I've looked into the source and now I can see why it happens. I think it's
a bug so filed an issue with exact description what should be fixed:
https://github.com/grpc/grpc-java/issues/8409
On Monday, August 16, 2021 at 5:42:50 PM UTC+7 Piotr Morgwai Kotarbinski
wrote:
> Hi all,
> I have a simplest possible server-streaming method:
>
> service CancelService {
> rpc fun(Empty) returns (stream Empty) {}
> }
>
> an implementation that sleeps for 1s and then sends reply:
>
> public class CancelService extends CancelServiceImplBase {
>
> @Override
> public void fun(Empty request, StreamObserver<Empty>
> basicResponseObserver) {
> final var responseObserver = (ServerCallStreamObserver<Empty>)
> basicResponseObserver;
> try {
> Thread.sleep(1000l); // longer than client's deadline
> System.out.println("isCancelled: " + responseObserver.isCancelled());
> responseObserver.onNext(request);
> responseObserver.onCompleted();
> System.out.println("completed successfully");
> } catch (StatusRuntimeException e) {
> System.out.println("StatusRuntimeException" + e);
> } catch (Throwable t) {
> System.out.println("server error" + t);
> responseObserver.onError(Status.INTERNAL.withCause(t).asException());
> if (t instanceof Error) throw (Error) t;
> }
> }
>
> public static void main(String[] args) throws Exception {
> final Server server = NettyServerBuilder
> .forPort(6666)
> .addService(new CancelService())
> .build()
> .start();
> Runtime.getRuntime().addShutdownHook(new Thread(() -> {
> try { server.shutdown().awaitTermination(5, TimeUnit.SECONDS); } catch
> (Exception e) {}
> }));
> System.out.println("server started");
> server.awaitTermination();
> }
> }
>
> and a client that sets deadline to 0.5s:
>
> public static void main(String[] args) throws Exception {
> final var channel = ManagedChannelBuilder
> .forTarget("localhost:6666")
> .usePlaintext()
> .build();
> final var connector = CancelServiceGrpc.newBlockingStub(channel)
> .withDeadlineAfter(500l, TimeUnit.MILLISECONDS);
> final var results = connector.fun(Empty.newBuilder().build());
> while (results.hasNext()) {
> System.out.println("got result: " + results.next());
> }
> System.out.println("call successful");
> }
>
> when run, on the client side I get an excp as expected:
>
> Exception in thread "main" io.grpc.StatusRuntimeException:
> DEADLINE_EXCEEDED: deadline exceeded (...)
>
> on the server however, responseObserver.isCancelled() returns true but
> StatusRuntimeException is not thrown when calling onNext(...) and
> onCompleted() and call finishes as normal:
>
> server started
> isCancelled: true
> completed successfully
>
> is this an expected behavior? I thought StatusRuntimeException with
> Status.CANCELLED should be thrown, no? (unless onCancelHandler is set,
> which is not the case here)
>
> To make things more confusing, if I dispatch work in fun(...) to some
> executor like this:
>
> ThreadPoolExecutor executor =
> new ThreadPoolExecutor(3, 3, 0, TimeUnit.DAYS, new
> LinkedBlockingQueue<>());
>
> @Override
> public void fun(Empty request, StreamObserver<Empty>
> basicResponseObserver) {
> final var responseObserver = (ServerCallStreamObserver<Empty>)
> basicResponseObserver;
> executor.execute(() -> {
> try {
> Thread.sleep(1000l); // longer than client's deadline
> System.out.println("isCancelled: " + responseObserver.isCancelled());
> responseObserver.onNext(request);
> responseObserver.onCompleted();
> System.out.println("completed successfully");
> } catch (StatusRuntimeException e) {
> System.out.println("StatusRuntimeException" + e);
> } catch (Throwable t) {
> System.out.println("server error" + t);
> responseObserver.onError(Status.INTERNAL.withCause(t).asException());
> if (t instanceof Error) throw (Error) t;
> }
> });
> }
>
>
> then I do get a StatusRuntimeException:
>
> server started
> isCancelled: true
> StatusRuntimeExceptionio.grpc.StatusRuntimeException: CANCELLED: call
> already cancelled. Use ServerCallStreamObserver.setOnCancelHandler() to
> disable this exception
>
> Shouldn't the behavior be consistent in both of these cases?
>
> Thanks!
>
>
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