- Change config builder to a static factory class.

- Remove validation and default value logic that already exists in providers from the factory.
- Using the PolicySelection in CdsUpdate instead of the JSON config.

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

@@ -23,14 +23,10 @@ import static io.grpc.xds.XdsLbPolicies.CLUSTER_RESOLVER_POLICY_NAME;
 import com.google.common.annotations.VisibleForTesting;
 import io.grpc.InternalLogId;
 import io.grpc.LoadBalancer;
-import io.grpc.LoadBalancerProvider;
 import io.grpc.LoadBalancerRegistry;
 import io.grpc.Status;
 import io.grpc.SynchronizationContext;
 import io.grpc.internal.ObjectPool;
-import io.grpc.internal.ServiceConfigUtil;
-import io.grpc.internal.ServiceConfigUtil.LbConfig;
-import io.grpc.internal.ServiceConfigUtil.PolicySelection;
 import io.grpc.xds.CdsLoadBalancerProvider.CdsConfig;
 import io.grpc.xds.ClusterResolverLoadBalancerProvider.ClusterResolverConfig;
 import io.grpc.xds.ClusterResolverLoadBalancerProvider.ClusterResolverConfig.DiscoveryMechanism;
@@ -185,17 +181,9 @@ final class CdsLoadBalancer2 extends LoadBalancer {
         return;
       }
 
-      // The LB policy config is provided in service_config.proto/JSON format. It is unwrapped
-      // to determine the name of the policy in the load balancer registry.
-      LbConfig unwrappedLbConfig = ServiceConfigUtil.unwrapLoadBalancingConfig(
-          root.result.lbPolicyConfig());
-      LoadBalancerProvider lbProvider = lbRegistry.getProvider(unwrappedLbConfig.getPolicyName());
-      Object lbConfig = lbProvider.parseLoadBalancingPolicyConfig(
-          unwrappedLbConfig.getRawConfigValue()).getConfig();
-
       ClusterResolverConfig config = new ClusterResolverConfig(
           Collections.unmodifiableList(instances),
-          new PolicySelection(lbProvider, lbConfig));
+          root.result.lbPolicySelection());
       if (childLb == null) {
         childLb = lbRegistry.getProvider(CLUSTER_RESOLVER_POLICY_NAME).newLoadBalancer(helper);
       }

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

@@ -67,6 +67,7 @@ import io.grpc.Context;
 import io.grpc.EquivalentAddressGroup;
 import io.grpc.Grpc;
 import io.grpc.InternalLogId;
+import io.grpc.LoadBalancerProvider;
 import io.grpc.LoadBalancerRegistry;
 import io.grpc.ManagedChannel;
 import io.grpc.NameResolver;
@@ -77,6 +78,7 @@ import io.grpc.SynchronizationContext.ScheduledHandle;
 import io.grpc.internal.BackoffPolicy;
 import io.grpc.internal.ServiceConfigUtil;
 import io.grpc.internal.ServiceConfigUtil.LbConfig;
+import io.grpc.internal.ServiceConfigUtil.PolicySelection;
 import io.grpc.internal.TimeProvider;
 import io.grpc.xds.AbstractXdsClient.ResourceType;
 import io.grpc.xds.Bootstrapper.AuthorityInfo;
@@ -138,14 +140,6 @@ final class ClientXdsClient extends XdsClient implements XdsResponseHandler, Res
   static final int INITIAL_RESOURCE_FETCH_TIMEOUT_SEC = 15;
   private static final String TRANSPORT_SOCKET_NAME_TLS = "envoy.transport_sockets.tls";
   @VisibleForTesting
-  static final long DEFAULT_RING_HASH_LB_POLICY_MIN_RING_SIZE = 1024L;
-  @VisibleForTesting
-  static final long DEFAULT_RING_HASH_LB_POLICY_MAX_RING_SIZE = 8 * 1024 * 1024L;
-  @VisibleForTesting
-  static final int DEFAULT_LEAST_REQUEST_CHOICE_COUNT = 2;
-  @VisibleForTesting
-  static final long MAX_RING_HASH_LB_POLICY_RING_SIZE = 8 * 1024 * 1024L;
-  @VisibleForTesting
   static final String AGGREGATE_CLUSTER_TYPE_NAME = "envoy.clusters.aggregate";
   @VisibleForTesting
   static final String HASH_POLICY_FILTER_STATE_KEY = "io.grpc.channel_id";
@@ -1643,21 +1637,16 @@ final class ClientXdsClient extends XdsClient implements XdsResponseHandler, Res
     }
     CdsUpdate.Builder updateBuilder = structOrError.getStruct();
 
-    // TODO: If load_balancing_policy is set in Cluster use it for LB config, otherwise fall back
+    LbConfig lbConfig = ServiceConfigUtil.unwrapLoadBalancingConfig(
-    // to using the legacy lb_policy field.
+        LegacyLoadBalancerConfigFactory.newConfig(cluster, enableLeastRequest));
-    ImmutableMap<String, ?> lbPolicyConfig = LegacyLoadBalancerConfigBuilder.forCluster(cluster,
+    LoadBalancerProvider lbProvider = loadBalancerRegistry.getProvider(lbConfig.getPolicyName());
-        enableLeastRequest).build();
+    NameResolver.ConfigOrError configOrError = lbProvider
-
+        .parseLoadBalancingPolicyConfig(lbConfig.getRawConfigValue());
-    // Validate the LB config by trying to parse it with the corresponding LB provider.
-    LbConfig lbConfig = ServiceConfigUtil.unwrapLoadBalancingConfig(lbPolicyConfig);
-    NameResolver.ConfigOrError configOrError = loadBalancerRegistry.getProvider(
-        lbConfig.getPolicyName()).parseLoadBalancingPolicyConfig(
-        lbConfig.getRawConfigValue());
     if (configOrError.getError() != null) {
       throw new ResourceInvalidException(structOrError.getErrorDetail());
     }
 
