Add watchAllResource subscriber (#1020)

CHANGELOG.md

@@ -14,6 +14,9 @@ and what APIs have changed, if applicable.
 
 ## [Unreleased]
 
+## [29.58.7] - 2024-09-13
+- Add WildcardResourceSubscriber which could subscribe to all resources, like NODE and URIMap resources.
+
 ## [29.58.6] - 2024-09-08
 - Allow for null paging inside Collection response envelopes
 
@@ -5728,7 +5731,8 @@ patch operations can re-use these classes for generating patch messages.
 
 ## [0.14.1]
 
-[Unreleased]: https://github.com/linkedin/rest.li/compare/v29.58.6...master
+[Unreleased]: https://github.com/linkedin/rest.li/compare/v29.58.7...master
+[29.58.7]: https://github.com/linkedin/rest.li/compare/v29.58.6...v29.58.7
 [29.58.6]: https://github.com/linkedin/rest.li/compare/v29.58.5...v29.58.6
 [29.58.5]: https://github.com/linkedin/rest.li/compare/v29.58.4...v29.58.5
 [29.58.4]: https://github.com/linkedin/rest.li/compare/v29.58.3...v29.58.4

d2/src/main/java/com/linkedin/d2/xds/XdsClient.java

@@ -95,6 +95,91 @@ final void onChanged(ResourceUpdate update)
     }
   }
 
+  public static abstract class WildcardResourceWatcher
+  {
+    private final ResourceType _type;
+
+    /**
+     * Defining a private constructor means only classes that are defined in this file can extend this class (see
+     * {@link ResourceWatcher}).
+     */
+    WildcardResourceWatcher(ResourceType type)
+    {
+      _type = type;
+    }
+
+    final ResourceType getType()
+    {
+      return _type;
+    }
+
+    /**
+     * Called when the resource discovery RPC encounters some transient error.
+     */
+    public abstract void onError(Status error);
+
+    /**
+     * Called when the resource discovery RPC reestablishes connection.
+     */
+    public abstract void onReconnect();
+
+    /**
+     * Called when a resource is added or updated.
+     * @param resourceName the name of the resource that was added or updated.
+     * @param update       the new data {@link ResourceUpdate} for the resource.
+     */
+    abstract void onChanged(String resourceName, ResourceUpdate update);
+
+    /**
+     * Called when a resource is removed.
+     * @param resourceName the name of the resource that was removed.
+     */
+    public abstract void onRemoval(String resourceName);
+  }
+
+  public static abstract class WildcardNodeResourceWatcher extends WildcardResourceWatcher
+  {
+    public WildcardNodeResourceWatcher()
+    {
+      super(ResourceType.NODE);
+    }
+
+    /**
+     * Called when a node resource is added or updated.
+     * @param resourceName the resource name of the {@link NodeUpdate} that was added or updated.
+     * @param update       the new data for the {@link NodeUpdate}, including D2 cluster and service information.
+     */
+    public abstract void onChanged(String resourceName, NodeUpdate update);
+
+    @Override
+    final void onChanged(String resourceName, ResourceUpdate update)
+    {
+      onChanged(resourceName, (NodeUpdate) update);
+    }
+  }
+
+  public static abstract class WildcardD2URIMapResourceWatcher extends WildcardResourceWatcher
+  {
+    public WildcardD2URIMapResourceWatcher()
+    {
+      super(ResourceType.D2_URI_MAP);
+    }
+
+    /**
+     * Called when a {@link D2URIMapUpdate} resource is added or updated.
+     * @param resourceName the resource name of the {@link D2URIMapUpdate} map resource that was added or updated.
+     *                     like the /d2/uris/clusterName
+     * @param update       the new data for the {@link D2URIMapUpdate} resource
+     */
+    public abstract void onChanged(String resourceName, D2URIMapUpdate update);
+
+    @Override
+    final void onChanged(String resourceName, ResourceUpdate update)
+    {
+      onChanged(resourceName, (D2URIMapUpdate) update);
+    }
+  }
+
   public interface ResourceUpdate
   {
     boolean isValid();
@@ -109,7 +194,7 @@ public static final class NodeUpdate implements ResourceUpdate
       _nodeData = nodeData;
     }
 
-    XdsD2.Node getNodeData()
+    public XdsD2.Node getNodeData()
     {
       return _nodeData;
     }
@@ -261,13 +346,32 @@ static ResourceType fromTypeUrl(String typeUrl)
    * will always notify the given watcher of the current data if it is already present, even if the given watcher was
    * already subscribed to said resource. However, the subscription will only be added once.
    */
-  abstract void watchXdsResource(String resourceName, ResourceWatcher watcher);
+  public abstract void watchXdsResource(String resourceName, ResourceWatcher watcher);
 
-  abstract void startRpcStream();
+  /**
+   * Subscribes the given {@link WildcardResourceWatcher} to all the resources of the corresponding type. The watcher
+   * will be notified whenever a resource is added or removed. Repeated calls to this function with the same watcher
+   * will always notify the given watcher of the current data.
+   */
+  public abstract void watchAllXdsResources(WildcardResourceWatcher watcher);
 
-  abstract void shutdown();
+  /**
+   * Initiates the RPC stream to the xDS server.
+   */
+  public abstract void startRpcStream();
+
+  /**
+   * Shuts down the xDS client.
+   */
+  public abstract void shutdown();
 
-  abstract String getXdsServerAuthority();
+  /**
+   * Returns the authority of the xDS server.
+   */
+  public abstract String getXdsServerAuthority();
 
-  abstract public XdsClientJmx getXdsClientJmx();
+  /**
+   * Returns the JMX bean for the xDS client.
+   */
+  public abstract XdsClientJmx getXdsClientJmx();
 }