1Appender::Buffer(3)   User Contributed Perl Documentation  Appender::Buffer(3)
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NAME

6           Log::Log4perl::Appender::Buffer - Buffering Appender
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SYNOPSIS

9           use Log::Log4perl qw(:easy);
10
11           my $conf = qq(
12           log4perl.category                  = DEBUG, Buffer
13
14               # Regular Screen Appender
15           log4perl.appender.Screen           = Log::Log4perl::Appender::Screen
16           log4perl.appender.Screen.stdout    = 1
17           log4perl.appender.Screen.layout    = PatternLayout
18           log4perl.appender.Screen.layout.ConversionPattern = %d %p %c %m %n
19
20               # Buffering appender, using the appender above as outlet
21           log4perl.appender.Buffer               = Log::Log4perl::Appender::Buffer
22           log4perl.appender.Buffer.appender      = Screen
23           log4perl.appender.Buffer.trigger_level = ERROR
24           );
25
26           Log::Log4perl->init(\$conf);
27
28           DEBUG("This message gets buffered.");
29           INFO("This message gets buffered also.");
30
31           # Time passes. Nothing happens. But then ...
32
33           print "It's GO time!!!\n";
34
35           ERROR("This message triggers a buffer flush.");
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DESCRIPTION

38       "Log::Log4perl::Appender::Buffer" takes these arguments:
39
40       "appender"
41           Specifies the name of the appender it buffers messages for. The
42           appender specified must be defined somewhere in the configuration
43           file, not necessarily before the definition of
44           "Log::Log4perl::Appender::Buffer".
45
46       "max_messages"
47           Specifies the maximum number of messages the appender will hold in
48           its ring buffer. "max_messages" is optional. By default,
49           "Log::Log4perl::Appender::Buffer" will not limit the number of
50           messages buffered. This might be undesirable in long-running
51           processes accumulating lots of messages before a flush happens. If
52           "max_messages" is set to a numeric value,
53           "Log::Log4perl::Appender::Buffer" will displace old messages in its
54           buffer to make room if the buffer is full.
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56       "trigger_level"
57           If trigger_level is set to one of Log4perl's levels (see
58           Log::Log4perl::Level), a "trigger" function will be defined
59           internally to flush the buffer if a message with a priority of
60           $level or higher comes along. This is just a convenience function.
61           Defining
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63               log4perl.appender.Buffer.trigger_level = ERROR
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65           is equivalent to creating a trigger function like
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67               log4perl.appender.Buffer.trigger = sub {   \
68                   my($self, $params) = @_;               \
69                   return $params->{log4p_level} >=       \
70                          $Log::Log4perl::Level::ERROR; }
71
72           See the next section for defining generic trigger functions.
73
74       "trigger"
75           "trigger" holds a reference to a subroutine, which
76           "Log::Log4perl::Appender::Buffer" will call on every incoming
77           message with the same parameters as the appender's "log()" method:
78
79                   my($self, $params) = @_;
80
81           $params references a hash containing the message priority (key
82           "l4p_level"), the message category (key "l4p_category") and the
83           content of the message (key "message").
84
85           If the subroutine returns 1, it will trigger a flush of buffered
86           messages.
87
88           Shortcut
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DEVELOPMENT NOTES

91       "Log::Log4perl::Appender::Buffer" is a composite appender.  Unlike
92       other appenders, it doesn't log any messages, it just passes them on to
93       its attached sub-appender.  For this reason, it doesn't need a layout
94       (contrary to regular appenders).  If it defines none, messages are
95       passed on unaltered.
96
97       Custom filters are also applied to the composite appender only.  They
98       are not applied to the sub-appender. Same applies to appender
99       thresholds. This behaviour might change in the future.
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102       Copyright 2002-2009 by Mike Schilli <m@perlmeister.com> and Kevin Goess
103       <cpan@goess.org>.
104
105       This library is free software; you can redistribute it and/or modify it
106       under the same terms as Perl itself.
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110perl v5.12.2                      2010-08-31               Appender::Buffer(3)
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