1.54.1'
 compileOnly 'org.apache.tomcat:annotations-api:6.0.53' // necessary for Java 9+
 ```
 
 [the JARs]:
-https://search.maven.org/search?q=g:io.grpc%20AND%20v:1.52.1
+https://search.maven.org/search?q=g:io.grpc%20AND%20v:1.54.1
 
 Development snapshots are available in [Sonatypes's snapshot
 repository](https://oss.sonatype.org/content/repositories/snapshots/).
@@ -127,7 +127,7 @@ For protobuf-based codegen integrated with the Maven build system, you can use
       <configuration>
         <protocArtifact>com.google.protobuf:protoc:3.21.7:exe:${os.detected.classifier}</protocArtifact>
         <pluginId>grpc-java</pluginId>
-        <pluginArtifact>io.grpc:protoc-gen-grpc-java:1.52.1:exe:${os.detected.classifier}</pluginArtifact>
+        <pluginArtifact>io.grpc:protoc-gen-grpc-java:1.54.1:exe:${os.detected.classifier}</pluginArtifact>
       </configuration>
       <executions>
         <execution>
@@ -157,7 +157,7 @@ protobuf {
   }
   plugins {
     grpc {
-      artifact = 'io.grpc:protoc-gen-grpc-java:1.52.1'
+      artifact = 'io.grpc:protoc-gen-grpc-java:1.54.1'
     }
   }
   generateProtoTasks {
@@ -190,7 +190,7 @@ protobuf {
   }
   plugins {
     grpc {
-      artifact = 'io.grpc:protoc-gen-grpc-java:1.52.1'
+      artifact = 'io.grpc:protoc-gen-grpc-java:1.54.1'
     }
   }
   generateProtoTasks {

RELEASING.md

@@ -26,18 +26,8 @@ $ VERSION_FILES=(
   examples/android/helloworld/app/build.gradle
   examples/android/routeguide/app/build.gradle
   examples/android/strictmode/app/build.gradle
-  examples/example-alts/build.gradle
-  examples/example-gauth/build.gradle
-  examples/example-gauth/pom.xml
-  examples/example-jwt-auth/build.gradle
-  examples/example-jwt-auth/pom.xml
-  examples/example-hostname/build.gradle
-  examples/example-hostname/pom.xml
-  examples/example-servlet/build.gradle
-  examples/example-tls/build.gradle
-  examples/example-tls/pom.xml
-  examples/example-xds/build.gradle
-  examples/example-orca/build.gradle
+  examples/example-*/build.gradle
+  examples/example-*/pom.xml
   )
 ```
 

build.gradle

@@ -20,7 +20,7 @@ subprojects {
     apply plugin: "net.ltgt.errorprone"
 
     group = "io.grpc"
-    version = "1.54.0-SNAPSHOT" // CURRENT_GRPC_VERSION
+    version = "1.54.1" // CURRENT_GRPC_VERSION
 
     repositories {
         maven { // The google mirror is less flaky than mavenCentral()

buildscripts/observability-test/run.sh

@@ -16,29 +16,14 @@
 set -ex
 cd "$(dirname "$0")"/../..
 
-# TODO(stanleycheung): replace positional parameters with explicit parameters
-#
-#             $1: server | client
-#
-# For server: $2: server_port
-#
-# For client: $2: server_host
-#             $3: server_port
-#             $4: test_case
-#             $5: num_times
-
 if [ "$1" = "server" ] ; then
-  /grpc-java/bin/gcp-observability-interop \
-    server --use_tls=false \
-    --port=$2
+  /grpc-java/bin/gcp-observability-interop server --use_tls=false "${@:2}"
 
 elif [ "$1" = "client" ] ; then
-  /grpc-java/bin/gcp-observability-interop \
-    client --use_tls=false \
-    --server_host=$2 --server_port=$3 \
-    --test_case=$4 --num_times=$5
+  /grpc-java/bin/gcp-observability-interop client --use_tls=false "${@:2}"
 
 else
-  echo "Invalid action: $1"
+  echo "Invalid action: $1. Usage:"
+  echo "  $ .../run.sh [server|client] --server_host=<hostname> --server_port=<port> ..."
   exit 1
 fi

census/src/main/java/io/grpc/census/CensusTracingModule.java

@@ -17,6 +17,7 @@
 package io.grpc.census;
 
 import static com.google.common.base.Preconditions.checkNotNull;
+import static io.grpc.census.internal.ObservabilityCensusConstants.CLIENT_TRACE_SPAN_CONTEXT_KEY;
 
 import com.google.common.annotations.VisibleForTesting;
 import io.grpc.Attributes;
@@ -41,6 +42,9 @@ import io.opencensus.trace.SpanContext;
 import io.opencensus.trace.Status;
 import io.opencensus.trace.Tracer;
 import io.opencensus.trace.propagation.BinaryFormat;
+import java.util.HashMap;
+import java.util.Locale;
+import java.util.Map;
 import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -92,12 +96,9 @@ final class CensusTracingModule {
   final Metadata.Key<SpanContext> tracingHeader;
   private final TracingClientInterceptor clientInterceptor = new TracingClientInterceptor();
   private final ServerTracerFactory serverTracerFactory = new ServerTracerFactory();
-  private final boolean addMessageEvents;
 
   CensusTracingModule(
-      Tracer censusTracer,
-      final BinaryFormat censusPropagationBinaryFormat,
-      boolean addMessageEvents) {
+      Tracer censusTracer, final BinaryFormat censusPropagationBinaryFormat) {
     this.censusTracer = checkNotNull(censusTracer, "censusTracer");
     checkNotNull(censusPropagationBinaryFormat, "censusPropagationBinaryFormat");
     this.tracingHeader =
@@ -117,7 +118,6 @@ final class CensusTracingModule {
               }
             }
           });
-    this.addMessageEvents = addMessageEvents;
   }
 
   /**
@@ -125,8 +125,8 @@ final class CensusTracingModule {
    */
   @VisibleForTesting
   CallAttemptsTracerFactory newClientCallTracer(
-      @Nullable Span parentSpan, MethodDescriptor<?, ?> method) {
-    return new CallAttemptsTracerFactory(parentSpan, method);
+      @Nullable Span clientSpan, MethodDescriptor<?, ?> method) {
+    return new CallAttemptsTracerFactory(clientSpan, method);
   }
 
   /**
@@ -218,9 +218,6 @@ final class CensusTracingModule {
   private void recordMessageEvent(
       Span span, MessageEvent.Type type,
       int seqNo, long optionalWireSize, long optionalUncompressedSize) {
-    if (!addMessageEvents) {
-      return;
-    }
     MessageEvent.Builder eventBuilder = MessageEvent.builder(type, seqNo);
     if (optionalUncompressedSize != -1) {
       eventBuilder.setUncompressedMessageSize(optionalUncompressedSize);
@@ -231,6 +228,19 @@ final class CensusTracingModule {
     span.addMessageEvent(eventBuilder.build());
   }
 
+  private void recordAnnotation(
+      Span span, MessageEvent.Type type, int seqNo, boolean isCompressed, long size) {
+    String messageType = isCompressed ? "compressed" : "uncompressed";
+    Map<String, AttributeValue> attributes = new HashMap<>();
+    attributes.put("id", AttributeValue.longAttributeValue(seqNo));
+    attributes.put("type", AttributeValue.stringAttributeValue(messageType));
+
+    String messageDirection = type == MessageEvent.Type.SENT ? "↗ " : "↘ ";
+    String inlineDescription =
+        messageDirection + size + " bytes " + type.name().toLowerCase(Locale.US);
+    span.addAnnotation(inlineDescription, attributes);
+  }
+
   @VisibleForTesting
   final class CallAttemptsTracerFactory extends ClientStreamTracer.Factory {
     volatile int callEnded;
@@ -239,17 +249,11 @@ final class CensusTracingModule {
     private final Span span;
     private final String fullMethodName;
 
-    CallAttemptsTracerFactory(@Nullable Span parentSpan, MethodDescriptor<?, ?> method) {
+    CallAttemptsTracerFactory(@Nullable Span clientSpan, MethodDescriptor<?, ?> method) {
       checkNotNull(method, "method");
       this.isSampledToLocalTracing = method.isSampledToLocalTracing();
       this.fullMethodName = method.getFullMethodName();
-      this.span =
-          censusTracer
-              .spanBuilderWithExplicitParent(
-                  generateTraceSpanName(false, fullMethodName),
-                  parentSpan)
-              .setRecordEvents(true)
-              .startSpan();
+      this.span = clientSpan;
     }
 
     @Override
@@ -265,7 +269,7 @@ final class CensusTracingModule {
           "previous-rpc-attempts", AttributeValue.longAttributeValue(info.getPreviousAttempts()));
       attemptSpan.putAttribute(
           "transparent-retry", AttributeValue.booleanAttributeValue(info.isTransparentRetry()));
-      return new ClientTracer(attemptSpan, tracingHeader, isSampledToLocalTracing);
+      return new ClientTracer(attemptSpan, span, tracingHeader, isSampledToLocalTracing);
     }
 
     /**
@@ -291,12 +295,16 @@ final class CensusTracingModule {
 
   private final class ClientTracer extends ClientStreamTracer {
     private final Span span;
+    private final Span parentSpan;
     final Metadata.Key<SpanContext> tracingHeader;
     final boolean isSampledToLocalTracing;
+    volatile int seqNo;
 
     ClientTracer(
-        Span span, Metadata.Key<SpanContext> tracingHeader, boolean isSampledToLocalTracing) {
+        Span span, Span parentSpan, Metadata.Key<SpanContext> tracingHeader,
+        boolean isSampledToLocalTracing) {
       this.span = checkNotNull(span, "span");
+      this.parentSpan = checkNotNull(parentSpan, "parent span");
       this.tracingHeader = tracingHeader;
       this.isSampledToLocalTracing = isSampledToLocalTracing;
     }
@@ -319,8 +327,19 @@ final class CensusTracingModule {
     @Override
     public void inboundMessageRead(
         int seqNo, long optionalWireSize, long optionalUncompressedSize) {
-      recordMessageEvent(
-          span, MessageEvent.Type.RECEIVED, seqNo, optionalWireSize, optionalUncompressedSize);
+      recordAnnotation(
+          span, MessageEvent.Type.RECEIVED, seqNo, true, optionalWireSize);
+    }
+
+    @Override
+    public void inboundMessage(int seqNo) {
+      this.seqNo = seqNo;
+    }
+
+    @Override
+    public void inboundUncompressedSize(long bytes) {
+      recordAnnotation(
+          parentSpan, MessageEvent.Type.RECEIVED, seqNo, false, bytes);
     }
 
     @Override
@@ -334,6 +353,7 @@ final class CensusTracingModule {
     private final Span span;
     volatile boolean isSampledToLocalTracing;
     volatile int streamClosed;
+    private int seqNo;
 
     ServerTracer(String fullMethodName, @Nullable SpanContext remoteSpan) {
       checkNotNull(fullMethodName, "fullMethodName");
@@ -396,8 +416,19 @@ final class CensusTracingModule {
     @Override
     public void inboundMessageRead(
         int seqNo, long optionalWireSize, long optionalUncompressedSize) {
-      recordMessageEvent(
-          span, MessageEvent.Type.RECEIVED, seqNo, optionalWireSize, optionalUncompressedSize);
+      recordAnnotation(
+          span, MessageEvent.Type.RECEIVED, seqNo, true, optionalWireSize);
+    }
+
+    @Override
+    public void inboundMessage(int seqNo) {
+      this.seqNo = seqNo;
+    }
+
+    @Override
+    public void inboundUncompressedSize(long bytes) {
+      recordAnnotation(
+          span, MessageEvent.Type.RECEIVED, seqNo, false, bytes);
     }
   }
 
@@ -425,13 +456,20 @@ final class CensusTracingModule {
       // Safe usage of the unsafe trace API because CONTEXT_SPAN_KEY.get() returns the same value
       // as Tracer.getCurrentSpan() except when no value available when the return value is null
       // for the direct access and BlankSpan when Tracer API is used.
-      final CallAttemptsTracerFactory tracerFactory =
-          newClientCallTracer(
-              io.opencensus.trace.unsafe.ContextUtils.getValue(Context.current()), method);
+      Span parentSpan = io.opencensus.trace.unsafe.ContextUtils.getValue(Context.current());
+      Span clientSpan = censusTracer
+          .spanBuilderWithExplicitParent(
+              generateTraceSpanName(false, method.getFullMethodName()),
+              parentSpan)
+          .setRecordEvents(true)
+          .startSpan();
+
+      final CallAttemptsTracerFactory tracerFactory = newClientCallTracer(clientSpan, method);
       ClientCall<ReqT, RespT> call =
           next.newCall(
               method,
-              callOptions.withStreamTracerFactory(tracerFactory));
+              callOptions.withStreamTracerFactory(tracerFactory)
+                  .withOption(CLIENT_TRACE_SPAN_CONTEXT_KEY, clientSpan.getContext()));
       return new SimpleForwardingClientCall<ReqT, RespT>(call) {
         @Override
         public void start(Listener<RespT> responseListener, Metadata headers) {

census/src/main/java/io/grpc/census/InternalCensusTracingAccessor.java

@@ -36,42 +36,21 @@ public final class InternalCensusTracingAccessor {
    * Returns a {@link ClientInterceptor} with default tracing implementation.
    */
   public static ClientInterceptor getClientInterceptor() {
-    return getClientInterceptor(true);
-  }
-
-  /**
-   * Returns the client interceptor that facilitates Census-based stats reporting.
-   *
-   * @param addMessageEvents add message events to Spans
-   * @return a {@link ClientInterceptor} with default tracing implementation.
-   */
-  public static ClientInterceptor getClientInterceptor(
-      boolean addMessageEvents) {
     CensusTracingModule censusTracing =
         new CensusTracingModule(
             Tracing.getTracer(),
-            Tracing.getPropagationComponent().getBinaryFormat(),
-            addMessageEvents);
+            Tracing.getPropagationComponent().getBinaryFormat());
     return censusTracing.getClientInterceptor();
   }
 
   /**
-   * Returns a {@link ServerStreamTracer.Factory} with default stats implementation.
+   * Returns a {@link ServerStreamTracer.Factory} with default tracing implementation.
    */
   public static ServerStreamTracer.Factory getServerStreamTracerFactory() {
-    return getServerStreamTracerFactory(true);
-  }
-
-  /**
-   * Returns a {@link ServerStreamTracer.Factory} with default stats implementation.
-   */
-  public static ServerStreamTracer.Factory getServerStreamTracerFactory(
-      boolean addMessageEvents) {
     CensusTracingModule censusTracing =
         new CensusTracingModule(
             Tracing.getTracer(),
-            Tracing.getPropagationComponent().getBinaryFormat(),
-            addMessageEvents);
+            Tracing.getPropagationComponent().getBinaryFormat());
     return censusTracing.getServerTracerFactory();
   }
 }

census/src/main/java/io/grpc/census/internal/ObservabilityCensusConstants.java

@@ -26,11 +26,13 @@ import static io.opencensus.contrib.grpc.metrics.RpcMeasureConstants.GRPC_SERVER
 import static io.opencensus.contrib.grpc.metrics.RpcMeasureConstants.GRPC_SERVER_STATUS;
 
 import com.google.common.annotations.VisibleForTesting;
+import io.grpc.CallOptions;
 import io.opencensus.contrib.grpc.metrics.RpcViewConstants;
 import io.opencensus.stats.Aggregation;
 import io.opencensus.stats.Measure;
 import io.opencensus.stats.Measure.MeasureDouble;
 import io.opencensus.stats.View;
+import io.opencensus.trace.SpanContext;
 import java.util.Arrays;
 
 // TODO(dnvindhya): Remove metric and view definitions from this class once it is moved to
@@ -42,6 +44,9 @@ import java.util.Arrays;
 @VisibleForTesting
 public final class ObservabilityCensusConstants {
 
+  public static CallOptions.Key<SpanContext> CLIENT_TRACE_SPAN_CONTEXT_KEY
+      = CallOptions.Key.createWithDefault("Client span context for tracing", SpanContext.INVALID);
+
   static final Aggregation AGGREGATION_WITH_BYTES_HISTOGRAM =
       RpcViewConstants.GRPC_CLIENT_SENT_BYTES_PER_RPC_VIEW.getAggregation();
 

census/src/test/java/io/grpc/census/CensusModulesTest.java

@@ -22,6 +22,7 @@ import static io.grpc.census.CensusStatsModule.CallAttemptsTracerFactory.RETRIES
 import static io.grpc.census.CensusStatsModule.CallAttemptsTracerFactory.RETRY_DELAY_PER_CALL;
 import static io.grpc.census.CensusStatsModule.CallAttemptsTracerFactory.TRANSPARENT_RETRIES_PER_CALL;
 import static io.grpc.census.internal.ObservabilityCensusConstants.API_LATENCY_PER_CALL;
+import static io.grpc.census.internal.ObservabilityCensusConstants.CLIENT_TRACE_SPAN_CONTEXT_KEY;
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
@@ -100,6 +101,7 @@ import io.opencensus.trace.propagation.SpanContextParseException;
 import java.io.InputStream;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Random;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicReference;
@@ -204,6 +206,8 @@ public class CensusModulesTest {
   private ArgumentCaptor<Status> statusCaptor;
   @Captor
   private ArgumentCaptor<MessageEvent> messageEventCaptor;
+  @Captor
+  private ArgumentCaptor<Map<String, AttributeValue>> annotationAttributesCaptor;
 
   private CensusStatsModule censusStats;
   private CensusTracingModule censusTracing;
@@ -229,7 +233,7 @@ public class CensusModulesTest {
         new CensusStatsModule(
             tagger, tagCtxSerializer, statsRecorder, fakeClock.getStopwatchSupplier(),
             true, true, true, false /* real-time */, true);
-    censusTracing = new CensusTracingModule(tracer, mockTracingPropagationHandler, true);
+    censusTracing = new CensusTracingModule(tracer, mockTracingPropagationHandler);
   }
 
   @After
@@ -314,6 +318,10 @@ public class CensusModulesTest {
         capturedCallOptions.get().getStreamTracerFactories().get(1)
         instanceof CensusStatsModule.CallAttemptsTracerFactory);
 
+    // The interceptor adds client SpanContext to CallOptions
+    assertTrue(capturedCallOptions.get().getOption(CLIENT_TRACE_SPAN_CONTEXT_KEY).isValid());
+    assertTrue(capturedCallOptions.get().getOption(CLIENT_TRACE_SPAN_CONTEXT_KEY) != null);
+
     // Make the call
     Metadata headers = new Metadata();
     call.start(mockClientCallListener, headers);
@@ -735,12 +743,10 @@ public class CensusModulesTest {
   @Test
   public void clientBasicTracingDefaultSpan() {
     CallAttemptsTracerFactory callTracer =
-        censusTracing.newClientCallTracer(null, method);
+        censusTracing.newClientCallTracer(spyClientSpan, method);
     Metadata headers = new Metadata();
     ClientStreamTracer clientStreamTracer = callTracer.newClientStreamTracer(STREAM_INFO, headers);
     clientStreamTracer.streamCreated(Attributes.EMPTY, headers);
-    verify(tracer).spanBuilderWithExplicitParent(
-        eq("Sent.package1.service2.method3"), ArgumentMatchers.<Span>isNull());
     verify(tracer).spanBuilderWithExplicitParent(
         eq("Attempt.package1.service2.method3"), eq(spyClientSpan));
     verify(spyClientSpan, never()).end(any(EndSpanOptions.class));
@@ -761,7 +767,7 @@ public class CensusModulesTest {
         .putAttribute("previous-rpc-attempts", AttributeValue.longAttributeValue(0));
     inOrder.verify(spyAttemptSpan)
         .putAttribute("transparent-retry", AttributeValue.booleanAttributeValue(false));
-    inOrder.verify(spyAttemptSpan, times(3)).addMessageEvent(messageEventCaptor.capture());
+    inOrder.verify(spyAttemptSpan, times(2)).addMessageEvent(messageEventCaptor.capture());
     List<MessageEvent> events = messageEventCaptor.getAllValues();
     assertEquals(
         MessageEvent.builder(MessageEvent.Type.SENT, 0).setCompressedMessageSize(882).build(),
@@ -769,12 +775,14 @@ public class CensusModulesTest {
     assertEquals(
         MessageEvent.builder(MessageEvent.Type.SENT, 1).setUncompressedMessageSize(27).build(),
         events.get(1));
-    assertEquals(
-        MessageEvent.builder(MessageEvent.Type.RECEIVED, 0)
-            .setCompressedMessageSize(255)
-            .setUncompressedMessageSize(90)
-            .build(),
-        events.get(2));
+    ArgumentCaptor<String> stringCaptor = ArgumentCaptor.forClass(String.class);
+    inOrder.verify(spyAttemptSpan, times(1))
+        .addAnnotation(stringCaptor.capture(), annotationAttributesCaptor.capture());
+    assertEquals("↘ 255 bytes received", stringCaptor.getValue());
+    assertThat(annotationAttributesCaptor.getValue().get("id"))
+        .isEqualTo(AttributeValue.longAttributeValue(0));
+    assertThat(annotationAttributesCaptor.getValue().get("type"))
+        .isEqualTo(AttributeValue.stringAttributeValue("compressed"));
     inOrder.verify(spyAttemptSpan).end(
         EndSpanOptions.builder()
             .setStatus(io.opencensus.trace.Status.OK)
@@ -792,7 +800,7 @@ public class CensusModulesTest {
   @Test
   public void clientTracingSampledToLocalSpanStore() {
     CallAttemptsTracerFactory callTracer =
-        censusTracing.newClientCallTracer(null, sampledMethod);
+        censusTracing.newClientCallTracer(spyClientSpan, sampledMethod);
     callTracer.callEnded(Status.OK);
 
     verify(spyClientSpan).end(
@@ -862,10 +870,7 @@ public class CensusModulesTest {
   @Test
   public void clientStreamNeverCreatedStillRecordTracing() {
     CallAttemptsTracerFactory callTracer =
-        censusTracing.newClientCallTracer(fakeClientParentSpan, method);
-    verify(tracer).spanBuilderWithExplicitParent(
-        eq("Sent.package1.service2.method3"), same(fakeClientParentSpan));
-    verify(spyClientSpanBuilder).setRecordEvents(eq(true));
+        censusTracing.newClientCallTracer(spyClientSpan, method);
 
     callTracer.callEnded(Status.DEADLINE_EXCEEDED.withDescription("3 seconds"));
     verify(spyClientSpan).end(
@@ -1041,18 +1046,15 @@ public class CensusModulesTest {
   @Test
   public void traceHeadersPropagateSpanContext() throws Exception {
     CallAttemptsTracerFactory callTracer =
-        censusTracing.newClientCallTracer(fakeClientParentSpan, method);
+        censusTracing.newClientCallTracer(spyClientSpan, method);
     Metadata headers = new Metadata();
     ClientStreamTracer streamTracer = callTracer.newClientStreamTracer(STREAM_INFO, headers);
     streamTracer.streamCreated(Attributes.EMPTY, headers);
 
     verify(mockTracingPropagationHandler).toByteArray(same(fakeAttemptSpanContext));
     verifyNoMoreInteractions(mockTracingPropagationHandler);
-    verify(tracer).spanBuilderWithExplicitParent(
-        eq("Sent.package1.service2.method3"), same(fakeClientParentSpan));
     verify(tracer).spanBuilderWithExplicitParent(
         eq("Attempt.package1.service2.method3"), same(spyClientSpan));
-    verify(spyClientSpanBuilder).setRecordEvents(eq(true));
     verifyNoMoreInteractions(tracer);
     assertTrue(headers.containsKey(censusTracing.tracingHeader));
 
