Get Output From the logging Module in IPython Notebook

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Question :

Get Output From the logging Module in IPython Notebook

When I running the following inside IPython Notebook I don’t see any output:

import logging

Anyone know how to make it so I can see the “test” message inside the notebook?

Answer #1:

Try following:

import logging
logger = logging.getLogger()

According to logging.basicConfig:

Does basic configuration for the logging system by creating a
StreamHandler with a default Formatter and adding it to the root
logger. The functions debug(), info(), warning(), error() and
critical() will call basicConfig() automatically if no handlers are
defined for the root logger.

This function does nothing if the root logger already has handlers
configured for it.

It seems like ipython notebook call basicConfig (or set handler) somewhere.

Answered By: falsetru

Answer #2:

If you still want to use basicConfig, reload the logging module like this

from importlib import reload  # Not needed in Python 2
import logging
logging.basicConfig(format='%(asctime)s %(levelname)s:%(message)s', level=logging.DEBUG, datefmt='%I:%M:%S')
Answered By: Marigold

Answer #3:

My understanding is that the IPython session starts up logging so basicConfig doesn’t work. Here is the setup that works for me (I wish this was not so gross looking since I want to use it for almost all my notebooks):

import logging
logger = logging.getLogger()
fhandler = logging.FileHandler(filename='mylog.log', mode='a')
formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')

Now when I run:

logging.debug('This is a debug message')'this is an info message')
logging.warning('tbllalfhldfhd, warning.')

I get a “mylog.log” file in the same directory as my notebook that contains:

2015-01-28 09:49:25,026 - root - ERROR - hello!
2015-01-28 09:49:25,028 - root - DEBUG - This is a debug message
2015-01-28 09:49:25,029 - root - INFO - this is an info message
2015-01-28 09:49:25,032 - root - WARNING - tbllalfhldfhd, warning.

Note that if you rerun this without restarting the IPython session it will write duplicate entries to the file since there would now be two file handlers defined

Answered By: skulz00

Answer #4:

Bear in mind that stderr is the default stream for the logging module, so in IPython and Jupyter notebooks you might not see anything unless you configure the stream to stdout:

import logging
import sys

logging.basicConfig(format='%(asctime)s | %(levelname)s : %(message)s',
                     level=logging.INFO, stream=sys.stdout)'Hello world!')
Answered By: Ataxias

Answer #5:

What worked for me now (Jupyter, notebook server is: 5.4.1, IPython 7.0.1)

import logging
logger = logging.getLogger('Something')

Now I can use logger to print info, otherwise I would see only message from the default level (logging.WARNING) or above.

Answered By: mcsim

Answer #6:

You can configure logging by running %config Application.log_level="INFO"

For more information, see IPython kernel options

Answered By: Garvey

Answer #7:

I setup a logger for both file and I wanted it to show up on the notebook. Turns out adding a filehandler clears out the default stream handlder.

logger = logging.getLogger()

formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')

# Setup file handler
fhandler  = logging.FileHandler('my.log')

# Configure stream handler for the cells
chandler = logging.StreamHandler()

# Add both handlers

# Show the handlers

# Log Something"Test info")
logger.debug("Test debug")
logger.error("Test error")
Answered By: Brig

Answer #8:

It seems that solutions that worked for older versions of ipython/jupyter no longer work.

Here is a working solution for ipython 7.9.0 (also tested with jupyter server 6.0.2):

import logging
logger = logging.getLogger()
logging.debug("test message")

DEBUG:root:test message
Answered By: stason

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