TypeError: can't pickle _thread.RLock objects

[flappy007]

Hi,
I tried the object detection example and i get below error:
File "c:\continuum\anaconda3\Lib\multiprocessing\reduction.py", line 60, in dump
ForkingPickler(file, protocol).dump(obj)
TypeError: can't pickle _thread.RLock objects

Could you please help. I am running it in windows and anaconda virtual environment

[jadielam]

@flappy007 Do you get the error when running other examples? Have you modified the object detection example in any way? What version of videoflow are you running? And what version of Python? Also, do you have more lines that you could provide on your error dump?

Will look into it.

[flappy007]

Hi @jadielam thanks for your prompt reply. I am using the example object detection.py but i even tried other example but got the same error for each one. Python version: 3.6 anaconda, tensorflow: 1.10.0 opencv: 4.1.0 and the latest version of videoflow pulled from git: 0.2.2. Error below:

fl.run()
File "C:\Continuum\Anaconda3\lib\site-packages\videoflow\core\flow.py", line 86, in run
self._execution_engine.allocate_and_run_tasks(tasks_data)
File "C:\Continuum\Anaconda3\lib\site-packages\videoflow\core\engine.py", line 111, in allocate_and_run_tasks
self._al_create_and_start_processes(tasks_data)
File "C:\Continuum\Anaconda3\lib\site-packages\videoflow\engines\batch.py", line 221, in _al_create_and_start_processes
proc.start()
File "C:\Continuum\Anaconda3\lib\multiprocessing\process.py", line 105, in start
self._popen = self._Popen(self)
File "C:\Continuum\Anaconda3\lib\multiprocessing\context.py", line 223, in _Popen
return _default_context.get_context().Process._Popen(process_obj)
File "C:\Continuum\Anaconda3\lib\multiprocessing\context.py", line 322, in _Popen
return Popen(process_obj)
File "C:\Continuum\Anaconda3\lib\multiprocessing\popen_spawn_win32.py", line 65, in init
reduction.dump(process_obj, to_child)
File "C:\Continuum\Anaconda3\lib\multiprocessing\reduction.py", line 60, in dump
ForkingPickler(file, protocol).dump(obj)
TypeError: can't pickle _thread.RLock objects

[jadielam]

I run a Mac and Python 3.7.2, and I don't get errors on this. First thing I will try to do is create an environment similar to yours with those versions and try to replicate, so that then I can see what's a good fix.

[flappy007]

Hi @jadielam any success on this. I too did run the code in Mac and it did not throw any error. The problem seems to be with windows system and how the process/thread is being pickled.

[jadielam]

I have been able to reproduce error in WIndows. Updating ticket to be a bug. I will see what I can do. I am not very experienced in Windows, but I hope that my Python can carry me far there.

[ociule]

FWIW, the stacktrace looks exactly like https://stackoverflow.com/questions/44144584/typeerror-cant-pickle-thread-lock-objects

So I think the fix suggested over there is worth testing.