Python logging - check location of log files?
Solution 1
The logging
module uses handlers attached to loggers to decide how, where, or even if messages ultimately get stored or displayed. You can configure logging
by default to write to a file as well. You should really read the docs, but if you call logging.basicConfig(filename=log_file_name)
where log_file_name
is the name of the file you want messages written to (note that you have to do this before anything else in logging
is called at all), then all messages logged to all loggers (unless some further reconfiguration happens later) will be written there. Be aware of what level the logger is set to though; if memory serves, info
is below the default log level, so you'd have to include level=logging.INFO
in the arguments to basicConfig
as well for your message to end up in the file.
As to the other part of your question, logging.getLogger(some_string)
returns a Logger
object, inserted in to the correct position in the hierarchy from the root logger, with the name being the value of some_string
. Called with no arguments, it returns the root logger. __name__
returns the name of the current module, so logging.getLogger(__name__)
returns a Logger
object with the name set to the name of the current module. This is a common pattern used with logging
, as it causes the logger structure to mirror your code's module structure, which often makes logging messages much more useful when debugging.
Solution 2
To get the log location of a simple file logger, try
logging.getLoggerClass().root.handlers[0].baseFilename
Solution 3
To find the logfile location, try instantiating your log
object in a Python shell in your environment and looking at the value of:
log.handlers[0].stream
Solution 4
Some good answers on this, but top answer didn't work for me because I was using a different type of file handler, and the handler.stream doesn't provide the path, but file handle, and getting the path out of that is somewhat non-obvious. Here's my solution:
import logging
from logging import FileHandler
# note, this will create a new logger if the name doesn't exist,
# which will have no handlers attached (yet)
logger = logging.getLogger('<name>')
for h in logger.handlers:
# check the handler is a file handler
# (rotating handler etc. inherit from this, so it will still work)
# stream handlers write to stderr, so their filename is not useful to us
if isinstance(h, FileHandler):
# h.stream should be an open file handle, it's name is the path
print(h.stream.name)
zallarak
Updated on July 09, 2022Comments
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zallarak almost 2 years
What is the methodology for knowing where Python log statements are stored?
i.e. if i do:
import logging log = logging.getLogger(__name__) log.info('Test')
Where could I find the logfile? Also, when I call:
logging.getLogger(__name__)
Is that somehow related to how the logger will behave/save?
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GyRo over 5 yearsIt throws exception to me
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Taran over 5 yearsWhat's the exception? You could try using a debugger and poking around those objects until you find what you need
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kakyo over 5 yearsThis assumes that the logger had a FileHandler, which is not always the case. Better make sure that the handlers contain a FileHandler object.
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Valentyn almost 5 yearsIt throws an exception to me as well: "AttributeError: 'StreamHandler' object has no attribute 'baseFilename'"
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Alon Gouldman almost 4 yearshow do you reconfigure the logger after some logs have been written already?
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Pogger over 3 yearsIn my case it is working logging.handlers[0].baseFilename
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deesolie over 3 yearsPer this SO answer, basicConfig sets the handler on the root logger object (or the logger object configured with your given module
example_logger = logging.getLogger('example')
). Thus, you could remove the existing handler and call basic config again. Alternatively, you could create a different logger objectexample2_logger = logging.getLogger('example')
and set different configs on this object. -
CodePrinz over 2 yearsI get an IndexError, since my object has no handlers.
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CodePrinz over 2 yearsImportError: cannot impart name 'FileHandler' from 'logging.handlers'
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CodePrinz over 2 yearsOr an AttributeErrror:'_LiveLoggingNullHandler' object has no attribute 'stream'
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Edward Spencer over 2 years@CodePrinz, good catch, the base class lives in the logging module, not the handlers module. Fixed now.