-    updateBuilder.lbPolicyConfig(lbPolicyConfig);
+    updateBuilder.lbPolicySelection(new PolicySelection(lbProvider, configOrError.getConfig()));
 
     return updateBuilder.build();
   }

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

@@ -1,140 +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.xds;
-
-import com.google.common.collect.ImmutableMap;
-import io.envoyproxy.envoy.config.cluster.v3.Cluster;
-import io.envoyproxy.envoy.config.cluster.v3.Cluster.LeastRequestLbConfig;
-import io.envoyproxy.envoy.config.cluster.v3.Cluster.RingHashLbConfig;
-import io.grpc.xds.ClientXdsClient.ResourceInvalidException;
-import java.util.Map;
-
-/**
- * Builds a JSON LB configuration based on the old style of using the xDS Cluster proto message. The
- * lb_policy field is used to select the policy and configuration is extracted from various policy
- * specific fields in Cluster.
- */
-abstract class LegacyLoadBalancerConfigBuilder {
-
-  /**
-   * Factory method for creating a new {link LoadBalancerConfigConverter} for a given xDS {@link
-   * Cluster}.
-   *
-   * @throws ResourceInvalidException If the {@link Cluster} has an invalid LB configuration.
-   */
-  static LegacyLoadBalancerConfigBuilder forCluster(Cluster cluster, boolean enableLeastRequest)
-      throws ResourceInvalidException {
-    switch (cluster.getLbPolicy()) {
-      case ROUND_ROBIN:
-        return new RoundRobinLoadBalancerConfigBuilder();
-      case RING_HASH:
-        return new RingHashLoadBalancerConfigBuilder(cluster);
-      case LEAST_REQUEST:
-        if (enableLeastRequest) {
-          return new LeastRequestLoadBalancerConfigBuilder(cluster);
-        }
-        break;
-      default:
-    }
-    throw new ResourceInvalidException(
-        "Cluster " + cluster.getName() + ": unsupported lb policy: " + cluster.getLbPolicy());
-  }
-
-  /**
-   * Builds the configuration {@link Map} based on the configuration data from the provider {@code
-   * Cluster}.
-   */
-  abstract ImmutableMap<String, ?> build();
-
-  /**
-   * Round robin does not support any configuration, a null value will always be built.
-   */
-  static class RoundRobinLoadBalancerConfigBuilder extends LegacyLoadBalancerConfigBuilder {
-
-    static final String LB_NAME_FIELD = "round_robin";
-
-    @Override
-    ImmutableMap<String, ?> build() {
-      return ImmutableMap.of(LB_NAME_FIELD, ImmutableMap.of());
-    }
-  }
-
-  /**
-   * Builds a load balancer config for the {@link RingHashLoadBalancerProvider}.
-   */
-  static class RingHashLoadBalancerConfigBuilder extends LegacyLoadBalancerConfigBuilder {
-
-    static final long DEFAULT_RING_HASH_LB_POLICY_MIN_RING_SIZE = 1024L;
-    static final long DEFAULT_RING_HASH_LB_POLICY_MAX_RING_SIZE = 8 * 1024 * 1024L;
-    static final long MAX_RING_HASH_LB_POLICY_RING_SIZE = 8 * 1024 * 1024L;
-
-    static final String LB_NAME_FIELD = "ring_hash_experimental";
-    static final String MIN_RING_SIZE_FIELD_NAME = "minRingSize";
-    static final String MAX_RING_SIZE_FIELD_NAME = "maxRingSize";
-
-    private final Long minRingSize;
-    private final Long maxRingSize;
-
-    RingHashLoadBalancerConfigBuilder(Cluster cluster) throws ResourceInvalidException {
-      RingHashLbConfig lbConfig = cluster.getRingHashLbConfig();
-      minRingSize = lbConfig.hasMinimumRingSize() ? lbConfig.getMinimumRingSize().getValue()
-          : DEFAULT_RING_HASH_LB_POLICY_MIN_RING_SIZE;
-      maxRingSize = lbConfig.hasMaximumRingSize() ? lbConfig.getMaximumRingSize().getValue()
-          : DEFAULT_RING_HASH_LB_POLICY_MAX_RING_SIZE;
-      if (lbConfig.getHashFunction() != RingHashLbConfig.HashFunction.XX_HASH
-          || minRingSize > maxRingSize || maxRingSize > MAX_RING_HASH_LB_POLICY_RING_SIZE) {
-        throw new ResourceInvalidException(
-            "Cluster " + cluster.getName() + ": invalid ring_hash_lb_config: " + lbConfig);
-      }
-    }
-
-    @Override
-    ImmutableMap<String, ?> build() {
-      ImmutableMap.Builder<String, Object> configBuilder = ImmutableMap.builder();
-      configBuilder.put(MIN_RING_SIZE_FIELD_NAME, minRingSize.doubleValue());
-      configBuilder.put(MAX_RING_SIZE_FIELD_NAME, maxRingSize.doubleValue());
-      return ImmutableMap.of(LB_NAME_FIELD, configBuilder.build());
-    }
-  }
-
-  static class LeastRequestLoadBalancerConfigBuilder extends LegacyLoadBalancerConfigBuilder {
-
-    static final long DEFAULT_LEAST_REQUEST_CHOICE_COUNT = 2L;
-
-    static final String LB_NAME_FIELD = "least_request_experimental";
-    static final String CHOICE_COUNT_FIELD_NAME = "choiceCount";
-
-    private final Long choiceCount;
-
-    LeastRequestLoadBalancerConfigBuilder(Cluster cluster) throws ResourceInvalidException {
-      LeastRequestLbConfig lbConfig = cluster.getLeastRequestLbConfig();
-      choiceCount = lbConfig.hasChoiceCount() ? lbConfig.getChoiceCount().getValue()
-          : DEFAULT_LEAST_REQUEST_CHOICE_COUNT;
-      if (choiceCount < DEFAULT_LEAST_REQUEST_CHOICE_COUNT) {
-        throw new ResourceInvalidException(
-            "Cluster " + cluster.getName() + ": invalid least_request_lb_config: " + lbConfig);
-      }
-    }
-
-    @Override
-    ImmutableMap<String, ?> build() {
-      ImmutableMap.Builder<String, Object> configBuilder = ImmutableMap.builder();
-      configBuilder.put(CHOICE_COUNT_FIELD_NAME, choiceCount.doubleValue());
-      return ImmutableMap.of(LB_NAME_FIELD, configBuilder.build());
-    }
-  }
-}

