xds: Fix XDS control plane client retry timer backoff duration when connection closes after results are received (#11766)

larry-safran · web-flow · commit ef7c2d59c1c9 · 2024-12-19T14:46:58.000-08:00
* Fix retry timer backoff duration.

* Reset stopwatch when we had results on AdsStream rather than change the delay calculation logic.
diff --git a/xds/src/main/java/io/grpc/xds/client/ControlPlaneClient.java b/xds/src/main/java/io/grpc/xds/client/ControlPlaneClient.java
@@ -446,6 +446,7 @@ private void handleRpcStreamClosed(Status status) {
         // Reset the backoff sequence if had received a response, or backoff sequence
         // has never been initialized.
         retryBackoffPolicy = backoffPolicyProvider.get();
+        stopwatch.reset();
       }
 
       // FakeClock in tests isn't thread-safe. Schedule the retry timer before notifying callbacks
diff --git a/xds/src/test/java/io/grpc/xds/GrpcXdsClientImplTestBase.java b/xds/src/test/java/io/grpc/xds/GrpcXdsClientImplTestBase.java
@@ -3524,6 +3524,7 @@ public void streamClosedAndRetryWithBackoff() {
     call.verifyRequest(EDS, EDS_RESOURCE, "", "", NODE);
 
     // Management server closes the RPC stream with an error.
+    fakeClock.forwardNanos(1000L); // Make sure retry isn't based on stopwatch 0
     call.sendError(Status.UNKNOWN.asException());
     verify(ldsResourceWatcher, Mockito.timeout(1000).times(1))
         .onError(errorCaptor.capture());

Original file line number	Diff line number	Diff line change
`@@ -446,6 +446,7 @@ private void handleRpcStreamClosed(Status status) {`
`446`	`446`	`// Reset the backoff sequence if had received a response, or backoff sequence`
`447`	`447`	`// has never been initialized.`
`448`	`448`	`retryBackoffPolicy = backoffPolicyProvider.get();`
	`449`	`+ stopwatch.reset();`
`449`	`450`	`}`
`450`	`451`
`451`	`452`	`// FakeClock in tests isn't thread-safe. Schedule the retry timer before notifying callbacks`