@@ -1310,7 +1312,7 @@ public class CensusModulesTest {
     serverStreamTracer.streamClosed(Status.CANCELLED);
 
     InOrder inOrder = inOrder(spyServerSpan);
-    inOrder.verify(spyServerSpan, times(3)).addMessageEvent(messageEventCaptor.capture());
+    inOrder.verify(spyServerSpan, times(2)).addMessageEvent(messageEventCaptor.capture());
     List<MessageEvent> events = messageEventCaptor.getAllValues();
     assertEquals(
         MessageEvent.builder(MessageEvent.Type.SENT, 0).setCompressedMessageSize(882).build(),
@@ -1318,12 +1320,16 @@ public class CensusModulesTest {
     assertEquals(
         MessageEvent.builder(MessageEvent.Type.SENT, 1).setUncompressedMessageSize(27).build(),
         events.get(1));
-    assertEquals(
-        MessageEvent.builder(MessageEvent.Type.RECEIVED, 0)
-            .setCompressedMessageSize(255)
-            .setUncompressedMessageSize(90)
-            .build(),
-        events.get(2));
+
+    ArgumentCaptor<String> stringCaptor = ArgumentCaptor.forClass(String.class);
+    inOrder.verify(spyServerSpan, times(1))
+        .addAnnotation(stringCaptor.capture(), annotationAttributesCaptor.capture());
+    assertEquals("↘ 255 bytes received", stringCaptor.getValue());
+    assertThat(annotationAttributesCaptor.getValue().get("id"))
+        .isEqualTo(AttributeValue.longAttributeValue(0));
+    assertThat(annotationAttributesCaptor.getValue().get("type"))
+        .isEqualTo(AttributeValue.stringAttributeValue("compressed"));
+
     inOrder.verify(spyServerSpan).end(
         EndSpanOptions.builder()
             .setStatus(io.opencensus.trace.Status.CANCELLED)

census/src/test/java/io/grpc/census/CensusTracingAnnotationEventTest.java

@@ -16,6 +16,8 @@
 
 package io.grpc.census;
 
+import static com.google.common.truth.Truth.assertThat;
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNull;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyString;
@@ -35,6 +37,7 @@ import io.grpc.census.CensusTracingModule.CallAttemptsTracerFactory;
 import io.grpc.internal.testing.StatsTestUtils.FakeStatsRecorder;
 import io.grpc.internal.testing.StatsTestUtils.MockableSpan;
 import io.grpc.testing.GrpcServerRule;
+import io.opencensus.trace.AttributeValue;
 import io.opencensus.trace.MessageEvent;
 import io.opencensus.trace.Span;
 import io.opencensus.trace.SpanBuilder;
@@ -42,6 +45,8 @@ import io.opencensus.trace.SpanContext;
 import io.opencensus.trace.Tracer;
 import io.opencensus.trace.propagation.BinaryFormat;
 import java.io.InputStream;
+import java.util.List;
+import java.util.Map;
 import java.util.Random;
 import org.junit.After;
 import org.junit.Before;
@@ -61,7 +66,7 @@ import org.mockito.junit.MockitoRule;
  * Test for {@link CensusTracingModule}.
  */
 @RunWith(JUnit4.class)
-public class CensusTracingNoMessageEventTest {
+public class CensusTracingAnnotationEventTest {
   private static final ClientStreamTracer.StreamInfo STREAM_INFO =
       ClientStreamTracer.StreamInfo.newBuilder().build();
 
@@ -125,6 +130,9 @@ public class CensusTracingNoMessageEventTest {
 
   @Captor
   private ArgumentCaptor<MessageEvent> messageEventCaptor;
+  @Captor
+  private ArgumentCaptor<Map<String, AttributeValue>> annotationAttributesCaptor;
+  private ArgumentCaptor<String> stringCaptor;
 
   private CensusTracingModule censusTracing;
 
@@ -145,8 +153,9 @@ public class CensusTracingNoMessageEventTest {
         .thenReturn(binarySpanContext);
     when(mockTracingPropagationHandler.fromByteArray(any(byte[].class)))
         .thenReturn(fakeAttemptSpanContext);
+    stringCaptor = ArgumentCaptor.forClass(String.class);
 
-    censusTracing = new CensusTracingModule(tracer, mockTracingPropagationHandler, false);
+    censusTracing = new CensusTracingModule(tracer, mockTracingPropagationHandler);
   }
 
   @After
@@ -155,9 +164,9 @@ public class CensusTracingNoMessageEventTest {
   }
 
   @Test
-  public void clientBasicTracingNoMessageEvents() {
+  public void clientBasicTracingUncompressedSizeAnnotation() {
     CallAttemptsTracerFactory callTracer =
-        censusTracing.newClientCallTracer(null, method);
+        censusTracing.newClientCallTracer(spyClientSpan, method);
     Metadata headers = new Metadata();
     ClientStreamTracer clientStreamTracer = callTracer.newClientStreamTracer(STREAM_INFO, headers);
     clientStreamTracer.streamCreated(Attributes.EMPTY, headers);
@@ -168,16 +177,63 @@ public class CensusTracingNoMessageEventTest {
     clientStreamTracer.outboundMessage(1);
     clientStreamTracer.outboundMessageSent(1, -1, 27);
     clientStreamTracer.inboundMessageRead(0, 255, 90);
+    clientStreamTracer.inboundUncompressedSize(90);
+    clientStreamTracer.inboundMessage(1);
+    clientStreamTracer.inboundMessageRead(1, 128, 60);
+    clientStreamTracer.inboundUncompressedSize(60);
 
     clientStreamTracer.streamClosed(Status.OK);
     callTracer.callEnded(Status.OK);
 
     InOrder inOrder = inOrder(spyClientSpan, spyAttemptSpan);
-    inOrder.verify(spyAttemptSpan, times(0)).addMessageEvent(messageEventCaptor.capture());
+    inOrder.verify(spyAttemptSpan, times(2)).addMessageEvent(messageEventCaptor.capture());
+    List<MessageEvent> events = messageEventCaptor.getAllValues();
+    assertEquals(
+        MessageEvent.builder(MessageEvent.Type.SENT, 0).setCompressedMessageSize(882).build(),
+        events.get(0));
+    assertEquals(
+        MessageEvent.builder(MessageEvent.Type.SENT, 1).setUncompressedMessageSize(27).build(),
+        events.get(1));
+
+    inOrder
+        .verify(spyAttemptSpan, times(1))
+        .addAnnotation(stringCaptor.capture(), annotationAttributesCaptor.capture());
+    assertEquals("↘ 255 bytes received", stringCaptor.getValue());
+    assertThat(annotationAttributesCaptor.getValue().get("id"))
+        .isEqualTo(AttributeValue.longAttributeValue(0));
+    assertThat(annotationAttributesCaptor.getValue().get("type"))
+        .isEqualTo(AttributeValue.stringAttributeValue("compressed"));
+
+    inOrder
+        .verify(spyClientSpan, times(1))
+        .addAnnotation(stringCaptor.capture(), annotationAttributesCaptor.capture());
+    assertEquals("↘ 90 bytes received", stringCaptor.getValue());
+    assertThat(annotationAttributesCaptor.getValue().get("id"))
+        .isEqualTo(AttributeValue.longAttributeValue(0));
+    assertThat(annotationAttributesCaptor.getValue().get("type"))
+        .isEqualTo(AttributeValue.stringAttributeValue("uncompressed"));
+
+    inOrder
+        .verify(spyAttemptSpan, times(1))
+        .addAnnotation(stringCaptor.capture(), annotationAttributesCaptor.capture());
+    assertEquals("↘ 128 bytes received", stringCaptor.getValue());
+    assertThat(annotationAttributesCaptor.getValue().get("id"))
+        .isEqualTo(AttributeValue.longAttributeValue(1));
+    assertThat(annotationAttributesCaptor.getValue().get("type"))
+        .isEqualTo(AttributeValue.stringAttributeValue("compressed"));
+
+    inOrder
+        .verify(spyClientSpan, times(1))
+        .addAnnotation(stringCaptor.capture(), annotationAttributesCaptor.capture());
+    assertEquals("↘ 60 bytes received", stringCaptor.getValue());
+    assertThat(annotationAttributesCaptor.getValue().get("id"))
+        .isEqualTo(AttributeValue.longAttributeValue(1));
+    assertThat(annotationAttributesCaptor.getValue().get("type"))
+        .isEqualTo(AttributeValue.stringAttributeValue("uncompressed"));
   }
 
   @Test
-  public void serverBasicTracingNoMessageEvents() {
+  public void serverBasicTracingUncompressedSizeAnnotation() {
     ServerStreamTracer.Factory tracerFactory = censusTracing.getServerTracerFactory();
     ServerStreamTracer serverStreamTracer =
         tracerFactory.newServerStreamTracer(method.getFullMethodName(), new Metadata());
@@ -191,10 +247,37 @@ public class CensusTracingNoMessageEventTest {
     serverStreamTracer.outboundMessage(1);
     serverStreamTracer.outboundMessageSent(1, -1, 27);
     serverStreamTracer.inboundMessageRead(0, 255, 90);
+    serverStreamTracer.inboundUncompressedSize(90);
 
     serverStreamTracer.streamClosed(Status.CANCELLED);
 
     InOrder inOrder = inOrder(spyServerSpan);
-    inOrder.verify(spyServerSpan, times(0)).addMessageEvent(messageEventCaptor.capture());
+    inOrder.verify(spyServerSpan, times(2)).addMessageEvent(messageEventCaptor.capture());
+    List<MessageEvent> events = messageEventCaptor.getAllValues();
+    assertEquals(
+        MessageEvent.builder(MessageEvent.Type.SENT, 0).setCompressedMessageSize(882).build(),
+        events.get(0));
+    assertEquals(
+        MessageEvent.builder(MessageEvent.Type.SENT, 1).setUncompressedMessageSize(27).build(),
+        events.get(1));
+
+    inOrder
+        .verify(spyServerSpan, times(2))
+        .addAnnotation(stringCaptor.capture(), annotationAttributesCaptor.capture());
+    List<String> annotationDescriptions = stringCaptor.getAllValues();
+    List<Map<String, AttributeValue>> annotationAttributes =
+        annotationAttributesCaptor.getAllValues();
+
+    assertEquals("↘ 255 bytes received", annotationDescriptions.get(0));
+    assertThat(annotationAttributes.get(0).get("id"))
+        .isEqualTo(AttributeValue.longAttributeValue(0));
+    assertThat(annotationAttributes.get(0).get("type"))
+        .isEqualTo(AttributeValue.stringAttributeValue("compressed"));
+
+    assertEquals("↘ 90 bytes received", annotationDescriptions.get(1));
+    assertThat(annotationAttributes.get(1).get("id"))
+        .isEqualTo(AttributeValue.longAttributeValue(0));
+    assertThat(annotationAttributes.get(1).get("type"))
+        .isEqualTo(AttributeValue.stringAttributeValue("uncompressed"));
   }
 }

compiler/src/test/golden/TestDeprecatedService.java.txt

@@ -8,7 +8,7 @@ import static io.grpc.MethodDescriptor.generateFullMethodName;
  * </pre>
  */
 @javax.annotation.Generated(
-    value = "by gRPC proto compiler (version 1.54.0-SNAPSHOT)",
+    value = "by gRPC proto compiler (version 1.54.1)",
     comments = "Source: grpc/testing/compiler/test.proto")
 @io.grpc.stub.annotations.GrpcGenerated
 @java.lang.Deprecated

compiler/src/test/golden/TestService.java.txt

@@ -8,7 +8,7 @@ import static io.grpc.MethodDescriptor.generateFullMethodName;
  * </pre>
  */
 @javax.annotation.Generated(
-    value = "by gRPC proto compiler (version 1.54.0-SNAPSHOT)",
+    value = "by gRPC proto compiler (version 1.54.1)",
     comments = "Source: grpc/testing/compiler/test.proto")
 @io.grpc.stub.annotations.GrpcGenerated
 public final class TestServiceGrpc {

compiler/src/testLite/golden/TestDeprecatedService.java.txt

@@ -8,7 +8,7 @@ import static io.grpc.MethodDescriptor.generateFullMethodName;
  * </pre>
  */
 @javax.annotation.Generated(
-    value = "by gRPC proto compiler (version 1.54.0-SNAPSHOT)",
+    value = "by gRPC proto compiler (version 1.54.1)",
     comments = "Source: grpc/testing/compiler/test.proto")
 @io.grpc.stub.annotations.GrpcGenerated
 @java.lang.Deprecated

compiler/src/testLite/golden/TestService.java.txt

@@ -8,7 +8,7 @@ import static io.grpc.MethodDescriptor.generateFullMethodName;
  * </pre>
  */
 @javax.annotation.Generated(
-    value = "by gRPC proto compiler (version 1.54.0-SNAPSHOT)",
+    value = "by gRPC proto compiler (version 1.54.1)",
     comments = "Source: grpc/testing/compiler/test.proto")
 @io.grpc.stub.annotations.GrpcGenerated
 public final class TestServiceGrpc {

core/src/main/java/io/grpc/internal/GrpcUtil.java

@@ -217,7 +217,7 @@ public final class GrpcUtil {
 
   public static final Splitter ACCEPT_ENCODING_SPLITTER = Splitter.on(',').trimResults();
 
-  private static final String IMPLEMENTATION_VERSION = "1.54.0-SNAPSHOT"; // CURRENT_GRPC_VERSION
+  private static final String IMPLEMENTATION_VERSION = "1.54.1"; // CURRENT_GRPC_VERSION
 
   /**
    * The default timeout in nanos for a keepalive ping request.

core/src/main/java/io/grpc/internal/RetriableStream.java

@@ -282,14 +282,12 @@ abstract class RetriableStream<ReqT> implements ClientStream {
 
       synchronized (lock) {
         savedState = state;
-        if (streamStarted) {
-          if (savedState.winningSubstream != null && savedState.winningSubstream != substream) {
-            // committed but not me, to be cancelled
-            break;
-          }
-          if (savedState.cancelled) {
-            break;
-          }
+        if (savedState.winningSubstream != null && savedState.winningSubstream != substream) {
+          // committed but not me, to be cancelled
+          break;
+        }
+        if (savedState.cancelled) {
+          break;
         }
         if (index == savedState.buffer.size()) { // I'm drained
           state = savedState.substreamDrained(substream);
@@ -326,15 +324,13 @@ abstract class RetriableStream<ReqT> implements ClientStream {
         if (bufferEntry instanceof RetriableStream.StartEntry) {
           streamStarted = true;
         }
-        if (streamStarted) {
-          savedState = state;
-          if (savedState.winningSubstream != null && savedState.winningSubstream != substream) {
-            // committed but not me, to be cancelled
-            break;
-          }
-          if (savedState.cancelled) {
-            break;
-          }
+        savedState = state;
+        if (savedState.winningSubstream != null && savedState.winningSubstream != substream) {
+          // committed but not me, to be cancelled
+          break;
+        }
+        if (savedState.cancelled) {
+          break;
         }
       }
     }
@@ -344,6 +340,10 @@ abstract class RetriableStream<ReqT> implements ClientStream {
       return;
     }
 
+    if (!streamStarted) {
+      // Start stream so inFlightSubStreams is decremented in Sublistener.closed()
+      substream.stream.start(new Sublistener(substream));
+    }
     substream.stream.cancel(
         state.winningSubstream == substream ? cancellationStatus : CANCELLED_BECAUSE_COMMITTED);
   }
@@ -484,6 +484,8 @@ abstract class RetriableStream<ReqT> implements ClientStream {
               }
 
               if (cancelled) {
+                // Start stream so inFlightSubStreams is decremented in Sublistener.closed()
+                newSubstream.stream.start(new Sublistener(newSubstream));
                 newSubstream.stream.cancel(Status.CANCELLED.withDescription("Unneeded hedging"));
                 return;
               }
@@ -507,6 +509,9 @@ abstract class RetriableStream<ReqT> implements ClientStream {
     Runnable runnable = commit(noopSubstream);
 
     if (runnable != null) {
+      synchronized (lock) {
+        state = state.substreamDrained(noopSubstream);
+      }
       runnable.run();
       safeCloseMasterListener(reason, RpcProgress.PROCESSED, new Metadata());
       return;

core/src/test/java/io/grpc/internal/RetriableStreamTest.java

@@ -188,7 +188,7 @@ public class RetriableStreamTest {
     }
   }
 
-  private final RetriableStream<String> retriableStream =
+  private RetriableStream<String> retriableStream =
       newThrottledRetriableStream(null /* throttle */);
   private final RetriableStream<String> hedgingStream =
       newThrottledHedgingStream(null /* throttle */);
@@ -196,10 +196,13 @@ public class RetriableStreamTest {
   private ClientStreamTracer bufferSizeTracer;
 
   private RetriableStream<String> newThrottledRetriableStream(Throttle throttle) {
+    return newThrottledRetriableStream(throttle, MoreExecutors.directExecutor());
+  }
+
+  private RetriableStream<String> newThrottledRetriableStream(Throttle throttle, Executor drainer) {
     return new RecordedRetriableStream(
         method, new Metadata(), channelBufferUsed, PER_RPC_BUFFER_LIMIT, CHANNEL_BUFFER_LIMIT,
-        MoreExecutors.directExecutor(), fakeClock.getScheduledExecutorService(), RETRY_POLICY,
-        null, throttle);
+        drainer, fakeClock.getScheduledExecutorService(), RETRY_POLICY, null, throttle);
   }
 
   private RetriableStream<String> newThrottledHedgingStream(Throttle throttle) {
@@ -598,6 +601,44 @@ public class RetriableStreamTest {
     inOrder.verify(retriableStreamRecorder, never()).postCommit();
   }
 
