Allow users outside of io.grpc.xds package to create custom xDS resou…

…rces (grpc#10834)

Currently few of the interfaces needed to define and start a watch for a xDS resource are package private, which can't be used externally outside of io.grpc.xds. Exposing them outside allows users to define their own custom resources and start a watch along with the default supported resources.

Also as part of this change, move an Exception defined in the XdsClientImpl into XdsResourceType. As XdsClientImpl is an implementation package, it makes more sense to expose it via the XdsResourceType class.

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

@@ -39,8 +39,8 @@
 import io.grpc.LoadBalancerRegistry;
 import io.grpc.internal.JsonParser;
 import io.grpc.xds.LoadBalancerConfigFactory.LoadBalancingPolicyConverter.MaxRecursionReachedException;
-import io.grpc.xds.XdsClientImpl.ResourceInvalidException;
 import io.grpc.xds.XdsLogger.XdsLogLevel;
+import io.grpc.xds.XdsResourceType.ResourceInvalidException;
 import java.io.IOException;
 import java.util.Map;
 

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

@@ -47,7 +47,7 @@
  * protocols (e.g., LDS, RDS, VHDS, CDS and EDS) over a single channel. Watch-based interfaces
  * are provided for each set of data needed by gRPC.
  */
-abstract class XdsClient {
+public abstract class XdsClient {
 
   static boolean isResourceNameValid(String resourceName, String typeUrl) {
     checkNotNull(resourceName, "resourceName");
@@ -110,8 +110,7 @@ static String percentEncodePath(String input) {
     return Joiner.on('/').join(encodedSegs);
   }
 
-  interface ResourceUpdate {
-  }
+  public interface ResourceUpdate {}
 
   /**
    * Watcher interface for a single requested xDS resource.

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

@@ -748,18 +748,6 @@ private void notifyWatcher(ResourceWatcher<T> watcher, T update) {
     }
   }
 
-  static final class ResourceInvalidException extends Exception {
-    private static final long serialVersionUID = 0L;
-
-    ResourceInvalidException(String message) {
-      super(message, null, false, false);
-    }
-
-    ResourceInvalidException(String message, Throwable cause) {
-      super(cause != null ? message + ": " + cause.getMessage() : message, cause, false, false);
-    }
-  }
-
   abstract static class XdsChannelFactory {
     static final XdsChannelFactory DEFAULT_XDS_CHANNEL_FACTORY = new XdsChannelFactory() {
       @Override

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

@@ -42,8 +42,8 @@
 import io.grpc.xds.EnvoyServerProtoData.OutlierDetection;
 import io.grpc.xds.EnvoyServerProtoData.UpstreamTlsContext;
 import io.grpc.xds.XdsClient.ResourceUpdate;
-import io.grpc.xds.XdsClientImpl.ResourceInvalidException;
 import io.grpc.xds.XdsClusterResource.CdsUpdate;
+import io.grpc.xds.XdsResourceType.ResourceInvalidException;
 import java.util.List;
 import java.util.Locale;
 import java.util.Set;
@@ -65,37 +65,36 @@ public static XdsClusterResource getInstance() {
 
   @Override
   @Nullable
-  String extractResourceName(Message unpackedResource) {
+  protected String extractResourceName(Message unpackedResource) {
     if (!(unpackedResource instanceof Cluster)) {
       return null;
     }
     return ((Cluster) unpackedResource).getName();
   }
 
   @Override
-  String typeName() {
+  protected String typeName() {
     return "CDS";
   }
 
   @Override
-  String typeUrl() {
+  protected String typeUrl() {
     return ADS_TYPE_URL_CDS;
   }
 
   @Override
-  boolean isFullStateOfTheWorld() {
+  protected boolean isFullStateOfTheWorld() {
     return true;
   }
 
   @Override
   @SuppressWarnings("unchecked")
-  Class<Cluster> unpackedClassName() {
+  protected Class<Cluster> unpackedClassName() {
     return Cluster.class;
   }
 
   @Override
-  CdsUpdate doParse(Args args, Message unpackedMessage)
-      throws ResourceInvalidException {
+  protected CdsUpdate doParse(Args args, Message unpackedMessage) throws ResourceInvalidException {
     if (!(unpackedMessage instanceof Cluster)) {
       throw new ResourceInvalidException("Invalid message type: " + unpackedMessage.getClass());
     }

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

@@ -28,8 +28,8 @@
 import io.grpc.xds.Endpoints.DropOverload;
 import io.grpc.xds.Endpoints.LocalityLbEndpoints;
 import io.grpc.xds.XdsClient.ResourceUpdate;
-import io.grpc.xds.XdsClientImpl.ResourceInvalidException;
 import io.grpc.xds.XdsEndpointResource.EdsUpdate;
+import io.grpc.xds.XdsResourceType.ResourceInvalidException;
 import java.net.InetSocketAddress;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -54,36 +54,35 @@ public static XdsEndpointResource getInstance() {
 
   @Override
   @Nullable
-  String extractResourceName(Message unpackedResource) {
+  protected String extractResourceName(Message unpackedResource) {
     if (!(unpackedResource instanceof ClusterLoadAssignment)) {
       return null;
     }
     return ((ClusterLoadAssignment) unpackedResource).getClusterName();
   }
 
