xds: Move LR and RLS experimental flags to where they are used

That's better for code organization and also removes some grpc-isms from
XdsResourceType.

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

@@ -22,6 +22,7 @@ import static io.grpc.xds.client.Bootstrapper.ServerInfo;
 import com.google.auto.value.AutoValue;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.MoreObjects;
+import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.protobuf.Duration;
@@ -50,6 +51,12 @@ import java.util.Set;
 import javax.annotation.Nullable;
 
 class XdsClusterResource extends XdsResourceType<CdsUpdate> {
+  @VisibleForTesting
+  static boolean enableLeastRequest =
+      !Strings.isNullOrEmpty(System.getenv("GRPC_EXPERIMENTAL_ENABLE_LEAST_REQUEST"))
+          ? Boolean.parseBoolean(System.getenv("GRPC_EXPERIMENTAL_ENABLE_LEAST_REQUEST"))
+          : Boolean.parseBoolean(System.getProperty("io.grpc.xds.experimentalEnableLeastRequest"));
+
   @VisibleForTesting
   static final String AGGREGATE_CLUSTER_TYPE_NAME = "envoy.clusters.aggregate";
   static final String ADS_TYPE_URL_CDS =

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

@@ -38,6 +38,7 @@ import io.envoyproxy.envoy.config.route.v3.RetryPolicy.RetryBackOff;
 import io.envoyproxy.envoy.config.route.v3.RouteConfiguration;
 import io.envoyproxy.envoy.type.v3.FractionalPercent;
 import io.grpc.Status;
+import io.grpc.internal.GrpcUtil;
 import io.grpc.xds.ClusterSpecifierPlugin.NamedPluginConfig;
 import io.grpc.xds.ClusterSpecifierPlugin.PluginConfig;
 import io.grpc.xds.Filter.FilterConfig;
@@ -67,6 +68,9 @@ import java.util.Set;
 import javax.annotation.Nullable;
 
 class XdsRouteConfigureResource extends XdsResourceType<RdsUpdate> {
+  @VisibleForTesting
+  static boolean enableRouteLookup = GrpcUtil.getFlag("GRPC_EXPERIMENTAL_XDS_RLS_LB", true);
+
   static final String ADS_TYPE_URL_RDS =
       "type.googleapis.com/envoy.config.route.v3.RouteConfiguration";
   private static final String TYPE_URL_FILTER_CONFIG =

xds/src/main/java/io/grpc/xds/client/XdsResourceType.java

@@ -21,7 +21,6 @@ import static io.grpc.xds.client.XdsClient.canonifyResourceName;
 import static io.grpc.xds.client.XdsClient.isResourceNameValid;
 
 import com.google.common.annotations.VisibleForTesting;
-import com.google.common.base.Strings;
 import com.google.protobuf.Any;
 import com.google.protobuf.InvalidProtocolBufferException;
 import com.google.protobuf.Message;
@@ -44,13 +43,6 @@ public abstract class XdsResourceType<T extends ResourceUpdate> {
   protected static final String TRANSPORT_SOCKET_NAME_TLS = "envoy.transport_sockets.tls";
   @VisibleForTesting
   public static final String HASH_POLICY_FILTER_STATE_KEY = "io.grpc.channel_id";
-  @VisibleForTesting
-  public static boolean enableRouteLookup = getFlag("GRPC_EXPERIMENTAL_XDS_RLS_LB", true);
-  @VisibleForTesting
-  public static boolean enableLeastRequest =
-      !Strings.isNullOrEmpty(System.getenv("GRPC_EXPERIMENTAL_ENABLE_LEAST_REQUEST"))
-          ? Boolean.parseBoolean(System.getenv("GRPC_EXPERIMENTAL_ENABLE_LEAST_REQUEST"))
-          : Boolean.parseBoolean(System.getProperty("io.grpc.xds.experimentalEnableLeastRequest"));
 
   protected static final String TYPE_URL_CLUSTER_CONFIG =
       "type.googleapis.com/envoy.extensions.clusters.aggregate.v3.ClusterConfig";
@@ -258,15 +250,6 @@ public abstract class XdsResourceType<T extends ResourceUpdate> {
     }
   }
 
-  private static boolean getFlag(String envVarName, boolean enableByDefault) {
-    String envVar = System.getenv(envVarName);
-    if (enableByDefault) {
-      return Strings.isNullOrEmpty(envVar) || Boolean.parseBoolean(envVar);
-    } else {
-      return !Strings.isNullOrEmpty(envVar) && Boolean.parseBoolean(envVar);
-    }
-  }
-
   @VisibleForTesting
   public static final class StructOrError<T> {
 

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

@@ -173,15 +173,15 @@ public class GrpcXdsClientImplDataTest {
 
   @Before
   public void setUp() {
-    originalEnableRouteLookup = XdsResourceType.enableRouteLookup;
-    originalEnableLeastRequest = XdsResourceType.enableLeastRequest;
+    originalEnableRouteLookup = XdsRouteConfigureResource.enableRouteLookup;
+    originalEnableLeastRequest = XdsClusterResource.enableLeastRequest;
     assertThat(originalEnableLeastRequest).isFalse();
   }
 
