Metric Attributes

gax-java/gax-grpc/src/main/java/com/google/api/gax/grpc/GrpcTransportChannel.java

@@ -35,6 +35,8 @@
 import com.google.auto.value.AutoValue;
 import io.grpc.Channel;
 import io.grpc.ManagedChannel;
+import java.util.HashMap;
+import java.util.Map;
 import java.util.concurrent.TimeUnit;
 
 /** Implementation of TransportChannel based on gRPC. */
@@ -100,17 +102,19 @@ public void close() {
   }
 
   public static Builder newBuilder() {
-    return new AutoValue_GrpcTransportChannel.Builder();
+    return new AutoValue_GrpcTransportChannel.Builder().setConfigurations(new HashMap<>());
   }
 
   public static GrpcTransportChannel create(ManagedChannel channel) {
-    return newBuilder().setManagedChannel(channel).build();
+    return newBuilder().setManagedChannel(channel).setConfigurations(new HashMap<>()).build();
   }
 
   @AutoValue.Builder
   public abstract static class Builder {
     public abstract Builder setManagedChannel(ManagedChannel value);
 
+    abstract Builder setConfigurations(Map<String, String> configurations);
+
     public abstract GrpcTransportChannel build();
   }
 }

gax-java/gax-grpc/src/main/java/com/google/api/gax/grpc/InstantiatingGrpcChannelProvider.java

@@ -40,6 +40,7 @@
 import com.google.api.gax.rpc.TransportChannelProvider;
 import com.google.api.gax.rpc.internal.EnvironmentProvider;
 import com.google.api.gax.rpc.mtls.MtlsProvider;
+import com.google.api.gax.tracing.ApiTracerFactory;
 import com.google.auth.Credentials;
 import com.google.auth.oauth2.ComputeEngineCredentials;
 import com.google.common.annotations.VisibleForTesting;
@@ -239,9 +240,15 @@ public TransportChannel getTransportChannel() throws IOException {
   }
 
   private TransportChannel createChannel() throws IOException {
-    return GrpcTransportChannel.create(
-        ChannelPool.create(
-            channelPoolSettings, InstantiatingGrpcChannelProvider.this::createSingleChannel));
+    return GrpcTransportChannel.newBuilder()
+        .setManagedChannel(
+            ChannelPool.create(
+                channelPoolSettings, InstantiatingGrpcChannelProvider.this::createSingleChannel))
+        .setConfigurations(
+            ImmutableMap.of(
+                ApiTracerFactory.MetricAttribute.DIRECTPATH_ENABLED.getAttribute(),
+                String.valueOf(isCompatibleForDirectPath())))
+        .build();
   }
 
   private boolean isDirectPathEnabled() {
@@ -370,10 +377,7 @@ private ManagedChannel createSingleChannel() throws IOException {
 
     // Check DirectPath traffic.
     boolean useDirectPathXds = false;
-    if (isDirectPathEnabled()
-        && isCredentialDirectPathCompatible()
-        && isOnComputeEngine()
-        && canUseDirectPathWithUniverseDomain()) {
+    if (isCompatibleForDirectPath()) {
       CallCredentials callCreds = MoreCallCredentials.from(credentials);
       ChannelCredentials channelCreds =
           GoogleDefaultChannelCredentials.newBuilder().callCredentials(callCreds).build();
@@ -446,6 +450,20 @@ && canUseDirectPathWithUniverseDomain()) {
     return managedChannel;
   }
 
+  /**
+   * DirectPath must be enabled via the settings and a few other configurations/settings must also
+   * be valid for the request to go through DirectPath (valid credentials, running on Compute, and
+   * routed through Google Servers).
+   *
+   * @return if DirectPath is enabled for the client and is compatible to be used with DirectPath
+   */
+  public boolean isCompatibleForDirectPath() {
+    return isDirectPathEnabled()
+        && isCredentialDirectPathCompatible()
+        && isOnComputeEngine()
+        && canUseDirectPathWithUniverseDomain();
+  }
+
   /** The endpoint to be used for the channel. */
   @Override
   public String getEndpoint() {

gax-java/gax-httpjson/src/main/java/com/google/api/gax/httpjson/HttpJsonTransportChannel.java

@@ -32,6 +32,8 @@
 import com.google.api.core.InternalExtensionOnly;
 import com.google.api.gax.rpc.TransportChannel;
 import com.google.auto.value.AutoValue;
+import java.util.HashMap;
+import java.util.Map;
 import java.util.concurrent.TimeUnit;
 
 /** Implementation of TransportChannel based on http/json. */
@@ -97,13 +99,15 @@ public static Builder newBuilder() {
   }
 
   public static HttpJsonTransportChannel create(ManagedHttpJsonChannel channel) {
-    return newBuilder().setManagedChannel(channel).build();
+    return newBuilder().setManagedChannel(channel).setConfigurations(new HashMap<>()).build();
   }
 
   @AutoValue.Builder
   public abstract static class Builder {
     public abstract Builder setManagedChannel(ManagedHttpJsonChannel value);
 
