forcing a log rotation in python logging module

Question

If I have a rotating logging file. (logging_file.log) that rotates when x condition is met. How do I make it rotate? I know the rotating log module rotates automatically when the size exceeds a certain amount, but how do I make this rotation happen in the logging module for a different condition that is not size. Or how do I just force it to rotate the logging into a new logging file for whatever reason. Is there a function or command for this? Simply put how do I manually rotate a logging file if I want to use a newer and archive the old one. something like

if lines_in_file > 3
    rotate()

[note: the condition to make it rotate is irrelevant but I'm trying to ask for what function will make this rotation happen. Is there a simple function that does the job of rotate?

Answer 1

You should have (or can save) a reference to the appropriate instance of RotatingFileHandler from when you configured the logger. You just need to invoke its doRollover method:

rfh = RotatingFileHandler('foo.log')

...

rfh.doRollover()

More generally, RotatingFileHandler.doRollover uses BaseRotatingHandler.rotate , which takes the source and destination file names. rotate either calls the handler's rotator attribute with the same arguments, or just moves the source to the destination.