api: move ATTR_ADDRESS_NAME to EquivalentAddressGroup (#13072)

Correction to the implementation of [gRFC
A81](https://github.com/grpc/proposal/blob/master/A81-xds-authority-rewriting.md)-xds-authority-rewriting.
The proposal says:
> Note that the resolver attribute used here should be a general-purpose
one, not something specific to EDS;

The endpoint hostname attribute from gRFC A81 is currently defined in
`XdsInternalAttributes`, which makes it unreachable from other modules.

Move the key to `EquivalentAddressGroup` alongside the other endpoint
attributes and re-export it via `InternalEquivalentAddressGroup`.
`XdsInternalAttributes` held nothing else, so it is removed and its
callers now reference the key directly.

This is needed by the autosharding LB policy [gRFC
A119](grpc/proposal#551), which keys its
endpoint map on the A81 hostname. `autosharding` cannot depend on `xds`
because `xds` will depend on autosharding.

Author: shivaspeaks

api/src/main/java/io/grpc/EquivalentAddressGroup.java

@@ -69,6 +69,12 @@ public final class EquivalentAddressGroup {
   @Attr
   static final Attributes.Key<Long> ATTR_WEIGHT =
       Attributes.Key.create("io.grpc.EquivalentAddressGroup.ATTR_WEIGHT");
+  /**
+   * Name associated with individual address, if available (e.g., DNS name).
+   */
+  @Attr
+  static final Attributes.Key<String> ATTR_ADDRESS_NAME =
+      Attributes.Key.create("io.grpc.EquivalentAddressGroup.ATTR_ADDRESS_NAME");
 
   private final List<SocketAddress> addrs;
   private final Attributes attrs;

api/src/main/java/io/grpc/InternalEquivalentAddressGroup.java

@@ -32,4 +32,10 @@ private InternalEquivalentAddressGroup() {}
    */
   public static final Attributes.Key<String> ATTR_BACKEND_SERVICE =
       EquivalentAddressGroup.ATTR_BACKEND_SERVICE;
+
+  /**
+   * Name associated with individual address, if available (e.g., DNS name).
+   */
+  public static final Attributes.Key<String> ATTR_ADDRESS_NAME =
+      EquivalentAddressGroup.ATTR_ADDRESS_NAME;
 }

xds/src/main/java/io/grpc/xds/CdsLoadBalancer2.java

@@ -61,7 +61,6 @@
 import io.grpc.xds.client.Locality;
 import io.grpc.xds.client.XdsLogger;
 import io.grpc.xds.client.XdsLogger.XdsLogLevel;
-import io.grpc.xds.internal.XdsInternalAttributes;
 import java.net.InetSocketAddress;
 import java.net.SocketAddress;
 import java.util.ArrayList;
@@ -417,7 +416,7 @@ StatusOr<ClusterResolutionResult> edsUpdateToResult(
                     .set(io.grpc.xds.XdsAttributes.ATTR_LOCALITY_WEIGHT,
                         localityLbInfo.localityWeight())
                     .set(io.grpc.xds.XdsAttributes.ATTR_SERVER_WEIGHT, weight)
-                    .set(XdsInternalAttributes.ATTR_ADDRESS_NAME, endpoint.hostname())
+                    .set(InternalEquivalentAddressGroup.ATTR_ADDRESS_NAME, endpoint.hostname())
                     .set(AddressFilter.PATH_CHAIN_KEY, pathChain)
                     .build();
             EquivalentAddressGroup eag;

xds/src/main/java/io/grpc/xds/ClusterImplLoadBalancer.java

@@ -30,6 +30,7 @@
 import io.grpc.ConnectivityState;
 import io.grpc.ConnectivityStateInfo;
 import io.grpc.EquivalentAddressGroup;
+import io.grpc.InternalEquivalentAddressGroup;
 import io.grpc.InternalLogId;
 import io.grpc.LoadBalancer;
 import io.grpc.Metadata;
@@ -53,7 +54,6 @@
 import io.grpc.xds.client.XdsClient;
 import io.grpc.xds.client.XdsLogger;
 import io.grpc.xds.client.XdsLogger.XdsLogLevel;
-import io.grpc.xds.internal.XdsInternalAttributes;
 import io.grpc.xds.internal.security.SecurityProtocolNegotiators;
 import io.grpc.xds.internal.security.SslContextProviderSupplier;
 import io.grpc.xds.orca.OrcaPerRequestUtil;
@@ -240,7 +240,7 @@ public Subchannel createSubchannel(CreateSubchannelArgs args) {
           .set(ATTR_CLUSTER_LOCALITY, localityAtomicReference);
       if (GrpcUtil.getFlag("GRPC_EXPERIMENTAL_XDS_AUTHORITY_REWRITE", false)) {
         String hostname = args.getAddresses().get(0).getAttributes()
-            .get(XdsInternalAttributes.ATTR_ADDRESS_NAME);
+            .get(InternalEquivalentAddressGroup.ATTR_ADDRESS_NAME);
         if (hostname != null) {
           attrsBuilder.set(ATTR_SUBCHANNEL_ADDRESS_NAME, hostname);
         }