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

@@ -0,0 +1,105 @@
+/*
+ * 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.xds;
+
+import com.google.common.collect.ImmutableMap;
+import io.envoyproxy.envoy.config.cluster.v3.Cluster;
+import io.envoyproxy.envoy.config.cluster.v3.Cluster.LeastRequestLbConfig;
+import io.envoyproxy.envoy.config.cluster.v3.Cluster.RingHashLbConfig;
+import io.grpc.xds.ClientXdsClient.ResourceInvalidException;
+
+/**
+ * Builds a JSON LB configuration based on the old style of using the xDS Cluster proto message. The
+ * lb_policy field is used to select the policy and configuration is extracted from various policy
+ * specific fields in Cluster.
+ */
+abstract class LegacyLoadBalancerConfigFactory {
+
+  static final String ROUND_ROBIN_FIELD_NAME = "round_robin";
+
+  static final String RING_HASH_FIELD_NAME = "ring_hash_experimental";
+  static final String MIN_RING_SIZE_FIELD_NAME = "minRingSize";
+  static final String MAX_RING_SIZE_FIELD_NAME = "maxRingSize";
+
+  static final String LEAST_REQUEST_FIELD_NAME = "least_request_experimental";
+  static final String CHOICE_COUNT_FIELD_NAME = "choiceCount";
+
+  /**
+   * Factory method for creating a new {link LoadBalancerConfigConverter} for a given xDS {@link
+   * Cluster}.
+   *
+   * @throws ResourceInvalidException If the {@link Cluster} has an invalid LB configuration.
+   */
+  static ImmutableMap<String, ?> newConfig(Cluster cluster, boolean enableLeastRequest)
+      throws ResourceInvalidException {
+    switch (cluster.getLbPolicy()) {
+      case ROUND_ROBIN:
+        return newRoundRobinConfig();
+      case RING_HASH:
+        return newRingHashConfig(cluster);
+      case LEAST_REQUEST:
+        if (enableLeastRequest) {
+          return newLeastRequestConfig(cluster);
+        }
+        break;
+      default:
+    }
+    throw new ResourceInvalidException(
+        "Cluster " + cluster.getName() + ": unsupported lb policy: " + cluster.getLbPolicy());
+  }
+
+  // Builds an empty configuration for round robin (it is not configurable).
+  private static ImmutableMap<String, ?> newRoundRobinConfig() {
+    return ImmutableMap.of(ROUND_ROBIN_FIELD_NAME, ImmutableMap.of());
+  }
+
+  // Builds a ring hash config and validates the hash function selection.
+  private static ImmutableMap<String, ?> newRingHashConfig(Cluster cluster)
+      throws ResourceInvalidException {
+    RingHashLbConfig lbConfig = cluster.getRingHashLbConfig();
+
+    // The hash function needs to be validated here as it is not exposed in the returned
+    // configuration for later validation.
+    if (lbConfig.getHashFunction() != RingHashLbConfig.HashFunction.XX_HASH) {
+      throw new ResourceInvalidException(
+          "Cluster " + cluster.getName() + ": invalid ring hash function: " + lbConfig);
+    }
+
+    ImmutableMap.Builder<String, Object> configBuilder = ImmutableMap.builder();
+    if (lbConfig.hasMinimumRingSize()) {
+      configBuilder.put(MIN_RING_SIZE_FIELD_NAME,
+          ((Long) lbConfig.getMinimumRingSize().getValue()).doubleValue());
+    }
+    if (lbConfig.hasMaximumRingSize()) {
+      configBuilder.put(MAX_RING_SIZE_FIELD_NAME,
+          ((Long) lbConfig.getMaximumRingSize().getValue()).doubleValue());
+    }
+    return ImmutableMap.of(RING_HASH_FIELD_NAME, configBuilder.build());
+  }
+
+  // Builds a new least request config.
+  private static ImmutableMap<String, ?> newLeastRequestConfig(Cluster cluster) {
+    LeastRequestLbConfig lbConfig = cluster.getLeastRequestLbConfig();
+
+    ImmutableMap.Builder<String, Object> configBuilder = ImmutableMap.builder();
+    if (lbConfig.hasChoiceCount()) {
+      configBuilder.put(CHOICE_COUNT_FIELD_NAME,
+          ((Integer) lbConfig.getChoiceCount().getValue()).doubleValue());
+    }
+    return ImmutableMap.of(LEAST_REQUEST_FIELD_NAME, configBuilder.build());
+  }
+}

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

@@ -24,19 +24,22 @@ import com.google.common.base.Joiner;
 import com.google.common.base.MoreObjects;
 import com.google.common.base.Splitter;
 import com.google.common.collect.ImmutableList;
-import com.google.common.collect.ImmutableMap;
 import com.google.common.net.UrlEscapers;
 import com.google.common.util.concurrent.ListenableFuture;
 import com.google.protobuf.Any;
+import io.grpc.LoadBalancerRegistry;
 import io.grpc.Status;
+import io.grpc.internal.ServiceConfigUtil.PolicySelection;
 import io.grpc.xds.AbstractXdsClient.ResourceType;
 import io.grpc.xds.Bootstrapper.ServerInfo;
 import io.grpc.xds.Endpoints.DropOverload;
 import io.grpc.xds.Endpoints.LocalityLbEndpoints;
 import io.grpc.xds.EnvoyServerProtoData.Listener;
 import io.grpc.xds.EnvoyServerProtoData.UpstreamTlsContext;
+import io.grpc.xds.LeastRequestLoadBalancer.LeastRequestConfig;
 import io.grpc.xds.LoadStatsManager2.ClusterDropStats;
 import io.grpc.xds.LoadStatsManager2.ClusterLocalityStats;
+import io.grpc.xds.RingHashLoadBalancer.RingHashConfig;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.util.ArrayList;
@@ -179,7 +182,7 @@ abstract class XdsClient {
 
     abstract ClusterType clusterType();
 
-    abstract ImmutableMap<String, ?> lbPolicyConfig();
+    abstract PolicySelection lbPolicySelection();
 
