Re: [log4perl-devel] Understanding the config

[Kevin M. G. <cp...@go...>]

>
> But, the application has to
> run in different environments (development, testing, staging,
> production) so we need slightly different configurations under each
> environment.
>
> So, I was looking at having a single log4perl config and then using
> environment-specific config files to alter the behavior.  The log
> message pattern might be the same under each mode, but the
> destination file might be different or the "owner" of the file might
> be different, for example.
>
> I have a way to handle this right now, but it just means I need
> separate log4perl config files for each operating environment.  So, I
> end up duplicating the config for the majority of the log4perl config.
>

Interesting.  The way they've solved that problem where I work, for  
*all* config files, not just log4perl, is to start with a base config  
file in a template, and when the service is started up, munge the  
config file based on per-host values.  Something like this:

----------------------
# the config file looks like this
log4perl.appender.file.filename = {$logfile}
log4perl.appender.file.owner = {$owner}
-----------------------

# the per-host values are set up somewhere like this
$hosts = {
    QA => {
         logfile => '/var/log/qa.out',
	owner => 'bob the tester',
    },
    PROD => {
        logfile => '/var/log/prod.out',
        owner => 'jerry the sysadmin',
   },
}

# a Text::Template might be filled in like this
$this_host = 'QA';
$munged_config = $template->fill_in(HASH => $hosts{$this_host}, ...);

# and now you're ready to init
Log::Log4perl::config(\$munged_config);