feat: Full Endpoint Resolution from EndpointContext (#2313)

* feat: Full endpoint resolution

* chore: Fix lint issues

* chore: Address PR comments

* chore: Do not set resolved universe domain for gdch

* chore: Move helper methods to the Builder class

* chore: Address PR comments

* chore: Add javadocs for universe domain

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

@@ -295,6 +295,10 @@ private void logDirectPathMisconfig() {
               Level.WARNING,
               "DirectPath is misconfigured. DirectPath is only available in a GCE environment.");
         }
+        if (!canUseDirectPathWithUniverseDomain()) {
+          LOG.log(
+              Level.WARNING, "DirectPath will only work in the the googleapis.com Universe Domain");
+        }
       }
     }
   }
@@ -325,6 +329,10 @@ static boolean isOnComputeEngine() {
     return false;
   }
 
+  private boolean canUseDirectPathWithUniverseDomain() {
+    return endpoint.contains("googleapis.com");
+  }
+
   @VisibleForTesting
   ChannelCredentials createMtlsChannelCredentials() throws IOException, GeneralSecurityException {
     if (mtlsProvider.useMtlsClientCertificate()) {
@@ -356,7 +364,10 @@ private ManagedChannel createSingleChannel() throws IOException {
 
     // Check DirectPath traffic.
     boolean useDirectPathXds = false;
-    if (isDirectPathEnabled() && isNonDefaultServiceAccountAllowed() && isOnComputeEngine()) {
+    if (isDirectPathEnabled()
+        && isNonDefaultServiceAccountAllowed()
+        && isOnComputeEngine()
+        && canUseDirectPathWithUniverseDomain()) {
       CallCredentials callCreds = MoreCallCredentials.from(credentials);
       ChannelCredentials channelCreds =
           GoogleDefaultChannelCredentials.newBuilder().callCredentials(callCreds).build();

gax-java/gax-grpc/src/test/java/com/google/api/gax/grpc/InstantiatingGrpcChannelProviderTest.java

@@ -290,6 +290,7 @@ public void testDirectPathXdsEnabled() throws IOException {
         InstantiatingGrpcChannelProvider.newBuilder()
             .setAttemptDirectPath(true)
             .setAttemptDirectPathXds()
+            .setEndpoint("test.googleapis.com:443")
             .build();
 
     assertThat(provider.isDirectPathXdsEnabled()).isTrue();
@@ -528,6 +529,7 @@ public void testLogDirectPathMisconfigWrongCredential() {
         InstantiatingGrpcChannelProvider.newBuilder()
             .setAttemptDirectPathXds()
             .setAttemptDirectPath(true)
+            .setEndpoint("test.googleapis.com:443")
             .build();
     assertThat(logHandler.getAllMessages())
         .contains(
@@ -545,6 +547,7 @@ public void testLogDirectPathMisconfigNotOnGCE() {
             .setAttemptDirectPathXds()
             .setAttemptDirectPath(true)
             .setAllowNonDefaultServiceAccount(true)
+            .setEndpoint("test.googleapis.com:443")
             .build();
     if (!InstantiatingGrpcChannelProvider.isOnComputeEngine()) {
       assertThat(logHandler.getAllMessages())
@@ -554,6 +557,22 @@ public void testLogDirectPathMisconfigNotOnGCE() {
     InstantiatingGrpcChannelProvider.LOG.removeHandler(logHandler);
   }
 
+  @Test
+  public void testLogDirectPathMisconfigNotInGDU() {
+    FakeLogHandler logHandler = new FakeLogHandler();
+    InstantiatingGrpcChannelProvider.LOG.addHandler(logHandler);
+    InstantiatingGrpcChannelProvider provider =
+        InstantiatingGrpcChannelProvider.newBuilder()
+            .setAttemptDirectPathXds()
+            .setAttemptDirectPath(true)
+            .setAllowNonDefaultServiceAccount(true)
+            .setEndpoint("test.random.endpoint.com:443")
+            .build();
+    assertThat(logHandler.getAllMessages())
+        .contains("DirectPath will only work in the the googleapis.com Universe Domain");
+    InstantiatingGrpcChannelProvider.LOG.removeHandler(logHandler);
+  }
+
   private static class FakeLogHandler extends Handler {
     List<LogRecord> records = new ArrayList<>();
 