+  @Test
+  public void transparentRetry_cancel_race() {
+    FakeClock drainer = new FakeClock();
+    retriableStream = newThrottledRetriableStream(null, drainer.getScheduledExecutorService());
+    ClientStream mockStream1 = mock(ClientStream.class);
+    doReturn(mockStream1).when(retriableStreamRecorder).newSubstream(0);
+    InOrder inOrder = inOrder(retriableStreamRecorder);
+
+    retriableStream.start(masterListener);
+
+    ArgumentCaptor<ClientStreamListener> sublistenerCaptor1 =
+        ArgumentCaptor.forClass(ClientStreamListener.class);
+    verify(mockStream1).start(sublistenerCaptor1.capture());
+
+    // retry, but don't drain
+    ClientStream mockStream2 = mock(ClientStream.class);
+    doReturn(mockStream2).when(retriableStreamRecorder).newSubstream(0);
+    sublistenerCaptor1.getValue().closed(
+        Status.fromCode(NON_RETRIABLE_STATUS_CODE), MISCARRIED, new Metadata());
+    assertEquals(1, drainer.numPendingTasks());
+
+    // cancel
+    retriableStream.cancel(Status.CANCELLED);
+    // drain transparent retry
+    drainer.runDueTasks();
+    inOrder.verify(retriableStreamRecorder).postCommit();
+
+    ArgumentCaptor<ClientStreamListener> sublistenerCaptor2 =
+        ArgumentCaptor.forClass(ClientStreamListener.class);
+    verify(mockStream2).start(sublistenerCaptor2.capture());
+    ArgumentCaptor<Status> statusCaptor = ArgumentCaptor.forClass(Status.class);
+    verify(mockStream2).cancel(statusCaptor.capture());
+    assertEquals(Status.CANCELLED.getCode(), statusCaptor.getValue().getCode());
+    assertEquals(CANCELLED_BECAUSE_COMMITTED, statusCaptor.getValue().getDescription());
+    sublistenerCaptor2.getValue().closed(statusCaptor.getValue(), PROCESSED, new Metadata());
+    verify(masterListener).closed(same(Status.CANCELLED), same(PROCESSED), any(Metadata.class));
+  }
+
   @Test
   public void unretriableClosed_cancel() {
     ClientStream mockStream1 = mock(ClientStream.class);

cronet/README.md

@@ -26,7 +26,7 @@ In your app module's `build.gradle` file, include a dependency on both `grpc-cro
 Google Play Services Client Library for Cronet
 
 ```
-implementation 'io.grpc:grpc-cronet:1.52.1'
+implementation 'io.grpc:grpc-cronet:1.54.1'
 implementation 'com.google.android.gms:play-services-cronet:16.0.0'
 ```
 

documentation/android-channel-builder.md

@@ -36,8 +36,8 @@ In your `build.gradle` file, include a dependency on both `grpc-android` and
 `grpc-okhttp`:
 
 ```
-implementation 'io.grpc:grpc-android:1.52.1'
-implementation 'io.grpc:grpc-okhttp:1.52.1'
+implementation 'io.grpc:grpc-android:1.54.1'
+implementation 'io.grpc:grpc-okhttp:1.54.1'
 ```
 
 You also need permission to access the device's network state in your

examples/android/clientcache/app/build.gradle

@@ -34,7 +34,7 @@ android {
 protobuf {
     protoc { artifact = 'com.google.protobuf:protoc:3.21.7' }
     plugins {
-        grpc { artifact = 'io.grpc:protoc-gen-grpc-java:1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
+        grpc { artifact = 'io.grpc:protoc-gen-grpc-java:1.54.1' // CURRENT_GRPC_VERSION
         }
     }
     generateProtoTasks {
@@ -54,12 +54,12 @@ dependencies {
     implementation 'com.android.support:appcompat-v7:27.0.2'
 
     // You need to build grpc-java to obtain these libraries below.
-    implementation 'io.grpc:grpc-okhttp:1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
-    implementation 'io.grpc:grpc-protobuf-lite:1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
-    implementation 'io.grpc:grpc-stub:1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
+    implementation 'io.grpc:grpc-okhttp:1.54.1' // CURRENT_GRPC_VERSION
+    implementation 'io.grpc:grpc-protobuf-lite:1.54.1' // CURRENT_GRPC_VERSION
+    implementation 'io.grpc:grpc-stub:1.54.1' // CURRENT_GRPC_VERSION
     implementation 'org.apache.tomcat:annotations-api:6.0.53'
 
     testImplementation 'junit:junit:4.13.2'
     testImplementation 'com.google.truth:truth:1.0.1'
-    testImplementation 'io.grpc:grpc-testing:1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
+    testImplementation 'io.grpc:grpc-testing:1.54.1' // CURRENT_GRPC_VERSION
 }

examples/android/helloworld/app/build.gradle

@@ -32,7 +32,7 @@ android {
 protobuf {
     protoc { artifact = 'com.google.protobuf:protoc:3.21.7' }
     plugins {
-        grpc { artifact = 'io.grpc:protoc-gen-grpc-java:1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
+        grpc { artifact = 'io.grpc:protoc-gen-grpc-java:1.54.1' // CURRENT_GRPC_VERSION
         }
     }
     generateProtoTasks {
@@ -52,8 +52,8 @@ dependencies {
     implementation 'com.android.support:appcompat-v7:27.0.2'
 
     // You need to build grpc-java to obtain these libraries below.
-    implementation 'io.grpc:grpc-okhttp:1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
-    implementation 'io.grpc:grpc-protobuf-lite:1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
-    implementation 'io.grpc:grpc-stub:1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
+    implementation 'io.grpc:grpc-okhttp:1.54.1' // CURRENT_GRPC_VERSION
+    implementation 'io.grpc:grpc-protobuf-lite:1.54.1' // CURRENT_GRPC_VERSION
+    implementation 'io.grpc:grpc-stub:1.54.1' // CURRENT_GRPC_VERSION
     implementation 'org.apache.tomcat:annotations-api:6.0.53'
 }

examples/android/routeguide/app/build.gradle

@@ -32,7 +32,7 @@ android {
 protobuf {
     protoc { artifact = 'com.google.protobuf:protoc:3.21.7' }
     plugins {
-        grpc { artifact = 'io.grpc:protoc-gen-grpc-java:1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
+        grpc { artifact = 'io.grpc:protoc-gen-grpc-java:1.54.1' // CURRENT_GRPC_VERSION
         }
     }
     generateProtoTasks {
@@ -52,8 +52,8 @@ dependencies {
     implementation 'com.android.support:appcompat-v7:27.0.2'
 
     // You need to build grpc-java to obtain these libraries below.
-    implementation 'io.grpc:grpc-okhttp:1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
-    implementation 'io.grpc:grpc-protobuf-lite:1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
-    implementation 'io.grpc:grpc-stub:1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
+    implementation 'io.grpc:grpc-okhttp:1.54.1' // CURRENT_GRPC_VERSION
+    implementation 'io.grpc:grpc-protobuf-lite:1.54.1' // CURRENT_GRPC_VERSION
+    implementation 'io.grpc:grpc-stub:1.54.1' // CURRENT_GRPC_VERSION
     implementation 'org.apache.tomcat:annotations-api:6.0.53'
 }

examples/android/strictmode/app/build.gradle

@@ -33,7 +33,7 @@ android {
 protobuf {
     protoc { artifact = 'com.google.protobuf:protoc:3.21.7' }
     plugins {
-        grpc { artifact = 'io.grpc:protoc-gen-grpc-java:1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
+        grpc { artifact = 'io.grpc:protoc-gen-grpc-java:1.54.1' // CURRENT_GRPC_VERSION
         }
     }
     generateProtoTasks {
@@ -53,8 +53,8 @@ dependencies {
     implementation 'com.android.support:appcompat-v7:28.0.0'
 
     // You need to build grpc-java to obtain these libraries below.
-    implementation 'io.grpc:grpc-okhttp:1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
-    implementation 'io.grpc:grpc-protobuf-lite:1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
-    implementation 'io.grpc:grpc-stub:1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
+    implementation 'io.grpc:grpc-okhttp:1.54.1' // CURRENT_GRPC_VERSION
+    implementation 'io.grpc:grpc-protobuf-lite:1.54.1' // CURRENT_GRPC_VERSION
+    implementation 'io.grpc:grpc-stub:1.54.1' // CURRENT_GRPC_VERSION
     implementation 'org.apache.tomcat:annotations-api:6.0.53'
 }

examples/build.gradle

@@ -21,7 +21,7 @@ targetCompatibility = 1.8
 
 // Feel free to delete the comment at the next line. It is just for safely
 // updating the version in our release process.
-def grpcVersion = '1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
+def grpcVersion = '1.54.1' // CURRENT_GRPC_VERSION
 def protobufVersion = '3.21.7'
 def protocVersion = protobufVersion
 

examples/example-alts/build.gradle

@@ -23,7 +23,7 @@ targetCompatibility = 1.8
 
 // Feel free to delete the comment at the next line. It is just for safely
 // updating the version in our release process.
-def grpcVersion = '1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
+def grpcVersion = '1.54.1' // CURRENT_GRPC_VERSION
 def protocVersion = '3.21.7'
 
 dependencies {

examples/example-gauth/build.gradle

@@ -23,7 +23,7 @@ targetCompatibility = 1.8
 
 // Feel free to delete the comment at the next line. It is just for safely
 // updating the version in our release process.
-def grpcVersion = '1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
+def grpcVersion = '1.54.1' // CURRENT_GRPC_VERSION
 def protobufVersion = '3.21.7'
 def protocVersion = protobufVersion
 

examples/example-gauth/pom.xml

@@ -6,13 +6,13 @@
   <packaging>jar</packaging>
   <!-- Feel free to delete the comment at the end of these lines. It is just
        for safely updating the version in our release process. -->
-  <version>1.54.0-SNAPSHOT</version><!-- CURRENT_GRPC_VERSION -->
+  <version>1.54.1</version><!-- CURRENT_GRPC_VERSION -->
   <name>example-gauth</name>
   <url>https://github.com/grpc/grpc-java</url>
 
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <grpc.version>1.54.0-SNAPSHOT</grpc.version><!-- CURRENT_GRPC_VERSION -->
+    <grpc.version>1.54.1</grpc.version><!-- CURRENT_GRPC_VERSION -->
     <protobuf.version>3.21.7</protobuf.version>
     <!-- required for jdk9 -->
     <maven.compiler.source>1.8</maven.compiler.source>

examples/example-gcp-observability/README.md

@@ -0,0 +1,39 @@
+gRPC GCP Observability Example
+================
+
+The GCP Observability example consists of a Hello World client and a Hello World server instrumented for logs, metrics and tracing. 
+
+__Please refer to Microservices Observability user guide for setup.__
+
+### Build the example
+
+Build the Observability client & server. From the `grpc-java/examples/example-gcp-observability`
+directory:
+```
+$ ../gradlew installDist
+```
+
+This creates the scripts `build/install/example-gcp-observability/bin/gcp-observability-client` and
+`build/install/example-gcp-observability/bin/gcp-observability-server`.
+
+### Run the example with configuration
+
+To use Observability, you should first setup and configure authorization as mentioned in the user guide. 
+
+You need to set the `GRPC_GCP_OBSERVABILITY_CONFIG_FILE` environment variable to point to the gRPC GCP Observability configuration file (preferred) or if that
+is not set then `GRPC_GCP_OBSERVABILITY_CONFIG` environment variable to gRPC GCP Observability configuration value. This is needed by both
+`build/install/example-gcp-observability/bin/gcp-observability-client` and
+`build/install/example-gcp-observability/bin/gcp-observability-server`.
+
+1. To start the observability-enabled example server on its default port of 50051, run:
+```
+$ export GRPC_GCP_OBSERVABILITY_CONFIG_FILE=src/main/resources/io/grpc/examples/gcpobservability/gcp_observability_server_config.json
+$ ./build/install/example-gcp-observability/bin/gcp-observability-server
+```
+
+2. In a different terminal window, run the observability-enabled example client:
+```
+$ export GRPC_GCP_OBSERVABILITY_CONFIG_FILE=src/main/resources/io/grpc/examples/gcpobservability/gcp_observability_client_config.json
+$ ./build/install/example-gcp-observability/bin/gcp-observability-client
+```
+

examples/example-gcp-observability/build.gradle

@@ -0,0 +1,68 @@
+plugins {
+    // Provide convenience executables for trying out the examples.
+    id 'application'
+    // ASSUMES GRADLE 5.6 OR HIGHER. Use plugin version 0.8.10 with earlier gradle versions
+    id 'com.google.protobuf' version '0.8.17'
+    // Generate IntelliJ IDEA's .idea & .iml project files
+    id 'idea'
+    id 'java'
+}
+
+repositories {
+    maven { // The google mirror is less flaky than mavenCentral()
+        url "https://maven-central.storage-download.googleapis.com/maven2/"
+    }
+    mavenCentral()
+    mavenLocal()
+}
+
+sourceCompatibility = 1.8
+targetCompatibility = 1.8
+
+// IMPORTANT: You probably want the non-SNAPSHOT version of gRPC. Make sure you
+// are looking at a tagged version of the example and not "master"!
+
+// Feel free to delete the comment at the next line. It is just for safely
+// updating the version in our release process.
+def grpcVersion = '1.54.1' // CURRENT_GRPC_VERSION
+def protocVersion = '3.21.7'
+
+dependencies {
+    implementation "io.grpc:grpc-protobuf:${grpcVersion}"
+    implementation "io.grpc:grpc-stub:${grpcVersion}"
+    implementation "io.grpc:grpc-gcp-observability:${grpcVersion}"
+    compileOnly "org.apache.tomcat:annotations-api:6.0.53"
+    runtimeOnly "io.grpc:grpc-netty-shaded:${grpcVersion}"
+}
+
+protobuf {
+    protoc { artifact = "com.google.protobuf:protoc:${protocVersion}" }
+    plugins {
+        grpc { artifact = "io.grpc:protoc-gen-grpc-java:${grpcVersion}" }
+    }
+    generateProtoTasks {
+        all()*.plugins { grpc {} }
+    }
+}
+
+startScripts.enabled = false
+
+task ObservabilityHelloWorldServer(type: CreateStartScripts) {
+    mainClass = 'io.grpc.examples.gcpobservability.GcpObservabilityServer'
+    applicationName = 'gcp-observability-server'
+    outputDir = new File(project.buildDir, 'tmp/scripts/' + name)
+    classpath = startScripts.classpath
+}
+
+task ObservabilityHelloWorldClient(type: CreateStartScripts) {
+    mainClass = 'io.grpc.examples.gcpobservability.GcpObservabilityClient'
+    applicationName = 'gcp-observability-client'
+    outputDir = new File(project.buildDir, 'tmp/scripts/' + name)
+    classpath = startScripts.classpath
+}
+
+applicationDistribution.into('bin') {
+    from(ObservabilityHelloWorldServer)
+    from(ObservabilityHelloWorldClient)
+    fileMode = 0755
+}

examples/example-gcp-observability/settings.gradle

@@ -0,0 +1 @@
+rootProject.name = 'example-gcp-observability'

examples/example-gcp-observability/src/main/java/io/grpc/examples/gcpobservability/GcpObservabilityClient.java

@@ -0,0 +1,93 @@
+/*
+ * Copyright 2023 The gRPC Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.grpc.examples.gcpobservability;
+
+import io.grpc.Channel;
+import io.grpc.Grpc;
+import io.grpc.InsecureChannelCredentials;
+import io.grpc.ManagedChannel;
+import io.grpc.StatusRuntimeException;
+import io.grpc.examples.helloworld.GreeterGrpc;
+import io.grpc.examples.helloworld.HelloReply;
+import io.grpc.examples.helloworld.HelloRequest;
+import io.grpc.gcp.observability.GcpObservability;
+import java.util.concurrent.TimeUnit;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/**
+ * A simple observability client that requests a greeting from the {@link HelloWorldServer} and
+ * generates logs, metrics and traces based on the configuration.
+ */
+public class GcpObservabilityClient {
+  private static final Logger logger = Logger.getLogger(GcpObservabilityClient.class.getName());
+
+  private final GreeterGrpc.GreeterBlockingStub blockingStub;
+
+  /** Construct client for accessing HelloWorld server using the existing channel. */
+  public GcpObservabilityClient(Channel channel) {
+    blockingStub = GreeterGrpc.newBlockingStub(channel);
+  }
+
+  /** Say hello to server. */
+  public void greet(String name) {
+    logger.info("Will try to greet " + name + " ...");
+    HelloRequest request = HelloRequest.newBuilder().setName(name).build();
+    HelloReply response;
+    try {
+      response = blockingStub.sayHello(request);
+    } catch (StatusRuntimeException e) {
+      logger.log(Level.WARNING, "RPC failed: {0}", e.getStatus());
+      return;
+    }
+    logger.info("Greeting: " + response.getMessage());
+  }
+
+  /**
+   * Greet server. If provided, the first element of {@code args} is the name to use in the
+   * greeting. The second argument is the target server.
+   */
+  public static void main(String[] args) throws Exception {
+    String user = "world";
+    String target = "localhost:50051";
+    if (args.length > 0) {
+      if ("--help".equals(args[0])) {
+        System.err.println("Usage: [name [target]]");
+        System.err.println("");
+        System.err.println("  name    The name you wish to be greeted by. Defaults to " + user);
+        System.err.println("  target  The server to connect to. Defaults to " + target);
+        System.exit(1);
+      }
+      user = args[0];
+    }
+    if (args.length > 1) {
+      target = args[1];
+    }
+
+    // Initialize observability
+    try (GcpObservability observability = GcpObservability.grpcInit()) {
+      ManagedChannel channel = Grpc.newChannelBuilder(target, InsecureChannelCredentials.create())
+          .build();
+      try {
+        GcpObservabilityClient client = new GcpObservabilityClient(channel);
+        client.greet(user);
+      } finally {
+        channel.shutdownNow().awaitTermination(5, TimeUnit.SECONDS);
+      }
+    } // observability.close() called implicitly
+  }
+}

examples/example-gcp-observability/src/main/java/io/grpc/examples/gcpobservability/GcpObservabilityServer.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright 2023 The gRPC Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.grpc.examples.gcpobservability;
+
+import io.grpc.Grpc;
+import io.grpc.InsecureServerCredentials;
+import io.grpc.Server;
+import io.grpc.examples.helloworld.GreeterGrpc;
+import io.grpc.examples.helloworld.HelloReply;
+import io.grpc.examples.helloworld.HelloRequest;
+import io.grpc.gcp.observability.GcpObservability;
+import io.grpc.stub.StreamObserver;
+import java.io.IOException;
+import java.util.concurrent.TimeUnit;
+import java.util.logging.Logger;
+
+/**
+ * Observability server that manages startup/shutdown of a {@code Greeter} server and generates
+ * logs, metrics and traces based on the configuration.
+ */
+public class GcpObservabilityServer {
+  private static final Logger logger = Logger.getLogger(GcpObservabilityServer.class.getName());
+
+  private Server server;
+
+  private void start() throws IOException {
+    int port = 50051;
+    server = Grpc.newServerBuilderForPort(port, InsecureServerCredentials.create())
+        .addService(new GreeterImpl())
+        .build()
+        .start();
+    logger.info("Server started, listening on " + port);
+  }
+
+  private void stop() throws InterruptedException {
+    if (server != null) {
+      server.shutdown().awaitTermination(30, TimeUnit.SECONDS);
+    }
+  }
+
+  private void blockUntilShutdown() throws InterruptedException {
+    if (server != null) {
+      server.awaitTermination();
+    }
+  }
+
+  /**
+   * Main launches the server from the command line.
+   */
+  public static void main(String[] args) throws IOException, InterruptedException {
+    // Initialize observability
+    GcpObservability observability = GcpObservability.grpcInit();
+    final GcpObservabilityServer server = new GcpObservabilityServer();
+    server.start();
+
+    Runtime.getRuntime().addShutdownHook(new Thread() {
+      @Override
+      public void run() {
+        System.err.println("*** shutting down gRPC server since JVM is shutting down");
+        try {
+          server.stop();
+        } catch (InterruptedException e) {
+          e.printStackTrace(System.err);
+        }
+        // Shut down observability
+        observability.close();
+        System.err.println("*** server shut down");
+      }
+    });
+
+    server.blockUntilShutdown();
+  }
+
+  static class GreeterImpl extends GreeterGrpc.GreeterImplBase {
+
+    @Override
+    public void sayHello(HelloRequest req, StreamObserver<HelloReply> responseObserver) {
+      HelloReply reply = HelloReply.newBuilder().setMessage("Hello " + req.getName()).build();
+      responseObserver.onNext(reply);
+      responseObserver.onCompleted();
+    }
+  }
+}

examples/example-gcp-observability/src/main/proto/helloworld/helloworld.proto

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2023 The gRPC Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+syntax = "proto3";
+
+option java_multiple_files = true;
+option java_package = "io.grpc.examples.helloworld";
+option java_outer_classname = "HelloWorldProto";
+option objc_class_prefix = "HLW";
+
+package helloworld;
+
+// The greeting service definition.
+service Greeter {
+  // Sends a greeting
+  rpc SayHello (HelloRequest) returns (HelloReply) {}
+}
+
+// The request message containing the user's name.
+message HelloRequest {
+  string name = 1;
+}
+
+// The response message containing the greetings
+message HelloReply {
+  string message = 1;
+}

examples/example-gcp-observability/src/main/resources/io/grpc/examples/gcpobservability/gcp_observability_client_config.json

@@ -0,0 +1,17 @@
+{
+  "cloud_monitoring": {},
+  "cloud_trace": {
+    "sampling_rate": 1.0
+  },
+  "cloud_logging": {
+    "client_rpc_events": [{
+      "methods": ["helloworld.Greeter/*"]
+    }],
+    "server_rpc_events": [{
+      "methods": ["helloworld.Greeter/*"]
+    }]
+  },
+  "labels": {
+    "environment" : "example-client"
+  }
+}

examples/example-gcp-observability/src/main/resources/io/grpc/examples/gcpobservability/gcp_observability_server_config.json

@@ -0,0 +1,17 @@
+{
+  "cloud_monitoring": {},
+  "cloud_trace": {
+    "sampling_rate": 1.0
+  },
+  "cloud_logging": {
+    "client_rpc_events": [{
+      "methods": ["helloworld.Greeter/*"]
+    }],
+    "server_rpc_events": [{
+      "methods": ["helloworld.Greeter/*"]
+    }]
+  },
+  "labels": {
+    "environment" : "example-server"
+  }
+}

examples/example-hostname/build.gradle

@@ -21,7 +21,7 @@ targetCompatibility = 1.8
 
 // Feel free to delete the comment at the next line. It is just for safely
 // updating the version in our release process.
-def grpcVersion = '1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
+def grpcVersion = '1.54.1' // CURRENT_GRPC_VERSION
 def protobufVersion = '3.21.7'
 
 dependencies {

examples/example-hostname/pom.xml

@@ -6,13 +6,13 @@
   <packaging>jar</packaging>
   <!-- Feel free to delete the comment at the end of these lines. It is just
        for safely updating the version in our release process. -->
-  <version>1.54.0-SNAPSHOT</version><!-- CURRENT_GRPC_VERSION -->
+  <version>1.54.1</version><!-- CURRENT_GRPC_VERSION -->
   <name>example-hostname</name>
   <url>https://github.com/grpc/grpc-java</url>
 