     // Only valid if lbPolicy is "ring_hash_experimental".
     abstract long minRingSize();
@@ -276,7 +279,7 @@ abstract class XdsClient {
       return MoreObjects.toStringHelper(this)
           .add("clusterName", clusterName())
           .add("clusterType", clusterType())
-          .add("lbPolicyConfig", lbPolicyConfig())
+          .add("lbPolicySelection", lbPolicySelection())
           .add("minRingSize", minRingSize())
           .add("maxRingSize", maxRingSize())
           .add("choiceCount", choiceCount())
@@ -297,21 +300,23 @@ abstract class XdsClient {
       // Private, use one of the static factory methods instead.
       protected abstract Builder clusterType(ClusterType clusterType);
 
-      protected abstract Builder lbPolicyConfig(ImmutableMap<String, ?> lbPolicyConfig);
+      protected abstract Builder lbPolicySelection(PolicySelection lbPolicySelection);
 
       Builder roundRobinLbPolicy() {
-        return this.lbPolicyConfig(ImmutableMap.of("round_robin", ImmutableMap.of()));
+        return this.lbPolicySelection(new PolicySelection(
+            LoadBalancerRegistry.getDefaultRegistry().getProvider("round_robin"), null));
       }
 
       Builder ringHashLbPolicy(Long minRingSize, Long maxRingSize) {
-        return this.lbPolicyConfig(ImmutableMap.of("ring_hash_experimental",
+        return this.lbPolicySelection(new PolicySelection(
-            ImmutableMap.of("minRingSize", minRingSize.doubleValue(), "maxRingSize",
+            LoadBalancerRegistry.getDefaultRegistry().getProvider("ring_hash_experimental"),
-                maxRingSize.doubleValue())));
+            new RingHashConfig(minRingSize, maxRingSize)));
       }
 
       Builder leastRequestLbPolicy(Integer choiceCount) {
-        return this.lbPolicyConfig(ImmutableMap.of("least_request_experimental",
+        return this.lbPolicySelection(new PolicySelection(
-            ImmutableMap.of("choiceCount", choiceCount.doubleValue())));
+            LoadBalancerRegistry.getDefaultRegistry().getProvider("least_request_experimental"),
+            new LeastRequestConfig(choiceCount)));
       }
 
       // Private, use leastRequestLbPolicy(int).

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

@@ -30,7 +30,6 @@ import com.google.protobuf.Message;
 import com.google.protobuf.StringValue;
 import com.google.protobuf.Struct;
 import com.google.protobuf.UInt32Value;
-import com.google.protobuf.UInt64Value;
 import com.google.protobuf.Value;
 import com.google.protobuf.util.Durations;
 import com.google.re2j.Pattern;
@@ -38,9 +37,6 @@ import io.envoyproxy.envoy.config.cluster.v3.Cluster;
 import io.envoyproxy.envoy.config.cluster.v3.Cluster.DiscoveryType;
 import io.envoyproxy.envoy.config.cluster.v3.Cluster.EdsClusterConfig;
 import io.envoyproxy.envoy.config.cluster.v3.Cluster.LbPolicy;
-import io.envoyproxy.envoy.config.cluster.v3.Cluster.LeastRequestLbConfig;
-import io.envoyproxy.envoy.config.cluster.v3.Cluster.RingHashLbConfig;
-import io.envoyproxy.envoy.config.cluster.v3.Cluster.RingHashLbConfig.HashFunction;
 import io.envoyproxy.envoy.config.core.v3.Address;
 import io.envoyproxy.envoy.config.core.v3.AggregatedConfigSource;
 import io.envoyproxy.envoy.config.core.v3.CidrRange;
@@ -108,9 +104,6 @@ import io.grpc.InsecureChannelCredentials;
 import io.grpc.LoadBalancer;
 import io.grpc.LoadBalancerRegistry;
 import io.grpc.Status.Code;
-import io.grpc.internal.JsonUtil;
-import io.grpc.internal.ServiceConfigUtil;
-import io.grpc.internal.ServiceConfigUtil.LbConfig;
 import io.grpc.lookup.v1.GrpcKeyBuilder;
 import io.grpc.lookup.v1.GrpcKeyBuilder.Name;
 import io.grpc.lookup.v1.NameMatcher;
@@ -1740,12 +1733,8 @@ public class ClientXdsClientDataTest {
     CdsUpdate update = ClientXdsClient.processCluster(
         cluster, new HashSet<String>(), null, LRS_SERVER_INFO,
         LoadBalancerRegistry.getDefaultRegistry());
-    LbConfig lbConfig = ServiceConfigUtil.unwrapLoadBalancingConfig(update.lbPolicyConfig());
+    assertThat(update.lbPolicySelection().getProvider().getPolicyName()).isEqualTo(
-    assertThat(lbConfig.getPolicyName()).isEqualTo("ring_hash_experimental");
+        "ring_hash_experimental");
-    assertThat(JsonUtil.getNumberAsLong(lbConfig.getRawConfigValue(), "minRingSize"))
-        .isEqualTo(ClientXdsClient.DEFAULT_RING_HASH_LB_POLICY_MIN_RING_SIZE);
-    assertThat(JsonUtil.getNumberAsLong(lbConfig.getRawConfigValue(), "maxRingSize"))
-        .isEqualTo(ClientXdsClient.DEFAULT_RING_HASH_LB_POLICY_MAX_RING_SIZE);
   }
 
   @Test
@@ -1766,10 +1755,8 @@ public class ClientXdsClientDataTest {
     CdsUpdate update = ClientXdsClient.processCluster(
         cluster, new HashSet<String>(), null, LRS_SERVER_INFO,
         LoadBalancerRegistry.getDefaultRegistry());
-    LbConfig lbConfig = ServiceConfigUtil.unwrapLoadBalancingConfig(update.lbPolicyConfig());
+    assertThat(update.lbPolicySelection().getProvider().getPolicyName()).isEqualTo(
-    assertThat(lbConfig.getPolicyName()).isEqualTo("least_request_experimental");
+        "least_request_experimental");
-    assertThat(JsonUtil.getNumberAsLong(lbConfig.getRawConfigValue(), "choiceCount"))
-        .isEqualTo(ClientXdsClient.DEFAULT_LEAST_REQUEST_CHOICE_COUNT);
   }
 
   @Test
@@ -1795,86 +1782,6 @@ public class ClientXdsClientDataTest {
         LoadBalancerRegistry.getDefaultRegistry());
   }
 
