Re: [log4perl-devel] Rotating log files

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

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