Edge case when handling KeyboardInterrupt module shutdown

[thclark]

Bug report

What is the current behavior?

Pressing ctrl+c on the raspberry pi during acquisition usually results in a safe shutdown.

However, I noticed that sometimes I have the following traceback in the middle:

 $ gateway start
/home/pi/.cache/pypoetry/virtualenvs/data-gateway-lz7aa1yn-py3.7/lib/python3.7/site-packages/google_crc32c/__init__.py:29: RuntimeWarning: As the c extension couldn't be imported, `google-crc32c` is using a pure python implementation that is significantly slower. If possible, please configure a c build environment and compile the extension
  warnings.warn(_SLOW_CRC32C_WARNING, RuntimeWarning)
[2022-06-09 14:29:20,591 | INFO | multiprocessing | MainProcess] No configuration file provided - using default configuration.
[2022-06-09 14:29:20,693 | WARNING | multiprocessing | MainProcess] No routine was provided and interactive mode is off - no commands will be sent to the sensors in this session.
[2022-06-09 14:29:20,705 | INFO | multiprocessing | MainProcess] allocating a new mmap of length 4096
[2022-06-09 14:29:20,718 | INFO | multiprocessing | Reader] child process calling self.run()
[2022-06-09 14:29:20,719 | INFO | multiprocessing | Reader] Packet reader process started.
[2022-06-09 14:29:20,725 | INFO | multiprocessing | Parser] child process calling self.run()
[2022-06-09 14:29:20,726 | INFO | multiprocessing | Parser] Packet parser process started.
[2022-06-09 14:29:20,751 | INFO | multiprocessing | Parser] Windows will be saved to 'data_gateway/661014/.backup' at intervals of 600.0 seconds.
[2022-06-09 14:29:20,751 | INFO | multiprocessing | Parser] Windows will be uploaded to 'data_gateway/661014' at intervals of 600.0 seconds.
^C[2022-06-09 14:29:53,966 | INFO | multiprocessing | Reader] Stopping gateway.
[2022-06-09 14:29:53,967 | INFO | multiprocessing | Reader] process shutting down
[2022-06-09 14:29:53,968 | INFO | multiprocessing | Reader] process exiting with exitcode 0
[2022-06-09 14:29:53,967 | INFO | multiprocessing | MainProcess] Sent 'stopBaros' command to sensors.
[2022-06-09 14:29:53,967 | ERROR | multiprocessing | Parser] expected str, bytes or os.PathLike object, not NoneType
Traceback (most recent call last):
  File "/home/pi/aerosense/install/data-gateway/data_gateway/packet_reader.py", line 169, in parse_packets
    packet_type, packet = packet_queue.get(timeout=timeout).values()
  File "/usr/lib/python3.7/multiprocessing/queues.py", line 104, in get
    if not self._poll(timeout):
  File "/usr/lib/python3.7/multiprocessing/connection.py", line 257, in poll
    return self._poll(timeout)
  File "/usr/lib/python3.7/multiprocessing/connection.py", line 414, in _poll
    r = wait([self], timeout)
  File "/usr/lib/python3.7/multiprocessing/connection.py", line 920, in wait
    ready = selector.select(timeout)
  File "/usr/lib/python3.7/selectors.py", line 415, in select
    fd_event_list = self._selector.poll(timeout)
KeyboardInterrupt

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/pi/aerosense/install/data-gateway/data_gateway/persistence.py", line 255, in _persist_window
    cloud_path=storage.path.generate_gs_path(self.bucket_name, self._generate_window_path()),
  File "/home/pi/.cache/pypoetry/virtualenvs/data-gateway-lz7aa1yn-py3.7/lib/python3.7/site-packages/octue/cloud/storage/path.py", line 63, in generate_gs_path
    return CLOUD_STORAGE_PROTOCOL + join(bucket_name, paths[0].lstrip("/"), *paths[1:])
  File "/home/pi/.cache/pypoetry/virtualenvs/data-gateway-lz7aa1yn-py3.7/lib/python3.7/site-packages/octue/cloud/storage/path.py", line 45, in join
    path = os.path.normpath(os.path.join(*paths)).replace("\\", "/")
  File "/usr/lib/python3.7/posixpath.py", line 80, in join
    a = os.fspath(a)
TypeError: expected str, bytes or os.PathLike object, not NoneType
[2022-06-09 14:29:54,005 | WARNING | multiprocessing | Parser] Upload of window may have failed - writing to disk at 'data_gateway/661014/.backup/window-0.json'.
[2022-06-09 14:29:54,009 | INFO | multiprocessing | Parser] Window 0 written to disk.
[2022-06-09 14:29:54,011 | INFO | multiprocessing | Parser] Stopping gateway.
[2022-06-09 14:29:54,012 | INFO | multiprocessing | Parser] process shutting down
[2022-06-09 14:29:54,014 | INFO | multiprocessing | Parser] process exiting with exitcode 0
[2022-06-09 14:29:58,977 | INFO | multiprocessing | MainProcess] Sent 'stopDiffBaros' command to sensors.
[2022-06-09 14:30:03,983 | INFO | multiprocessing | MainProcess] Sent 'stopIMU' command to sensors.
[2022-06-09 14:30:08,989 | INFO | multiprocessing | MainProcess] Sent 'stopMics' command to sensors.

What is the expected behavior?

KeyboardInterrupt shuts down with no exception

Your environment

• Library Version: about 0.11.11 at this commit
• Platform MacOS | RPi