multi-process solution

["dB." <db...@dblock.org>]

Many log4cxx users raise this question: how do I use log4cxx in a
multi-process environment? Currently log4cxx gives a "don't" answer or a
"use a different log file per process" answer, which are correct, but
sometimes not very easy to implement. We had the same problem in our
product, we spawn a process with the same name many times and that
architecture isn't going to change. 

 

I think I have implemented a large part of a solution. 

 

Issue 1: how can one name a log file differently per-process without any
code?

 

I added two formatting pattern converters: ProcessIdPatternConverter and
ProcessNamePatternConverter. %p translates to the process ID and %n to
the process name.  This is very nice because it's zero code to enable
multi-process logging and works for the RollingFileAppender as well. So
my log files look like this: SomeExecutable.1234.log. 

 

Issue 2: with the above scheme there's a proliferation of log files (one
per process x rolling file appender maxindex). How can I clean them up?


I added a purge option. When the logger initializes (activateOptions) it
will take the filename pattern, format it, but instead of using a
ProcessIdPatternConverter it will use some star pattern converter
producing SomeExecutable.*.log for example. Then I just delete files
that match this pattern. This cleans up old log files.

 

Repeat this with the rolling filenames, except %i also gets replaced
with *.

 

What do you guys think? I have this for Windows (GetProcessID,
GetModuleFilename, FindFirstFile, DeleteFile etc.), but I don't know how
to make it portable. I need some help with that.

 

Cheers

dB.

 

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