#!@@PERL@@ -w
# -*- perl -*-

=head1 NAME

courier_mta_mailvolume - Plugin to monitor the volume og mails
delivered by courier-mta

=head1 CONFIGURATION

The following environent variables are used by this plugin:

 logdir  - Where to find logfiles
 logfile - What file to read in logdir

=head1 AUTHOR

Rune Nordbøe Skillingstad <runesk@linpro.no>

=head1 LICENSE

GPLv2

=head1 MAGIC MARKERS

 #%# family=auto
 #%# capabilities=autoconf

=cut

my $statefile = "$ENV{MUNIN_PLUGSTATE}/munin-plugin-courier_mta_mailvolume.state";
my $pos       = undef;
my $volume    = 0;
my $LOGDIR    = $ENV{'logdir'}  || '/var/log';
my $LOGFILE   = $ENV{'logfile'} || 'mail.log';
my $COURIER   = $ENV{'courier'} || '/usr/sbin/courier';

if ( $ARGV[0] and $ARGV[0] eq "autoconf" )
{
    my $logfile;
    if(-x $COURIER) {
	if(-d $LOGDIR) {
	    $logfile = "$LOGDIR/$LOGFILE";
	    if(-f $logfile) {
		if(-r "$logfile") {
		    print "yes\n";
		    exit 0;
		} else {
		    print "no (logfile not readable)\n";
		}
	    } else {
		print "no (logfile not found)\n";
	    }
	} else {
	    print "no (could not find logdir)\n";
	}
    } else {
	print "no (could not find executable)\n";
    }
    exit 0;
}

my $logfile = "$LOGDIR/$LOGFILE";
my $prevdate = get_prev_date();

if(-f "$logfile.$prevdate") {
    $rotlogfile = "$logfile.$prevdate";
} elsif (-f "$logfile.0") {
    $rotlogfile = $logfile . ".0";
} elsif (-f "$logfile.1") {
    $rotlogfile = $logfile . ".1";
} elsif (-f "$logfile.01") {
    $rotlogfile = $logfile . ".01";
} else {
    $rotlogfile = $logfile . ".0";
}

if(-f "$statefile") {
    open (IN, "$statefile") or exit 4;
    if(<IN> =~ /^(\d+):(\d+)/) {
	($pos, $volume) = ($1, $2);
    }
    close IN;
}

if(! -f $logfile and ! -f $rotlogfile) {
    print "volume.value U\n";
    exit 0;
}


$startsize = (stat $logfile)[7];

if(!defined $pos) {
    # Initial run.
    $pos = $startsize;
}

if($startsize < $pos) {
    # Log rotated
    parseLogfile ($rotlogfile, $pos, (stat $rotlogfile)[7]);
    $pos = 0;
}

parseLogfile ($logfile, $pos, $startsize);
$pos = $startsize;

if($ARGV[0] and $ARGV[0] eq "config") {
    print "graph_title Courier MTA mailvolume throughput\n";
    print "graph_args --base 1000 -l 0\n";
    print "graph_vlabel bytes / \${graph_period}\n";
    print "graph_scale  no\n";
    print "graph_total  Total\n";
    print "volume.label throughput\n";
    print "volume.type DERIVE\n";
    print "volume.min 0\n";
    exit 0;
}

print "volume.value $volume\n";

if(-l $statefile) {
    die("$statefile is a symbolic link, refusing to touch it.");
}
open (OUT, ">$statefile") or exit 4;
print OUT "$pos:$volume\n";
close OUT;

sub parseLogfile {
    my ($fname, $start, $stop) = @_;
    open (LOGFILE, $fname) or exit 3;
    seek (LOGFILE, $start, 0) or exit 2;

    while (tell (LOGFILE) < $stop) {
	my $line =<LOGFILE>;
	chomp ($line);
	if($line =~ /(?:courierlocal|courieresmtp): id=.*,from=.*,addr=.*,size=(\d+),success:.*delivered/) {
	    $volume += $1;
	}
    }
    close(LOGFILE);
}

sub get_prev_date {
	my @date = localtime (time - 86400);
	my $prevdate = $date[5]+1900 . $date[4]+1 . $date[3];
	return $prevdate;
}
