Log::Log4perl::Appender::Buffer - Buffering Appender
use Log::Log4perl qw(:easy);
my $conf = qq( log4perl.category = DEBUG, Buffer
# Regular Screen Appender log4perl.appender.Screen = Log::Log4perl::Appender::Screen log4perl.appender.Screen.stdout = 1 log4perl.appender.Screen.layout = PatternLayout log4perl.appender.Screen.layout.ConversionPattern = %d %p %c %m %n
# Buffering appender, using the appender above as outlet log4perl.appender.Buffer = Log::Log4perl::Appender::Buffer log4perl.appender.Buffer.appender = Screen log4perl.appender.Buffer.trigger_level = ERROR );
Log::Log4perl->init(\$conf);
DEBUG("This message gets buffered."); INFO("This message gets buffered also.");
# Time passes. Nothing happens. But then ...
print "It's GO time!!!\n";
ERROR("This message triggers a buffer flush.");
Log::Log4perl::Appender::Buffer
takes these arguments:
appender
Log::Log4perl::Appender::Buffer
.
max_messages
max_messages
is optional. By default,
Log::Log4perl::Appender::Buffer
will not limit the number of
messages buffered. This might be undesirable in long-running processes
accumulating lots of messages before a flush happens. If
max_messages
is set to a numeric value,
Log::Log4perl::Appender::Buffer
will displace old messages in its
buffer to make room if the buffer is full.
trigger_level
trigger
function will be defined internally
to flush the buffer if a message with a priority of $level or higher
comes along. This is just a convenience function. Defining
log4perl.appender.Buffer.trigger_level = ERROR
is equivalent to creating a trigger function like
log4perl.appender.Buffer.trigger = sub { \ my($self, $params) = @_; \ return $params->{log4p_level} >= \ $Log::Log4perl::Level::ERROR; }
See the next section for defining generic trigger functions.
trigger
trigger
holds a reference to a subroutine, which
Log::Log4perl::Appender::Buffer
will call on every incoming message
with the same parameters as the appender's log()
method:
my($self, $params) = @_;
$params
references a hash containing
the message priority (key l4p_level
), the
message category (key l4p_category
) and the content of the message
(key message
).
If the subroutine returns 1, it will trigger a flush of buffered messages.
Shortcut
Log::Log4perl::Appender::Buffer
is a composite appender.
Unlike other appenders, it doesn't log any messages, it just
passes them on to its attached sub-appender.
For this reason, it doesn't need a layout (contrary to regular appenders).
If it defines none, messages are passed on unaltered.
Custom filters are also applied to the composite appender only. They are not applied to the sub-appender. Same applies to appender thresholds. This behaviour might change in the future.
Copyright 2004 by Mike Schilli, all rights reserved. This program is free software, you can redistribute it and/or modify it under the same terms as Perl itself.
2004, Mike Schilli <m@perlmeister.com>