ServerCall#close(Status, Metadata) never called for client-cancelled calls #7571
Description
What version of gRPC-Java are you using?
- 1.33.0
- also affects previous versions
What is your environment?
- Windows 10 x64
- Java 11 x64
What do you wish to achieve
I wish to report the request count/duration including the result status (including CANCELLED ones).
https://github.com/yidongnan/grpc-spring-boot-starter/blob/master/grpc-server-spring-boot-autoconfigure/src/main/java/net/devh/boot/grpc/server/metric/MetricCollectingServerCall.java#L63
See also:
https://github.com/yidongnan/grpc-spring-boot-starter/issues/438
What did you expect to see?
No error in the attached test / ServerCall#close(Status, Metadata) should have been called with status Status.Code.CANCELLED.
What did you see instead?
org.opentest4j.AssertionFailedError: Call closed ==> expected: <true> but was: <false>Which might lead to a memory leak if a resource is attached to the ServerCall instead of the ServerCall.Listener.
Steps to reproduce the bug
class CloseTest extends SimpleGrpc.SimpleImplBase implements ServerInterceptor {
private boolean callClosed = false;
private boolean listenerClosed = false;
@Test
void testCallClosed() throws IOException, InterruptedException, ExecutionException {
final Server server = InProcessServerBuilder.forName("self")
.addService(ServerInterceptors.intercept(this, this))
.build();
server.start();
final ManagedChannel channel = InProcessChannelBuilder.forName("self")
.usePlaintext()
.build();
final SimpleStub stub = SimpleGrpc.newStub(channel);
final CountDownLatch counter = new CountDownLatch(1);
final AtomicReference<Throwable> error = new AtomicReference<>();
final ClientCallStreamObserver<Message> observer = (ClientCallStreamObserver<Message>) stub
.echo(new StreamObserver<Message>() {
@Override
public void onNext(final Message value) {
// Do nothing
}
@Override
public void onError(final Throwable t) {
error.set(t);
counter.countDown();
}
@Override
public void onCompleted() {
counter.countDown();
}
});
observer.cancel("Cancelled", null);
counter.await();
assertNotNull(error.get());
assertEquals(Code.CANCELLED, ((StatusRuntimeException) error.get()).getStatus().getCode());
assertTrue(this.listenerClosed, "Listener closed");
assertTrue(this.callClosed, "Call closed"); // <-- BOOM
channel.shutdown();
server.shutdown();
}
@Override
public StreamObserver<Message> echo(final StreamObserver<Message> responseObserver) {
return responseObserver;
}
@Override
public <ReqT, RespT> Listener<ReqT> interceptCall(final ServerCall<ReqT, RespT> call, final Metadata headers,
final ServerCallHandler<ReqT, RespT> next) {
final ServerCall<ReqT, RespT> metricsCall = new SimpleForwardingServerCall<>(call) {
@Override
public void close(final Status status, final Metadata trailers) {
CloseTest.this.callClosed = true;
super.close(status, trailers);
}
};
return new SimpleForwardingServerCallListener<>(next.startCall(metricsCall, headers)) {
public void onCancel() {
CloseTest.this.listenerClosed = true;
super.onCancel();
}
};
}
}syntax = "proto3";
option java_multiple_files = true;
option java_package = "test";
option java_outer_classname = "SimpleProto";
service Simple {
rpc echo(stream Message) returns (stream Message) {}
}
message Message {
string text = 1;
}Possible workarounds
- Add a custom cancel method to the
ServerCalland call it from theListener#onCancelled - Use the GrpcContext#addCancellationListener to mark the call as cancelled (not tested)
Expected changes
ServerCall#closeis also called for (client-side) cancellations.
or
ServerCall#close's documentation is amended stating that it won't be called for (client-side) cancellations and other client errors such as connection loss/timeout(?).