I want to use Python logging/rotating settings on multiple modules.

Asked 2 months ago, Updated 2 months ago, 3 views

Windows 10 Python 3.6

directory example

| -- main.py
|-- modules/
|   |--_init__.py
|   ` -- funcs.py
`-- log/
    `-- root.log

If you want to log from multiple modules (from main.py and from funcs.py),
https://docs.python.jp/3/howto/logging.html#logging-from-multiple-modules
If you follow the instructions in , you can output the log without any problems.

However, if you want to customize the rotation method, visit
main.py. https://docs.python.jp/3/howto/logging-cookbook.html#using-a-rotator-and-namer-to-customize-log-rotation-processing
After writing and giving the logger a handler, the log from main.py has been customized for rotation.
If I want to apply the same customization to logs from funcs.py, how should I write it on funcs.py (I want to print it to the same log file /log/root.log)?
PermissionError: [WinError32] if you describe it exactly like main.py.


If possible, logging.config.fileConfig(...) will make the program smoother, but if you want to apply rotation customization, is there no way to do it?

main.py

import logging
import modules.funcs

logger = logging.getLogger()
logger.setLevel(logging.DEBUG)
trh=logging.handlers.TimedRotatingFileHandler(...)
trh.rotator=rotator#rotator is created separately
logger.addHandler(trh)

logger.debug('rotate test')

funcs.py

import logging

logger = logging.getLogger()
# Do you want to set/describe any settings here?

logger.debug('rotate [email protected]')

python logging

2022-09-30 12:09

2 Answers

funcs.py should not have to do anything. If you configure something in funcs.py, it will be a different logger object, so if you try to print it to the same log file, you will get PermissionError: WinError32.

·Official document logging --- logging function for Python Logger object

Note that loggers cannot be instantiated directly and are always instantiated through the module function logging.getLogger(name).Calling getLogger() multiple times with the same name always returns a reference to the same logger object.

The name is a potentially hierarchical value, divided by periods (but may be just plain foo), such as foo.bar.baz.The lower loggers in the hierarchical list are children of the higher loggers.For example, when there is a logger named foo, all the loggers named foo.bar, foo.bar.baz, foo.bam are descendants of foo.The hierarchy of logger names is similar to the Python package hierarchy, and if you configure the logger on a per-module basis using the recommended build method logging.getLogger(__name__), it will be identical to the Python package hierarchy.This is because __name__ is the module name in the Python package namespace.


2022-09-30 12:09

Does PermissionError mean you are running multiple processes?

In that case, Logging from multiple processes to a single file

introduces the following techniques:

About logging.config

fileConfig in logging.config is easy to configure if you have a configuration file.

  • DictConfig in JSON/YAML, etc. (load) makes the description easier to understand and more convenient
  • Standard Logging Handler (RotatingFileHandler or TimedRotatingFileHandler) is easy to use, but handling customized handlers tends to be troublesome

That's what it looks like

But first, I'll modularize the custom logging handler. Why don't we start by import and running each program (each process)?


2022-09-30 12:09

If you have any answers or tips


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