Logging in Python: Conclusion

Hello.

logging.info("Malef's gratitude for clear explanation of useful topic is recorded.")

Thanks, RealPython.

How to append the date to the log file name ?

Very useful course - I’ve already added simple logging to my app based on the lessons here. Thanks!

Excelent!

If you want the date/time in the log file name, you could do something like…

from datetime import datetime

time = datetime.now() file_out = time.strftime(“%Y-%m-%d %H:%M:%S”) + “.log”

file_handler = logging.FileHandler(file_out)

all these examples were using main module.

However, If I want to write a package with multiple python modules (multiple .py files) and then create a python script which import one or more modules from this package, what is the correct way to implement logging?

Does each module (.py file) will have a logger (with its own StreamHandler and FileHandlers) at the beginning of the file? If yes, how many log files gets created and which module’s logger formatter will take the preference etc?

Thanks for the tutorial! You made it look very simple and easy for me.

Excellent. Just the right level of detail. Good pace. Really helpful - thanks.

Great course!

Very good course. I’ll continue down the logging course path from here.

Very useful course; thanks!

Awesome course!

Thanks Austin - helpful - I will try to follow along and get a better feel for how to use custom loggers - this is the most confusing part for me - as I’ve implemented basic config.

I found a helpful format for me is to include module and function names int the logs, and then when I import my logging config, I can see it moving around in my logs.

format = '%(asctime)s : %(levelname)s : %(module)s : %(funcName)s : %(lineno)d : %(message)s',

More info here: 3.10 Logging Doc

Very useful course, thanks!

To answer the earlier poster’s question about inserting datestamping into the filename, or for anyone else wondering, using the TimedRotatingFileHandler might help. It inserts a date-time stamp into the filename, although it is primarily designed to rotate logfiles at a preset interval or time of day or day of week. See here, and also RotatingFileHandler for a filesize-based rotating file handler. docs.python.org/3/library/logging.handlers.html#logging.handlers.TimedRotatingFileHandler

Good intro course to logging. It would be useful to have a follow-up course (or expand this course), which covers the following:

1. How to use the same logger across different classes and modules (spoiler: the logging module can do this seamlessly)
2. Guidelines on what you should log, and why, and at which levels.
3. Guilelines on when you should print vs. when you should log, with different scenarios, eg. a script vs. an interactive console app vs. a Flask/Django app, etc. The console app would obviously use print for normal interactions, and logging to file and/or console for errors etc. A script that processes hundreds of files would almost exclusively use file logging, presumably.
4. Tips on the Rotating File Handler classes within the logging module, which helps with auto-rotating logfiles above a certain size, etc.
5. A link or mention to whatever RealPython course would teach the user how to save all that boilerplate logging setup code for easy reuse (it’s off-topic for the logging course, but this was a question I thought of, particularly if you really prefer to do the config inside the code rather than config file).