[Tutor] Python logging

Scott SA pydev at rscorp.ab.ca
Sun Apr 19 21:18:12 CEST 2009

Hi Stephan & Kent,

On Apr 19, 2009, at 6:12 AM, Stefan Behnel wrote:

> just commenting on this part:
>> ... which basically says append WARNING messages to the rotating file
>> handler in DatetimeLevelMessage format to a log-file named  
>> test_warn.log
>> splitting the log-file when it exceeds 125829120 bytes.
> You may have a reason to cut these at "125829120" bytes, but it's  
> usually a
> bad idea to cut log files by size. It's much more natural to have time
> sliced log files (one per day or per hour), so that you directly  
> know which
> file you have to look at to analyse that stuff that went so terribly  
> wrong
> yesterday evening (especially once they get archived somewhere).

I didn't set-up this portion of the file config. file and have not  
found much documentation for the conf-file formating (much of the rest  
is very well documented). I guess I should really find the actual code  
and read what it is doing... as Kent very gently prodded me with. I  
did go through a few PEPs too, and I don't recall seeing anything  
about time-based rotation ... but then maybe it was there and it  
didn't register with me. Thanks for the heads-up, I'll go back and re- 
read the material.

> Looking at the code for the logging module, I think it will work to
> create the RotatingFileHandler with the parameter delay=True, then in
> your code get the handler and change its baseFilename attribute to be
> the path you want, e.g.
> "/home/user/workspace/logged_app/test_warn.log".

That's an interesting feature, I'll have to go look and see what other  
jewels are lurking in various modules. So far I've not spent a lot of  
time going through the code for modules like this, but obviously I  
should (I often learn more than just how a bit of code works by  
reading how others have solved problems).

Thank you both!


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