-  @Test
-  public void parseCluster_ringHashLbPolicy_invalidRingSizeConfig_minGreaterThanMax()
-      throws ResourceInvalidException {
-    Cluster cluster = Cluster.newBuilder()
-        .setName("cluster-foo.googleapis.com")
-        .setType(DiscoveryType.EDS)
-        .setEdsClusterConfig(
-            EdsClusterConfig.newBuilder()
-                .setEdsConfig(
-                    ConfigSource.newBuilder()
-                        .setAds(AggregatedConfigSource.getDefaultInstance()))
-                .setServiceName("service-foo.googleapis.com"))
-        .setLbPolicy(LbPolicy.RING_HASH)
-        .setRingHashLbConfig(
-            RingHashLbConfig.newBuilder()
-                .setHashFunction(HashFunction.XX_HASH)
-                .setMinimumRingSize(UInt64Value.newBuilder().setValue(1000L))
-                .setMaximumRingSize(UInt64Value.newBuilder().setValue(100L)))
-        .build();
-
-    thrown.expect(ResourceInvalidException.class);
-    thrown.expectMessage("Cluster cluster-foo.googleapis.com: invalid ring_hash_lb_config");
-    ClientXdsClient.processCluster(cluster, new HashSet<String>(), null, LRS_SERVER_INFO,
-        LoadBalancerRegistry.getDefaultRegistry());
-  }
-
-  @Test
-  public void parseCluster_ringHashLbPolicy_invalidRingSizeConfig_tooLargeRingSize()
-      throws ResourceInvalidException {
-    Cluster cluster = Cluster.newBuilder()
-        .setName("cluster-foo.googleapis.com")
-        .setType(DiscoveryType.EDS)
-        .setEdsClusterConfig(
-            EdsClusterConfig.newBuilder()
-                .setEdsConfig(
-                    ConfigSource.newBuilder()
-                        .setAds(AggregatedConfigSource.getDefaultInstance()))
-                .setServiceName("service-foo.googleapis.com"))
-        .setLbPolicy(LbPolicy.RING_HASH)
-        .setRingHashLbConfig(
-            RingHashLbConfig.newBuilder()
-                .setHashFunction(HashFunction.XX_HASH)
-                .setMinimumRingSize(UInt64Value.newBuilder().setValue(1000L))
-                .setMaximumRingSize(
-                    UInt64Value.newBuilder()
-                        .setValue(ClientXdsClient.MAX_RING_HASH_LB_POLICY_RING_SIZE + 1)))
-        .build();
-
-    thrown.expect(ResourceInvalidException.class);
-    thrown.expectMessage("Cluster cluster-foo.googleapis.com: invalid ring_hash_lb_config");
-    ClientXdsClient.processCluster(cluster, new HashSet<String>(), null, LRS_SERVER_INFO,
-        LoadBalancerRegistry.getDefaultRegistry());
-  }
-
-  @Test
-  public void parseCluster_leastRequestLbPolicy_invalidChoiceCountConfig_tooSmallChoiceCount()
-      throws ResourceInvalidException {
-    ClientXdsClient.enableLeastRequest = true;
-    Cluster cluster = Cluster.newBuilder()
-        .setName("cluster-foo.googleapis.com")
-        .setType(DiscoveryType.EDS)
-        .setEdsClusterConfig(
-            EdsClusterConfig.newBuilder()
-                .setEdsConfig(
-                    ConfigSource.newBuilder()
-                        .setAds(AggregatedConfigSource.getDefaultInstance()))
-                .setServiceName("service-foo.googleapis.com"))
-        .setLbPolicy(LbPolicy.LEAST_REQUEST)
-        .setLeastRequestLbConfig(
-            LeastRequestLbConfig.newBuilder()
-                .setChoiceCount(UInt32Value.newBuilder().setValue(1))
-        )
-        .build();
-
-    thrown.expect(ResourceInvalidException.class);
-    thrown.expectMessage("Cluster cluster-foo.googleapis.com: invalid least_request_lb_config");
-    ClientXdsClient.processCluster(cluster, new HashSet<String>(), null, LRS_SERVER_INFO,
-        LoadBalancerRegistry.getDefaultRegistry());
-  }
-
   @Test
   public void parseCluster_validateEdsSourceConfig() throws ResourceInvalidException {
     Set<String> retainedEdsResources = new HashSet<>();

