Heartbeat does not respond to timeout while waiting for a response from the server

[IstominP]

If heartbeat is waiting for a response from the server and the response did not come within the allotted time, then we must kill the session because the server is not responding, in which case the lack of response to waiting for a response in org.apache.sshd.client.session.ClientConnectionService#sendHeartBeat looks like wrong behavior.

Should we do something like
if (!replyReceived.await(toWait, TimeUnit.MILLISECONDS)) { throw new TimeoutException("No response from server"); }
when waiting response on heartbeat request

Am I understanding heartbeat logic correctly?

[tomaswolf]

Looks like you've found a bug. Indeed we neglect to deal with the return value of the await() call. On second thought, I have the impression this change in this class should just be rolled back. It has no benefit at all.

[Brikman]

@tomaswolf can you explain in more detail please?

Did I understand correctly that you are proposing to roll back and generally refuse to wait for a response to a heartbeat?

Are there any disadvantages or fundamental errors in the solution proposed by @robober? Is it correct in principle to wait response to every heartbeat?

[tomaswolf]

proposing to roll back

Yes.

and generally refuse to wait for a response to a heartbeat?

No. Seems to me that rolling back would use the synchronous session.request() method (again), which does wait for the response and which does throw a SocketTimeoutException if a timeout occurs. If that is correct, then rolling back would be the preferred solution since it simplifies the code quite a bit.

Are there any disadvantages or fundamental errors in the solution proposed by @robober?

No. But looking back at this code, I don't see anymore why I even changed it. Using the asynchronous global request but then waiting on the latch is still blocking of course. But heartbeats are sent from separate threads anyway, so this doesn't block an I/O thread.

[Brikman]

Thank you for explanation.

In this case, we will use our modified heartbeat for a while, waiting for fix in library.