Re: [log4perl-devel] Rotating log files

[Kevin G. <ke...@go...>]

Stylin! I've added a map to the log4j syntax so it can be set up like this:

log4j.appender.apndr=org.apache.log4j.RollingFileAppender
log4j.appender.apndr.File=app.log
log4j.appender.apndr.MaxFileSize=15_000_000
log4j.appender.apndr.MaxBackupIndex=2
log4j.appender.apndr.layout=org.apache.log4j.SimpleLayout

I don't suppose you have an overwhelming urge to implement 
DailyRollingFileAppender while you're at it?


mark pfeiffer wrote:
> A new version has just been uploaded to PAUSE:
> 
> 	M/MA/MARKPF/Log-Dispatch-FileRotate-1.03.tar.gz
> 
> should handle multiple writers.
> 
> On Mon, 18 Nov 2002 09:23:02 +1100 mark pfeiffer's good news was:
>   > 
>   > Thanks for the feedback Kevin. I'll chase up your leads and do some
>   > proper testing... What you are saying is absolutely correct!
>   > 
>   > On Fri, 15 Nov 2002 10:35:19 -0800 Kevin Goess's good news was:
>   >   > Mark, nice job and thanks, but how are you handling multiple processes 
>   >   > writing to the same log file?  If you have a web server with 20 children 
>   >   > logging to the same file, you're going to get race conditions like this:
>   >   > 
>   >   > 	child1: hey, the log file is too big, time to rotate!
>   >   > 	child2: hey, the log file is too big, time to rotate!
>   >   > 	child1: renames current file to backup
>   >   > 	child2: renames empty current file to backup, kiboshes data
>   >   > 
>   >   > That's why the apache utilities cronolog and rotatelogs both take the 
>   >   > strategy of just writing to a different file after the cutoff, leaving 
>   >   > the old file alone.  I think the log4j method works for log4j because 
>   >   > they typically only one JVM per machine and thus only one singleton logger.
>   >   > 
>   >   > To do it the log4j way, we'd need to lock the log file before messing 
>   >   > with it. (Actually, if we're renaming it, we need to keep the lock on a 
>   >   > separate file).  See the floc docs under perlfaq5 or File::Lock or maybe 
>   >   > Logfile::Rotate, which looks like it uses locks, might be useful.
>   >   > 
>   >   > What do you think?
>   >   > 
>   ... snip ...
> 
> cheers
> mark


-- 
Happy Trails . . .

Kevin M. Goess
(and Anne and Frank)
904 Carmel Ave.
Albany, CA  94706
(510) 525-5217