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

@@ -56,9 +56,7 @@ import io.grpc.internal.BackoffPolicy;
 import io.grpc.internal.FakeClock;
 import io.grpc.internal.FakeClock.ScheduledTask;
 import io.grpc.internal.FakeClock.TaskFilter;
-import io.grpc.internal.JsonUtil;
+import io.grpc.internal.ServiceConfigUtil.PolicySelection;
-import io.grpc.internal.ServiceConfigUtil;
-import io.grpc.internal.ServiceConfigUtil.LbConfig;
 import io.grpc.internal.TimeProvider;
 import io.grpc.testing.GrpcCleanupRule;
 import io.grpc.xds.AbstractXdsClient.ResourceType;
@@ -72,7 +70,9 @@ import io.grpc.xds.Endpoints.LocalityLbEndpoints;
 import io.grpc.xds.EnvoyProtoData.Node;
 import io.grpc.xds.EnvoyServerProtoData.FilterChain;
 import io.grpc.xds.FaultConfig.FractionalPercent.DenominatorType;
+import io.grpc.xds.LeastRequestLoadBalancer.LeastRequestConfig;
 import io.grpc.xds.LoadStatsManager2.ClusterDropStats;
+import io.grpc.xds.RingHashLoadBalancer.RingHashConfig;
 import io.grpc.xds.XdsClient.CdsResourceWatcher;
 import io.grpc.xds.XdsClient.CdsUpdate;
 import io.grpc.xds.XdsClient.CdsUpdate.ClusterType;
@@ -1617,8 +1617,8 @@ public abstract class ClientXdsClientTestBase {
     assertThat(cdsUpdate.clusterName()).isEqualTo(CDS_RESOURCE);
     assertThat(cdsUpdate.clusterType()).isEqualTo(ClusterType.EDS);
     assertThat(cdsUpdate.edsServiceName()).isNull();
-    assertThat(ServiceConfigUtil.unwrapLoadBalancingConfig(cdsUpdate.lbPolicyConfig())
+    assertThat(cdsUpdate.lbPolicySelection().getProvider().getPolicyName()).isEqualTo(
-        .getPolicyName()).isEqualTo("round_robin");
+        "round_robin");
     assertThat(cdsUpdate.lrsServerInfo()).isNull();
     assertThat(cdsUpdate.maxConcurrentRequests()).isNull();
     assertThat(cdsUpdate.upstreamTlsContext()).isNull();
@@ -1640,8 +1640,8 @@ public abstract class ClientXdsClientTestBase {
     assertThat(cdsUpdate.clusterName()).isEqualTo(CDS_RESOURCE);
     assertThat(cdsUpdate.clusterType()).isEqualTo(ClusterType.EDS);
     assertThat(cdsUpdate.edsServiceName()).isNull();
-    assertThat(ServiceConfigUtil.unwrapLoadBalancingConfig(cdsUpdate.lbPolicyConfig())
+    assertThat(cdsUpdate.lbPolicySelection().getProvider().getPolicyName()).isEqualTo(
-        .getPolicyName()).isEqualTo("round_robin");
+        "round_robin");
     assertThat(cdsUpdate.lrsServerInfo()).isNull();
     assertThat(cdsUpdate.maxConcurrentRequests()).isNull();
     assertThat(cdsUpdate.upstreamTlsContext()).isNull();
@@ -1668,9 +1668,10 @@ public abstract class ClientXdsClientTestBase {
     assertThat(cdsUpdate.clusterName()).isEqualTo(CDS_RESOURCE);
     assertThat(cdsUpdate.clusterType()).isEqualTo(ClusterType.EDS);
     assertThat(cdsUpdate.edsServiceName()).isNull();
-    LbConfig lbConfig = ServiceConfigUtil.unwrapLoadBalancingConfig(cdsUpdate.lbPolicyConfig());
+    PolicySelection policySelection = cdsUpdate.lbPolicySelection();
-    assertThat(lbConfig.getPolicyName()).isEqualTo("least_request_experimental");
+    assertThat(policySelection.getProvider().getPolicyName()).isEqualTo(
-    assertThat(lbConfig.getRawConfigValue().get("choiceCount")).isEqualTo(3);
+        "least_request_experimental");
+    assertThat(((LeastRequestConfig) policySelection.getConfig()).choiceCount).isEqualTo(3);
     assertThat(cdsUpdate.lrsServerInfo()).isNull();
     assertThat(cdsUpdate.maxConcurrentRequests()).isNull();
     assertThat(cdsUpdate.upstreamTlsContext()).isNull();
@@ -1696,12 +1697,10 @@ public abstract class ClientXdsClientTestBase {
     assertThat(cdsUpdate.clusterName()).isEqualTo(CDS_RESOURCE);
     assertThat(cdsUpdate.clusterType()).isEqualTo(ClusterType.EDS);
     assertThat(cdsUpdate.edsServiceName()).isNull();
-    LbConfig lbConfig = ServiceConfigUtil.unwrapLoadBalancingConfig(cdsUpdate.lbPolicyConfig());
+    PolicySelection policySelection = cdsUpdate.lbPolicySelection();
-    assertThat(lbConfig.getPolicyName()).isEqualTo("ring_hash_experimental");
+    assertThat(policySelection.getProvider().getPolicyName()).isEqualTo("ring_hash_experimental");
-    assertThat(JsonUtil.getNumberAsLong(lbConfig.getRawConfigValue(), "minRingSize")).isEqualTo(
+    assertThat(((RingHashConfig) policySelection.getConfig()).minRingSize).isEqualTo(10L);
-        10L);
+    assertThat(((RingHashConfig) policySelection.getConfig()).maxRingSize).isEqualTo(100L);
-    assertThat(JsonUtil.getNumberAsLong(lbConfig.getRawConfigValue(), "maxRingSize")).isEqualTo(
-        100L);
     assertThat(cdsUpdate.lrsServerInfo()).isNull();
     assertThat(cdsUpdate.maxConcurrentRequests()).isNull();
     assertThat(cdsUpdate.upstreamTlsContext()).isNull();
@@ -1725,8 +1724,8 @@ public abstract class ClientXdsClientTestBase {
     CdsUpdate cdsUpdate = cdsUpdateCaptor.getValue();
     assertThat(cdsUpdate.clusterName()).isEqualTo(CDS_RESOURCE);
     assertThat(cdsUpdate.clusterType()).isEqualTo(ClusterType.AGGREGATE);
-    assertThat(ServiceConfigUtil.unwrapLoadBalancingConfig(cdsUpdate.lbPolicyConfig())
+    assertThat(cdsUpdate.lbPolicySelection().getProvider().getPolicyName()).isEqualTo(
-        .getPolicyName()).isEqualTo("round_robin");
+        "round_robin");
     assertThat(cdsUpdate.prioritizedClusterNames()).containsExactlyElementsIn(candidates).inOrder();
     verifyResourceMetadataAcked(CDS, CDS_RESOURCE, clusterAggregate, VERSION_1, TIME_INCREMENT);
     verifySubscribedResourcesMetadataSizes(0, 1, 0, 0);
@@ -1747,8 +1746,8 @@ public abstract class ClientXdsClientTestBase {
     assertThat(cdsUpdate.clusterName()).isEqualTo(CDS_RESOURCE);
