[log4perl-devel] Overwrite Properties in config files

[Mike S. <msc...@ao...>]

Hi there,

Kai Poitschke has brought up an interestingfeature request: Suppose, 
your application had a configuration "-l logfilename" option to specify 
the name of the log file to be used. Now, if you have an external 
configuration file (as opposed to a string ref passed to init()), how 
would you be able to adapt the config file setting in the code?

He suggests to have init() overwrite certain properties of the config 
file like in:

 Dump2OWH.conf:

log4perl.category.Dump2OWH = INFO, File, Screen

log4perl.appender.File           = Log::Dispatch::File
log4perl.appender.File.filename  = Dump2OWH.log
log4perl.appender.File.mode      = write
log4perl.appender.File.layout    = Log::Log4perl::Layout::PatternLayout
log4perl.appender.File.layout.ConversionPattern = %d: %m%n

log4perl.appender.Screen         = Log::Dispatch::Screen
log4perl.appender.Screen.stderr  = 0
log4perl.appender.Screen.layout  = Log::Log4perl::Layout::PatternLayout
log4perl.appender.Screen.layout.ConversionPattern = %-5p> %m%n


test.pl:
 # Einstellungen z.B. aus Programmflags bestimmt
 $more_conf = q(log4perl.appender.File.filename = test.log
                log4perl.appender.File.mode = append);

 Log::Log4perl::init('Dump2OWH.conf', $more_conf);


I can see at least one other way to implement it: a 
not-yet-implemented-in-Log4perl feature like variables in config files 
(log4j has something like that but I don't think they can specify the 
variable replacement values via code) and a mechanism to define the 
placeholders in init(conf_file, key => value, key => value);

Any other ideas? Sounds like a pretty useful feature to me.


-- -- Mike Mike Schilli
 log...@pe...