c2p resolver: use federation if enabled via env var (#9660)

googleapis/src/main/java/io/grpc/googleapis/GoogleCloudToProdNameResolver.java

@@ -21,6 +21,7 @@ import static com.google.common.base.Preconditions.checkNotNull;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Charsets;
 import com.google.common.base.Preconditions;
+import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.io.CharStreams;
@@ -54,6 +55,7 @@ final class GoogleCloudToProdNameResolver extends NameResolver {
   @VisibleForTesting
   static final String METADATA_URL_SUPPORT_IPV6 =
       "http://metadata.google.internal/computeMetadata/v1/instance/network-interfaces/0/ipv6s";
+  static final String C2P_AUTHORITY = "traffic-director-c2p.xds.googleapis.com";
   @VisibleForTesting
   static boolean isOnGcp = InternalCheckGcpEnvironment.isOnGcp();
   @VisibleForTesting
@@ -62,6 +64,10 @@ final class GoogleCloudToProdNameResolver extends NameResolver {
           || System.getProperty("io.grpc.xds.bootstrap") != null
           || System.getenv("GRPC_XDS_BOOTSTRAP_CONFIG") != null
           || System.getProperty("io.grpc.xds.bootstrapConfig") != null;
+  @VisibleForTesting
+  static boolean enableFederation =
+      !Strings.isNullOrEmpty(System.getenv("GRPC_EXPERIMENTAL_XDS_FEDERATION"))
+          && Boolean.parseBoolean(System.getenv("GRPC_EXPERIMENTAL_XDS_FEDERATION"));
 
   private static final String serverUriOverride =
       System.getenv("GRPC_TEST_ONLY_GOOGLE_C2P_RESOLVER_TRAFFIC_DIRECTOR_URI");
@@ -76,7 +82,10 @@ final class GoogleCloudToProdNameResolver extends NameResolver {
   private final boolean usingExecutorResource;
   // It's not possible to use both PSM and DirectPath C2P in the same application.
   // Delegate to DNS if user-provided bootstrap is found.
-  private final String schemeOverride = !isOnGcp || xdsBootstrapProvided ? "dns" : "xds";
+  private final String schemeOverride =
+      !isOnGcp
+      || (xdsBootstrapProvided && !enableFederation)
+      ? "dns" : "xds";
   private Executor executor;
   private Listener2 listener;
   private boolean succeeded;
@@ -103,8 +112,12 @@ final class GoogleCloudToProdNameResolver extends NameResolver {
         targetUri);
     authority = GrpcUtil.checkAuthority(targetPath.substring(1));
     syncContext = checkNotNull(args, "args").getSynchronizationContext();
+    targetUri = overrideUriScheme(targetUri, schemeOverride);
+    if (schemeOverride.equals("xds") && enableFederation) {
+      targetUri = overrideUriAuthority(targetUri, C2P_AUTHORITY);
+    }
     delegate = checkNotNull(nameResolverFactory, "nameResolverFactory").newNameResolver(
-        overrideUriScheme(targetUri, schemeOverride), args);
+        targetUri, args);
     executor = args.getOffloadExecutor();
     usingExecutorResource = executor == null;
   }
@@ -193,7 +206,7 @@ final class GoogleCloudToProdNameResolver extends NameResolver {
     serverBuilder.put("server_features", ImmutableList.of("xds_v3"));
     ImmutableMap.Builder<String, Object> authoritiesBuilder = ImmutableMap.builder();
     authoritiesBuilder.put(
-        "traffic-director-c2p.xds.googleapis.com",
+        C2P_AUTHORITY,
         ImmutableMap.of("xds_servers", ImmutableList.of(serverBuilder.buildOrThrow())));
     return ImmutableMap.of(
         "node", nodeBuilder.buildOrThrow(),
@@ -271,6 +284,16 @@ final class GoogleCloudToProdNameResolver extends NameResolver {
     return res;
   }
 
+  private static URI overrideUriAuthority(URI uri, String authority) {
+    URI res;
+    try {
+      res = new URI(uri.getScheme(), authority, uri.getPath(), uri.getQuery(), uri.getFragment());
+    } catch (URISyntaxException ex) {
+      throw new IllegalArgumentException("Invalid authority: " + authority, ex);
+    }
+    return res;
+  }
+
   private enum HttpConnectionFactory implements HttpConnectionProvider {
     INSTANCE;
 

googleapis/src/test/java/io/grpc/googleapis/GoogleCloudToProdNameResolverTest.java

@@ -66,7 +66,7 @@ public class GoogleCloudToProdNameResolverTest {
   @Rule
   public final MockitoRule mocks = MockitoJUnit.rule();
 
-  private static final URI TARGET_URI = URI.create("google-c2p-experimental:///googleapis.com");
+  private static final URI TARGET_URI = URI.create("google-c2p:///googleapis.com");
   private static final String ZONE = "us-central1-a";
   private static final int DEFAULT_PORT = 887;
 
@@ -187,6 +187,40 @@ public class GoogleCloudToProdNameResolverTest {
         "server_uri", "directpath-pa.googleapis.com",
         "channel_creds", ImmutableList.of(ImmutableMap.of("type", "google_default")),
         "server_features", ImmutableList.of("xds_v3"));
+    Map<String, ?> authorities = (Map<String, ?>) bootstrap.get("authorities");
+    assertThat(authorities).containsExactly(
+        "traffic-director-c2p.xds.googleapis.com",
+        ImmutableMap.of("xds_servers", ImmutableList.of(server)));
+  }
+
+  @SuppressWarnings("unchecked")
+  @Test
+  public void onGcpAndProvidedBootstrapAndFederationEnabledDelegateToXds() {
+    GoogleCloudToProdNameResolver.isOnGcp = true;
+    GoogleCloudToProdNameResolver.xdsBootstrapProvided = true;
+    GoogleCloudToProdNameResolver.enableFederation = true;
+    createResolver();
+    resolver.start(mockListener);
+    fakeExecutor.runDueTasks();
+    assertThat(delegatedResolver.keySet()).containsExactly("xds");
+    verify(Iterables.getOnlyElement(delegatedResolver.values())).start(mockListener);
+    // check bootstrap
+    Map<String, ?> bootstrap = fakeBootstrapSetter.bootstrapRef.get();
+    Map<String, ?> node = (Map<String, ?>) bootstrap.get("node");
+    assertThat(node).containsExactly(
+        "id", "C2P-991614323",
+        "locality", ImmutableMap.of("zone", ZONE),
+        "metadata", ImmutableMap.of("TRAFFICDIRECTOR_DIRECTPATH_C2P_IPV6_CAPABLE", true));
+    Map<String, ?> server = Iterables.getOnlyElement(
+        (List<Map<String, ?>>) bootstrap.get("xds_servers"));
+    assertThat(server).containsExactly(
+        "server_uri", "directpath-pa.googleapis.com",
+        "channel_creds", ImmutableList.of(ImmutableMap.of("type", "google_default")),
+        "server_features", ImmutableList.of("xds_v3"));
+    Map<String, ?> authorities = (Map<String, ?>) bootstrap.get("authorities");
+    assertThat(authorities).containsExactly(
+        "traffic-director-c2p.xds.googleapis.com",
+        ImmutableMap.of("xds_servers", ImmutableList.of(server)));
   }
 
   @Test