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

@@ -25,4 +25,10 @@
     <className>com/google/api/gax/rpc/TransportChannelProvider</className>
     <method>* getEndpoint()</method>
   </difference>
+  <!-- Add Universe Domain to ClientContext -->
+  <difference>
+    <differenceType>7013</differenceType>
+    <className>com/google/api/gax/rpc/ClientContext*</className>
+    <method>* *UniverseDomain*(*)</method>
+  </difference>
 </differences>

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

@@ -104,6 +104,9 @@ public abstract class ClientContext {
   @Nullable
   abstract String getServiceName();
 
+  @Nullable
+  public abstract String getUniverseDomain();
+
   @Nullable
   public abstract String getEndpoint();
 
@@ -157,15 +160,28 @@ public static ClientContext create(StubSettings settings) throws IOException {
     final ScheduledExecutorService backgroundExecutor = backgroundExecutorProvider.getExecutor();
 
     Credentials credentials = settings.getCredentialsProvider().getCredentials();
+    boolean usingGDCH = credentials instanceof GdchCredentials;
+    EndpointContext endpointContext =
+        EndpointContext.newBuilder()
+            .setServiceName(settings.getServiceName())
+            .setUniverseDomain(settings.getUniverseDomain())
+            .setClientSettingsEndpoint(settings.getEndpoint())
+            .setTransportChannelProviderEndpoint(
+                settings.getTransportChannelProvider().getEndpoint())
+            .setMtlsEndpoint(settings.getMtlsEndpoint())
+            .setSwitchToMtlsEndpointAllowed(settings.getSwitchToMtlsEndpointAllowed())
+            .setUsingGDCH(usingGDCH)
+            .build();
+    String endpoint = endpointContext.resolvedEndpoint();
 
     String settingsGdchApiAudience = settings.getGdchApiAudience();
-    if (credentials instanceof GdchCredentials) {
+    if (usingGDCH) {
       // We recompute the GdchCredentials with the audience
       String audienceString;
       if (!Strings.isNullOrEmpty(settingsGdchApiAudience)) {
         audienceString = settingsGdchApiAudience;
-      } else if (!Strings.isNullOrEmpty(settings.getEndpoint())) {
-        audienceString = settings.getEndpoint();
+      } else if (!Strings.isNullOrEmpty(endpoint)) {
+        audienceString = endpoint;
       } else {
         throw new IllegalArgumentException("Could not infer GDCH api audience from settings");
       }
@@ -204,16 +220,6 @@ public static ClientContext create(StubSettings settings) throws IOException {
     if (transportChannelProvider.needsCredentials() && credentials != null) {
       transportChannelProvider = transportChannelProvider.withCredentials(credentials);
     }
-    EndpointContext endpointContext =
-        EndpointContext.newBuilder()
-            .setServiceName(settings.getServiceName())
-            .setClientSettingsEndpoint(settings.getEndpoint())
-            .setTransportChannelProviderEndpoint(
-                settings.getTransportChannelProvider().getEndpoint())
-            .setMtlsEndpoint(settings.getMtlsEndpoint())
-            .setSwitchToMtlsEndpointAllowed(settings.getSwitchToMtlsEndpointAllowed())
-            .build();
-    String endpoint = endpointContext.getResolvedEndpoint();
     if (transportChannelProvider.needsEndpoint()) {
       transportChannelProvider = transportChannelProvider.withEndpoint(endpoint);
     }
@@ -264,6 +270,7 @@ public static ClientContext create(StubSettings settings) throws IOException {
         .setClock(clock)
         .setDefaultCallContext(defaultCallContext)
         .setServiceName(settings.getServiceName())
+        .setUniverseDomain(settings.getUniverseDomain())
         .setEndpoint(settings.getEndpoint())
         .setQuotaProjectId(settings.getQuotaProjectId())
         .setStreamWatchdog(watchdog)
@@ -332,6 +339,8 @@ public abstract static class Builder {
     // Package-Private scope for internal use only. Shared between StubSettings and ClientContext
     abstract Builder setServiceName(String serviceName);
 
+    public abstract Builder setUniverseDomain(String universeDomain);
+
     public abstract Builder setEndpoint(String endpoint);
 
     public abstract Builder setQuotaProjectId(String QuotaProjectId);