#!/usr/bin/perl
BEGIN { unshift @INC, '/etc/snmp/uloganalyser-plugin'; }
use strict;
use warnings;
# process a log with plugins and place the results in a file

# Copyright (C) 2009-2011  Glen Pitt-Pladdy
#
# 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
#
#
# See: http://www.pitt-pladdy.com/blog/_20110615-093433_0100_Universal_Log_Analyser_and_snmpd_extension_scripts/
#
my $VERSION = 20120420;
#
# Thanks for ideas, unhandled log lines, patches and feedback to:
#
# Przemek Orzechowski



# usage:  postfix-loganalyser <old mail log> <current mail log> <stats file>
my ( $logold, $lognew, $statsfile, @modules ) = @ARGV;
# quick and dirty plugin setup - depends on module returning ref to register sub
my @lines;
my @ends;
foreach (@modules) {
	my $register = require "$_.pm";
	&$register ( \@lines, \@ends, $VERSION );
}


# santiy check
if ( ! $logold or  ! -f $logold ) {
#	warn "WARNING - old mail log file not found\n";
}
if ( ! $lognew or ! -f $lognew ) {
	die "FATAL - current mail log file not found\n";
}
if ( ! $statsfile ) {
	die "FATAL - stats file not specified\n";
}

# read in the current stats if it exists
my %stats;
my $repeatline = '';
if ( -f $statsfile ) {
	open ST, $statsfile or die "FATAL - can't read previous statistics: $!\n";
	while ( defined ( my $line = <ST> ) ) {
		chomp $line;
		if ( $line =~ /^([\w\-_:]+)=([\d\.]+)$/ ) {
			$stats{$1} = $2;
		} elsif ( $line =~ /^repeatline=(.*)$/ ) {
			$repeatline = $1;
		} else {
			die "FATAL - don't understand line \"$line\" in stats\n";
		}
	}
	close ST;
}

# initialise basics
if ( ! $stats{'lastrun'} ) { $stats{'lastrun'} = $^T; }
if ( ! $stats{'lastline'} ) { $stats{'lastline'} = 0; }
if ( ! $stats{'lastposition'} ) { $stats{'lastposition'} = 0; }

# process the log files
# we only look at the old log file if it is newer than the last run
if ( $stats{'lastinode'} and -f $logold and ( stat ( $logold ) )[1] == $stats{'lastinode'} ) {
	# read in old file from $stats{lastline}
	readlogfile ( $logold );
	# set $stats{lastline} to zero to start at the beginning of the new file
	$stats{'lastline'} = 0;
	$stats{'lastposition'} = 0;
}
# current log file
readlogfile ( $lognew );
# wrap up with end stuff
for (@ends) {
	if ( $_ ) { &$_( \%stats ) };
}

# update for our run
$stats{'lastrun'} = $^T;

# write stats to temporary file
open ST, ">$statsfile.TMP.$$"
	or die "FATAL - can't write \"$statsfile.TMP.$$\": $!\n";
print ST "lastrun=$stats{lastrun}\n";
delete $stats{'lastrun'};
print ST "lastline=$stats{lastline}\n";
delete $stats{'lastline'};
print ST "lastposition=$stats{lastposition}\n";
delete $stats{'lastposition'};
print ST "repeatline=$repeatline\n";
# dump rest of stats
foreach my $stat (sort keys %stats) {
	print ST "$stat=$stats{$stat}\n";
}
close ST;
rename "$statsfile.TMP.$$", $statsfile
	or die "FATAL - can't move \"$statsfile.TMP.$$\" to \"$statsfile\": $!\n";


sub readlogfile {
	my $log = shift;
	open LOG, $log or die "FATAL - can't read \"$log\": $!\n";
	# skip to where we left off
	seek LOG, $stats{'lastposition'}, 0;
	my $i = $stats{'lastline'};
	# read lines from here
	my $line;
	while ( defined ( $line = <LOG> ) ) {
		chomp $line;
		# check for repeats & expand if needed
		if ( $line =~ / message repeated (\d+) times?$/ ) {
			my $repeat = $1;
			while ( $repeat-- > 0 ) {
				for (@lines) {
					&$_( $repeatline, $i, $log, \%stats ) and last;
				}
			}
		} else {
			# run through each plugin 
			for (@lines) {
				&$_( $line, $i, $log, \%stats ) and last;
			}
			$repeatline = $line;
		}
		++$i;
	}
	$stats{'lastline'} = $i;	# save for next time
	$stats{'lastposition'} = tell LOG;	# save for next time
	$stats{'lastinode'} = ( stat LOG )[1];
	close LOG;
}