Re: [log4perl-devel] Rotating log files

[mark p. <mar...@ed...>]

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?
  > 
  > 
  > Pfeiffer, Mark (EDS) wrote:
  > > Mike sorry draggin my heals on this :-(
  > > 
  > > I have uploaded:
  > > 
  > > 	M/MA/MARKPF/Log-Dispatch-FileRotate-1.02.tar.gz
  > > 
  > > to PAUSE for your consideration. It still needs plenty of work but at
  > > least it is a start.
  > > 
  > > Please note EDS email sucs. Please use the Reply-To field if you wish to
  > > respond to me directly. Most "reasonable" email clients will understand.
  > > 
  > > On Wed, 25 Sep 2002 19:54:02 EDT Msc...@ao...'s good news was:
  > >   > 
  > >   > 
  > >   > In a message dated 9/25/02 4:21:35 PM Pacific Daylight Time,
  > >   > mar...@ed... writes: 
  > >   > 
  > >   > 
  > >   > 
  > >   > 
  > >   > I'll have a little look at Log::Dispatch and some of its sub-classes to 
  > >   > see how it works. 
  > >   > 
  > >   > 
  > >   > 
  > >   > 
  > >   > Also, the Java implementation shows some interesting ideas: 
  > >   > 
  > >   >  
  > >   > http://jakarta.apache.org/log4j/docs/api/org/apache/log4j/RollingFileApp
  > >   > ender.html 
  > >   > 
  > >   > Not that I'm implying you should provide the same interface, though :) 
  > >   > 
  > >   > -- Mike 
  > >   > 
  > >   > Mike Schilli 
  > >   > log...@pe... 
  > >   > http://perlmeister.com 
  > >   > http://log4perl.sourceforge.net
  > >   > 
  > > 
  > > 
  > > cheers
  > > markpf
  > > 
  > > 
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  > 
  > 
  > -- 
  > Happy Trails . . .
  > 
  > Kevin M. Goess
  > (and Anne and Frank)
  > 904 Carmel Ave.
  > Albany, CA  94706
  > (510) 525-5217

cheers
mark
__
Mark Pfeiffer <mar...@ed...>
Mark Pfeiffer <ma...@ml...>
TCNZA EMC IB | Mobile: 0414 771 245 | Phone:  +61 2 9378 5024
Snail:  L5, 48 Martin Place, Sydney, Australia

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