+    abstract Builder setConfigurations(Map<String, String> configurations);
+
     public abstract HttpJsonTransportChannel build();
   }
 }

gax-java/gax-httpjson/src/main/java/com/google/api/gax/httpjson/InstantiatingHttpJsonChannelProvider.java

@@ -37,8 +37,10 @@
 import com.google.api.gax.rpc.HeaderProvider;
 import com.google.api.gax.rpc.TransportChannelProvider;
 import com.google.api.gax.rpc.mtls.MtlsProvider;
+import com.google.api.gax.tracing.ApiTracerFactory;
 import com.google.auth.Credentials;
 import com.google.common.annotations.VisibleForTesting;
+import com.google.common.collect.ImmutableMap;
 import java.io.IOException;
 import java.security.GeneralSecurityException;
 import java.security.KeyStore;
@@ -203,7 +205,12 @@ private HttpJsonTransportChannel createChannel() throws IOException, GeneralSecu
       }
     }
 
-    return HttpJsonTransportChannel.newBuilder().setManagedChannel(channel).build();
+    return HttpJsonTransportChannel.newBuilder()
+        .setManagedChannel(channel)
+        .setConfigurations(
+            ImmutableMap.of(
+                ApiTracerFactory.MetricAttribute.DIRECTPATH_ENABLED.getAttribute(), "false"))
+        .build();
   }
 
   /** The endpoint to be used for the channel. */

gax-java/gax-httpjson/src/test/java/com/google/api/gax/httpjson/HttpJsonCallContextTest.java

@@ -86,8 +86,7 @@ public void testWithTransportChannel() {
 
     HttpJsonCallContext context =
         HttpJsonCallContext.createDefault()
-            .withTransportChannel(
-                HttpJsonTransportChannel.newBuilder().setManagedChannel(channel).build());
+            .withTransportChannel(HttpJsonTransportChannel.create(channel));
     Truth.assertThat(context.getChannel()).isSameInstanceAs(channel);
   }
 

gax-java/gax/clirr-ignored-differences.xml

@@ -42,4 +42,14 @@
     <className>com/google/api/gax/rpc/ApiCallContext</className>
     <method>* validateUniverseDomain()</method>
   </difference>
+  <difference>
+    <differenceType>7012</differenceType>
+    <className>com/google/api/gax/rpc/TransportChannel</className>
+    <method>* getConfigurations()</method>
+  </difference>
+  <difference>
+    <differenceType>7012</differenceType>
+    <className>com/google/api/gax/tracing/ApiTracerFactory</className>
+    <method>* addAttributes(*)</method>
+  </difference>
 </differences>

gax-java/gax/src/main/java/com/google/api/gax/rpc/ClientContext.java

@@ -154,6 +154,8 @@ public static ClientContext create(ClientSettings settings) throws IOException {
    * settings.
    */
   public static ClientContext create(StubSettings settings) throws IOException {
+    Map<String, String> clientInitializationOtelAttributes = new HashMap<>();
+
     ApiClock clock = settings.getClock();
 
     ExecutorProvider backgroundExecutorProvider = settings.getBackgroundExecutorProvider();
@@ -224,6 +226,9 @@ public static ClientContext create(StubSettings settings) throws IOException {
       transportChannelProvider = transportChannelProvider.withEndpoint(endpoint);
     }
     TransportChannel transportChannel = transportChannelProvider.getTransportChannel();
+    clientInitializationOtelAttributes.put(
+        "directpath_enabled",
+        String.valueOf(transportChannel.getConfigurations().get("directpath_enabled")));
 
     ApiCallContext defaultCallContext =
         transportChannel.getEmptyCallContext().withTransportChannel(transportChannel);
@@ -261,6 +266,9 @@ public static ClientContext create(StubSettings settings) throws IOException {
       backgroundResources.add(watchdog);
     }
 
+    ApiTracerFactory apiTracerFactory = settings.getTracerFactory();
+    apiTracerFactory.addAttributes(clientInitializationOtelAttributes);
+
     return newBuilder()
         .setBackgroundResources(backgroundResources.build())
         .setExecutor(backgroundExecutor)
@@ -276,7 +284,7 @@ public static ClientContext create(StubSettings settings) throws IOException {
         .setQuotaProjectId(settings.getQuotaProjectId())
         .setStreamWatchdog(watchdog)
         .setStreamWatchdogCheckInterval(settings.getStreamWatchdogCheckInterval())
-        .setTracerFactory(settings.getTracerFactory())
+        .setTracerFactory(apiTracerFactory)
         .build();
   }
 

gax-java/gax/src/main/java/com/google/api/gax/rpc/TransportChannel.java

@@ -31,6 +31,7 @@
 
 import com.google.api.core.InternalExtensionOnly;
 import com.google.api.gax.core.BackgroundResource;
+import java.util.Map;
 