xds/src/main/java/io/grpc/xds/internal/XdsInternalAttributes.java

@@ -22,6 +22,7 @@
 import com.google.common.base.Strings;
 import io.grpc.Attributes;
 import io.grpc.Grpc;
+import io.grpc.InternalEquivalentAddressGroup;
 import io.grpc.internal.GrpcUtil;
 import io.grpc.internal.ObjectPool;
 import io.grpc.netty.GrpcHttp2ConnectionHandler;
@@ -32,7 +33,6 @@
 import io.grpc.netty.ProtocolNegotiationEvent;
 import io.grpc.xds.EnvoyServerProtoData;
 import io.grpc.xds.EnvoyServerProtoData.UpstreamTlsContext;
-import io.grpc.xds.internal.XdsInternalAttributes;
 import io.grpc.xds.internal.security.trust.CertificateUtils;
 import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelHandlerAdapter;
@@ -150,7 +150,7 @@ public ChannelHandler newHandler(GrpcHttp2ConnectionHandler grpcHandler) {
         return fallbackProtocolNegotiator.newHandler(grpcHandler);
       }
       return new ClientSecurityHandler(grpcHandler, localSslContextProviderSupplier,
-          grpcHandler.getEagAttributes().get(XdsInternalAttributes.ATTR_ADDRESS_NAME));
+          grpcHandler.getEagAttributes().get(InternalEquivalentAddressGroup.ATTR_ADDRESS_NAME));
     }
 
     @Override

xds/src/main/java/io/grpc/xds/internal/security/SecurityProtocolNegotiators.java

@@ -39,6 +39,7 @@
 import io.grpc.ConnectivityStateInfo;
 import io.grpc.EquivalentAddressGroup;
 import io.grpc.InsecureChannelCredentials;
+import io.grpc.InternalEquivalentAddressGroup;
 import io.grpc.LoadBalancer;
 import io.grpc.LoadBalancer.CreateSubchannelArgs;
 import io.grpc.LoadBalancer.FixedResultPicker;
@@ -81,7 +82,6 @@
 import io.grpc.xds.client.Stats.ClusterStats;
 import io.grpc.xds.client.Stats.UpstreamLocalityStats;
 import io.grpc.xds.client.XdsClient;
-import io.grpc.xds.internal.XdsInternalAttributes;
 import io.grpc.xds.internal.security.CommonTlsContextTestsUtil;
 import io.grpc.xds.internal.security.SecurityProtocolNegotiators;
 import io.grpc.xds.internal.security.SslContextProvider;
@@ -917,7 +917,7 @@ public void endpointAddressesAttachedWithClusterName() {
       assertThat(subchannel.getAttributes().get(ATTR_SUBCHANNEL_ADDRESS_NAME)).isEqualTo(
           "authority-host-name");
       for (EquivalentAddressGroup eag : subchannel.getAllAddresses()) {
-        assertThat(eag.getAttributes().get(XdsInternalAttributes.ATTR_ADDRESS_NAME))
+        assertThat(eag.getAttributes().get(InternalEquivalentAddressGroup.ATTR_ADDRESS_NAME))
             .isEqualTo("authority-host-name");
       }
 
@@ -968,7 +968,7 @@ public void endpointAddressesAttachedWithClusterName() {
     // Sub Channel wrapper args won't have the address name although addresses will.
     assertThat(subchannel.getAttributes().get(ATTR_SUBCHANNEL_ADDRESS_NAME)).isNull();
     for (EquivalentAddressGroup eag : subchannel.getAllAddresses()) {
-      assertThat(eag.getAttributes().get(XdsInternalAttributes.ATTR_ADDRESS_NAME))
+      assertThat(eag.getAttributes().get(InternalEquivalentAddressGroup.ATTR_ADDRESS_NAME))
           .isEqualTo("authority-host-name");
     }
 
@@ -1123,7 +1123,7 @@ public String toString() {
         // Unique but arbitrary string
         .set(EquivalentAddressGroup.ATTR_LOCALITY_NAME, locality.toString());
     if (authorityHostname != null) {
-      attributes.set(XdsInternalAttributes.ATTR_ADDRESS_NAME, authorityHostname);
+      attributes.set(InternalEquivalentAddressGroup.ATTR_ADDRESS_NAME, authorityHostname);
     }
     EquivalentAddressGroup eag = new EquivalentAddressGroup(new FakeSocketAddress(name),
         attributes.build());