   @Override
-  String typeName() {
+  protected String typeName() {
     return "EDS";
   }
 
   @Override
-  String typeUrl() {
+  protected String typeUrl() {
     return ADS_TYPE_URL_EDS;
   }
 
   @Override
-  boolean isFullStateOfTheWorld() {
+  protected boolean isFullStateOfTheWorld() {
     return false;
   }
 
   @Override
-  Class<ClusterLoadAssignment> unpackedClassName() {
+  protected Class<ClusterLoadAssignment> unpackedClassName() {
     return ClusterLoadAssignment.class;
   }
 
   @Override
-  EdsUpdate doParse(Args args, Message unpackedMessage)
-      throws ResourceInvalidException {
+  protected EdsUpdate doParse(Args args, Message unpackedMessage) throws ResourceInvalidException {
     if (!(unpackedMessage instanceof ClusterLoadAssignment)) {
       throw new ResourceInvalidException("Invalid message type: " + unpackedMessage.getClass());
     }

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

@@ -18,8 +18,8 @@
 
 import static com.google.common.base.Preconditions.checkNotNull;
 import static io.grpc.xds.XdsClient.ResourceUpdate;
-import static io.grpc.xds.XdsClientImpl.ResourceInvalidException;
 import static io.grpc.xds.XdsClusterResource.validateCommonTlsContext;
+import static io.grpc.xds.XdsResourceType.ResourceInvalidException;
 import static io.grpc.xds.XdsRouteConfigureResource.extractVirtualHosts;
 
 import com.github.udpa.udpa.type.v1.TypedStruct;
@@ -66,35 +66,35 @@ public static XdsListenerResource getInstance() {
 
   @Override
   @Nullable
-  String extractResourceName(Message unpackedResource) {
+  protected String extractResourceName(Message unpackedResource) {
     if (!(unpackedResource instanceof Listener)) {
       return null;
     }
     return ((Listener) unpackedResource).getName();
   }
 
   @Override
-  String typeName() {
+  protected String typeName() {
     return "LDS";
   }
 
   @Override
-  Class<Listener> unpackedClassName() {
+  protected Class<Listener> unpackedClassName() {
     return Listener.class;
   }
 
   @Override
-  String typeUrl() {
+  protected String typeUrl() {
     return ADS_TYPE_URL_LDS;
   }
 
   @Override
-  boolean isFullStateOfTheWorld() {
+  protected boolean isFullStateOfTheWorld() {
     return true;
   }
 
   @Override
-  LdsUpdate doParse(Args args, Message unpackedMessage)
+  protected LdsUpdate doParse(Args args, Message unpackedMessage)
       throws ResourceInvalidException {
     if (!(unpackedMessage instanceof Listener)) {
       throw new ResourceInvalidException("Invalid message type: " + unpackedMessage.getClass());

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

@@ -21,15 +21,17 @@
 import static io.grpc.xds.XdsClient.ResourceUpdate;
 import static io.grpc.xds.XdsClient.canonifyResourceName;
 import static io.grpc.xds.XdsClient.isResourceNameValid;
-import static io.grpc.xds.XdsClientImpl.ResourceInvalidException;
 
 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;
 import io.envoyproxy.envoy.service.discovery.v3.Resource;
+import io.grpc.ExperimentalApi;
 import io.grpc.LoadBalancerRegistry;
+import io.grpc.xds.Bootstrapper.ServerInfo;
+import io.grpc.xds.XdsClient.ResourceUpdate;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -38,7 +40,8 @@
 import java.util.Set;
 import javax.annotation.Nullable;
 
-abstract class XdsResourceType<T extends ResourceUpdate> {
+@ExperimentalApi("https://github.com/grpc/grpc-java/issues/10847")
+public abstract class XdsResourceType<T extends ResourceUpdate> {
   static final String TYPE_URL_RESOURCE =
       "type.googleapis.com/envoy.service.discovery.v3.Resource";
   static final String TRANSPORT_SOCKET_NAME_TLS = "envoy.transport_sockets.tls";
@@ -68,22 +71,22 @@ abstract class XdsResourceType<T extends ResourceUpdate> {
       "type.googleapis.com/xds.type.v3.TypedStruct";
 
   @Nullable
-  abstract String extractResourceName(Message unpackedResource);
+  protected abstract String extractResourceName(Message unpackedResource);
 
-  abstract Class<? extends com.google.protobuf.Message> unpackedClassName();
+  protected abstract Class<? extends com.google.protobuf.Message> unpackedClassName();
 
-  abstract String typeName();
+  protected abstract String typeName();
 
-  abstract String typeUrl();
+  protected abstract String typeUrl();
 
   // Do not confuse with the SotW approach: it is the mechanism in which the client must specify all
   // resource names it is interested in with each request. Different resource types may behave
   // differently in this approach. For LDS and CDS resources, the server must return all resources
   // that the client has subscribed to in each request. For RDS and EDS, the server may only return
   // the resources that need an update.
-  abstract boolean isFullStateOfTheWorld();
+  protected abstract boolean isFullStateOfTheWorld();
 
