NAME¶
Log::Log4perl::Appender::Limit - Limit message delivery via block period
SYNOPSIS¶
use Log::Log4perl qw(:easy);
my $conf = qq(
log4perl.category = WARN, Limiter
# Email appender
log4perl.appender.Mailer = Log::Dispatch::Email::MailSend
log4perl.appender.Mailer.to = drone\@pageme.com
log4perl.appender.Mailer.subject = Something's broken!
log4perl.appender.Mailer.buffered = 0
log4perl.appender.Mailer.layout = PatternLayout
log4perl.appender.Mailer.layout.ConversionPattern=%d %m %n
# Limiting appender, using the email appender above
log4perl.appender.Limiter = Log::Log4perl::Appender::Limit
log4perl.appender.Limiter.appender = Mailer
log4perl.appender.Limiter.block_period = 3600
);
Log::Log4perl->init(\$conf);
WARN("This message will be sent immediately.");
WARN("This message will be delayed by one hour.");
sleep(3601);
WARN("This message plus the last one will be sent now, separately.");
DESCRIPTION¶
- "appender"
- Specifies the name of the appender used by the limiter. The appender
specified must be defined somewhere in the configuration file, not
necessarily before the definition of
"Log::Log4perl::Appender::Limit".
- "block_period"
- Period in seconds between delivery of messages. If messages arrive in
between, they will be either saved (if "accumulate" is set to a
true value) or discarded (if "accumulate" isn't set).
- "persistent"
- File name in which "Log::Log4perl::Appender::Limit" persistently
stores delivery times. If omitted, the appender will have no recollection
of what happened when the program restarts.
- "max_until_flushed"
- Maximum number of accumulated messages. If exceeded, the appender flushes
all messages, regardless if the interval set in "block_period"
has passed or not. Don't mix with "max_until_discarded".
- "max_until_discarded"
- Maximum number of accumulated messages. If exceeded, the appender will
simply discard additional messages, waiting for "block_period"
to expire to flush all accumulated messages. Don't mix with
"max_until_flushed".
- "appender_method_on_flush"
- Optional method name to be called on the appender attached to the limiter
when messages are flushed. For example, to have the sample code in the
SYNOPSIS section bundle buffered emails into one, change the mailer's
"buffered" parameter to 1 and set the limiters
"appender_method_on_flush" value to the string
"flush":
log4perl.category = WARN, Limiter
# Email appender
log4perl.appender.Mailer = Log::Dispatch::Email::MailSend
log4perl.appender.Mailer.to = drone\@pageme.com
log4perl.appender.Mailer.subject = Something's broken!
log4perl.appender.Mailer.buffered = 1
log4perl.appender.Mailer.layout = PatternLayout
log4perl.appender.Mailer.layout.ConversionPattern=%d %m %n
# Limiting appender, using the email appender above
log4perl.appender.Limiter = Log::Log4perl::Appender::Limit
log4perl.appender.Limiter.appender = Mailer
log4perl.appender.Limiter.block_period = 3600
log4perl.appender.Limiter.appender_method_on_flush = flush
This will cause the mailer to buffer messages and wait for
"flush()" to send out the whole batch. The limiter will then
call the appender's "flush()" method when it's own buffer gets
flushed out.
If the appender attached to "Limit" uses "PatternLayout"
with a timestamp specifier, you will notice that the message timestamps are
reflecting the original log event, not the time of the message rendering in
the attached appender. Major trickery has been applied to accomplish this
(Cough!).
DEVELOPMENT NOTES¶
"Log::Log4perl::Appender::Limit" 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.
LICENSE¶
Copyright 2002-2013 by Mike Schilli <m@perlmeister.com> and Kevin Goess
<cpan@goess.org>.
This library is free software; you can redistribute it and/or modify it under
the same terms as Perl itself.
AUTHOR¶
Please contribute patches to the project on Github:
http://github.com/mschilli/log4perl
Send bug reports or requests for enhancements to the authors via our
MAILING LIST (questions, bug reports, suggestions/patches):
log4perl-devel@lists.sourceforge.net
Authors (please contact them via the list above, not directly): Mike Schilli
<m@perlmeister.com>, Kevin Goess <cpan@goess.org>
Contributors (in alphabetical order): Ateeq Altaf, Cory Bennett, Jens Berthold,
Jeremy Bopp, Hutton Davidson, Chris R. Donnelly, Matisse Enzer, Hugh Esco,
Anthony Foiani, James FitzGibbon, Carl Franks, Dennis Gregorovic, Andy
Grundman, Paul Harrington, Alexander Hartmaier David Hull, Robert Jacobson,
Jason Kohles, Jeff Macdonald, Markus Peter, Brett Rann, Peter Rabbitson, Erik
Selberg, Aaron Straup Cope, Lars Thegler, David Viner, Mac Yang.