When the TCP connection is detected to be broken, all RPCs on that connection are cancelled. This calls context.cancel() <https://grpc.github.io/grpc-java/javadoc/io/grpc/Context.CancellableContext.html#cancel-java.lang.Throwable->. That immediately does two things: changes the boolean that isCancelled() returns and calls/schedules all cancellation listeners (registered via addListener() <https://grpc.github.io/grpc-java/javadoc/io/grpc/Context.html#addListener-io.grpc.Context.CancellationListener-java.util.concurrent.Executor->). So the isCancelled() method is passive.
On Sat, May 4, 2019 at 3:39 AM Isuru Samaraweera <[email protected]> wrote: > Hi Carl, > So when you enable keep alive with 5 mins and 10 second keepalivetimeout > connection will be checked for activeness and if time out elapsed it will > be closed. Thats clear..So whats happening when you say > Context.current().isCancelled()??Does it do ping internally ?How it is > done? > Because when network cable is unplugged from server > Context.current().isCancelled() takes sometime to detect cable > detachment(like 1-2 seconds).When I delay main thread by Thread.sleep(500) > I can reduce data stream loss which is fine in my case.My question is on > how Context.current().isCancelled() is implemented??Is it doing a real > time ping or listening to a flag set by another thread? > > Thanks > Isuru > > On Thu, May 2, 2019 at 10:44 PM 'Carl Mastrangelo' via grpc.io < > [email protected]> wrote: > >> You can turn on keep alives on the channel / server builder, but that's >> about the best you can do. The problem is that a broken connection just >> means silence. You can't tell the difference between the packets taking a >> long time, and the the packets not arriving. Keep-alives let you check the >> connection is still active, and close it after a time out (like 10s). >> >> On Tuesday, April 30, 2019 at 9:10:22 AM UTC-7, Isuru Samaraweera wrote: >>> >>> Hi All, >>> I am using grpc java with serverside streaming.In the grpc server side >>> streaming service I am doing streaming such as below to detect stream >>> cancellations due to network errors. >>> >>> while(true) { >>> if(Context.current().isCancelled()) { >>> responseObserver.onNext(response) >>> } else break; >>> >>> The issue is when I disconnect the client still onNext invokes around >>> 100 times before network failure is detected by >>> Context.current().isCancelled(). >>> >>> To prevent this I did as below. >>> while(true) { >>> Thread.sleep(500) >>> if(Context.current().isCancelled()) { >>> responseObserver.onNext(response) >>> } else break; >>> >>> Now it seems isCancelled is detected before onNext is called when >>> network between client and server is disrupted.This implies cancel=true is >>> updated by a separate thread apart from main thread?? >>> >>> >>> Is there any better way of doing this using GRPC Java? >>> >>> Thanks >>> Isuru >>> >>> >>> >>> >>> >>> -- >> You received this message because you are subscribed to the Google Groups >> "grpc.io" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To post to this group, send email to [email protected]. >> Visit this group at https://groups.google.com/group/grpc-io. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/grpc-io/4dc517ad-195c-420f-9f7a-4e73aa78b659%40googlegroups.com >> <https://groups.google.com/d/msgid/grpc-io/4dc517ad-195c-420f-9f7a-4e73aa78b659%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> For more options, visit https://groups.google.com/d/optout. >> > > > -- > Isuru Samaraweera > > -- > You received this message because you are subscribed to the Google Groups " > grpc.io" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at https://groups.google.com/group/grpc-io. > To view this discussion on the web visit > https://groups.google.com/d/msgid/grpc-io/CAOtGh-rYyqWaKPLxyEyS9xXQOhyP0P8FS1MwyibO8Ke-VbXDiQ%40mail.gmail.com > <https://groups.google.com/d/msgid/grpc-io/CAOtGh-rYyqWaKPLxyEyS9xXQOhyP0P8FS1MwyibO8Ke-VbXDiQ%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "grpc.io" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/grpc-io. To view this discussion on the web visit https://groups.google.com/d/msgid/grpc-io/CA%2B4M1oMyLxtp%3Dj0u1G5cbnL_6%3DbUPOvViNejhGWHxr6VRFivRw%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
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