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

@@ -98,7 +98,6 @@
 import io.grpc.xds.client.Bootstrapper.ServerInfo;
 import io.grpc.xds.client.LoadStatsManager2;
 import io.grpc.xds.client.XdsClient;
-import io.grpc.xds.internal.XdsInternalAttributes;
 import java.net.InetSocketAddress;
 import java.net.URI;
 import java.util.ArrayList;
@@ -428,7 +427,7 @@ public void edsClustersEndpointHostname_addedToAddressAttribute() {
 
     assertThat(
         childBalancer.addresses.get(0).getAttributes()
-            .get(XdsInternalAttributes.ATTR_ADDRESS_NAME)).isEqualTo("hostname1");
+            .get(InternalEquivalentAddressGroup.ATTR_ADDRESS_NAME)).isEqualTo("hostname1");
   }
 
   @Test
@@ -931,7 +930,7 @@ public void onlyLogicalDnsCluster_endpointsResolved() {
     assertThat(childBalancer.addresses.get(0).getAttributes()
         .get(InternalEquivalentAddressGroup.ATTR_BACKEND_SERVICE)).isEqualTo(CLUSTER);
     assertThat(childBalancer.addresses.get(0).getAttributes()
-        .get(XdsInternalAttributes.ATTR_ADDRESS_NAME)).isEqualTo(DNS_HOST_NAME + ":9000");
+        .get(InternalEquivalentAddressGroup.ATTR_ADDRESS_NAME)).isEqualTo(DNS_HOST_NAME + ":9000");
   }
 
   @Test

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

@@ -43,6 +43,7 @@
 import io.grpc.Grpc;
 import io.grpc.InsecureChannelCredentials;
 import io.grpc.InsecureServerCredentials;
+import io.grpc.InternalEquivalentAddressGroup;
 import io.grpc.ManagedChannelBuilder;
 import io.grpc.NameResolver;
 import io.grpc.NameResolverProvider;
@@ -71,7 +72,6 @@
 import io.grpc.xds.client.Bootstrapper;
 import io.grpc.xds.client.CommonBootstrapperTestUtils;
 import io.grpc.xds.internal.Matchers.HeaderMatcher;
-import io.grpc.xds.internal.XdsInternalAttributes;
 import io.grpc.xds.internal.security.CommonTlsContextTestsUtil;
 import io.grpc.xds.internal.security.SecurityProtocolNegotiators;
 import io.grpc.xds.internal.security.SslContextProviderSupplier;
@@ -843,7 +843,8 @@ private SimpleServiceGrpc.SimpleServiceBlockingStub getBlockingStub(
                 upstreamTlsContext, tlsContextManagerForClient))
         : Attributes.newBuilder();
     if (addrNameAttribute != null) {
-      sslContextAttributesBuilder.set(XdsInternalAttributes.ATTR_ADDRESS_NAME, addrNameAttribute);
+      sslContextAttributesBuilder.set(
+          InternalEquivalentAddressGroup.ATTR_ADDRESS_NAME, addrNameAttribute);
     }
     sslContextAttributes = sslContextAttributesBuilder.build();
     fakeNameResolverFactory.setServers(

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

@@ -38,6 +38,7 @@
 import io.grpc.Attributes;
 import io.grpc.ChannelLogger;
 import io.grpc.ChannelLogger.ChannelLogLevel;
+import io.grpc.InternalEquivalentAddressGroup;
 import io.grpc.internal.FakeClock;
 import io.grpc.internal.TestUtils.NoopChannelLogger;
 import io.grpc.netty.GrpcHttp2ConnectionHandler;
@@ -50,7 +51,6 @@
 import io.grpc.xds.TlsContextManager;
 import io.grpc.xds.client.Bootstrapper;
 import io.grpc.xds.client.CommonBootstrapperTestUtils;
-import io.grpc.xds.internal.XdsInternalAttributes;
 import io.grpc.xds.internal.security.SecurityProtocolNegotiators.ClientSecurityHandler;
 import io.grpc.xds.internal.security.SecurityProtocolNegotiators.ClientSecurityProtocolNegotiator;
 import io.grpc.xds.internal.security.certprovider.CommonCertProviderTestUtils;
@@ -165,7 +165,7 @@ public void clientSecurityProtocolNegotiator_autoHostSni_hostnamePassedToClientS
             Attributes.newBuilder()
                 .set(SecurityProtocolNegotiators.ATTR_SSL_CONTEXT_PROVIDER_SUPPLIER,
                     new SslContextProviderSupplier(upstreamTlsContext, mockTlsContextManager))
-                .set(XdsInternalAttributes.ATTR_ADDRESS_NAME, FAKE_AUTHORITY)
+                .set(InternalEquivalentAddressGroup.ATTR_ADDRESS_NAME, FAKE_AUTHORITY)
                 .build());
     ChannelHandler newHandler = pn.newHandler(mockHandler);
     assertThat(newHandler).isNotNull();