mod_aws_transcribe locks when calls is destroyed before transcription is stopped about drachtio-freeswitch-modules HOT 3 CLOSED

The issue seems to be that the processData() function, which is running in the thread created to process responses from aws for that call, does not exit. I think to troubleshoot I suggest adding some more logging there.

Specifically, I wonder about this if condition

If that is not true -- if switch_core_session_locate(m_sessionId.c_str()); returns null, meaning the session is gone, I think we should add a log message so we can see that.

This log message:

stream got final response

Is the event that should cause the processData function to exit, and the thread to therefore end.

So if that is happening (I'm not sure it is) then we won't hit this code below in that if condition

				std::lock_guard<std::mutex> lk(m_mutex);
				m_finished = true;
				m_cond.notify_one();

				switch_core_session_rwunlock(psession);

That setting of the condition is what "wakes up" the processData() here:

		while (true) {
			std::unique_lock<std::mutex> lk(m_mutex);
			m_cond.wait(lk, [&, this] { 
				return (!m_deqAudio.empty() && !m_finishing)  || m_transcript.TranscriptHasBeenSet() || m_finished  || (m_finishing && !shutdownInitiated);
			});

Therefore, that thread may block there, waiting for a condition that never happens.

Just an idea, but try adding that logging to get further.

So...to summarize this theory:

1. The session ends, as part of that we call m_pStream->close() at line 272
2. This in turn causes AWS to complete transcribing and invoke OnResponseCallback
3. In OnResponseCallback the call to switch_core_session_locate(m_sessionId.c_str()); fails because the session is gone
4. Therefore no condition is raised and processData() blocks forever in its while loop

Please investigate when you have time @byoungdale and let me know what you think

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Yes, thank you. Just saw this. The psession is gone, I had checked that. So, I added this else to the if (psession) { block:

				} else {
					switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "GStreamer %p session is closed/hungup. Need to unblock thread.\n", this);
					std::lock_guard<std::mutex> lk(m_mutex);
					m_finished = true;
					m_cond.notify_one();
				}

and it unblocks processData's loop, I see the await ep.destroy() finishing, and I don't see the zombie call anymore.

But, does onResponseCallback only run when the transcription stream is finished? I'm having trouble finding AWS C++ SDK documentation that references onResponseCallback.

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Ah, I see onResponseCallback is passed to StartStreamTranscriptionAsync.

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