Fixed Resource timer and cache issue

packages/grpc-js-xds/src/xds-client.ts

@@ -150,6 +150,7 @@ class ResourceTimer {
     if (!resourceState) {
       return;
     }
+    resourceState.cachedResource = null;
     resourceState.meta.clientStatus = 'DOES_NOT_EXIST';
     for (const watcher of resourceState.watchers) {
       watcher.onResourceDoesNotExist();
@@ -372,6 +373,7 @@ class AdsCallState {
                 experimental.log(logVerbosity.ERROR, 'Ignoring nonexistent resource ' + xdsResourceNameToString({authority, key}, result.type!.getTypeUrl()));
                 resourceState.deletionIgnored = true;
               } else {
+                resourceState.cachedResource = null;
                 resourceState.meta.clientStatus = 'DOES_NOT_EXIST';
                 process.nextTick(() => {
                   for (const watcher of resourceState.watchers) {
@@ -404,6 +406,13 @@ class AdsCallState {
     this.trace(
       'ADS stream ended. code=' + streamStatus.code + ' details= ' + streamStatus.details
     );
+    for (const typeState of this.typeStates.values()) {
+      for (const authorityMap of typeState.subscribedResources.values()) {
+        for (const timer of authorityMap.values()) {
+          timer.maybeCancelTimer();
+        }
+      }
+    }
     if (streamStatus.code !== status.OK && !this.receivedAnyResponse) {
       for (const watcher of this.allWatchers()) {
         watcher.onError(streamStatus);
@@ -458,6 +467,7 @@ class AdsCallState {
     if (!authorityMap) {
       return;
     }
+    authorityMap.get(name.key)?.maybeCancelTimer();
     authorityMap.delete(name.key);
     if (authorityMap.size === 0) {
       typeState.subscribedResources.delete(name.authority);
@@ -937,6 +947,9 @@ class XdsSingleServerClient {
     const metadata = new Metadata({waitForReady: true});
     const call = this.adsClient.StreamAggregatedResources(metadata);
     this.adsCallState = new AdsCallState(this, call, this.xdsClient.adsNode!);
+    if (this.adsClient.getChannel().getConnectivityState(false) === connectivityState.READY) {
+      this.adsCallState.markStreamStarted();
+    }
     this.adsBackoff.runOnce();
   }
 

packages/grpc-js-xds/test/test-core.ts

@@ -197,5 +197,47 @@ describe('core xDS functionality', () => {
     xdsServer.setRdsResource(routeGroup2.getRouteConfiguration());
     await cluster2.waitForAllBackendsToReceiveTraffic();
     client.stopCalls();
-  })
+  });
+  it('should recover when a deleted LDS resource is restored with identical content', async () => {
+    const [backend] = await createBackends(1);
+    const serverRoute = new FakeServerRoute(backend.getPort(), 'serverRoute');
+    xdsServer.setRdsResource(serverRoute.getRouteConfiguration());
+    xdsServer.setLdsResource(serverRoute.getListener());
+    xdsServer.addResponseListener((typeUrl, responseState) => {
+      if (responseState.state === 'NACKED') {
+        client?.stopCalls();
+        assert.fail(`Client NACKED ${typeUrl} resource with message ${responseState.errorMessage}`);
+      }
+    });
+    const cluster = new FakeEdsCluster('cluster1', 'endpoint1', [{backends: [backend], locality: {region: 'region1'}}]);
+    const routeGroup = new FakeRouteGroup('listener1', 'route1', [{cluster: cluster}]);
+    await routeGroup.startAllBackends(xdsServer);
+    xdsServer.setEdsResource(cluster.getEndpointConfig());
+    xdsServer.setCdsResource(cluster.getClusterConfig());
+    xdsServer.setRdsResource(routeGroup.getRouteConfiguration());
+    xdsServer.setLdsResource(routeGroup.getListener());
+    client = XdsTestClient.createFromServer('listener1', xdsServer);
+    client.startCalls(100);
+    await routeGroup.waitForAllBackendsToReceiveTraffic();
+    client.stopCalls();
+
+    // Trigger transient LDS deletion (control plane flap)
+    xdsServer.unsetLdsResource('listener1');
+
+    // Verify call fails while resource is deleted
+    await new Promise<void>((resolve) => {
+      client.sendOneCall((error) => {
+        assert(error, 'Expected RPC to fail after LDS deletion');
+        resolve();
+      });
+    });
+
+    // Restore identical LDS resource
+    xdsServer.setLdsResource(routeGroup.getListener());
+
+    // Verify client recovers and traffic flows normally
+    client.startCalls(100);
+    await routeGroup.waitForAllBackendsToReceiveTraffic();
+    client.stopCalls();
+  });
 });