xds: stop setting PROXYLESS_CLIENT_HOSTNAME node metadata in LRS requests (grpc#7459)

The PROXYLESS_CLIENT_HOSTNAME node metadata was a temporary workaround for management server to not send back all backend services as load reporting clusters. Now the management server is able to use `send_all_clusters` field to let the client side decide the group of clusters it is reporting loads for. So this node metadata is no longer needed.

Author: voidzcy

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

@@ -39,9 +39,7 @@
 import io.grpc.xds.XdsClient.XdsChannel;
 import io.grpc.xds.XdsLogger.XdsLogLevel;
 import java.util.ArrayList;
-import java.util.HashMap;
 import java.util.List;
-import java.util.Map;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Nullable;
@@ -53,9 +51,6 @@
  */
 @NotThreadSafe
 final class LoadReportClient {
-  @VisibleForTesting
-  static final String TARGET_NAME_METADATA_KEY = "PROXYLESS_CLIENT_HOSTNAME";
-
   private final InternalLogId logId;
   private final XdsLogger logger;
   private final XdsChannel xdsChannel;
@@ -91,14 +86,7 @@ final class LoadReportClient {
     this.backoffPolicyProvider = checkNotNull(backoffPolicyProvider, "backoffPolicyProvider");
     checkNotNull(stopwatchSupplier, "stopwatchSupplier");
     this.retryStopwatch = stopwatchSupplier.get();
-    checkNotNull(targetName, "targetName");
-    checkNotNull(node, "node");
-    Map<String, Object> newMetadata = new HashMap<>();
-    if (node.getMetadata() != null) {
-      newMetadata.putAll(node.getMetadata());
-    }
-    newMetadata.put(TARGET_NAME_METADATA_KEY, targetName);
-    this.node = node.toBuilder().setMetadata(newMetadata).build();
+    this.node = checkNotNull(node, "node");
     logId = InternalLogId.allocate("lrs-client", targetName);
     logger = XdsLogger.withLogId(logId);
     logger.log(XdsLogLevel.INFO, "Created");

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

@@ -469,10 +469,7 @@ private static LoadStatsRequest buildInitialRequest() {
                         Struct.newBuilder()
                             .putFields(
                                 "TRAFFICDIRECTOR_NETWORK_HOSTNAME",
-                                Value.newBuilder().setStringValue("default").build())
-                            .putFields(
-                                LoadReportClient.TARGET_NAME_METADATA_KEY,
-                                Value.newBuilder().setStringValue(TARGET_NAME).build())))
+                                Value.newBuilder().setStringValue("default").build())))
             .build();
   }
 
@@ -490,11 +487,6 @@ private static class LoadStatsRequestMatcher implements ArgumentMatcher<LoadStat
 
     @Override
     public boolean matches(LoadStatsRequest argument) {
-      if (!argument.getNode().getMetadata()
-          .getFieldsOrThrow(LoadReportClient.TARGET_NAME_METADATA_KEY)
-          .getStringValue().equals(TARGET_NAME)) {
-        return false;
-      }
       if (argument.getClusterStatsCount() != expectedStats.size()) {
         return false;
       }