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Ubuntu – How to suppress an exception output in python code that is using pyshark?

Running the following python 3.10.12 code on Ubuntu 22.04.4 using pyshark 0.6 seems to ignore the try-except statement of python:

capture = pyshark.FileCapture(filename)
try:
    for packet in capture:
        pass 
except:
    print("exception")

Even I enclosed the reading loop in a try-except statement I get the following output:

exception
Exception ignored in: <function Capture.__del__ at 0x79b5be57c3a0>
Traceback (most recent call last):
  File "/home/alex/.local/lib/python3.10/site-packages/pyshark/capture/capture.py", line 405, in __del__
    self.close()
  File "/home/alex/.local/lib/python3.10/site-packages/pyshark/capture/capture.py", line 393, in close
    self.eventloop.run_until_complete(self.close_async())
  File "/usr/lib/python3.10/asyncio/base_events.py", line 649, in run_until_complete
    return future.result()
  File "/home/alex/.local/lib/python3.10/site-packages/pyshark/capture/capture.py", line 397, in close_async
    await self._cleanup_subprocess(process)
  File "/home/alex/.local/lib/python3.10/site-packages/pyshark/capture/capture.py", line 379, in _cleanup_subprocess
    raise TSharkCrashException(f"TShark (pid {process.pid}) seems to have crashed (retcode: {process.returncode}).n"
pyshark.capture.capture.TSharkCrashException: TShark (pid 8097) seems to have crashed (retcode: 2).
Last error line: tshark: The file "/home/alex/Work/Data/test.pcap" appears to have been cut short in the middle of a packet.
Try rerunning in debug mode [ capture_obj.set_debug() ] or try updating tshark.

How to suppress this output?

To clarify: I am not interested to fix any problem or error. I am just interested into suppressing this output of the exception!

Maybe there is a way to have pyshark ignore errors?
Or I can redirect all error output from pyshark?

Tags:

2

Answers


  1. Chosen as BEST ANSWER
    0

    I think I found a way to suppress this output. First, you have to put the loop and the close statement into a try-except statement:

    capture = pyshark.FileCapture(filename)
try:
    for packet in capture:
        ...
except pyshark.capture.capture.TSharkCrashException:
    pass

try:
    capture.close()
except pyshark.capture.capture.TSharkCrashException:
    pass

    and then at the very end of your code you have to redirect the stderr to /dev/null:

    devnull = open(os.devnull, 'w')
sys.stderr = devnull

    Not sure what is going on, but it seems to work!


  2. 0

    according to the issue: https://github.com/KimiNewt/pyshark/issues/339

    and the source code of pyshark latest version, in here https://github.com/KimiNewt/pyshark/blob/master/src/pyshark/capture/capture.py
    line 366 in _cleanup_subprocess method the code looks like this:

        async def _cleanup_subprocess(self, process):
        """Kill the given process and properly closes any pipes connected to it."""
        self._log.debug(f"Cleanup Subprocess (pid {process.pid})")
        if process.returncode is None:
            try:
                process.kill()
                return await asyncio.wait_for(process.wait(), 1)
            except asyncTimeoutError:
                self._log.debug(
                    "Waiting for process to close failed, may have zombie process.")
            except ProcessLookupError:
                pass
            except OSError:
                if os.name != "nt":
                    raise
        elif process.returncode > 0:
            if process.returncode != 1 or self._eof_reached:
                raise TSharkCrashException(f"TShark (pid {process.pid}) seems to have crashed (retcode: {process.returncode}).n"
                                           f"Last error line: {self._last_error_line}n"
                                           "Try rerunning in debug mode [ capture_obj.set_debug() ] or try updating tshark.")

    what I think is that you are handling the Exception because you are printing the exception in your terminal
    this Exception that raises and you didn’t catch it as occurring after that
    try to closing your capture with:

    capture = pyshark.FileCapture(filename)
try:
    for packet in capture:
        pass 
except:
    print("exception")

capture.close()
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