 /** Class whose instances can issue RPCs on a particular transport. */
 @InternalExtensionOnly
@@ -47,4 +48,6 @@ public interface TransportChannel extends BackgroundResource {
    * Returns an empty {@link ApiCallContext} that is compatible with this {@code TransportChannel}.
    */
   ApiCallContext getEmptyCallContext();
+
+  Map<String, String> getConfigurations();
 }

gax-java/gax/src/main/java/com/google/api/gax/tracing/ApiTracerFactory.java

@@ -31,6 +31,9 @@
 
 import com.google.api.core.InternalApi;
 import com.google.api.core.InternalExtensionOnly;
+import com.google.common.collect.ImmutableSet;
+import java.util.Map;
+import java.util.Set;
 
 /**
  * A factory to create new instances of {@link ApiTracer}s.
@@ -53,6 +56,36 @@ enum OperationType {
     BidiStreaming
   }
 
+  enum MetricFlags {
+    DIRECTPATH(
+        ImmutableSet.of(MetricAttribute.DIRECTPATH_ENABLED, MetricAttribute.DIRECTPATH_USED));
+
+    private final Set<MetricAttribute> otelAttributeKey;
+
+    MetricFlags(Set<MetricAttribute> otelAttributeKey) {
+      this.otelAttributeKey = otelAttributeKey;
+    }
+
+    public Set<MetricAttribute> getOtelAttributeKey() {
+      return otelAttributeKey;
+    }
+  }
+
+  enum MetricAttribute {
+    DIRECTPATH_ENABLED("directpath_enabled"),
+    DIRECTPATH_USED("directpath_used");
+
+    private final String attribute;
+
+    MetricAttribute(String attribute) {
+      this.attribute = attribute;
+    }
+
+    public String getAttribute() {
+      return attribute;
+    }
+  }
+
   /**
    * Create a new {@link ApiTracer} that will be a child of the current context.
    *
@@ -61,4 +94,6 @@ enum OperationType {
    * @param operationType the type of operation that the tracer will trace
    */
   ApiTracer newTracer(ApiTracer parent, SpanName spanName, OperationType operationType);
+
+  default void addAttributes(Map<String, String> attributes) {}
 }

gax-java/gax/src/main/java/com/google/api/gax/tracing/MetricsTracerFactory.java

@@ -31,6 +31,10 @@
 
 import com.google.api.core.BetaApi;
 import com.google.api.core.InternalApi;
+import com.google.common.collect.ImmutableSet;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
 
 /**
  * A {@link ApiTracerFactory} to build instances of {@link MetricsTracer}.
@@ -45,13 +49,44 @@
 public class MetricsTracerFactory implements ApiTracerFactory {
   protected MetricsRecorder metricsRecorder;
 
+  private final Set<MetricFlags> metricFlagsSet;
+
+  private final Map<String, String> additionalDefaultAttributes;
+
   public MetricsTracerFactory(MetricsRecorder metricsRecorder) {
+    this(metricsRecorder, ImmutableSet.of());
+  }
+
+  public MetricsTracerFactory(MetricsRecorder metricsRecorder, Set<MetricFlags> metricFlagsSet) {
     this.metricsRecorder = metricsRecorder;
+    this.metricFlagsSet = metricFlagsSet;
+    this.additionalDefaultAttributes = new HashMap<>();
   }
 
   @Override
   public ApiTracer newTracer(ApiTracer parent, SpanName spanName, OperationType operationType) {
-    return new MetricsTracer(
-        MethodName.of(spanName.getClientName(), spanName.getMethodName()), metricsRecorder);
+    MetricsTracer metricsTracer =
+        new MetricsTracer(
+            MethodName.of(spanName.getClientName(), spanName.getMethodName()), metricsRecorder);
+    for (Map.Entry<String, String> additionalDefaultAttribute :
+        additionalDefaultAttributes.entrySet()) {
+      metricsTracer.addAttributes(
+          additionalDefaultAttribute.getKey(), additionalDefaultAttribute.getValue());
+    }
+    return metricsTracer;
+  }
+
+  @Override
+  public void addAttributes(Map<String, String> attributes) {
+    for (Map.Entry<String, String> attributeEntry : attributes.entrySet()) {
+      String attribute = attributeEntry.getKey();
+      for (MetricFlags metricFlags : metricFlagsSet) {
+        for (MetricAttribute metricAttribute : metricFlags.getOtelAttributeKey()) {
+          if (metricAttribute.getAttribute().equals(attribute)) {
+            additionalDefaultAttributes.put(attributeEntry.getKey(), attributeEntry.getValue());
+          }
+        }
+      }
+    }
   }
 }

gax-java/gax/src/test/java/com/google/api/gax/rpc/testing/FakeTransportChannel.java

@@ -31,6 +31,7 @@
 
 import com.google.api.core.InternalApi;
 import com.google.api.gax.rpc.TransportChannel;
+import com.google.common.collect.ImmutableMap;
 import java.util.Map;
 import java.util.concurrent.Executor;
 import java.util.concurrent.TimeUnit;
@@ -65,6 +66,11 @@ public FakeCallContext getEmptyCallContext() {
     return FakeCallContext.createDefault();
   }
 
+  @Override
+  public Map<String, String> getConfigurations() {
+    return ImmutableMap.of();
+  }
+
   @Override
   public void shutdown() {
     isShutdown = true;