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <grpc.version>1.54.0-SNAPSHOT</grpc.version><!-- CURRENT_GRPC_VERSION -->
+    <grpc.version>1.54.1</grpc.version><!-- CURRENT_GRPC_VERSION -->
     <protoc.version>3.21.7</protoc.version>
     <!-- required for jdk9 -->
     <maven.compiler.source>1.8</maven.compiler.source>

examples/example-jwt-auth/build.gradle

@@ -22,7 +22,7 @@ targetCompatibility = 1.8
 
 // Feel free to delete the comment at the next line. It is just for safely
 // updating the version in our release process.
-def grpcVersion = '1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
+def grpcVersion = '1.54.1' // CURRENT_GRPC_VERSION
 def protobufVersion = '3.21.7'
 def protocVersion = protobufVersion
 

examples/example-jwt-auth/pom.xml

@@ -7,13 +7,13 @@
   <packaging>jar</packaging>
   <!-- Feel free to delete the comment at the end of these lines. It is just
        for safely updating the version in our release process. -->
-  <version>1.54.0-SNAPSHOT</version><!-- CURRENT_GRPC_VERSION -->
+  <version>1.54.1</version><!-- CURRENT_GRPC_VERSION -->
   <name>example-jwt-auth</name>
   <url>https://github.com/grpc/grpc-java</url>
 
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <grpc.version>1.54.0-SNAPSHOT</grpc.version><!-- CURRENT_GRPC_VERSION -->
+    <grpc.version>1.54.1</grpc.version><!-- CURRENT_GRPC_VERSION -->
     <protobuf.version>3.21.7</protobuf.version>
     <protoc.version>3.21.7</protoc.version>
     <!-- required for jdk9 -->

examples/example-orca/build.gradle

@@ -17,7 +17,7 @@ repositories {
 sourceCompatibility = 1.8
 targetCompatibility = 1.8
 
-def grpcVersion = '1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
+def grpcVersion = '1.54.1' // CURRENT_GRPC_VERSION
 def protocVersion = '3.21.7'
 
 dependencies {

examples/example-servlet/build.gradle

@@ -15,7 +15,7 @@ repositories {
 sourceCompatibility = 1.8
 targetCompatibility = 1.8
 
-def grpcVersion = '1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
+def grpcVersion = '1.54.1' // CURRENT_GRPC_VERSION
 def protocVersion = '3.21.7'
 
 dependencies {

examples/example-tls/build.gradle

@@ -23,7 +23,7 @@ targetCompatibility = 1.8
 
 // Feel free to delete the comment at the next line. It is just for safely
 // updating the version in our release process.
-def grpcVersion = '1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
+def grpcVersion = '1.54.1' // CURRENT_GRPC_VERSION
 def protocVersion = '3.21.7'
 
 dependencies {

examples/example-tls/pom.xml

@@ -6,13 +6,13 @@
   <packaging>jar</packaging>
   <!-- Feel free to delete the comment at the end of these lines. It is just
        for safely updating the version in our release process. -->
-  <version>1.54.0-SNAPSHOT</version><!-- CURRENT_GRPC_VERSION -->
+  <version>1.54.1</version><!-- CURRENT_GRPC_VERSION -->
   <name>example-tls</name>
   <url>https://github.com/grpc/grpc-java</url>
 
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <grpc.version>1.54.0-SNAPSHOT</grpc.version><!-- CURRENT_GRPC_VERSION -->
+    <grpc.version>1.54.1</grpc.version><!-- CURRENT_GRPC_VERSION -->
     <protoc.version>3.21.7</protoc.version>
     <netty.tcnative.version>2.0.56.Final</netty.tcnative.version>
     <!-- required for jdk9 -->

examples/example-xds/build.gradle

@@ -22,7 +22,7 @@ targetCompatibility = 1.8
 
 // Feel free to delete the comment at the next line. It is just for safely
 // updating the version in our release process.
-def grpcVersion = '1.54.0-SNAPSHOT' // CURRENT_GRPC_VERSION
+def grpcVersion = '1.54.1' // CURRENT_GRPC_VERSION
 def nettyTcNativeVersion = '2.0.56.Final'
 def protocVersion = '3.21.7'
 

examples/pom.xml

@@ -6,13 +6,13 @@
   <packaging>jar</packaging>
   <!-- Feel free to delete the comment at the end of these lines. It is just
        for safely updating the version in our release process. -->
-  <version>1.54.0-SNAPSHOT</version><!-- CURRENT_GRPC_VERSION -->
+  <version>1.54.1</version><!-- CURRENT_GRPC_VERSION -->
   <name>examples</name>
   <url>https://github.com/grpc/grpc-java</url>
 
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <grpc.version>1.54.0-SNAPSHOT</grpc.version><!-- CURRENT_GRPC_VERSION -->
+    <grpc.version>1.54.1</grpc.version><!-- CURRENT_GRPC_VERSION -->
     <protobuf.version>3.21.7</protobuf.version>
     <protoc.version>3.21.7</protoc.version>
     <!-- required for JDK 8 -->

gcp-observability/build.gradle

@@ -20,11 +20,13 @@ tasks.named("compileJava").configure {
 }
 
 dependencies {
-    def cloudLoggingVersion = '3.6.1'
+    def cloudLoggingVersion = '3.14.5'
 
     annotationProcessor libraries.auto.value
     api project(':grpc-api')
-    
+
+    // TODO(dnvindhya): Prefer using our own libraries, update the dependencies
+    //  in gradle/libs.versions instead
     implementation project(':grpc-protobuf'),
             project(':grpc-stub'),
             project(':grpc-alts'),
@@ -35,12 +37,10 @@ dependencies {
             libraries.opencensus.exporter.trace.stackdriver,
             project(':grpc-xds'), // Align grpc versions
             project(':grpc-services'), // Align grpc versions
-            libraries.animalsniffer.annotations, // Prefer our version
-            libraries.google.auth.credentials, // Prefer our version
-            libraries.protobuf.java.util, // Prefer our version
-            libraries.gson, // Prefer our version
-            libraries.perfmark.api, // Prefer our version
-            libraries.re2j, // Prefer our version
+            ('com.google.protobuf:protobuf-java:3.21.12'),
+            ('com.google.api.grpc:proto-google-common-protos:2.14.2'),
+            ('com.google.auth:google-auth-library-oauth2-http:1.16.0'),
+            ('io.opencensus:opencensus-api:0.31.1'),
             ('com.google.guava:guava:31.1-jre')
 
     runtimeOnly libraries.opencensus.impl

gcp-observability/interop/src/main/java/io/grpc/gcp/observability/interop/TestServiceInterop.java

@@ -20,7 +20,6 @@ import io.grpc.gcp.observability.GcpObservability;
 import io.grpc.testing.integration.TestServiceClient;
 import io.grpc.testing.integration.TestServiceServer;
 import java.util.Arrays;
-import java.util.concurrent.TimeUnit;
 
 /**
  * Combined interop client and server for observability testing.
@@ -47,11 +46,6 @@ public final class TestServiceInterop {
       } else {
         TestServiceServer.main(args);
       }
-      // TODO(stanleycheung): remove this once the observability exporter plugin is able to
-      //                      gracefully flush observability data to cloud at shutdown
-      final int o11yCloseSleepSeconds = 65;
-      System.out.println("Sleeping " + o11yCloseSleepSeconds + " seconds before exiting");
-      Thread.sleep(TimeUnit.MILLISECONDS.convert(o11yCloseSleepSeconds, TimeUnit.SECONDS));
     }
   }
 

gcp-observability/src/main/java/io/grpc/gcp/observability/GcpObservability.java

@@ -21,7 +21,6 @@ import static com.google.common.base.Preconditions.checkNotNull;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.collect.ImmutableSet;
 import io.grpc.ClientInterceptor;
-import io.grpc.ExperimentalApi;
 import io.grpc.InternalGlobalInterceptors;
 import io.grpc.ManagedChannelProvider.ProviderNotFoundException;
 import io.grpc.ServerInterceptor;
@@ -36,6 +35,7 @@ import io.grpc.gcp.observability.interceptors.InternalLoggingServerInterceptor;
 import io.grpc.gcp.observability.interceptors.LogHelper;
 import io.grpc.gcp.observability.logging.GcpLogSink;
 import io.grpc.gcp.observability.logging.Sink;
+import io.grpc.gcp.observability.logging.TraceLoggingHelper;
 import io.opencensus.common.Duration;
 import io.opencensus.contrib.grpc.metrics.RpcViewConstants;
 import io.opencensus.exporter.stats.stackdriver.StackdriverStatsConfiguration;
@@ -50,17 +50,30 @@ import io.opencensus.trace.AttributeValue;
 import io.opencensus.trace.Tracing;
 import io.opencensus.trace.config.TraceConfig;
 import java.io.IOException;
+import java.lang.management.ManagementFactory;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.security.SecureRandom;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.Map;
+import java.util.concurrent.TimeUnit;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 import java.util.stream.Collectors;
 
 /** The main class for gRPC Google Cloud Platform Observability features. */
-@ExperimentalApi("https://github.com/grpc/grpc-java/issues/8869")
 public final class GcpObservability implements AutoCloseable {
+
+  private static final Logger logger = Logger.getLogger(GcpObservability.class.getName());
   private static final int METRICS_EXPORT_INTERVAL = 30;
-  private static final ImmutableSet<String> SERVICES_TO_EXCLUDE = ImmutableSet.of(
+
+  static final String DEFAULT_METRIC_CUSTOM_TAG_KEY = "opencensus_task";
+  @VisibleForTesting
+  static final ImmutableSet<String> SERVICES_TO_EXCLUDE = ImmutableSet.of(
       "google.logging.v2.LoggingServiceV2", "google.monitoring.v3.MetricService",
       "google.devtools.cloudtrace.v2.TraceService");
+
   private static GcpObservability instance = null;
   private final Sink sink;
   private final ObservabilityConfig config;
@@ -75,11 +88,11 @@ public final class GcpObservability implements AutoCloseable {
    */
   public static synchronized GcpObservability grpcInit() throws IOException {
     if (instance == null) {
-      GlobalLocationTags globalLocationTags = new GlobalLocationTags();
       ObservabilityConfigImpl observabilityConfig = ObservabilityConfigImpl.getInstance();
-      Sink sink = new GcpLogSink(observabilityConfig.getProjectId(),
-          globalLocationTags.getLocationTags(), observabilityConfig.getCustomTags(),
-          SERVICES_TO_EXCLUDE);
+      TraceLoggingHelper traceLoggingHelper = new TraceLoggingHelper(
+          observabilityConfig.getProjectId());
+      Sink sink = new GcpLogSink(observabilityConfig.getProjectId(), observabilityConfig,
+          SERVICES_TO_EXCLUDE, traceLoggingHelper);
       LogHelper helper = new LogHelper(sink);
       ConfigFilterHelper configFilterHelper = ConfigFilterHelper.getInstance(observabilityConfig);
       instance = grpcInit(sink, observabilityConfig,
@@ -113,6 +126,16 @@ public final class GcpObservability implements AutoCloseable {
         throw new IllegalStateException("GcpObservability already closed!");
       }
       sink.close();
+      if (config.isEnableCloudMonitoring() || config.isEnableCloudTracing()) {
+        try {
+          // Sleeping before shutdown to ensure all metrics and traces are flushed
+          Thread.sleep(
+              TimeUnit.MILLISECONDS.convert(2 * METRICS_EXPORT_INTERVAL, TimeUnit.SECONDS));
+        } catch (InterruptedException e) {
+          Thread.currentThread().interrupt();
+          logger.log(Level.SEVERE, "Caught exception during sleep", e);
+        }
+      }
       instance = null;
     }
   }
@@ -128,14 +151,14 @@ public final class GcpObservability implements AutoCloseable {
     }
     if (config.isEnableCloudMonitoring()) {
       clientInterceptors.add(getConditionalInterceptor(
-          InternalCensusStatsAccessor.getClientInterceptor(true, true, true, true)));
+          InternalCensusStatsAccessor.getClientInterceptor(true, true, false, true)));
       tracerFactories.add(
-          InternalCensusStatsAccessor.getServerStreamTracerFactory(true, true, true));
+          InternalCensusStatsAccessor.getServerStreamTracerFactory(true, true, false));
     }
     if (config.isEnableCloudTracing()) {
       clientInterceptors.add(
-          getConditionalInterceptor(InternalCensusTracingAccessor.getClientInterceptor(false)));
-      tracerFactories.add(InternalCensusTracingAccessor.getServerStreamTracerFactory(false));
+          getConditionalInterceptor(InternalCensusTracingAccessor.getClientInterceptor()));
+      tracerFactories.add(InternalCensusTracingAccessor.getServerStreamTracerFactory());
     }
 
     InternalGlobalInterceptors.setInterceptorsTracers(
@@ -180,12 +203,17 @@ public final class GcpObservability implements AutoCloseable {
       if (projectId != null) {
         statsConfigurationBuilder.setProjectId(projectId);
       }
+      Map<LabelKey, LabelValue> constantLabels = new HashMap<>();
+      constantLabels.put(
+          LabelKey.create(DEFAULT_METRIC_CUSTOM_TAG_KEY, DEFAULT_METRIC_CUSTOM_TAG_KEY),
+          LabelValue.create(generateDefaultMetricTagValue()));
       if (customTags != null) {
-        Map<LabelKey, LabelValue> constantLabels = customTags.entrySet().stream()
-            .collect(Collectors.toMap(e -> LabelKey.create(e.getKey(), e.getKey()),
-                e -> LabelValue.create(e.getValue())));
-        statsConfigurationBuilder.setConstantLabels(constantLabels);
+        for (Map.Entry<String, String> mapEntry : customTags.entrySet()) {
+          constantLabels.putIfAbsent(LabelKey.create(mapEntry.getKey(), mapEntry.getKey()),
+              LabelValue.create(mapEntry.getValue()));
+        }
       }
+      statsConfigurationBuilder.setConstantLabels(constantLabels);
       statsConfigurationBuilder.setExportInterval(Duration.create(METRICS_EXPORT_INTERVAL, 0));
       StackdriverStatsExporter.createAndRegister(statsConfigurationBuilder.build());
     }
@@ -209,6 +237,20 @@ public final class GcpObservability implements AutoCloseable {
     }
   }
 
+  private static String generateDefaultMetricTagValue() {
+    final String jvmName = ManagementFactory.getRuntimeMXBean().getName();
+    if (jvmName.indexOf('@') < 1) {
+      String hostname = "localhost";
+      try {
+        hostname = InetAddress.getLocalHost().getHostName();
+      } catch (UnknownHostException e) {
+        logger.log(Level.INFO, "Unable to get the hostname.", e);
+      }
+      return "java-" + new SecureRandom().nextInt() + "@" + hostname;
+    }
+    return "java-" + jvmName;
+  }
+
   private GcpObservability(
       Sink sink,
       ObservabilityConfig config) {

gcp-observability/src/main/java/io/grpc/gcp/observability/GlobalLocationTags.java

@@ -1,148 +0,0 @@
-/*
- * Copyright 2022 The gRPC Authors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package io.grpc.gcp.observability;
-
-import com.google.api.client.http.HttpTransport;
-import com.google.api.client.http.javanet.NetHttpTransport;
-import com.google.api.client.util.Strings;
-import com.google.auth.http.HttpTransportFactory;
-import com.google.common.annotations.VisibleForTesting;
-import com.google.common.base.Charsets;
-import com.google.common.collect.ImmutableMap;
-import java.io.IOException;
-import java.nio.file.Files;
-import java.nio.file.Path;
-import java.nio.file.Paths;
-import java.util.Map;
-import java.util.Scanner;
-import java.util.function.Function;
-import java.util.logging.Level;
-import java.util.logging.Logger;
-
-/** A container of all global location tags used for observability. */
-final class GlobalLocationTags {
-  private static final Logger logger = Logger.getLogger(GlobalLocationTags.class.getName());
-
-  private final Map<String, String> locationTags;
-
-  GlobalLocationTags() {
-    ImmutableMap.Builder<String, String> locationTagsBuilder = ImmutableMap.builder();
-    populate(locationTagsBuilder);
-    locationTags = locationTagsBuilder.buildOrThrow();
-  }
-
-  private static String applyTrim(String value) {
-    if (!Strings.isNullOrEmpty(value)) {
-      value = value.trim();
-    }
-    return value;
-  }
-
-  Map<String, String> getLocationTags() {
-    return locationTags;
-  }
-
-  @VisibleForTesting
-  static void populateFromMetadataServer(ImmutableMap.Builder<String, String> locationTags) {
-    MetadataConfig metadataConfig = new MetadataConfig(new DefaultHttpTransportFactory());
-    metadataConfig.init();
-    locationTags.putAll(metadataConfig.getAllValues());
-  }
-
-  @VisibleForTesting
-  static void populateFromKubernetesValues(ImmutableMap.Builder<String, String> locationTags,
-      String namespaceFile,
-      String hostnameFile, String cgroupFile) {
-    // namespace name: contents of file /var/run/secrets/kubernetes.io/serviceaccount/namespace
-    populateFromFileContents(locationTags, "namespace_name",
-        namespaceFile, GlobalLocationTags::applyTrim);
-
-    // pod_name: hostname i.e. contents of /etc/hostname
-    populateFromFileContents(locationTags, "pod_name", hostnameFile,
-        GlobalLocationTags::applyTrim);
-
-    // container_id: parsed from /proc/self/cgroup . Note: only works for Linux-based containers
-    populateFromFileContents(locationTags, "container_id", cgroupFile,
-        (value) -> getContainerIdFromFileContents(value));
-  }
-
-  @VisibleForTesting
-  static void populateFromFileContents(ImmutableMap.Builder<String, String> locationTags,
-      String key, String filePath, Function<String, String> parser) {
-    String value = parser.apply(readFileContents(filePath));
-    if (value != null) {
-      locationTags.put(key, value);
-    }
-  }
-
-  /**
-   * Parse from a line such as this.
-   * 1:name=systemd:/kubepods/burstable/podf5143dd2/de67c4419b20924eaa141813
-   *
-   * @param value file contents
-   * @return container-id parsed ("podf5143dd2/de67c4419b20924eaa141813" from the above snippet)
-   */
-  @VisibleForTesting static String getContainerIdFromFileContents(String value) {
-    if (value != null) {
-      try (Scanner scanner = new Scanner(value)) {
-        while (scanner.hasNextLine()) {
-          String line = scanner.nextLine();
-          String[] tokens = line.split(":");
-          if (tokens.length == 3 && tokens[2].startsWith("/kubepods/burstable/")) {
-            tokens = tokens[2].split("/");
-            if (tokens.length == 5) {
-              return tokens[4];
-            }
-          }
-        }
-      }
-    }
-    return null;
-  }
-
-  private static String readFileContents(String file) {
-    Path fileName = Paths.get(file);
-    if (Files.isReadable(fileName)) {
-      try {
-        byte[] bytes = Files.readAllBytes(fileName);
-        return new String(bytes, Charsets.US_ASCII);
-      } catch (IOException e) {
-        logger.log(Level.FINE, "Reading file:" + file, e);
-      }
-    } else {
-      logger.log(Level.FINE, "File:" + file + " is not readable (or missing?)");
-    }
-    return null;
-  }
-
-  static void populate(ImmutableMap.Builder<String, String> locationTags) {
-    populateFromMetadataServer(locationTags);
-    populateFromKubernetesValues(locationTags,
-        "/var/run/secrets/kubernetes.io/serviceaccount/namespace",
-        "/etc/hostname", "/proc/self/cgroup");
-  }
-
-  private static class DefaultHttpTransportFactory implements HttpTransportFactory {
-
-    private static final HttpTransport netHttpTransport = new NetHttpTransport();
-
-    @Override
-    public HttpTransport create() {
-      return netHttpTransport;
-    }
-  }
-}

gcp-observability/src/main/java/io/grpc/gcp/observability/MetadataConfig.java

@@ -1,107 +0,0 @@
-/*
- * Copyright 2022 The gRPC Authors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package io.grpc.gcp.observability;
-
-import com.google.api.client.http.GenericUrl;
-import com.google.api.client.http.HttpHeaders;
-import com.google.api.client.http.HttpRequest;
-import com.google.api.client.http.HttpRequestFactory;
-import com.google.api.client.http.HttpResponse;
-import com.google.api.client.http.HttpStatusCodes;
-import com.google.api.client.http.HttpTransport;
-import com.google.auth.http.HttpTransportFactory;
-import com.google.common.annotations.VisibleForTesting;
-import com.google.common.collect.ImmutableMap;
-import java.io.IOException;
-import java.io.InputStream;
-import java.util.logging.Level;
-import java.util.logging.Logger;
-
-/** Class to read Google Metadata Server values. */
-final class MetadataConfig {
-  private static final Logger logger = Logger.getLogger(MetadataConfig.class.getName());
-
-  private static final int TIMEOUT_MS = 5000;
-  private static final String METADATA_URL = "http://metadata.google.internal/computeMetadata/v1/";
-  private HttpRequestFactory requestFactory;
-  private HttpTransportFactory transportFactory;
-
-  @VisibleForTesting public MetadataConfig(HttpTransportFactory transportFactory) {
-    this.transportFactory = transportFactory;
-
-  }
-
-  void init() {
-    HttpTransport httpTransport = transportFactory.create();
-    requestFactory = httpTransport.createRequestFactory();
-  }
-
-  /** gets all the values from the MDS we need to set in our logging tags. */
-  ImmutableMap<String, String> getAllValues() {
-    ImmutableMap.Builder<String, String> builder = ImmutableMap.builder();
-    //addValueFor(builder, "instance/hostname", "GCE_INSTANCE_HOSTNAME");
-    addValueFor(builder, "instance/id", "gke_node_id");
-    //addValueFor(builder, "instance/zone", "GCE_INSTANCE_ZONE");
-    addValueFor(builder, "project/project-id", "project_id");
-    addValueFor(builder, "project/numeric-project-id", "project_numeric_id");
-    addValueFor(builder, "instance/attributes/cluster-name", "cluster_name");
-    addValueFor(builder, "instance/attributes/cluster-uid", "cluster_uid");
-    addValueFor(builder, "instance/attributes/cluster-location", "location");
-    try {
-      requestFactory.getTransport().shutdown();
-    } catch (IOException e) {
-      logger.log(Level.FINE, "Calling HttpTransport.shutdown()", e);
-    }
-    return builder.buildOrThrow();
-  }
-
-  void addValueFor(ImmutableMap.Builder<String, String> builder, String attribute, String key) {
-    try {
-      String value = getAttribute(attribute);
-      if (value != null) {
-        builder.put(key, value);
-      }
-    } catch (IOException e) {
-      logger.log(Level.FINE, "Calling getAttribute('" + attribute +  "')", e);
-    }
-  }
-
-  String getAttribute(String attributeName) throws IOException {
-    GenericUrl url = new GenericUrl(METADATA_URL + attributeName);
-    HttpRequest request = requestFactory.buildGetRequest(url);
-    request = request.setReadTimeout(TIMEOUT_MS);
-    request = request.setConnectTimeout(TIMEOUT_MS);
-    request = request.setHeaders(new HttpHeaders().set("Metadata-Flavor", "Google"));
-    HttpResponse response = null;
-    try {
-      response = request.execute();
-      if (response.getStatusCode() == HttpStatusCodes.STATUS_CODE_OK) {
-        InputStream stream = response.getContent();
-        if (stream != null) {
-          byte[] bytes = new byte[stream.available()];
-          stream.read(bytes);
-          return new String(bytes, response.getContentCharset());
-        }
-      }
-    } finally {
-      if (response != null) {
-        response.disconnect();
-      }
-    }
-    return null;
-  }
-}

gcp-observability/src/main/java/io/grpc/gcp/observability/interceptors/InternalLoggingChannelInterceptor.java

