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debian/smokeping/usr/share/perl5/Smokeping/matchers/CheckLoss.pm

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+package Smokeping::matchers::CheckLoss;
+
+=head1 NAME
+
+Smokeping::matchers::CheckLoss - Edge triggered alert to check loss is under a value for x number of samples
+
+=head1 DESCRIPTION
+
+Call the matcher with the following sequence:
+
+ type = matcher
+ edgetrigger = yes
+ pattern =  CheckLoss(l=>loss to check against,x=>num samples required for a match)
+
+This will create a matcher which checks for "l" loss or greater over "x" samples before raising, 
+and will hold the alert until "x" samples under "l" before clearing
+
+=head1 COPYRIGHT
+
+Copyright (c) 2006 Dylan C Vanderhoof, Semaphore Corporation
+
+=head1 LICENSE
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+=head1 AUTHOR
+
+Dylan Vanderhoof <dylanv@semaphore.com>
+
+=cut
+
+use strict;
+use base qw(Smokeping::matchers::base);
+use vars qw($VERSION);
+$VERSION = 1.0;
+use Carp;
+use List::Util qw(min max);
+
+# I never checked why Median works, but for some reason the first part of the hash was being passed as the rules instead
+sub new(@) {
+    my $class = shift;
+    my $rules = {
+        l => '\d+',
+        x => '\d+'
+    };
+    my $self = $class->SUPER::new( $rules, @_ );
+    return $self;
+}
+
+# how many values should we require before raising?
+sub Length($) {
+    my $self = shift;
+    return $self->{param}{x};    # Because we're edge triggered, we don't need any more than the required samples
+}
+
+sub Desc ($) {
+    croak "Monitor loss with a cooldown period for clearing the alert";
+}
+
+sub Test($$) {
+    my $self   = shift;
+    my $data   = shift;               # @{$data->{rtt}} and @{$data->{loss}}
+    my $target = $self->{param}{l};
+    my $count  = 0;
+    my $loss;
+    my $x = min($self->{param}{x}, scalar @{ $data->{loss} });
+    
+    #Iterate thru last x number of samples, starting with the most recent
+    for (my $i=1;$i<=$x;$i++) {
+        $loss = $data->{loss}[$_-$i];
+        # If there's an S in the array anywhere, return prevmatch
+        if ( $loss =~ /S/ ) { return $data->{prevmatch}; }
+        if ( $data->{prevmatch} ) {
+
+            # Alert has already been raised.  Evaluate and count consecutive loss values that are below threshold.
+            if ( $loss < $target ) { $count++; }
+        } else {
+
+            # Alert is not raised.  Evaluate and count consecutive loss values that are above threshold.
+            if ( $loss >= $target ) { $count++; }
+        }
+    }
+    if ( $count >= $self->{param}{x} ) {
+        return !$data->{prevmatch};
+    }
+
+    return $data->{prevmatch};
+}