     assertThat(cdsUpdate.clusterType()).isEqualTo(ClusterType.EDS);
     assertThat(cdsUpdate.edsServiceName()).isNull();
-    assertThat(ServiceConfigUtil.unwrapLoadBalancingConfig(cdsUpdate.lbPolicyConfig())
+    assertThat(cdsUpdate.lbPolicySelection().getProvider().getPolicyName()).isEqualTo(
-        .getPolicyName()).isEqualTo("round_robin");
+        "round_robin");
     assertThat(cdsUpdate.lrsServerInfo()).isNull();
     assertThat(cdsUpdate.maxConcurrentRequests()).isEqualTo(200L);
     assertThat(cdsUpdate.upstreamTlsContext()).isNull();
@@ -1898,8 +1897,8 @@ public abstract class ClientXdsClientTestBase {
     assertThat(cdsUpdate.clusterName()).isEqualTo(CDS_RESOURCE);
     assertThat(cdsUpdate.clusterType()).isEqualTo(ClusterType.EDS);
     assertThat(cdsUpdate.edsServiceName()).isNull();
-    assertThat(ServiceConfigUtil.unwrapLoadBalancingConfig(cdsUpdate.lbPolicyConfig())
+    assertThat(cdsUpdate.lbPolicySelection().getProvider().getPolicyName()).isEqualTo(
-        .getPolicyName()).isEqualTo("round_robin");
+        "round_robin");
     assertThat(cdsUpdate.lrsServerInfo()).isNull();
     assertThat(cdsUpdate.maxConcurrentRequests()).isNull();
     assertThat(cdsUpdate.upstreamTlsContext()).isNull();
@@ -1941,8 +1940,8 @@ public abstract class ClientXdsClientTestBase {
     assertThat(cdsUpdate.clusterName()).isEqualTo(CDS_RESOURCE);
     assertThat(cdsUpdate.clusterType()).isEqualTo(ClusterType.LOGICAL_DNS);
     assertThat(cdsUpdate.dnsHostName()).isEqualTo(dnsHostAddr + ":" + dnsHostPort);
-    assertThat(ServiceConfigUtil.unwrapLoadBalancingConfig(cdsUpdate.lbPolicyConfig())
+    assertThat(cdsUpdate.lbPolicySelection().getProvider().getPolicyName()).isEqualTo(
-        .getPolicyName()).isEqualTo("round_robin");
+        "round_robin");
     assertThat(cdsUpdate.lrsServerInfo()).isNull();
     assertThat(cdsUpdate.maxConcurrentRequests()).isNull();
     assertThat(cdsUpdate.upstreamTlsContext()).isNull();
@@ -1961,8 +1960,8 @@ public abstract class ClientXdsClientTestBase {
     assertThat(cdsUpdate.clusterName()).isEqualTo(CDS_RESOURCE);
     assertThat(cdsUpdate.clusterType()).isEqualTo(ClusterType.EDS);
     assertThat(cdsUpdate.edsServiceName()).isEqualTo(edsService);
-    assertThat(ServiceConfigUtil.unwrapLoadBalancingConfig(cdsUpdate.lbPolicyConfig())
+    assertThat(cdsUpdate.lbPolicySelection().getProvider().getPolicyName()).isEqualTo(
-        .getPolicyName()).isEqualTo("round_robin");
+        "round_robin");
     assertThat(cdsUpdate.lrsServerInfo()).isEqualTo(lrsServerInfo);
     assertThat(cdsUpdate.maxConcurrentRequests()).isNull();
     assertThat(cdsUpdate.upstreamTlsContext()).isNull();
@@ -1983,8 +1982,8 @@ public abstract class ClientXdsClientTestBase {
     assertThat(cdsUpdate.clusterName()).isEqualTo(CDS_RESOURCE);
     assertThat(cdsUpdate.clusterType()).isEqualTo(ClusterType.EDS);
     assertThat(cdsUpdate.edsServiceName()).isNull();
-    assertThat(ServiceConfigUtil.unwrapLoadBalancingConfig(cdsUpdate.lbPolicyConfig())
+    assertThat(cdsUpdate.lbPolicySelection().getProvider().getPolicyName()).isEqualTo(
-        .getPolicyName()).isEqualTo("round_robin");
+        "round_robin");
     assertThat(cdsUpdate.lrsServerInfo()).isNull();
     assertThat(cdsUpdate.maxConcurrentRequests()).isNull();
     assertThat(cdsUpdate.upstreamTlsContext()).isNull();
@@ -2036,8 +2035,8 @@ public abstract class ClientXdsClientTestBase {
     assertThat(cdsUpdate.clusterName()).isEqualTo(CDS_RESOURCE);
     assertThat(cdsUpdate.clusterType()).isEqualTo(ClusterType.LOGICAL_DNS);
     assertThat(cdsUpdate.dnsHostName()).isEqualTo(dnsHostAddr + ":" + dnsHostPort);
-    assertThat(ServiceConfigUtil.unwrapLoadBalancingConfig(cdsUpdate.lbPolicyConfig())
+    assertThat(cdsUpdate.lbPolicySelection().getProvider().getPolicyName()).isEqualTo(
-        .getPolicyName()).isEqualTo("round_robin");
+        "round_robin");
     assertThat(cdsUpdate.lrsServerInfo()).isNull();
     assertThat(cdsUpdate.maxConcurrentRequests()).isNull();
     assertThat(cdsUpdate.upstreamTlsContext()).isNull();
@@ -2046,8 +2045,8 @@ public abstract class ClientXdsClientTestBase {
     assertThat(cdsUpdate.clusterName()).isEqualTo(cdsResourceTwo);
     assertThat(cdsUpdate.clusterType()).isEqualTo(ClusterType.EDS);
     assertThat(cdsUpdate.edsServiceName()).isEqualTo(edsService);
-    assertThat(ServiceConfigUtil.unwrapLoadBalancingConfig(cdsUpdate.lbPolicyConfig())
+    assertThat(cdsUpdate.lbPolicySelection().getProvider().getPolicyName()).isEqualTo(
-        .getPolicyName()).isEqualTo("round_robin");
+        "round_robin");
     assertThat(cdsUpdate.lrsServerInfo()).isEqualTo(lrsServerInfo);
     assertThat(cdsUpdate.maxConcurrentRequests()).isNull();
     assertThat(cdsUpdate.upstreamTlsContext()).isNull();
@@ -2056,8 +2055,8 @@ public abstract class ClientXdsClientTestBase {
     assertThat(cdsUpdate.clusterName()).isEqualTo(cdsResourceTwo);
     assertThat(cdsUpdate.clusterType()).isEqualTo(ClusterType.EDS);
     assertThat(cdsUpdate.edsServiceName()).isEqualTo(edsService);
-    assertThat(ServiceConfigUtil.unwrapLoadBalancingConfig(cdsUpdate.lbPolicyConfig())
+    assertThat(cdsUpdate.lbPolicySelection().getProvider().getPolicyName()).isEqualTo(
-        .getPolicyName()).isEqualTo("round_robin");
+        "round_robin");
     assertThat(cdsUpdate.lrsServerInfo()).isEqualTo(lrsServerInfo);
     assertThat(cdsUpdate.maxConcurrentRequests()).isNull();
     assertThat(cdsUpdate.upstreamTlsContext()).isNull();