@@ -16,6 +16,8 @@
 
 package io.grpc.gcp.observability.interceptors;
 
+import static io.grpc.census.internal.ObservabilityCensusConstants.CLIENT_TRACE_SPAN_CONTEXT_KEY;
+
 import com.google.protobuf.Duration;
 import com.google.protobuf.util.Durations;
 import io.grpc.CallOptions;
@@ -33,6 +35,7 @@ import io.grpc.Status;
 import io.grpc.gcp.observability.interceptors.ConfigFilterHelper.FilterParams;
 import io.grpc.observabilitylog.v1.GrpcLogRecord.EventLogger;
 import io.grpc.observabilitylog.v1.GrpcLogRecord.EventType;
+import io.opencensus.trace.SpanContext;
 import java.util.UUID;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicLong;
@@ -92,6 +95,7 @@ public final class InternalLoggingChannelInterceptor implements ClientIntercepto
     // Get the stricter deadline to calculate the timeout once the call starts
     final Deadline deadline = LogHelper.min(callOptions.getDeadline(),
         Context.current().getDeadline());
+    final SpanContext clientSpanContext = callOptions.getOption(CLIENT_TRACE_SPAN_CONTEXT_KEY);
 
     FilterParams filterParams = filterHelper.logRpcMethod(method.getFullMethodName(), true);
     if (!filterParams.log()) {
@@ -122,7 +126,8 @@ public final class InternalLoggingChannelInterceptor implements ClientIntercepto
               maxHeaderBytes,
               EventLogger.CLIENT,
               callId,
-              null);
+              null,
+              clientSpanContext);
         } catch (Exception e) {
           // Catching generic exceptions instead of specific ones for all the events.
           // This way we can catch both expected and unexpected exceptions instead of re-throwing
@@ -148,7 +153,8 @@ public final class InternalLoggingChannelInterceptor implements ClientIntercepto
                       message,
                       maxMessageBytes,
                       EventLogger.CLIENT,
-                      callId);
+                      callId,
+                      clientSpanContext);
                 } catch (Exception e) {
                   logger.log(Level.SEVERE, "Unable to log response message", e);
                 }
@@ -168,7 +174,8 @@ public final class InternalLoggingChannelInterceptor implements ClientIntercepto
                       maxHeaderBytes,
                       EventLogger.CLIENT,
                       callId,
-                      LogHelper.getPeerAddress(getAttributes()));
+                      LogHelper.getPeerAddress(getAttributes()),
+                      clientSpanContext);
                 } catch (Exception e) {
                   logger.log(Level.SEVERE, "Unable to log response header", e);
                 }
@@ -189,7 +196,8 @@ public final class InternalLoggingChannelInterceptor implements ClientIntercepto
                       maxHeaderBytes,
                       EventLogger.CLIENT,
                       callId,
-                      LogHelper.getPeerAddress(getAttributes()));
+                      LogHelper.getPeerAddress(getAttributes()),
+                      clientSpanContext);
                 } catch (Exception e) {
                   logger.log(Level.SEVERE, "Unable to log trailer", e);
                 }
@@ -212,7 +220,8 @@ public final class InternalLoggingChannelInterceptor implements ClientIntercepto
               message,
               maxMessageBytes,
               EventLogger.CLIENT,
-              callId);
+              callId,
+              clientSpanContext);
         } catch (Exception e) {
           logger.log(Level.SEVERE, "Unable to log request message", e);
         }
@@ -229,7 +238,8 @@ public final class InternalLoggingChannelInterceptor implements ClientIntercepto
               methodName,
               authority,
               EventLogger.CLIENT,
-              callId);
+              callId,
+              clientSpanContext);
         } catch (Exception e) {
           logger.log(Level.SEVERE, "Unable to log half close", e);
         }
@@ -246,7 +256,8 @@ public final class InternalLoggingChannelInterceptor implements ClientIntercepto
               methodName,
               authority,
               EventLogger.CLIENT,
-              callId);
+              callId,
+              clientSpanContext);
         } catch (Exception e) {
           logger.log(Level.SEVERE, "Unable to log cancel", e);
         }

gcp-observability/src/main/java/io/grpc/gcp/observability/interceptors/InternalLoggingServerInterceptor.java

@@ -31,6 +31,9 @@ import io.grpc.Status;
 import io.grpc.gcp.observability.interceptors.ConfigFilterHelper.FilterParams;
 import io.grpc.observabilitylog.v1.GrpcLogRecord.EventLogger;
 import io.grpc.observabilitylog.v1.GrpcLogRecord.EventType;
+import io.opencensus.trace.Span;
+import io.opencensus.trace.SpanContext;
+import io.opencensus.trace.unsafe.ContextHandleUtils;
 import java.net.SocketAddress;
 import java.util.UUID;
 import java.util.concurrent.TimeUnit;
@@ -91,6 +94,8 @@ public final class InternalLoggingServerInterceptor implements ServerInterceptor
     Deadline deadline = Context.current().getDeadline();
     final Duration timeout = deadline == null ? null
         : Durations.fromNanos(deadline.timeRemaining(TimeUnit.NANOSECONDS));
+    Span span = ContextHandleUtils.getValue(ContextHandleUtils.currentContext());
+    final SpanContext serverSpanContext = span == null ? SpanContext.INVALID : span.getContext();
 
     FilterParams filterParams =
         filterHelper.logRpcMethod(call.getMethodDescriptor().getFullMethodName(), false);
@@ -113,7 +118,8 @@ public final class InternalLoggingServerInterceptor implements ServerInterceptor
           maxHeaderBytes,
           EventLogger.SERVER,
           callId,
-          peerAddress);
+          peerAddress,
+          serverSpanContext);
     } catch (Exception e) {
       // Catching generic exceptions instead of specific ones for all the events.
       // This way we can catch both expected and unexpected exceptions instead of re-throwing
@@ -139,7 +145,8 @@ public final class InternalLoggingServerInterceptor implements ServerInterceptor
                   maxHeaderBytes,
                   EventLogger.SERVER,
                   callId,
-                  null);
+                  null,
+                  serverSpanContext);
             } catch (Exception e) {
               logger.log(Level.SEVERE, "Unable to log response header", e);
             }
@@ -160,7 +167,8 @@ public final class InternalLoggingServerInterceptor implements ServerInterceptor
                   message,
                   maxMessageBytes,
                   EventLogger.SERVER,
-                  callId);
+                  callId,
+                  serverSpanContext);
             } catch (Exception e) {
               logger.log(Level.SEVERE, "Unable to log response message", e);
             }
@@ -181,7 +189,8 @@ public final class InternalLoggingServerInterceptor implements ServerInterceptor
                   maxHeaderBytes,
                   EventLogger.SERVER,
                   callId,
-                  null);
+                  null,
+                  serverSpanContext);
             } catch (Exception e) {
               logger.log(Level.SEVERE, "Unable to log trailer", e);
             }
@@ -206,7 +215,8 @@ public final class InternalLoggingServerInterceptor implements ServerInterceptor
               message,
               maxMessageBytes,
               EventLogger.SERVER,
-              callId);
+              callId,
+              serverSpanContext);
         } catch (Exception e) {
           logger.log(Level.SEVERE, "Unable to log request message", e);
         }
@@ -223,7 +233,8 @@ public final class InternalLoggingServerInterceptor implements ServerInterceptor
               methodName,
               authority,
               EventLogger.SERVER,
-              callId);
+              callId,
+              serverSpanContext);
         } catch (Exception e) {
           logger.log(Level.SEVERE, "Unable to log half close", e);
         }
@@ -240,7 +251,8 @@ public final class InternalLoggingServerInterceptor implements ServerInterceptor
               methodName,
               authority,
               EventLogger.SERVER,
-              callId);
+              callId,
+              serverSpanContext);
         } catch (Exception e) {
           logger.log(Level.SEVERE, "Unable to log cancel", e);
         }

gcp-observability/src/main/java/io/grpc/gcp/observability/interceptors/LogHelper.java

@@ -23,6 +23,7 @@ import static io.grpc.InternalMetadata.BASE64_ENCODING_OMIT_PADDING;
 import com.google.common.base.Joiner;
 import com.google.protobuf.ByteString;
 import com.google.protobuf.Duration;
+import com.google.rpc.Code;
 import io.grpc.Attributes;
 import io.grpc.Deadline;
 import io.grpc.Grpc;
@@ -35,6 +36,7 @@ import io.grpc.observabilitylog.v1.GrpcLogRecord;
 import io.grpc.observabilitylog.v1.GrpcLogRecord.EventLogger;
 import io.grpc.observabilitylog.v1.GrpcLogRecord.EventType;
 import io.grpc.observabilitylog.v1.Payload;
+import io.opencensus.trace.SpanContext;
 import java.net.Inet4Address;
 import java.net.Inet6Address;
 import java.net.InetAddress;
@@ -87,7 +89,8 @@ public class LogHelper {
       GrpcLogRecord.EventLogger eventLogger,
       String callId,
       // null on client side
-      @Nullable SocketAddress peerAddress) {
+      @Nullable SocketAddress peerAddress,
+      SpanContext spanContext) {
     checkNotNull(serviceName, "serviceName");
     checkNotNull(methodName, "methodName");
     checkNotNull(authority, "authority");
@@ -113,7 +116,7 @@ public class LogHelper {
     if (peerAddress != null) {
       logEntryBuilder.setPeer(socketAddressToProto(peerAddress));
     }
-    sink.write(logEntryBuilder.build());
+    sink.write(logEntryBuilder.build(), spanContext);
   }
 
   /**
@@ -128,7 +131,8 @@ public class LogHelper {
       int maxHeaderBytes,
       GrpcLogRecord.EventLogger eventLogger,
       String callId,
-      @Nullable SocketAddress peerAddress) {
+      @Nullable SocketAddress peerAddress,
+      SpanContext spanContext) {
     checkNotNull(serviceName, "serviceName");
     checkNotNull(methodName, "methodName");
     checkNotNull(authority, "authority");
@@ -154,7 +158,7 @@ public class LogHelper {
     if (peerAddress != null) {
       logEntryBuilder.setPeer(socketAddressToProto(peerAddress));
     }
-    sink.write(logEntryBuilder.build());
+    sink.write(logEntryBuilder.build(), spanContext);
   }
 
   /**
@@ -170,7 +174,8 @@ public class LogHelper {
       int maxHeaderBytes,
       GrpcLogRecord.EventLogger eventLogger,
       String callId,
-      @Nullable SocketAddress peerAddress) {
+      @Nullable SocketAddress peerAddress,
+      SpanContext spanContext) {
     checkNotNull(serviceName, "serviceName");
     checkNotNull(methodName, "methodName");
     checkNotNull(authority, "authority");
@@ -182,7 +187,7 @@ public class LogHelper {
 
     PayloadBuilderHelper<Payload.Builder> pair =
         createMetadataProto(metadata, maxHeaderBytes);
-    pair.payloadBuilder.setStatusCode(status.getCode().value());
+    pair.payloadBuilder.setStatusCode(Code.forNumber(status.getCode().value()));
     String statusDescription = status.getDescription();
     if (statusDescription != null) {
       pair.payloadBuilder.setStatusMessage(statusDescription);
@@ -204,7 +209,7 @@ public class LogHelper {
     if (peerAddress != null) {
       logEntryBuilder.setPeer(socketAddressToProto(peerAddress));
     }
-    sink.write(logEntryBuilder.build());
+    sink.write(logEntryBuilder.build(), spanContext);
   }
 
   /**
@@ -219,7 +224,8 @@ public class LogHelper {
       T message,
       int maxMessageBytes,
       EventLogger eventLogger,
-      String callId) {
+      String callId,
+      SpanContext spanContext) {
     checkNotNull(serviceName, "serviceName");
     checkNotNull(methodName, "methodName");
     checkNotNull(authority, "authority");
@@ -259,7 +265,7 @@ public class LogHelper {
       logEntryBuilder.setPayload(pair.payloadBuilder)
           .setPayloadTruncated(pair.truncated);
     }
-    sink.write(logEntryBuilder.build());
+    sink.write(logEntryBuilder.build(), spanContext);
   }
 
   /**
@@ -271,7 +277,8 @@ public class LogHelper {
       String methodName,
       String authority,
       GrpcLogRecord.EventLogger eventLogger,
-      String callId) {
+      String callId,
+      SpanContext spanContext) {
     checkNotNull(serviceName, "serviceName");
     checkNotNull(methodName, "methodName");
     checkNotNull(authority, "authority");
@@ -285,7 +292,7 @@ public class LogHelper {
         .setType(EventType.CLIENT_HALF_CLOSE)
         .setLogger(eventLogger)
         .setCallId(callId);
-    sink.write(logEntryBuilder.build());
+    sink.write(logEntryBuilder.build(), spanContext);
   }
 
   /**
@@ -297,7 +304,8 @@ public class LogHelper {
       String methodName,
       String authority,
       GrpcLogRecord.EventLogger eventLogger,
-      String callId) {
+      String callId,
+      SpanContext spanContext) {
     checkNotNull(serviceName, "serviceName");
     checkNotNull(methodName, "methodName");
     checkNotNull(authority, "authority");
@@ -311,7 +319,7 @@ public class LogHelper {
         .setType(EventType.CANCEL)
         .setLogger(eventLogger)
         .setCallId(callId);
-    sink.write(logEntryBuilder.build());
+    sink.write(logEntryBuilder.build(), spanContext);
   }
 
   // TODO(DNVindhya): Evaluate if we need following clause for metadata logging in GcpObservability
@@ -404,10 +412,10 @@ public class LogHelper {
     if (address instanceof InetSocketAddress) {
       InetAddress inetAddress = ((InetSocketAddress) address).getAddress();
       if (inetAddress instanceof Inet4Address) {
-        builder.setType(Address.Type.TYPE_IPV4)
+        builder.setType(Address.Type.IPV4)
             .setAddress(InetAddressUtil.toAddrString(inetAddress));
       } else if (inetAddress instanceof Inet6Address) {
-        builder.setType(Address.Type.TYPE_IPV6)
+        builder.setType(Address.Type.IPV6)
             .setAddress(InetAddressUtil.toAddrString(inetAddress));
       } else {
         logger.log(Level.SEVERE, "unknown type of InetSocketAddress: {}", address);
@@ -417,7 +425,7 @@ public class LogHelper {
     } else if (address.getClass().getName().equals("io.netty.channel.unix.DomainSocketAddress")) {
       // To avoid a compiled time dependency on grpc-netty, we check against the
       // runtime class name.
-      builder.setType(Address.Type.TYPE_UNIX)
+      builder.setType(Address.Type.UNIX)
           .setAddress(address.toString());
     } else {
       builder.setType(Address.Type.TYPE_UNKNOWN).setAddress(address.toString());

gcp-observability/src/main/java/io/grpc/gcp/observability/logging/GcpLogSink.java

@@ -18,29 +18,31 @@ package io.grpc.gcp.observability.logging;
 
 import static com.google.common.base.Preconditions.checkNotNull;
 
-import com.google.cloud.MonitoredResource;
+import com.google.api.gax.batching.BatchingSettings;
+import com.google.api.gax.batching.FlowController;
 import com.google.cloud.logging.LogEntry;
 import com.google.cloud.logging.Logging;
 import com.google.cloud.logging.LoggingOptions;
 import com.google.cloud.logging.Payload.JsonPayload;
 import com.google.cloud.logging.Severity;
+import com.google.cloud.logging.v2.stub.LoggingServiceV2StubSettings;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.ImmutableSet;
 import com.google.protobuf.util.JsonFormat;
 import io.grpc.Internal;
+import io.grpc.gcp.observability.ObservabilityConfig;
 import io.grpc.internal.JsonParser;
 import io.grpc.observabilitylog.v1.GrpcLogRecord;
+import io.opencensus.trace.SpanContext;
 import java.io.IOException;
 import java.time.Instant;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Map;
-import java.util.Objects;
-import java.util.Set;
 import java.util.logging.Level;
 import java.util.logging.Logger;
+import org.threeten.bp.Duration;
 
 /**
  * Sink for Google Cloud Logging.
@@ -52,22 +54,22 @@ public class GcpLogSink implements Sink {
   private static final String DEFAULT_LOG_NAME =
       "microservices.googleapis.com%2Fobservability%2Fgrpc";
   private static final Severity DEFAULT_LOG_LEVEL = Severity.DEBUG;
-  private static final String K8S_MONITORED_RESOURCE_TYPE = "k8s_container";
-  private static final Set<String> kubernetesResourceLabelSet
-      = ImmutableSet.of("project_id", "location", "cluster_name", "namespace_name",
-      "pod_name", "container_name");
   private final String projectId;
   private final Map<String, String> customTags;
-  private final MonitoredResource kubernetesResource;
   /** Lazily initialize cloud logging client to avoid circular initialization. Because cloud
    * logging APIs also uses gRPC. */
   private volatile Logging gcpLoggingClient;
   private final Collection<String> servicesToExclude;
+  private final boolean isTraceEnabled;
+
+  private final TraceLoggingHelper traceLoggingHelper;
+
 
   @VisibleForTesting
-  GcpLogSink(Logging loggingClient, String projectId, Map<String, String> locationTags,
-      Map<String, String> customTags, Collection<String> servicesToExclude) {
-    this(projectId, locationTags, customTags, servicesToExclude);
+  GcpLogSink(Logging loggingClient, String projectId,
+      ObservabilityConfig config, Collection<String> servicesToExclude,
+      TraceLoggingHelper traceLoggingHelper) {
+    this(projectId, config, servicesToExclude, traceLoggingHelper);
     this.gcpLoggingClient = loggingClient;
   }
 
@@ -77,12 +79,14 @@ public class GcpLogSink implements Sink {
    * @param projectId GCP project id to write logs
    * @param servicesToExclude service names for which log entries should not be generated
    */
-  public GcpLogSink(String projectId, Map<String, String> locationTags,
-      Map<String, String> customTags, Collection<String> servicesToExclude) {
+  public GcpLogSink(String projectId,
+      ObservabilityConfig config, Collection<String> servicesToExclude,
+      TraceLoggingHelper traceLoggingHelper) {
     this.projectId = projectId;
-    this.customTags = getCustomTags(customTags, locationTags, projectId);
-    this.kubernetesResource = getResource(locationTags);
+    this.customTags = getCustomTags(config.getCustomTags());
     this.servicesToExclude = checkNotNull(servicesToExclude, "servicesToExclude");
+    this.isTraceEnabled = config.isEnableCloudTracing();
+    this.traceLoggingHelper = traceLoggingHelper;
   }
 