-  static class Args {
+  public static class Args {
     final ServerInfo serverInfo;
     final String versionInfo;
     final String nonce;
@@ -114,6 +117,18 @@ public Args(ServerInfo serverInfo, String versionInfo, String nonce,
     }
   }
 
+  public static final class ResourceInvalidException extends Exception {
+    private static final long serialVersionUID = 0L;
+
+    public ResourceInvalidException(String message) {
+      super(message, null, false, false);
+    }
+
+    public ResourceInvalidException(String message, Throwable cause) {
+      super(cause != null ? message + ": " + cause.getMessage() : message, cause, false, false);
+    }
+  }
+
   ValidatedResourceUpdate<T> parse(Args args, List<Any> resources) {
     Map<String, ParsedResource<T>> parsedResources = new HashMap<>(resources.size());
     Set<String> unpackedResources = new HashSet<>(resources.size());
@@ -147,7 +162,7 @@ ValidatedResourceUpdate<T> parse(Args args, List<Any> resources) {
       T resourceUpdate;
       try {
         resourceUpdate = doParse(args, unpackedMessage);
-      } catch (XdsClientImpl.ResourceInvalidException e) {
+      } catch (ResourceInvalidException e) {
         errors.add(String.format("%s response %s '%s' validation error: %s",
                 typeName(), unpackedClassName().getSimpleName(), cname, e.getMessage()));
         invalidResources.add(cname);
@@ -162,7 +177,7 @@ ValidatedResourceUpdate<T> parse(Args args, List<Any> resources) {
 
   }
 
-  abstract T doParse(Args args, Message unpackedMessage) throws ResourceInvalidException;
+  protected abstract T doParse(Args args, Message unpackedMessage) throws ResourceInvalidException;
 
   /**
    * Helper method to unpack serialized {@link com.google.protobuf.Any} message, while replacing

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

@@ -49,7 +49,7 @@
 import io.grpc.xds.VirtualHost.Route.RouteMatch;
 import io.grpc.xds.VirtualHost.Route.RouteMatch.PathMatcher;
 import io.grpc.xds.XdsClient.ResourceUpdate;
-import io.grpc.xds.XdsClientImpl.ResourceInvalidException;
+import io.grpc.xds.XdsResourceType.ResourceInvalidException;
 import io.grpc.xds.XdsRouteConfigureResource.RdsUpdate;
 import io.grpc.xds.internal.MatcherParser;
 import io.grpc.xds.internal.Matchers;
@@ -85,35 +85,35 @@ public static XdsRouteConfigureResource getInstance() {
 
   @Override
   @Nullable
-  String extractResourceName(Message unpackedResource) {
+  protected String extractResourceName(Message unpackedResource) {
     if (!(unpackedResource instanceof RouteConfiguration)) {
       return null;
     }
     return ((RouteConfiguration) unpackedResource).getName();
   }
 
   @Override
-  String typeName() {
+  protected String typeName() {
     return "RDS";
   }
 
   @Override
-  String typeUrl() {
+  protected String typeUrl() {
     return ADS_TYPE_URL_RDS;
   }
 
   @Override
-  boolean isFullStateOfTheWorld() {
+  protected boolean isFullStateOfTheWorld() {
     return false;
   }
 
   @Override
-  Class<RouteConfiguration> unpackedClassName() {
+  protected Class<RouteConfiguration> unpackedClassName() {
     return RouteConfiguration.class;
   }
 
   @Override
-  RdsUpdate doParse(XdsResourceType.Args args, Message unpackedMessage)
+  protected RdsUpdate doParse(XdsResourceType.Args args, Message unpackedMessage)
       throws ResourceInvalidException {
     if (!(unpackedMessage instanceof RouteConfiguration)) {
       throw new ResourceInvalidException("Invalid message type: " + unpackedMessage.getClass());

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

@@ -52,7 +52,7 @@
 import io.grpc.internal.JsonUtil;
 import io.grpc.internal.ServiceConfigUtil;
 import io.grpc.internal.ServiceConfigUtil.LbConfig;
-import io.grpc.xds.XdsClientImpl.ResourceInvalidException;
+import io.grpc.xds.XdsResourceType.ResourceInvalidException;
 import java.util.List;
 import org.junit.After;
 import org.junit.Test;

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

@@ -134,8 +134,8 @@
 import io.grpc.xds.VirtualHost.Route.RouteMatch;
 import io.grpc.xds.VirtualHost.Route.RouteMatch.PathMatcher;
 import io.grpc.xds.WeightedRoundRobinLoadBalancer.WeightedRoundRobinLoadBalancerConfig;
-import io.grpc.xds.XdsClientImpl.ResourceInvalidException;
 import io.grpc.xds.XdsClusterResource.CdsUpdate;
+import io.grpc.xds.XdsResourceType.ResourceInvalidException;
 import io.grpc.xds.XdsResourceType.StructOrError;
 import io.grpc.xds.internal.Matchers;
 import io.grpc.xds.internal.Matchers.FractionMatcher;