log4perl-devel

[log4perl-devel] override_appender for different log levels

[<tod...@ex...>]

Im trying to set dynamic PallernLayouts depending on the log level called.



Using my current logger, call $log->enter and $log->exit at the beginning and end of my subroutines. I then generate XML using XML::Writer in my logging routines. This XML is transformed using an XSLT stylesheet to give different views of the logged data.



It works great, but I need to extend it to provide multiple channels.



To get the ->enter and ->exit routines, I used:



L::L4p::Logger::create_custom_level("ENTER", "FATAL");

L::L4p::Logger::create_custom_level("EXIT", "ENTER");



I set my config as follows:



l4p.a.myLW.layout = Log::Log4perl::Layout::PatternLayout

l4p.a.myLW.layout.ConversionPattern = <%p>(%M)%m</%p>%n



What I cant figure out is how to change the ConversionPattern dynamically when either ->enter or ->exit is called.



I can figure out HOW, I found http://search.cpan.org/~mschilli/Log-Log4perl-0.49/eg/override_appender



I cant figure out where to put the following code:



sub enter {

  my $self = shift;

  my $appenders = Palace::Log::Log4perl->appenders();

  my $hold = $appenders->{PalaceLogWriter}->layout();

  my $layout = __PACKAGE__->new('<function name="%M" docUri="%M">%n');

  $appenders->{PalaceLogWriter}->layout($layout);

  $Log::Log4perl::caller_depth++;

  $self->extra( @_ );

  $Log::Log4perl::caller_depth--;

  $appenders->{PalaceLogWriter}->layout($hold);

}



sub exit {

  my $self = shift;

  my $appenders = Palace::Log::Log4perl->appenders();

  my $hold = $appenders->{PalaceLogWriter}->layout();

  my $layout = __PACKAGE__->new('</function>%n');

  $appenders->{PalaceLogWriter}->layout($layout);

  $Log::Log4perl::caller_depth++;

  $self->extra( @_ );

  $Log::Log4perl::caller_depth--;

  $appenders->{PalaceLogWriter}->layout($hold);

}



Ive tried overloading the ->log() method of my appender and overloading the ->render() method of PatternLayout.



The closest I ever got was calling the ->define() method in my ->render() method and the setting $self->{printformat} back to its old value, after calling ->SUPER::render(), but I got strange results.



Any assistance will be appreciated,



Todd W.





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Re: [log4perl-devel] override_appender for different log levels

[Mike S. <m...@pe...>]

On Mon, 13 Dec 2004, tod...@ex... wrote:

> Im trying to set dynamic PallernLayouts depending on the log level called.
> ...
> L::L4p::Logger::create_custom_level("ENTER", "FATAL");
> L::L4p::Logger::create_custom_level("EXIT", "ENTER");

Hmm, seems like you're using levels not as message priorities but to
trigger certain actions in your appender. This way, you'll get some
broken XML if you set the log level to ENTER, etc., so I'd recommend
not doing that.

How about this:

1) Write your own XML appender (see FAQ), featuring an enter() and and
   exit() method, which just set the state within the appender
2) On log(), have the appender store the message(s).
3) On exit(), have the appender format all messages as XML and write them
   out.
4) At the beginning and end of every function, place calls to trigger
   YourAppender->enter(), YourAppender->exit();
5) In between, use Log4perl's regular $logger->debug("..."); etc. calls.

This would fit better into L4p's architecture. What do you think?

-- Mike

Mike Schilli
m...@pe...