Spyder IDE; resetting IPython console state due to weird logging issue

Question

In one of the scripts logging is set up like so:

logging configuration - two handlers
logger = logging.getLogger()
logger.setLevel(logging.DEBUG)
fh = logging.FileHandler('logfile')
fh.setLevel(logging.DEBUG)
ch = logging.StreamHandler()
ch.setLevel(logging.ERROR)
formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
fh.setFormatter(formatter)
ch.setFormatter(formatter)
logger.addHandler(fh)
logger.addHandler(ch)

Pretty usual logger, right? Sure, yet it causes Spyder's IPython console to behave in a weird way.

Each subsequent script launch (Spyder's 'Run' through internal IPython console) increments the number of times each one of the log messages is being logged, ie the second time the script is launched the message appears twice, third time three times and so on.

2018-12-06 17:03:44,888 - root - DEBUG - Start.
2018-12-06 17:03:44,891 - root - DEBUG - Exit.
2018-12-06 17:03:45,982 - root - DEBUG - Start.
2018-12-06 17:03:45,982 - root - DEBUG - Start.
2018-12-06 17:03:45,984 - root - DEBUG - Exit.
2018-12-06 17:03:45,984 - root - DEBUG - Exit.
2018-12-06 17:03:49,739 - root - DEBUG - Start.
2018-12-06 17:03:49,739 - root - DEBUG - Start.
2018-12-06 17:03:49,739 - root - DEBUG - Start.
2018-12-06 17:03:49,742 - root - DEBUG - Exit.
2018-12-06 17:03:49,742 - root - DEBUG - Exit.
2018-12-06 17:03:49,742 - root - DEBUG - Exit.

Restarting the IPython's kernel or spanning a new console instance resets this behaviour. 'Resetting variables' seems to have no effect on this, should it?

I think new instances of 'fileHandlers' are added to the 'logger' object on each subsequent launch. Note exact same timestamp on each of the duplicate log entries.

Any ideas how to avoid / fix this?

Answer 1

I think a new instance of 'fileHandler' is added to the 'logger' object on each subsequent launch

Yes, I think that's right. To avoid this, you can detect if fh and ch are already defined, so you don't redefine them and add them to logging on each run.

For that you could add a code like this:

from IPython import get_ipython

if not 'fh' in get_ipython().user_ns:
    fh = logging.FileHandler('logfile')
    fh.setLevel(logging.DEBUG)
    ...

and the same for ch .