   /**
@@ -91,7 +95,7 @@ public class GcpLogSink implements Sink {
    * @param logProto gRPC logging proto containing the message to be logged
    */
   @Override
-  public void write(GrpcLogRecord logProto) {
+  public void write(GrpcLogRecord logProto, SpanContext spanContext) {
     if (gcpLoggingClient == null) {
       synchronized (this) {
         if (gcpLoggingClient == null) {
@@ -102,6 +106,7 @@ public class GcpLogSink implements Sink {
     if (servicesToExclude.contains(logProto.getServiceName())) {
       return;
     }
+    LogEntry grpcLogEntry = null;
     try {
       GrpcLogRecord.EventType eventType = logProto.getType();
       // TODO(DNVindhya): make sure all (int, long) values are not displayed as double
@@ -111,59 +116,65 @@ public class GcpLogSink implements Sink {
           LogEntry.newBuilder(JsonPayload.of(logProtoMap))
               .setSeverity(DEFAULT_LOG_LEVEL)
               .setLogName(DEFAULT_LOG_NAME)
-              .setResource(kubernetesResource)
               .setTimestamp(Instant.now());
 
       if (!customTags.isEmpty()) {
         grpcLogEntryBuilder.setLabels(customTags);
       }
-      LogEntry grpcLogEntry = grpcLogEntryBuilder.build();
+
+      addTraceData(grpcLogEntryBuilder, spanContext);
+      grpcLogEntry = grpcLogEntryBuilder.build();
+
       synchronized (this) {
         logger.log(Level.FINEST, "Writing gRPC event : {0} to Cloud Logging", eventType);
         gcpLoggingClient.write(Collections.singleton(grpcLogEntry));
       }
+    } catch (FlowController.FlowControlRuntimeException e) {
+      String grpcLogEntryString = null;
+      if (grpcLogEntry != null) {
+        grpcLogEntryString = grpcLogEntry.toStructuredJsonString();
+      }
+      logger.log(Level.SEVERE, "Limit exceeded while writing log entry to cloud logging");
+      logger.log(Level.SEVERE, "Log entry = ", grpcLogEntryString);
     } catch (Exception e) {
       logger.log(Level.SEVERE, "Caught exception while writing to Cloud Logging", e);
     }
   }
 
+  void addTraceData(LogEntry.Builder builder, SpanContext spanContext) {
+    if (!isTraceEnabled) {
+      return;
+    }
+    traceLoggingHelper.enhanceLogEntry(builder, spanContext);
+  }
+
   Logging createLoggingClient() {
     LoggingOptions.Builder builder = LoggingOptions.newBuilder();
     if (!Strings.isNullOrEmpty(projectId)) {
       builder.setProjectId(projectId);
     }
+    BatchingSettings loggingDefaultBatchingSettings = LoggingServiceV2StubSettings.newBuilder()
+        .writeLogEntriesSettings().getBatchingSettings();
+    // Custom batching settings
+    BatchingSettings grpcLoggingVBatchingSettings = loggingDefaultBatchingSettings.toBuilder()
+        .setDelayThreshold(Duration.ofSeconds(1L)).setFlowControlSettings(
+            loggingDefaultBatchingSettings.getFlowControlSettings().toBuilder()
+                .setMaxOutstandingRequestBytes(52428800L) //50 MiB
+                .setLimitExceededBehavior(FlowController.LimitExceededBehavior.ThrowException)
+                .build()).build();
+    builder.setBatchingSettings(grpcLoggingVBatchingSettings);
     return builder.build().getService();
   }
 
   @VisibleForTesting
-  static Map<String, String> getCustomTags(Map<String, String> customTags,
-      Map<String, String> locationTags, String projectId) {
+  static Map<String, String> getCustomTags(Map<String, String> customTags) {
     ImmutableMap.Builder<String, String> tagsBuilder = ImmutableMap.builder();
-    String sourceProjectId = locationTags.get("project_id");
-    if (!Strings.isNullOrEmpty(projectId)
-        && !Strings.isNullOrEmpty(sourceProjectId)
-        && !Objects.equals(sourceProjectId, projectId)) {
-      tagsBuilder.put("source_project_id", sourceProjectId);
-    }
     if (customTags != null) {
       tagsBuilder.putAll(customTags);
     }
     return tagsBuilder.buildOrThrow();
   }
 
-  @VisibleForTesting
-  static MonitoredResource getResource(Map<String, String> resourceTags) {
-    MonitoredResource.Builder builder = MonitoredResource.newBuilder(K8S_MONITORED_RESOURCE_TYPE);
-    if ((resourceTags != null) && !resourceTags.isEmpty()) {
-      for (Map.Entry<String, String> entry : resourceTags.entrySet()) {
-        String resourceKey = entry.getKey();
-        if (kubernetesResourceLabelSet.contains(resourceKey)) {
-          builder.addLabel(resourceKey, entry.getValue());
-        }
-      }
-    }
-    return builder.build();
-  }
 
   @SuppressWarnings("unchecked")
   private Map<String, Object> protoToMapConverter(GrpcLogRecord logProto)

gcp-observability/src/main/java/io/grpc/gcp/observability/logging/Sink.java

@@ -18,6 +18,7 @@ package io.grpc.gcp.observability.logging;
 
 import io.grpc.Internal;
 import io.grpc.observabilitylog.v1.GrpcLogRecord;
+import io.opencensus.trace.SpanContext;
 
 /**
  * Sink for GCP observability.
@@ -27,7 +28,7 @@ public interface Sink {
   /**
    * Writes the {@code message} to the destination.
    */
-  void write(GrpcLogRecord message);
+  void write(GrpcLogRecord message, SpanContext spanContext);
 
   /**
    * Closes the sink.

gcp-observability/src/main/java/io/grpc/gcp/observability/logging/TraceLoggingHelper.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2023 The gRPC Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.grpc.gcp.observability.logging;
+
+import com.google.cloud.logging.LogEntry;
+import com.google.common.annotations.VisibleForTesting;
+import io.grpc.Internal;
+import io.opencensus.trace.SpanContext;
+import io.opencensus.trace.TraceId;
+
+@Internal
+public class TraceLoggingHelper {
+
+  private final String tracePrefix;
+
+  public TraceLoggingHelper(String projectId) {
+    this.tracePrefix = "projects/" + projectId + "/traces/";;
+  }
+
+  @VisibleForTesting
+  void enhanceLogEntry(LogEntry.Builder builder, SpanContext spanContext) {
+    addTracingData(tracePrefix, spanContext, builder);
+  }
+
+  private static void addTracingData(
+      String tracePrefix, SpanContext spanContext, LogEntry.Builder builder) {
+    builder.setTrace(formatTraceId(tracePrefix, spanContext.getTraceId()));
+    builder.setSpanId(spanContext.getSpanId().toLowerBase16());
+    builder.setTraceSampled(spanContext.getTraceOptions().isSampled());
+  }
+
+  private static String formatTraceId(String tracePrefix, TraceId traceId) {
+    return tracePrefix + traceId.toLowerBase16();
+  }
+}

gcp-observability/src/main/proto/grpc/observabilitylog/v1/observabilitylog.proto

@@ -20,6 +20,7 @@ package grpc.observabilitylog.v1;
 
 import "google/protobuf/duration.proto";
 import "google/protobuf/timestamp.proto";
+import "google/rpc/code.proto";
 
 option java_multiple_files = true;
 option java_package = "io.grpc.observabilitylog.v1";
@@ -97,7 +98,7 @@ message Payload {
   // the RPC timeout value
   google.protobuf.Duration timeout = 2;
   // The gRPC status code
-  uint32 status_code = 3;
+  google.rpc.Code status_code = 3;
   // The gRPC status message
   string status_message = 4;
   // The value of the grpc-status-details-bin metadata key, if any.
@@ -115,9 +116,9 @@ message Payload {
 message Address {
   enum Type {
     TYPE_UNKNOWN = 0;
-    TYPE_IPV4 = 1;  // in 1.2.3.4 form
-    TYPE_IPV6 = 2;  // IPv6 canonical form (RFC5952 section 4)
-    TYPE_UNIX = 3;  // UDS string
+    IPV4 = 1;  // in 1.2.3.4 form
+    IPV6 = 2;  // IPv6 canonical form (RFC5952 section 4)
+    UNIX = 3;  // UDS string
   }
   Type type = 1;
   string address = 2;

gcp-observability/src/test/java/io/grpc/gcp/observability/GlobalLocationTagsTest.java

@@ -1,110 +0,0 @@
-/*
- * Copyright 2022 The gRPC Authors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package io.grpc.gcp.observability;
-
-import static com.google.common.truth.Truth.assertThat;
-
-import com.google.common.collect.ImmutableMap;
-import com.google.common.io.Files;
-import java.io.File;
-import java.io.IOException;
-import java.nio.charset.StandardCharsets;
-import org.junit.Rule;
-import org.junit.Test;
-import org.junit.rules.TemporaryFolder;
-import org.junit.runner.RunWith;
-import org.junit.runners.JUnit4;
-
-@RunWith(JUnit4.class)
-public class GlobalLocationTagsTest {
-  private static String FILE_CONTENTS =
-      "12:perf_event:/kubepods/burstable/podc43b6442-0725-4fb8-bb1c-d17f5122155c/"
-          + "fe61ca6482b58f4a9831d08d6ea15db25f9fd19b4be19a54df8c6c0eab8742b7\n"
-          + "11:freezer:/kubepods/burstable/podc43b6442-0725-4fb8-bb1c-d17f5122155c/"
-          + "fe61ca6482b58f4a9831d08d6ea15db25f9fd19b4be19a54df8c6c0eab8742b7\n"
-          + "2:rdma:/\n"
-          + "1:name=systemd:/kubepods/burstable/podc43b6442-0725-4fb8-bb1c-d17f5122155c/"
-          + "fe61ca6482b58f4a9831d08d6ea15db25f9fd19b4be19a54df8c6c0eab8742b7\n"
-          + "0::/system.slice/containerd.service\n";
-
-  private static String FILE_CONTENTS_LAST_LINE =
-      "0::/system.slice/containerd.service\n"
-          + "6442-0725-4fb8-bb1c-d17f5122155cslslsl/fe61ca6482b58f4a9831d08d6ea15db25f\n"
-          + "\n"
-          + "12:perf_event:/kubepods/burstable/podc43b6442-0725-4fb8-bb1c-d17f5122155c/e19a54df\n";
-
-  @Rule public TemporaryFolder namespaceFolder = new TemporaryFolder();
-  @Rule public TemporaryFolder hostnameFolder = new TemporaryFolder();
-  @Rule public TemporaryFolder cgroupFolder = new TemporaryFolder();
-
-  @Test
-  public void testContainerIdParsing_lastLine() {
-    String containerId = GlobalLocationTags.getContainerIdFromFileContents(FILE_CONTENTS_LAST_LINE);
-    assertThat(containerId).isEqualTo("e19a54df");
-  }
-
-  @Test
-  public void testContainerIdParsing_fewerFields_notFound() {
-    String containerId = GlobalLocationTags.getContainerIdFromFileContents(
-        "12:/kubepods/burstable/podc43b6442-0725-4fb8-bb1c-d17f5122155c/"
-            + "fe61ca6482b58f4a9831d08d6ea15db25f9fd19b4be19a54df8c6c0eab8742b7\n");
-    assertThat(containerId).isNull();
-  }
-
-  @Test
-  public void testContainerIdParsing_fewerPaths_notFound() {
-    String containerId = GlobalLocationTags.getContainerIdFromFileContents(
-        "12:xdf:/kubepods/podc43b6442-0725-4fb8-bb1c-d17f5122155c/"
-            + "fe61ca6482b58f4a9831d08d6ea15db25f9fd19b4be19a54df8c6c0eab8742b7\n");
-    assertThat(containerId).isNull();
-  }
-
-  @Test
-  public void testPopulateKubernetesValues() throws IOException {
-    File namespaceFile = namespaceFolder.newFile();
-    File hostnameFile = hostnameFolder.newFile();
-    File cgroupFile = cgroupFolder.newFile();
-
-    Files.write("test-namespace1".getBytes(StandardCharsets.UTF_8), namespaceFile);
-    Files.write("test-hostname2\n".getBytes(StandardCharsets.UTF_8), hostnameFile);
-    Files.write(FILE_CONTENTS.getBytes(StandardCharsets.UTF_8), cgroupFile);
-
-    ImmutableMap.Builder<String, String> locationTags = ImmutableMap.builder();
-    GlobalLocationTags.populateFromKubernetesValues(locationTags, namespaceFile.getAbsolutePath(),
-        hostnameFile.getAbsolutePath(), cgroupFile.getAbsolutePath());
-    assertThat(locationTags.buildOrThrow()).containsExactly("container_id",
-        "fe61ca6482b58f4a9831d08d6ea15db25f9fd19b4be19a54df8c6c0eab8742b7", "namespace_name",
-        "test-namespace1", "pod_name", "test-hostname2");
-  }
-
-  @Test
-  public void testNonKubernetesInstanceValues() throws IOException {
-    String namespaceFilePath = "/var/run/secrets/kubernetes.io/serviceaccount/namespace";
-    File hostnameFile = hostnameFolder.newFile();
-    File cgroupFile = cgroupFolder.newFile();
-
-    Files.write("test-hostname2\n".getBytes(StandardCharsets.UTF_8), hostnameFile);
-    Files.write(FILE_CONTENTS.getBytes(StandardCharsets.UTF_8), cgroupFile);
-
-    ImmutableMap.Builder<String, String> locationTags = ImmutableMap.builder();
-    GlobalLocationTags.populateFromKubernetesValues(locationTags,
-        namespaceFilePath, hostnameFile.getAbsolutePath(), cgroupFile.getAbsolutePath());
-    assertThat(locationTags.buildOrThrow()).containsExactly("container_id",
-        "fe61ca6482b58f4a9831d08d6ea15db25f9fd19b4be19a54df8c6c0eab8742b7",
-        "pod_name", "test-hostname2");
-  }
-}

gcp-observability/src/test/java/io/grpc/gcp/observability/LoggingTest.java

@@ -38,9 +38,11 @@ import io.grpc.gcp.observability.interceptors.InternalLoggingServerInterceptor;
 import io.grpc.gcp.observability.interceptors.LogHelper;
 import io.grpc.gcp.observability.logging.GcpLogSink;
 import io.grpc.gcp.observability.logging.Sink;
+import io.grpc.gcp.observability.logging.TraceLoggingHelper;
 import io.grpc.observabilitylog.v1.GrpcLogRecord;
 import io.grpc.testing.GrpcCleanupRule;
 import io.grpc.testing.protobuf.SimpleServiceGrpc;
+import io.opencensus.trace.SpanContext;
 import java.io.IOException;
 import java.util.Collections;
 import java.util.regex.Pattern;
@@ -49,7 +51,9 @@ import org.junit.Ignore;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
+import org.mockito.AdditionalMatchers;
 import org.mockito.ArgumentCaptor;
+import org.mockito.ArgumentMatchers;
 import org.mockito.Mockito;
 
 @RunWith(JUnit4.class)
@@ -59,12 +63,6 @@ public class LoggingTest {
   public static final GrpcCleanupRule cleanupRule = new GrpcCleanupRule();
 
   private static final String PROJECT_ID = "PROJECT";
-  private static final ImmutableMap<String, String> LOCATION_TAGS = ImmutableMap.of(
-      "project_id", "PROJECT",
-      "location", "us-central1-c",
-      "cluster_name", "grpc-observability-cluster",
-      "namespace_name", "default" ,
-      "pod_name", "app1-6c7c58f897-n92c5");
   private static final ImmutableMap<String, String> CUSTOM_TAGS = ImmutableMap.of(
       "KEY1", "Value1",
       "KEY2", "VALUE2");
@@ -111,10 +109,12 @@ public class LoggingTest {
 
     @Override
     public void run() {
+      ObservabilityConfig config = mock(ObservabilityConfig.class);
+      when(config.getCustomTags()).thenReturn(CUSTOM_TAGS);
       Sink sink =
           new GcpLogSink(
-              PROJECT_ID, LOCATION_TAGS, CUSTOM_TAGS, Collections.emptySet());
-      ObservabilityConfig config = mock(ObservabilityConfig.class);
+              PROJECT_ID, config, Collections.emptySet(),
+              mock(TraceLoggingHelper.class));
       LogHelper spyLogHelper = spy(new LogHelper(sink));
       ConfigFilterHelper mockFilterHelper = mock(ConfigFilterHelper.class);
       InternalLoggingChannelInterceptor.Factory channelInterceptorFactory =
@@ -237,7 +237,9 @@ public class LoggingTest {
         // = 8
         assertThat(Mockito.mockingDetails(mockSink).getInvocations().size()).isEqualTo(12);
         ArgumentCaptor<GrpcLogRecord> captor = ArgumentCaptor.forClass(GrpcLogRecord.class);
-        verify(mockSink, times(12)).write(captor.capture());
+        verify(mockSink, times(12)).write(captor.capture(),
+            AdditionalMatchers.or(ArgumentMatchers.isNull(),
+                ArgumentMatchers.any(SpanContext.class)));
         for (GrpcLogRecord record : captor.getAllValues()) {
           assertThat(record.getType()).isInstanceOf(GrpcLogRecord.EventType.class);
           assertThat(record.getLogger()).isInstanceOf(GrpcLogRecord.EventLogger.class);

gcp-observability/src/test/java/io/grpc/gcp/observability/MetadataConfigTest.java

@@ -1,56 +0,0 @@
-/*
- * Copyright 2022 The gRPC Authors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package io.grpc.gcp.observability;
-
-import static com.google.common.truth.Truth.assertThat;
-import static org.mockito.Mockito.when;
-
-import com.google.api.client.testing.http.MockHttpTransport;
-import com.google.api.client.testing.http.MockLowLevelHttpResponse;
-import com.google.auth.http.HttpTransportFactory;
-import java.io.IOException;
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-import org.junit.runners.JUnit4;
-import org.mockito.Mock;
-import org.mockito.MockitoAnnotations;
-
-@RunWith(JUnit4.class)
-public class MetadataConfigTest {
-
-  @Mock HttpTransportFactory httpTransportFactory;
-
-  @Before
-  public void setUp() {
-    MockitoAnnotations.initMocks(this);
-  }
-
-  @Test
-  public void testGetAttribute() throws IOException {
-    MockHttpTransport.Builder builder = new MockHttpTransport.Builder();
-    MockLowLevelHttpResponse response = new MockLowLevelHttpResponse();
-    response.setContent("foo");
-    builder.setLowLevelHttpResponse(response);
-    MockHttpTransport httpTransport = builder.build();
-    when(httpTransportFactory.create()).thenReturn(httpTransport);
-    MetadataConfig metadataConfig = new MetadataConfig(httpTransportFactory);
-    metadataConfig.init();
-    String val = metadataConfig.getAttribute("instance/attributes/cluster-name");
-    assertThat(val).isEqualTo("foo");
-  }
-}

gcp-observability/src/test/java/io/grpc/gcp/observability/interceptors/InternalLoggingChannelInterceptorTest.java

