Cannot get jupyter notebook to log to a file

Question

I haven't been able to find a solution to this problem elsewhere, even though it seems it should be a common one.

import logging
logging.basicConfig(filename='logs.log', level=logging.INFO)

logging.info('something happened')

I want to create and write to the log file, but instead it displays the messages in the notebook output cell.

score 12 · Accepted Answer · answered Dec 28 '17 at 10:42

12

Solved: the root of the problem was the fact that subsequent calls to logging.basicConfig do nothing, only the first call affects the basic config of the root handler. So nothing worked until I restarted the kernel in my notebook or something.

answered Dec 28 '17 at 10:42

jsstuball

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This is the right answer – Yanghoon Nov 24 '21 at 00:08
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Add force=True to basicConfig() and it will not require a restart of the kernel anymore. Apparently level=... is not really needed. – Florin Andrei Sep 01 '22 at 03:32
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Note that the force=True addition was made with python 3.8, so make sure you update to that if you want/need to use it. – Matthijs Kramer Sep 21 '22 at 09:37

srikavineehari · Answer 2 · 2017-12-28T07:21:28.360

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I've just tried your code in Jupyter Notebook. It ran just fine. I'm using Python 3.6 and this is on Windows 10:

In [1]: import logging

        logging.basicConfig(filename='logs.log', level=logging.INFO)

        logging.info('something happened')

In [2]: with open("logs.log") as log:
            print(log.read())

        INFO:root:something happened

edited Dec 28 '17 at 07:21

answered Dec 28 '17 at 07:03

srikavineehari

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Where did your file logs.log get created? In my case the notebook just outputs the logs in the cell below the code and no file is created (unless it is doing both and I cannot find it) – jsstuball Dec 28 '17 at 07:13
@JSStuball, the file got created in my current directory. – srikavineehari Dec 28 '17 at 07:16
As you can see in the image, that was the second time I logged to the file. – srikavineehari Dec 28 '17 at 07:24

Christian Sauer · Answer 3 · 2017-12-28T06:49:04.783

Logging in Python is surprisingly difficult to configure - imo one of the worst libraries in the python universe. You might try the package logbook, which claims to have a better experience.

M.e. you are missing a call like this:

logger = logging.getlogger("mymodile")
logger.info("blub")

Sorry, I first ignored the bit about jupyter but that'S an important clue. JUpyter set's up a logger so it can capture logging for you and print it - but that disables basicConfig. This thread contains information about how to circumvent the problem: Get Output From the logging Module in IPython Notebook the answer from skulz00 seems to be ok.

score 0 · Answer 4 · answered Feb 22 '19 at 13:28

0

log both file and jupyter

fh = logging.FileHandler('example.log')
fh.setLevel(logging.DEBUG)
logger.addHandler(fh)
logging.info('Hello world')

answered Feb 22 '19 at 13:28

Gabri

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score 0 · Answer 5 · answered Oct 10 '20 at 10:59

If you are encountering this issue in Jupyter Lab, it might also be because of this problem. Jupyter Lab doesn't seem to show the updated versions of log files that are opened even though they are updated. That's why I recommend using another application for specifically viewing log files like Visual Studio Code.

Cannot get jupyter notebook to log to a file

5 Answers5