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

@@ -35,17 +35,17 @@ import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
 
 /**
- * Unit test for {@link LegacyLoadBalancerConfigBuilder}.
+ * Unit test for {@link LegacyLoadBalancerConfigFactory}.
  */
 @RunWith(JUnit4.class)
-public class LegacyLoadBalancerConfigBuilderTest {
+public class LegacyLoadBalancerConfigFactoryTest {
 
   @Test
   public void roundRobin() throws ResourceInvalidException {
     Cluster cluster = Cluster.newBuilder().setLbPolicy(LbPolicy.ROUND_ROBIN).build();
 
     LbConfig lbConfig = ServiceConfigUtil.unwrapLoadBalancingConfig(
-        LegacyLoadBalancerConfigBuilder.forCluster(cluster, true).build());
+        LegacyLoadBalancerConfigFactory.newConfig(cluster, true));
 
     assertThat(lbConfig.getPolicyName()).isEqualTo("round_robin");
     assertThat(lbConfig.getRawConfigValue()).isEmpty();
@@ -59,7 +59,7 @@ public class LegacyLoadBalancerConfigBuilderTest {
             .setMaximumRingSize(UInt64Value.newBuilder().setValue(2).build()).build()).build();
 
     LbConfig lbConfig = ServiceConfigUtil.unwrapLoadBalancingConfig(
-        LegacyLoadBalancerConfigBuilder.forCluster(cluster, true).build());
+        LegacyLoadBalancerConfigFactory.newConfig(cluster, true));
 
     assertThat(lbConfig.getPolicyName()).isEqualTo("ring_hash_experimental");
     assertThat(JsonUtil.getNumberAsLong(lbConfig.getRawConfigValue(), "minRingSize")).isEqualTo(1);
@@ -73,42 +73,9 @@ public class LegacyLoadBalancerConfigBuilderTest {
 
     try {
       ServiceConfigUtil.unwrapLoadBalancingConfig(
-          LegacyLoadBalancerConfigBuilder.forCluster(cluster, true).build());
+          LegacyLoadBalancerConfigFactory.newConfig(cluster, true));
     } catch (ResourceInvalidException e) {
-      assertThat(e).hasMessageThat().contains("invalid ring_hash_lb_config");
+      assertThat(e).hasMessageThat().contains("invalid ring hash function");
-      return;
-    }
-    fail("ResourceInvalidException not thrown");
-  }
-
-  @Test
-  public void ringHash_minRingSizeLargerThanMax() throws ResourceInvalidException {
-    Cluster cluster = Cluster.newBuilder().setLbPolicy(LbPolicy.RING_HASH).setRingHashLbConfig(
-        RingHashLbConfig.newBuilder()
-            .setMinimumRingSize(UInt64Value.newBuilder().setValue(2).build())
-            .setMaximumRingSize(UInt64Value.newBuilder().setValue(1).build())).build();
-
-    try {
-      ServiceConfigUtil.unwrapLoadBalancingConfig(
-          LegacyLoadBalancerConfigBuilder.forCluster(cluster, true).build());
-    } catch (ResourceInvalidException e) {
-      assertThat(e).hasMessageThat().contains("invalid ring_hash_lb_config");
-      return;
-    }
-    fail("ResourceInvalidException not thrown");
-  }
-
-  @Test
-  public void ringHash_maxRingSizeTooLarge() throws ResourceInvalidException {
-    Cluster cluster = Cluster.newBuilder().setLbPolicy(LbPolicy.RING_HASH).setRingHashLbConfig(
-        RingHashLbConfig.newBuilder()
-            .setMaximumRingSize(UInt64Value.newBuilder().setValue(Long.MAX_VALUE).build())).build();
-
-    try {
-      ServiceConfigUtil.unwrapLoadBalancingConfig(
-          LegacyLoadBalancerConfigBuilder.forCluster(cluster, true).build());
-    } catch (ResourceInvalidException e) {
-      assertThat(e).hasMessageThat().contains("invalid ring_hash_lb_config");
       return;
     }
     fail("ResourceInvalidException not thrown");
@@ -123,29 +90,12 @@ public class LegacyLoadBalancerConfigBuilderTest {
             .setChoiceCount(UInt32Value.newBuilder().setValue(10).build())).build();
 
     LbConfig lbConfig = ServiceConfigUtil.unwrapLoadBalancingConfig(
-        LegacyLoadBalancerConfigBuilder.forCluster(cluster, true).build());
+        LegacyLoadBalancerConfigFactory.newConfig(cluster, true));
 
     assertThat(lbConfig.getPolicyName()).isEqualTo("least_request_experimental");
     assertThat(JsonUtil.getNumberAsLong(lbConfig.getRawConfigValue(), "choiceCount")).isEqualTo(10);
   }
 
-  @Test
-  public void leastRequest_choiceCountTooSmall() throws ResourceInvalidException {
-    System.setProperty("io.grpc.xds.experimentalEnableLeastRequest", "true");
-
-    Cluster cluster = Cluster.newBuilder().setLbPolicy(LbPolicy.LEAST_REQUEST)
-        .setLeastRequestLbConfig(LeastRequestLbConfig.newBuilder()
-            .setChoiceCount(UInt32Value.newBuilder().setValue(1).build())).build();
-
-    try {
-      ServiceConfigUtil.unwrapLoadBalancingConfig(
-          LegacyLoadBalancerConfigBuilder.forCluster(cluster, true).build());
-    } catch (ResourceInvalidException e) {
-      assertThat(e).hasMessageThat().contains("invalid least_request_lb_config");
-      return;
-    }
-    fail("ResourceInvalidException not thrown");
-  }
 
   @Test
   public void leastRequest_notEnabled() throws ResourceInvalidException {
@@ -155,7 +105,7 @@ public class LegacyLoadBalancerConfigBuilderTest {
 
     try {
       ServiceConfigUtil.unwrapLoadBalancingConfig(
-          LegacyLoadBalancerConfigBuilder.forCluster(cluster, false).build());
+          LegacyLoadBalancerConfigFactory.newConfig(cluster, false));
     } catch (ResourceInvalidException e) {
       assertThat(e).hasMessageThat().contains("unsupported lb policy");
       return;