@@ -17,6 +17,7 @@
 package io.grpc.gcp.observability.interceptors;
 
 import static com.google.common.truth.Truth.assertThat;
+import static io.grpc.census.internal.ObservabilityCensusConstants.CLIENT_TRACE_SPAN_CONTEXT_KEY;
 import static io.grpc.gcp.observability.interceptors.LogHelperTest.BYTEARRAY_MARSHALLER;
 import static org.junit.Assert.assertSame;
 import static org.mockito.ArgumentMatchers.any;
@@ -52,6 +53,11 @@ import io.grpc.internal.NoopClientCall;
 import io.grpc.observabilitylog.v1.GrpcLogRecord;
 import io.grpc.observabilitylog.v1.GrpcLogRecord.EventLogger;
 import io.grpc.observabilitylog.v1.GrpcLogRecord.EventType;
+import io.opencensus.trace.SpanContext;
+import io.opencensus.trace.SpanId;
+import io.opencensus.trace.TraceId;
+import io.opencensus.trace.TraceOptions;
+import io.opencensus.trace.Tracestate;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import java.net.SocketAddress;
@@ -83,6 +89,14 @@ public class InternalLoggingChannelInterceptorTest {
   public final MockitoRule mockito = MockitoJUnit.rule();
 
   private static final Charset US_ASCII = StandardCharsets.US_ASCII;
+  private static final SpanContext DEFAULT_CLIENT_SPAN_CONTEXT = SpanContext.INVALID;
+  private static final SpanContext SPAN_CONTEXT = SpanContext.create(
+      TraceId.fromLowerBase16("4c6af40c499951eb7de2777ba1e4fefa"),
+      SpanId.fromLowerBase16("de52e84d13dd232d"),
+      TraceOptions.builder().setIsSampled(true).build(),
+      Tracestate.builder().build());
+  private static final CallOptions CALL_OPTIONS_WITH_SPAN_CONTEXT =
+      CallOptions.DEFAULT.withOption(CLIENT_TRACE_SPAN_CONTEXT_KEY, SPAN_CONTEXT);
 
   private InternalLoggingChannelInterceptor.Factory factory;
   private AtomicReference<ClientCall.Listener<byte[]>> interceptedListener;
@@ -192,7 +206,8 @@ public class InternalLoggingChannelInterceptorTest {
           eq(filterParams.headerBytes()),
           eq(EventLogger.CLIENT),
           anyString(),
-          ArgumentMatchers.isNull());
+          ArgumentMatchers.isNull(),
+          eq(DEFAULT_CLIENT_SPAN_CONTEXT));
       verifyNoMoreInteractions(mockLogHelper);
       assertSame(clientInitial, actualClientInitial.get());
     }
@@ -213,7 +228,8 @@ public class InternalLoggingChannelInterceptorTest {
           eq(filterParams.headerBytes()),
           eq(EventLogger.CLIENT),
           anyString(),
-          same(peer));
+          same(peer),
+          any(SpanContext.class));
       verifyNoMoreInteractions(mockLogHelper);
       verify(mockListener).onHeaders(same(serverInitial));
     }
@@ -234,7 +250,8 @@ public class InternalLoggingChannelInterceptorTest {
           same(request),
           eq(filterParams.messageBytes()),
           eq(EventLogger.CLIENT),
-          anyString());
+          anyString(),
+          any(SpanContext.class));
       verifyNoMoreInteractions(mockLogHelper);
       assertSame(request, actualRequest.get());
     }
@@ -251,7 +268,8 @@ public class InternalLoggingChannelInterceptorTest {
           eq("method"),
           eq("the-authority"),
           eq(EventLogger.CLIENT),
-          anyString());
+          anyString(),
+          any(SpanContext.class));
       halfCloseCalled.get(1, TimeUnit.MILLISECONDS);
       verifyNoMoreInteractions(mockLogHelper);
     }
@@ -272,7 +290,8 @@ public class InternalLoggingChannelInterceptorTest {
           same(response),
           eq(filterParams.messageBytes()),
           eq(EventLogger.CLIENT),
-          anyString());
+          anyString(),
+          any(SpanContext.class));
       verifyNoMoreInteractions(mockLogHelper);
       verify(mockListener).onMessage(same(response));
     }
@@ -295,7 +314,8 @@ public class InternalLoggingChannelInterceptorTest {
           eq(filterParams.headerBytes()),
           eq(EventLogger.CLIENT),
           anyString(),
-          same(peer));
+          same(peer),
+          any(SpanContext.class));
       verifyNoMoreInteractions(mockLogHelper);
       verify(mockListener).onClose(same(status), same(trailers));
     }
@@ -312,7 +332,8 @@ public class InternalLoggingChannelInterceptorTest {
           eq("method"),
           eq("the-authority"),
           eq(EventLogger.CLIENT),
-          anyString());
+          anyString(),
+          any(SpanContext.class));
       cancelCalled.get(1, TimeUnit.MILLISECONDS);
     }
   }
@@ -363,7 +384,8 @@ public class InternalLoggingChannelInterceptorTest {
             any(GrpcLogRecord.EventLogger.class),
             anyString(),
             AdditionalMatchers.or(ArgumentMatchers.isNull(),
-                ArgumentMatchers.any()));
+                ArgumentMatchers.any()),
+            any(SpanContext.class));
     Duration timeout = callOptTimeoutCaptor.getValue();
     assertThat(TimeUnit.SECONDS.toNanos(1) - Durations.toNanos(timeout))
         .isAtMost(TimeUnit.MILLISECONDS.toNanos(250));
@@ -422,7 +444,8 @@ public class InternalLoggingChannelInterceptorTest {
             any(GrpcLogRecord.EventLogger.class),
             anyString(),
             AdditionalMatchers.or(ArgumentMatchers.isNull(),
-                ArgumentMatchers.any()));
+                ArgumentMatchers.any()),
+            any(SpanContext.class));
     Duration timeout = contextTimeoutCaptor.getValue();
     assertThat(TimeUnit.SECONDS.toNanos(1) - Durations.toNanos(timeout))
         .isAtMost(TimeUnit.MILLISECONDS.toNanos(250));
@@ -484,7 +507,8 @@ public class InternalLoggingChannelInterceptorTest {
             any(GrpcLogRecord.EventLogger.class),
             anyString(),
             AdditionalMatchers.or(ArgumentMatchers.isNull(),
-                ArgumentMatchers.any()));
+                ArgumentMatchers.any()),
+            any(SpanContext.class));
     Duration timeout = timeoutCaptor.getValue();
     assertThat(LogHelper.min(contextDeadline, callOptionsDeadline))
         .isSameInstanceAs(contextDeadline);
@@ -633,4 +657,172 @@ public class InternalLoggingChannelInterceptorTest {
       assertThat(Mockito.mockingDetails(mockLogHelper).getInvocations().size()).isEqualTo(7);
     }
   }
+
+  @Test
+  public void clientSpanContextLogged_contextSetViaCallOption() {
+    Channel channel = new Channel() {
+      @Override
+      public <RequestT, ResponseT> ClientCall<RequestT, ResponseT> newCall(
+          MethodDescriptor<RequestT, ResponseT> methodDescriptor, CallOptions callOptions) {
+        return new NoopClientCall<RequestT, ResponseT>() {
+          @Override
+          @SuppressWarnings("unchecked")
+          public void start(Listener<ResponseT> responseListener, Metadata headers) {
+            interceptedListener.set((Listener<byte[]>) responseListener);
+            actualClientInitial.set(headers);
+          }
+
+          @Override
+          public void sendMessage(RequestT message) {
+            actualRequest.set(message);
+          }
+
+          @Override
+          public void cancel(String message, Throwable cause) {
+            cancelCalled.set(null);
+          }
+
+          @Override
+          public void halfClose() {
+            halfCloseCalled.set(null);
+          }
+
+          @Override
+          public Attributes getAttributes() {
+            return Attributes.newBuilder().set(Grpc.TRANSPORT_ATTR_REMOTE_ADDR, peer).build();
+          }
+        };
+      }
+
+      @Override
+      public String authority() {
+        return "the-authority";
+      }
+    };
+
+    @SuppressWarnings("unchecked")
+    ClientCall.Listener<byte[]> mockListener = mock(ClientCall.Listener.class);
+
+    MethodDescriptor<byte[], byte[]> method =
+        MethodDescriptor.<byte[], byte[]>newBuilder()
+            .setType(MethodType.UNKNOWN)
+            .setFullMethodName("service/method")
+            .setRequestMarshaller(BYTEARRAY_MARSHALLER)
+            .setResponseMarshaller(BYTEARRAY_MARSHALLER)
+            .build();
+    when(mockFilterHelper.logRpcMethod(method.getFullMethodName(), true))
+        .thenReturn(FilterParams.create(true, 10, 10));
+
+    ClientCall<byte[], byte[]> interceptedLoggingCall =
+        factory.create()
+            .interceptCall(method,
+                CALL_OPTIONS_WITH_SPAN_CONTEXT,
+                channel);
+
+    {
+      interceptedLoggingCall.start(mockListener, new Metadata());
+      ArgumentCaptor<SpanContext> callOptSpanContextCaptor = ArgumentCaptor.forClass(
+          SpanContext.class);
+      verify(mockLogHelper, times(1))
+          .logClientHeader(
+              anyLong(),
+              AdditionalMatchers.or(ArgumentMatchers.isNull(), anyString()),
+              AdditionalMatchers.or(ArgumentMatchers.isNull(), anyString()),
+              AdditionalMatchers.or(ArgumentMatchers.isNull(), anyString()),
+              ArgumentMatchers.isNull(),
+              any(Metadata.class),
+              anyInt(),
+              any(GrpcLogRecord.EventLogger.class),
+              anyString(),
+              AdditionalMatchers.or(ArgumentMatchers.isNull(),
+                  ArgumentMatchers.any()),
+              callOptSpanContextCaptor.capture());
+      SpanContext spanContext = callOptSpanContextCaptor.getValue();
+      assertThat(spanContext).isEqualTo(SPAN_CONTEXT);
+    }
+  }
+
+  @Test
+  public void clientSpanContextLogged_contextNotSetViaCallOption() {
+    Channel channel = new Channel() {
+      @Override
+      public <RequestT, ResponseT> ClientCall<RequestT, ResponseT> newCall(
+          MethodDescriptor<RequestT, ResponseT> methodDescriptor, CallOptions callOptions) {
+        return new NoopClientCall<RequestT, ResponseT>() {
+          @Override
+          @SuppressWarnings("unchecked")
+          public void start(Listener<ResponseT> responseListener, Metadata headers) {
+            interceptedListener.set((Listener<byte[]>) responseListener);
+            actualClientInitial.set(headers);
+          }
+
+          @Override
+          public void sendMessage(RequestT message) {
+            actualRequest.set(message);
+          }
+
+          @Override
+          public void cancel(String message, Throwable cause) {
+            cancelCalled.set(null);
+          }
+
+          @Override
+          public void halfClose() {
+            halfCloseCalled.set(null);
+          }
+
+          @Override
+          public Attributes getAttributes() {
+            return Attributes.newBuilder().set(Grpc.TRANSPORT_ATTR_REMOTE_ADDR, peer).build();
+          }
+        };
+      }
+
+      @Override
+      public String authority() {
+        return "the-authority";
+      }
+    };
+
+    @SuppressWarnings("unchecked")
+    ClientCall.Listener<byte[]> mockListener = mock(ClientCall.Listener.class);
+
+    MethodDescriptor<byte[], byte[]> method =
+        MethodDescriptor.<byte[], byte[]>newBuilder()
+            .setType(MethodType.UNKNOWN)
+            .setFullMethodName("service/method")
+            .setRequestMarshaller(BYTEARRAY_MARSHALLER)
+            .setResponseMarshaller(BYTEARRAY_MARSHALLER)
+            .build();
+    when(mockFilterHelper.logRpcMethod(method.getFullMethodName(), true))
+        .thenReturn(FilterParams.create(true, 10, 10));
+
+    ClientCall<byte[], byte[]> interceptedLoggingCall =
+        factory.create()
+            .interceptCall(method,
+                CallOptions.DEFAULT,
+                channel);
+
+    {
+      interceptedLoggingCall.start(mockListener, new Metadata());
+      ArgumentCaptor<SpanContext> callOptSpanContextCaptor = ArgumentCaptor.forClass(
+          SpanContext.class);
+      verify(mockLogHelper, times(1))
+          .logClientHeader(
+              anyLong(),
+              AdditionalMatchers.or(ArgumentMatchers.isNull(), anyString()),
+              AdditionalMatchers.or(ArgumentMatchers.isNull(), anyString()),
+              AdditionalMatchers.or(ArgumentMatchers.isNull(), anyString()),
+              ArgumentMatchers.isNull(),
+              any(Metadata.class),
+              anyInt(),
+              any(GrpcLogRecord.EventLogger.class),
+              anyString(),
+              AdditionalMatchers.or(ArgumentMatchers.isNull(),
+                  ArgumentMatchers.any()),
+              callOptSpanContextCaptor.capture());
+      SpanContext spanContext = callOptSpanContextCaptor.getValue();
+      assertThat(spanContext).isEqualTo(DEFAULT_CLIENT_SPAN_CONTEXT);
+    }
+  }
 }

gcp-observability/src/test/java/io/grpc/gcp/observability/interceptors/InternalLoggingServerInterceptorTest.java

@@ -45,6 +45,7 @@ import io.grpc.gcp.observability.interceptors.ConfigFilterHelper.FilterParams;
 import io.grpc.internal.NoopServerCall;
 import io.grpc.observabilitylog.v1.GrpcLogRecord.EventLogger;
 import io.grpc.observabilitylog.v1.GrpcLogRecord.EventType;
+import io.opencensus.trace.SpanContext;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import java.net.SocketAddress;
@@ -171,7 +172,8 @@ public class InternalLoggingServerInterceptorTest {
           eq(filterParams.headerBytes()),
           eq(EventLogger.SERVER),
           anyString(),
-          same(peer));
+          same(peer),
+          eq(SpanContext.INVALID));
       verifyNoMoreInteractions(mockLogHelper);
     }
 
@@ -191,7 +193,8 @@ public class InternalLoggingServerInterceptorTest {
           eq(filterParams.headerBytes()),
           eq(EventLogger.SERVER),
           anyString(),
-          ArgumentMatchers.isNull());
+          ArgumentMatchers.isNull(),
+          eq(SpanContext.INVALID));
       verifyNoMoreInteractions(mockLogHelper);
       assertSame(serverInitial, actualServerInitial.get());
     }
@@ -212,7 +215,8 @@ public class InternalLoggingServerInterceptorTest {
           same(request),
           eq(filterParams.messageBytes()),
           eq(EventLogger.SERVER),
-          anyString());
+          anyString(),
+          eq(SpanContext.INVALID));
       verifyNoMoreInteractions(mockLogHelper);
       verify(mockListener).onMessage(same(request));
     }
@@ -229,7 +233,8 @@ public class InternalLoggingServerInterceptorTest {
           eq("method"),
           eq("the-authority"),
           eq(EventLogger.SERVER),
-          anyString());
+          anyString(),
+          eq(SpanContext.INVALID));
       verifyNoMoreInteractions(mockLogHelper);
       verify(mockListener).onHalfClose();
     }
@@ -250,7 +255,8 @@ public class InternalLoggingServerInterceptorTest {
           same(response),
           eq(filterParams.messageBytes()),
           eq(EventLogger.SERVER),
-          anyString());
+          anyString(),
+          eq(SpanContext.INVALID));
       verifyNoMoreInteractions(mockLogHelper);
       assertSame(response, actualResponse.get());
     }
@@ -273,7 +279,8 @@ public class InternalLoggingServerInterceptorTest {
           eq(filterParams.headerBytes()),
           eq(EventLogger.SERVER),
           anyString(),
-          ArgumentMatchers.isNull());
+          ArgumentMatchers.isNull(),
+          eq(SpanContext.INVALID));
       verifyNoMoreInteractions(mockLogHelper);
       assertSame(status, actualStatus.get());
       assertSame(trailers, actualTrailers.get());
@@ -291,7 +298,8 @@ public class InternalLoggingServerInterceptorTest {
           eq("method"),
           eq("the-authority"),
           eq(EventLogger.SERVER),
-          anyString());
+          anyString(),
+          eq(SpanContext.INVALID));
       verify(mockListener).onCancel();
     }
   }
@@ -342,7 +350,8 @@ public class InternalLoggingServerInterceptorTest {
         eq(filterParams.headerBytes()),
         eq(EventLogger.SERVER),
         anyString(),
-        ArgumentMatchers.isNull());
+        ArgumentMatchers.isNull(),
+            eq(SpanContext.INVALID));
     verifyNoMoreInteractions(mockLogHelper);
     Duration timeout = timeoutCaptor.getValue();
     assertThat(TimeUnit.SECONDS.toNanos(1) - Durations.toNanos(timeout))

gcp-observability/src/test/java/io/grpc/gcp/observability/interceptors/LogHelperTest.java

@@ -29,6 +29,7 @@ import static org.mockito.Mockito.verify;
 import com.google.protobuf.ByteString;
 import com.google.protobuf.Duration;
 import com.google.protobuf.util.Durations;
+import com.google.rpc.Code;
 import io.grpc.Attributes;
 import io.grpc.Grpc;
 import io.grpc.Metadata;
@@ -42,6 +43,11 @@ import io.grpc.observabilitylog.v1.GrpcLogRecord;
 import io.grpc.observabilitylog.v1.GrpcLogRecord.EventLogger;
 import io.grpc.observabilitylog.v1.GrpcLogRecord.EventType;
 import io.grpc.observabilitylog.v1.Payload;
+import io.opencensus.trace.SpanContext;
+import io.opencensus.trace.SpanId;
+import io.opencensus.trace.TraceId;
+import io.opencensus.trace.TraceOptions;
+import io.opencensus.trace.Tracestate;
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
@@ -74,11 +80,22 @@ public class LogHelperTest {
       Metadata.Key.of("c", Metadata.ASCII_STRING_MARSHALLER);
   private static final int HEADER_LIMIT = 10;
   private static final int MESSAGE_LIMIT = Integer.MAX_VALUE;
+  private static final SpanContext CLIENT_SPAN_CONTEXT = SpanContext.create(
+      TraceId.fromLowerBase16("4c6af40c499951eb7de2777ba1e4fefa"),
+      SpanId.fromLowerBase16("de52e84d13dd232d"),
+      TraceOptions.builder().setIsSampled(true).build(),
+      Tracestate.builder().build());
+  private static final SpanContext SERVER_SPAN_CONTEXT = SpanContext.create(
+      TraceId.fromLowerBase16("549a8a64db2d0c757fdf6bb1bfe84e2c"),
+      SpanId.fromLowerBase16("a5b7704614fe903d"),
+      TraceOptions.builder().setIsSampled(true).build(),
+      Tracestate.builder().build());
 
   private final Metadata nonEmptyMetadata = new Metadata();
   private final Sink sink = mock(GcpLogSink.class);
   private final LogHelper logHelper = new LogHelper(sink);
 
+
   @Before
   public void setUp() {
     nonEmptyMetadata.put(KEY_A, DATA_A);
@@ -94,7 +111,7 @@ public class LogHelperTest {
     assertThat(LogHelper.socketAddressToProto(socketAddress))
         .isEqualTo(Address
             .newBuilder()
-            .setType(Address.Type.TYPE_IPV4)
+            .setType(Address.Type.IPV4)
             .setAddress("127.0.0.1")
             .setIpPort(12345)
             .build());
@@ -109,7 +126,7 @@ public class LogHelperTest {
     assertThat(LogHelper.socketAddressToProto(socketAddress))
         .isEqualTo(Address
             .newBuilder()
-            .setType(Address.Type.TYPE_IPV6)
+            .setType(Address.Type.IPV6)
             .setAddress("2001:db8::2:1") // RFC 5952 section 4: ipv6 canonical form required
             .setIpPort(12345)
             .build());
@@ -287,8 +304,9 @@ public class LogHelperTest {
           HEADER_LIMIT,
           EventLogger.CLIENT,
           callId,
-          null);
-      verify(sink).write(base);
+          null,
+          CLIENT_SPAN_CONTEXT);
+      verify(sink).write(base, CLIENT_SPAN_CONTEXT);
     }
 
     // logged on server
@@ -303,12 +321,14 @@ public class LogHelperTest {
           HEADER_LIMIT,
           EventLogger.SERVER,
           callId,
-          peerAddress);
+          peerAddress,
+          SERVER_SPAN_CONTEXT);
       verify(sink).write(
           base.toBuilder()
               .setPeer(LogHelper.socketAddressToProto(peerAddress))
               .setLogger(EventLogger.SERVER)
-              .build());
+              .build(),
+          SERVER_SPAN_CONTEXT);
     }
 
     // timeout is null
@@ -323,11 +343,13 @@ public class LogHelperTest {
           HEADER_LIMIT,
           EventLogger.CLIENT,
           callId,
-          null);
+          null,
+          CLIENT_SPAN_CONTEXT);
       verify(sink).write(
           base.toBuilder()
               .setPayload(base.getPayload().toBuilder().clearTimeout().build())
-              .build());
+              .build(),
+          CLIENT_SPAN_CONTEXT);
     }
 
     // peerAddress is not null (error on client)
@@ -342,7 +364,8 @@ public class LogHelperTest {
           HEADER_LIMIT,
           EventLogger.CLIENT,
           callId,
-          peerAddress);
+          peerAddress,
+          CLIENT_SPAN_CONTEXT);
       fail();
     } catch (IllegalArgumentException expected) {
       assertThat(expected).hasMessageThat().contains("peerAddress can only be specified by server");
@@ -385,8 +408,9 @@ public class LogHelperTest {
           HEADER_LIMIT,
           EventLogger.CLIENT,
           callId,
-          peerAddress);
-      verify(sink).write(base);
+          peerAddress,
+          CLIENT_SPAN_CONTEXT);
+      verify(sink).write(base, CLIENT_SPAN_CONTEXT);
     }
 
     // logged on server
@@ -400,12 +424,14 @@ public class LogHelperTest {
           HEADER_LIMIT,
           EventLogger.SERVER,
           callId,
-          null);
+          null,
+          SERVER_SPAN_CONTEXT);
       verify(sink).write(
           base.toBuilder()
               .setLogger(EventLogger.SERVER)
               .clearPeer()
-              .build());
+              .build(),
+          SERVER_SPAN_CONTEXT);
     }
 
     // peerAddress is not null (error on server)
@@ -419,7 +445,8 @@ public class LogHelperTest {
           HEADER_LIMIT,
           EventLogger.SERVER,
           callId,
-          peerAddress);
+          peerAddress,
+          SERVER_SPAN_CONTEXT);
 
       fail();
     } catch (IllegalArgumentException expected) {
@@ -454,7 +481,7 @@ public class LogHelperTest {
     builder.setPeer(LogHelper.socketAddressToProto(peer));
     builder.setPayload(
         builder.getPayload().toBuilder()
-            .setStatusCode(Status.INTERNAL.getCode().value())
+            .setStatusCode(Code.forNumber(Status.INTERNAL.getCode().value()))
             .setStatusMessage("test description")
             .build());
     GrpcLogRecord base = builder.build();
@@ -471,8 +498,9 @@ public class LogHelperTest {
           HEADER_LIMIT,
           EventLogger.CLIENT,
           callId,
-          peer);
-      verify(sink).write(base);
+          peer,
+          CLIENT_SPAN_CONTEXT);
+      verify(sink).write(base, CLIENT_SPAN_CONTEXT);
     }
 
     // logged on server
@@ -487,12 +515,14 @@ public class LogHelperTest {
           HEADER_LIMIT,
           EventLogger.SERVER,
           callId,
-          null);
+          null,
+          SERVER_SPAN_CONTEXT);
       verify(sink).write(
           base.toBuilder()
               .clearPeer()
               .setLogger(EventLogger.SERVER)
-              .build());
+              .build(),
+          SERVER_SPAN_CONTEXT);
     }
 