   @After
   public void tearDown() {
-    XdsResourceType.enableRouteLookup = originalEnableRouteLookup;
-    XdsResourceType.enableLeastRequest = originalEnableLeastRequest;
+    XdsRouteConfigureResource.enableRouteLookup = originalEnableRouteLookup;
+    XdsClusterResource.enableLeastRequest = originalEnableLeastRequest;
   }
 
   @Test
@@ -860,7 +860,7 @@ public class GrpcXdsClientImplDataTest {
 
   @Test
   public void parseRouteAction_clusterSpecifier_routeLookupDisabled() {
-    XdsResourceType.enableRouteLookup = false;
+    XdsRouteConfigureResource.enableRouteLookup = false;
     io.envoyproxy.envoy.config.route.v3.RouteAction proto =
         io.envoyproxy.envoy.config.route.v3.RouteAction.newBuilder()
             .setClusterSpecifierPlugin(CLUSTER_SPECIFIER_PLUGIN.name())
@@ -1465,7 +1465,7 @@ public class GrpcXdsClientImplDataTest {
 
   @Test
   public void parseHttpConnectionManager_clusterSpecifierPlugin() throws Exception {
-    XdsResourceType.enableRouteLookup = true;
+    XdsRouteConfigureResource.enableRouteLookup = true;
     RouteLookupConfig routeLookupConfig = RouteLookupConfig.newBuilder()
         .addGrpcKeybuilders(
             GrpcKeyBuilder.newBuilder()
@@ -1521,7 +1521,7 @@ public class GrpcXdsClientImplDataTest {
 
   @Test
   public void parseHttpConnectionManager_duplicatePluginName() throws Exception {
-    XdsResourceType.enableRouteLookup = true;
+    XdsRouteConfigureResource.enableRouteLookup = true;
     RouteLookupConfig routeLookupConfig1 = RouteLookupConfig.newBuilder()
         .addGrpcKeybuilders(
             GrpcKeyBuilder.newBuilder()
@@ -1594,7 +1594,7 @@ public class GrpcXdsClientImplDataTest {
 
   @Test
   public void parseHttpConnectionManager_pluginNameNotFound() throws Exception {
-    XdsResourceType.enableRouteLookup = true;
+    XdsRouteConfigureResource.enableRouteLookup = true;
     RouteLookupConfig routeLookupConfig = RouteLookupConfig.newBuilder()
         .addGrpcKeybuilders(
             GrpcKeyBuilder.newBuilder()
@@ -1647,7 +1647,7 @@ public class GrpcXdsClientImplDataTest {
 
   @Test
   public void parseHttpConnectionManager_optionalPlugin() throws ResourceInvalidException {
-    XdsResourceType.enableRouteLookup = true;
+    XdsRouteConfigureResource.enableRouteLookup = true;
 
     // RLS Plugin, and a route to it.
     RouteLookupConfig routeLookupConfig = RouteLookupConfig.newBuilder()
@@ -1729,7 +1729,7 @@ public class GrpcXdsClientImplDataTest {
 
   @Test
   public void parseHttpConnectionManager_validateRdsConfigSource() throws Exception {
-    XdsResourceType.enableRouteLookup = true;
+    XdsRouteConfigureResource.enableRouteLookup = true;
 
     HttpConnectionManager hcm1 =
         HttpConnectionManager.newBuilder()
@@ -1967,7 +1967,7 @@ public class GrpcXdsClientImplDataTest {
 
   @Test
   public void parseCluster_leastRequestLbPolicy_defaultLbConfig() throws ResourceInvalidException {
-    XdsResourceType.enableLeastRequest = true;
+    XdsClusterResource.enableLeastRequest = true;
     Cluster cluster = Cluster.newBuilder()
         .setName("cluster-foo.googleapis.com")
         .setType(DiscoveryType.EDS)

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

@@ -304,8 +304,8 @@ public abstract class GrpcXdsClientImplTestBase {
     when(backoffPolicy2.nextBackoffNanos()).thenReturn(20L, 200L);
 
     // Start the server and the client.
-    originalEnableLeastRequest = XdsResourceType.enableLeastRequest;
-    XdsResourceType.enableLeastRequest = true;
+    originalEnableLeastRequest = XdsClusterResource.enableLeastRequest;
+    XdsClusterResource.enableLeastRequest = true;
     xdsServer = cleanupRule.register(InProcessServerBuilder
         .forName(serverName)
         .addService(adsService)
@@ -376,7 +376,7 @@ public abstract class GrpcXdsClientImplTestBase {
 
   @After
   public void tearDown() {
-    XdsResourceType.enableLeastRequest = originalEnableLeastRequest;
+    XdsClusterResource.enableLeastRequest = originalEnableLeastRequest;
     xdsClient.shutdown();
     channel.shutdown();  // channel not owned by XdsClient
     assertThat(adsEnded.get()).isTrue();