On Thu, 30 Oct 2008, Erskine, Thomas (IT) wrote:
The problem with setting a threshold on the appender to cause it not
ot log is that I don't see a way to programmatically set the threshold
to a specific level. It can be bumped up or down, but that requires
the program to know where the threshold was set in the configuration.
I.E. configuration in the program, which I'm trying to avoid.
It's a bit tricky because you need access to Log4perl's appender
wrapper, not the appender itself:
"The previously mentioned method "appender_by_name()" returns a refer-
rence to the real appender object. If you want access to the wrapper
class (e.g. if you want to modify the appender’s threshold), use the
hash $Log::Log4perl::Logger::APPENDER_BY_NAME{...} instead, which holds
references all appender wrapper objects." [perldoc Log::Log4perl]
So, if you have a disabled appender like
log4perl.appender.SCREEN=Log::Log4perl::Appender::Screen
log4perl.appender.SCREEN.layout = SimpleLayout
log4perl.appender.SCREEN.Threshold = OFF
in your configuration, you can retrieve its threshold setting via
my $app = $Log::Log4perl::Logger::APPENDER_BY_NAME{"SCREEN"};
my $threshold = $app->threshold();
and print it out like
print "Threshold set to ",
Log::Log4perl::Level::to_level( $threshold ),
"\n";
If you want to enable the appender, set
$threshold = $app->threshold( $ALL );
If you want to disable it again, set
$threshold = $app->threshold( $OFF );
-- Mike
Mike Schilli
[EMAIL PROTECTED]
The best I've been able to come up with is to define a logger with a
threshold which won't log, call it deactivated, and assign this appender
to it. Then to activate this appender, I can use appender_by_name(...)
and get_root_logger()->add_appender(...). It took me a while to find it
as get_root_logger is only defined on Log::Log4perl::Logger, not in
Log::Log4perl.
Thomas Erskine
Consultant | Technology
2000 Barrington St | Suite 300 | Floor 04
Halifax, NS B3J3K1
Phone: +1 902 442-4709
[EMAIL PROTECTED]
-----Original Message-----
From: Mike Schilli [mailto:[EMAIL PROTECTED]
Sent: Wednesday, October 29, 2008 5:29 PM
To: Erskine, Thomas (IT)
Cc: log4perl-devel@lists.sourceforge.net
Subject: Re: [log4perl-devel] activating appenders
On Wed, 29 Oct 2008, Erskine, Thomas (IT) wrote:
I want to be able to define an appender in the log4perl
config file,
but not activated and then activate it programmatically However,
Log::Log4perl->appender_by_name('SCREENDEBUG') returns undef.
I guess I could add SCREENDEBUG to the log4perl.logger line
and define
it with a threshold which won't log anything and then bump the
threshold up at runtime, but it seems wrong somehow.
An appender that's not assigned to any logger in the
configuration is ignored by Log4perl at this point -- I think
that using a threshold, as you've suggested, is a perfectly
valid solution, though.
Alternatively, you can define the appender programmatically
and add it to the logger via add_appender().
-- Mike
Mike Schilli
[EMAIL PROTECTED]
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