     // peer address is null
@@ -507,11 +537,13 @@ public class LogHelperTest {
           HEADER_LIMIT,
           EventLogger.CLIENT,
           callId,
-          null);
+          null,
+          CLIENT_SPAN_CONTEXT);
       verify(sink).write(
           base.toBuilder()
               .clearPeer()
-              .build());
+              .build(),
+          CLIENT_SPAN_CONTEXT);
     }
 
     // status description is null
@@ -526,11 +558,13 @@ public class LogHelperTest {
           HEADER_LIMIT,
           EventLogger.CLIENT,
           callId,
-          peer);
+          peer,
+          CLIENT_SPAN_CONTEXT);
       verify(sink).write(
           base.toBuilder()
               .setPayload(base.getPayload().toBuilder().clearStatusMessage().build())
-              .build());
+              .build(),
+          CLIENT_SPAN_CONTEXT);
     }
   }
 
@@ -590,8 +624,9 @@ public class LogHelperTest {
           message,
           MESSAGE_LIMIT,
           EventLogger.CLIENT,
-          callId);
-      verify(sink).write(base);
+          callId,
+          CLIENT_SPAN_CONTEXT);
+      verify(sink).write(base, CLIENT_SPAN_CONTEXT);
     }
     // response message, logged on client
     {
@@ -604,11 +639,13 @@ public class LogHelperTest {
           message,
           MESSAGE_LIMIT,
           EventLogger.CLIENT,
-          callId);
+          callId,
+          CLIENT_SPAN_CONTEXT);
       verify(sink).write(
           base.toBuilder()
               .setType(EventType.SERVER_MESSAGE)
-              .build());
+              .build(),
+          CLIENT_SPAN_CONTEXT);
     }
     // request message, logged on server
     {
@@ -621,11 +658,13 @@ public class LogHelperTest {
           message,
           MESSAGE_LIMIT,
           EventLogger.SERVER,
-          callId);
+          callId,
+          SERVER_SPAN_CONTEXT);
       verify(sink).write(
           base.toBuilder()
               .setLogger(EventLogger.SERVER)
-              .build());
+              .build(),
+          SERVER_SPAN_CONTEXT);
     }
     // response message, logged on server
     {
@@ -638,12 +677,14 @@ public class LogHelperTest {
           message,
           MESSAGE_LIMIT,
           EventLogger.SERVER,
-          callId);
+          callId,
+          SpanContext.INVALID);
       verify(sink).write(
           base.toBuilder()
               .setType(EventType.SERVER_MESSAGE)
               .setLogger(EventLogger.SERVER)
-              .build());
+              .build(),
+          SpanContext.INVALID);
     }
     // message is not of type : com.google.protobuf.Message or byte[]
     {
@@ -656,12 +697,14 @@ public class LogHelperTest {
           "message",
           MESSAGE_LIMIT,
           EventLogger.CLIENT,
-          callId);
+          callId,
+          CLIENT_SPAN_CONTEXT);
       verify(sink).write(
           base.toBuilder()
               .clearPayload()
               .clearPayloadTruncated()
-              .build());
+              .build(),
+          CLIENT_SPAN_CONTEXT);
     }
   }
 

gcp-observability/src/test/java/io/grpc/gcp/observability/logging/GcpLogSinkTest.java

@@ -22,8 +22,8 @@ import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyNoInteractions;
 import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.Mockito.when;
 
-import com.google.cloud.MonitoredResource;
 import com.google.cloud.logging.LogEntry;
 import com.google.cloud.logging.Logging;
 import com.google.common.collect.ImmutableMap;
@@ -31,9 +31,15 @@ import com.google.protobuf.Duration;
 import com.google.protobuf.Struct;
 import com.google.protobuf.Value;
 import com.google.protobuf.util.Durations;
+import io.grpc.gcp.observability.ObservabilityConfig;
 import io.grpc.observabilitylog.v1.GrpcLogRecord;
 import io.grpc.observabilitylog.v1.GrpcLogRecord.EventLogger;
 import io.grpc.observabilitylog.v1.GrpcLogRecord.EventType;
+import io.opencensus.trace.SpanContext;
+import io.opencensus.trace.SpanId;
+import io.opencensus.trace.TraceId;
+import io.opencensus.trace.TraceOptions;
+import io.opencensus.trace.Tracestate;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
@@ -57,12 +63,6 @@ public class GcpLogSinkTest {
   @Rule
   public final MockitoRule mockito = MockitoJUnit.rule();
 
-  private static final ImmutableMap<String, String> LOCATION_TAGS =
-      ImmutableMap.of("project_id", "PROJECT",
-      "location", "us-central1-c",
-      "cluster_name", "grpc-observability-cluster",
-      "namespace_name", "default" ,
-      "pod_name", "app1-6c7c58f897-n92c5");
   private static final ImmutableMap<String, String> CUSTOM_TAGS =
       ImmutableMap.of("KEY1", "Value1",
       "KEY2", "VALUE2");
@@ -105,13 +105,16 @@ public class GcpLogSinkTest {
       .build();
   @Mock
   private Logging mockLogging;
+  @Mock
+  private ObservabilityConfig mockConfig;
 
   @Test
   @SuppressWarnings("unchecked")
   public void verifyWrite() throws Exception {
-    GcpLogSink sink = new GcpLogSink(mockLogging, DEST_PROJECT_NAME, LOCATION_TAGS,
-        CUSTOM_TAGS, Collections.emptySet());
-    sink.write(LOG_PROTO);
+    when(mockConfig.getCustomTags()).thenReturn(CUSTOM_TAGS);
+    GcpLogSink sink = new GcpLogSink(mockLogging, DEST_PROJECT_NAME,
+        mockConfig, Collections.emptySet(), new TraceLoggingHelper(DEST_PROJECT_NAME));
+    sink.write(LOG_PROTO, null);
 
     ArgumentCaptor<Collection<LogEntry>> logEntrySetCaptor = ArgumentCaptor.forClass(
         (Class) Collection.class);
@@ -127,10 +130,10 @@ public class GcpLogSinkTest {
   @Test
   @SuppressWarnings("unchecked")
   public void verifyWriteWithTags() {
-    GcpLogSink sink = new GcpLogSink(mockLogging, DEST_PROJECT_NAME, LOCATION_TAGS,
-        CUSTOM_TAGS, Collections.emptySet());
-    MonitoredResource expectedMonitoredResource = GcpLogSink.getResource(LOCATION_TAGS);
-    sink.write(LOG_PROTO);
+    when(mockConfig.getCustomTags()).thenReturn(CUSTOM_TAGS);
+    GcpLogSink sink = new GcpLogSink(mockLogging, DEST_PROJECT_NAME,
+        mockConfig, Collections.emptySet(), new TraceLoggingHelper(DEST_PROJECT_NAME));
+    sink.write(LOG_PROTO, null);
 
     ArgumentCaptor<Collection<LogEntry>> logEntrySetCaptor = ArgumentCaptor.forClass(
         (Class) Collection.class);
@@ -138,7 +141,6 @@ public class GcpLogSinkTest {
     System.out.println(logEntrySetCaptor.getValue());
     for (Iterator<LogEntry> it = logEntrySetCaptor.getValue().iterator(); it.hasNext(); ) {
       LogEntry entry = it.next();
-      assertThat(entry.getResource()).isEqualTo(expectedMonitoredResource);
       assertThat(entry.getLabels()).isEqualTo(CUSTOM_TAGS);
       assertThat(entry.getPayload().getData()).isEqualTo(EXPECTED_STRUCT_LOG_PROTO);
       assertThat(entry.getLogName()).isEqualTo(EXPECTED_LOG_NAME);
@@ -150,10 +152,11 @@ public class GcpLogSinkTest {
   @SuppressWarnings("unchecked")
   public void emptyCustomTags_labelsNotSet() {
     Map<String, String> emptyCustomTags = null;
+    when(mockConfig.getCustomTags()).thenReturn(emptyCustomTags);
     Map<String, String> expectedEmptyLabels = new HashMap<>();
-    GcpLogSink sink = new GcpLogSink(mockLogging, DEST_PROJECT_NAME, LOCATION_TAGS,
-        emptyCustomTags, Collections.emptySet());
-    sink.write(LOG_PROTO);
+    GcpLogSink sink = new GcpLogSink(mockLogging, DEST_PROJECT_NAME,
+        mockConfig, Collections.emptySet(), new TraceLoggingHelper(DEST_PROJECT_NAME));
+    sink.write(LOG_PROTO, null);
 
     ArgumentCaptor<Collection<LogEntry>> logEntrySetCaptor = ArgumentCaptor.forClass(
         (Class) Collection.class);
@@ -169,12 +172,13 @@ public class GcpLogSinkTest {
   @SuppressWarnings("unchecked")
   public void emptyCustomTags_setSourceProject() {
     Map<String, String> emptyCustomTags = null;
+    when(mockConfig.getCustomTags()).thenReturn(emptyCustomTags);
     String projectId = "PROJECT";
-    Map<String, String> expectedLabels = GcpLogSink.getCustomTags(emptyCustomTags, LOCATION_TAGS,
-        projectId);
-    GcpLogSink sink = new GcpLogSink(mockLogging, projectId, LOCATION_TAGS,
-        emptyCustomTags, Collections.emptySet());
-    sink.write(LOG_PROTO);
+    Map<String, String> expectedLabels = GcpLogSink.getCustomTags(emptyCustomTags
+    );
+    GcpLogSink sink = new GcpLogSink(mockLogging, projectId,
+        mockConfig, Collections.emptySet(), new TraceLoggingHelper(DEST_PROJECT_NAME));
+    sink.write(LOG_PROTO, null);
 
     ArgumentCaptor<Collection<LogEntry>> logEntrySetCaptor = ArgumentCaptor.forClass(
         (Class) Collection.class);
@@ -188,9 +192,9 @@ public class GcpLogSinkTest {
 
   @Test
   public void verifyClose() throws Exception {
-    GcpLogSink sink = new GcpLogSink(mockLogging, DEST_PROJECT_NAME, LOCATION_TAGS,
-        CUSTOM_TAGS, Collections.emptySet());
-    sink.write(LOG_PROTO);
+    GcpLogSink sink = new GcpLogSink(mockLogging, DEST_PROJECT_NAME,
+        mockConfig, Collections.emptySet(), new TraceLoggingHelper(DEST_PROJECT_NAME));
+    sink.write(LOG_PROTO, null);
     verify(mockLogging, times(1)).write(anyIterable());
     sink.close();
     verify(mockLogging).close();
@@ -199,9 +203,107 @@ public class GcpLogSinkTest {
 
   @Test
   public void verifyExclude() throws Exception {
-    Sink mockSink = new GcpLogSink(mockLogging, DEST_PROJECT_NAME, LOCATION_TAGS,
-        CUSTOM_TAGS, Collections.singleton("service"));
-    mockSink.write(LOG_PROTO);
+    Sink mockSink = new GcpLogSink(mockLogging, DEST_PROJECT_NAME,
+        mockConfig, Collections.singleton("service"), new TraceLoggingHelper(DEST_PROJECT_NAME));
+    mockSink.write(LOG_PROTO, null);
     verifyNoInteractions(mockLogging);
   }
+
+  @Test
+  @SuppressWarnings("unchecked")
+  public void verifyNoTraceDataInLogs_withTraceDisabled() throws Exception {
+    SpanContext validSpanContext = SpanContext.create(
+        TraceId.fromLowerBase16("4c6af40c499951eb7de2777ba1e4fefa"),
+        SpanId.fromLowerBase16("de52e84d13dd232d"),
+        TraceOptions.builder().setIsSampled(true).build(),
+        Tracestate.builder().build());
+
+    TraceLoggingHelper traceLoggingHelper = new TraceLoggingHelper(DEST_PROJECT_NAME);
+    when(mockConfig.isEnableCloudTracing()).thenReturn(false);
+    Sink mockSink = new GcpLogSink(mockLogging, DEST_PROJECT_NAME,
+        mockConfig, Collections.emptySet(), traceLoggingHelper);
+    mockSink.write(LOG_PROTO, validSpanContext);
+
+    ArgumentCaptor<Collection<LogEntry>> logEntrySetCaptor = ArgumentCaptor.forClass(
+        (Class) Collection.class);
+    verify(mockLogging, times(1)).write(logEntrySetCaptor.capture());
+    for (Iterator<LogEntry> it = logEntrySetCaptor.getValue().iterator(); it.hasNext(); ) {
+      LogEntry entry = it.next();
+      assertThat(entry.getTrace()).isNull(); // Field not present
+      assertThat(entry.getSpanId()).isNull(); // Field not present
+      assertThat(entry.getTraceSampled()).isFalse(); // Default value
+      assertThat(entry.getPayload().getData()).isEqualTo(EXPECTED_STRUCT_LOG_PROTO);
+    }
+  }
+
+  @Test
+  @SuppressWarnings("unchecked")
+  public void verifyTraceDataInLogs_withValidSpanContext() throws Exception {
+    CharSequence traceIdSeq = "4c6af40c499951eb7de2777ba1e4fefa";
+    CharSequence spanIdSeq = "de52e84d13dd232d";
+    TraceId traceId = TraceId.fromLowerBase16(traceIdSeq);
+    SpanId spanId = SpanId.fromLowerBase16(spanIdSeq);
+    boolean traceSampled = true;
+
+    SpanContext validSpanContext = SpanContext.create(traceId, spanId,
+        TraceOptions.builder().setIsSampled(traceSampled).build(),
+        Tracestate.builder().build());
+
+    TraceLoggingHelper traceLoggingHelper = new TraceLoggingHelper(DEST_PROJECT_NAME);
+    when(mockConfig.isEnableCloudTracing()).thenReturn(true);
+    Sink mockSink = new GcpLogSink(mockLogging, DEST_PROJECT_NAME,
+        mockConfig, Collections.emptySet(), traceLoggingHelper);
+    mockSink.write(LOG_PROTO, validSpanContext);
+
+    String expectedTrace = "projects/" + DEST_PROJECT_NAME + "/traces/" + traceIdSeq;
+
+    ArgumentCaptor<Collection<LogEntry>> logEntrySetCaptor = ArgumentCaptor.forClass(
+        (Class) Collection.class);
+    verify(mockLogging, times(1)).write(logEntrySetCaptor.capture());
+    for (Iterator<LogEntry> it = logEntrySetCaptor.getValue().iterator(); it.hasNext(); ) {
+      LogEntry entry = it.next();
+      assertThat(entry.getTrace()).isEqualTo(expectedTrace);
+      assertThat(entry.getSpanId()).isEqualTo("" + spanIdSeq);
+      assertThat(entry.getTraceSampled()).isEqualTo(traceSampled);
+      assertThat(entry.getPayload().getData()).isEqualTo(EXPECTED_STRUCT_LOG_PROTO);
+    }
+
+  }
+
+  @Test
+  @SuppressWarnings("unchecked")
+  public void verifyTraceDataLogs_withNullSpanContext() throws Exception {
+    TraceLoggingHelper traceLoggingHelper = new TraceLoggingHelper(DEST_PROJECT_NAME);
+    when(mockConfig.isEnableCloudTracing()).thenReturn(true);
+    Sink mockSink = new GcpLogSink(mockLogging, DEST_PROJECT_NAME,
+        mockConfig, Collections.emptySet(), traceLoggingHelper);
+
+    String expectedTrace =
+        "projects/" + DEST_PROJECT_NAME + "/traces/00000000000000000000000000000000";
+    String expectedSpanId = "0000000000000000";
+
+    ArgumentCaptor<Collection<LogEntry>> logEntrySetCaptor = ArgumentCaptor.forClass(
+        (Class) Collection.class);
+
+    // Client log with default span context
+    mockSink.write(LOG_PROTO , SpanContext.INVALID);
+    verify(mockLogging, times(1)).write(logEntrySetCaptor.capture());
+    for (Iterator<LogEntry> it = logEntrySetCaptor.getValue().iterator(); it.hasNext(); ) {
+      LogEntry entry = it.next();
+      assertThat(entry.getTrace()).isEqualTo(expectedTrace);
+      assertThat(entry.getSpanId()).isEqualTo(expectedSpanId);
+      assertThat(entry.getTraceSampled()).isFalse();
+    }
+
+    // Server log
+    GrpcLogRecord serverLogProto = LOG_PROTO.toBuilder().setLogger(EventLogger.SERVER).build();
+    mockSink.write(serverLogProto , SpanContext.INVALID);
+    verify(mockLogging, times(2)).write(logEntrySetCaptor.capture());
+    for (Iterator<LogEntry> it = logEntrySetCaptor.getValue().iterator(); it.hasNext(); ) {
+      LogEntry entry = it.next();
+      assertThat(entry.getTrace()).isEqualTo(expectedTrace);
+      assertThat(entry.getSpanId()).isEqualTo(expectedSpanId);
+      assertThat(entry.getTraceSampled()).isFalse();
+    }
+  }
 }

gcp-observability/src/test/java/io/grpc/gcp/observability/logging/TraceLoggingHelperTest.java

@@ -0,0 +1,91 @@
+/*
+ * Copyright 2023 The gRPC Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.grpc.gcp.observability.logging;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.cloud.logging.LogEntry;
+import io.opencensus.trace.SpanContext;
+import io.opencensus.trace.SpanId;
+import io.opencensus.trace.TraceId;
+import io.opencensus.trace.TraceOptions;
+import io.opencensus.trace.Tracestate;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/**
+ * Tests for {@link TraceLoggingHelper}.
+ */
+@RunWith(JUnit4.class)
+public class TraceLoggingHelperTest {
+
+  private static final String PROJECT = "PROJECT";
+  private static final Tracestate EMPTY_TRACESTATE = Tracestate.builder().build();
+  private static TraceLoggingHelper traceLoggingHelper;
+
+  @Before
+  public void setUp() {
+    traceLoggingHelper = new TraceLoggingHelper(PROJECT);
+  }
+
+  @Test
+  public void enhanceLogEntry_AddSampledSpanContextToLogEntry() {
+    SpanContext spanContext = SpanContext.create(
+        TraceId.fromLowerBase16("5ce724c382c136b2a67bb447e6a6bd27"),
+        SpanId.fromLowerBase16("de52e84d13dd232d"),
+        TraceOptions.builder().setIsSampled(true).build(),
+        EMPTY_TRACESTATE);
+    LogEntry logEntry = getEnhancedLogEntry(traceLoggingHelper, spanContext);
+    assertThat(logEntry.getTraceSampled()).isTrue();
+    assertThat(logEntry.getTrace())
+        .isEqualTo("projects/PROJECT/traces/5ce724c382c136b2a67bb447e6a6bd27");
+    assertThat(logEntry.getSpanId()).isEqualTo("de52e84d13dd232d");
+  }
+
+  @Test
+  public void enhanceLogEntry_AddNonSampledSpanContextToLogEntry() {
+    SpanContext spanContext = SpanContext.create(
+        TraceId.fromLowerBase16("649a8a64db2d0c757fd06bb1bfe84e2c"),
+        SpanId.fromLowerBase16("731e102335b7a5a0"),
+        TraceOptions.builder().setIsSampled(false).build(),
+        EMPTY_TRACESTATE);
+    LogEntry logEntry = getEnhancedLogEntry(traceLoggingHelper, spanContext);
+    assertThat(logEntry.getTraceSampled()).isFalse();
+    assertThat(logEntry.getTrace())
+        .isEqualTo("projects/PROJECT/traces/649a8a64db2d0c757fd06bb1bfe84e2c");
+    assertThat(logEntry.getSpanId()).isEqualTo("731e102335b7a5a0");
+  }
+
+  @Test
+  public void enhanceLogEntry_AddBlankSpanContextToLogEntry() {
+    SpanContext spanContext = SpanContext.INVALID;
+    LogEntry logEntry = getEnhancedLogEntry(traceLoggingHelper, spanContext);
+    assertThat(logEntry.getTraceSampled()).isFalse();
+    assertThat(logEntry.getTrace())
+        .isEqualTo("projects/PROJECT/traces/00000000000000000000000000000000");
+    assertThat(logEntry.getSpanId()).isEqualTo("0000000000000000");
+  }
+
+  private static LogEntry getEnhancedLogEntry(TraceLoggingHelper traceLoggingHelper,
+      SpanContext spanContext) {
+    LogEntry.Builder logEntryBuilder = LogEntry.newBuilder(null);
+    traceLoggingHelper.enhanceLogEntry(logEntryBuilder, spanContext);
+    return logEntryBuilder.build();
+  }
+}

interop-testing/src/main/java/io/grpc/testing/integration/TestServiceClient.java

@@ -71,7 +71,6 @@ public class TestServiceClient {
     } finally {
       client.tearDown();
     }
-    System.exit(0);
   }
 
   private String serverHost = "localhost";

xds/src/test/java/io/grpc/xds/WeightedRoundRobinLoadBalancerTest.java

@@ -638,7 +638,8 @@ public class WeightedRoundRobinLoadBalancerTest {
       pickCount.put(result, pickCount.getOrDefault(result, 0) + 1);
     }
     for (int i = 0; i < capacity; i++) {
-      assertThat(Math.abs(pickCount.get(i) / 1000.0 - weights[i] / totalWeight) ).isAtMost(0.01);
+      assertThat(Math.abs(pickCount.getOrDefault(i, 0) / 1000.0 - weights[i] / totalWeight) )
+          .isAtMost(0.01);
     }
   }