Munin contributed plugins

#!/usr/bin/perl

# vim: set filetype=perl sw=4 tabstop=4 expandtab smartindent: #

=head1 NAME

  du - Plugin to monitor multiple directories size

=head1 AUTHOR AND COPYRIGHT

  Copyright 2011-2012 Luc Didry <luc AT didry.org>

=head1 HOWTO CONFIGURE AND USE :

=over

=item - /etc/munin/plugin-conf.d/du_

     [du]

     user root

     env.interval 20 # INTERVAL OF DU POLLING IN MINUTES

     env.dirs /home/foo /home/bar # DIRECTORIES TO POLL

     env.suppr /home/ # PLEASE USE \# INSTEAD OF #

     timeout 900 # 15 MINUTES IN SECONDS

=item - /etc/munin/plugins-enabled

     ln -svf ../plugins-available/site/du

=item - restart Munin node

     sudo killall -TERM munin-node

=back

=head1 CREDITS

  Based on the 'du_multidirs-v2' initially written in Bash by Christian Kujau <lists@nerdbynature.de> and modified by dano229.

  This script was based on the 'homedirs' plugin, initially written in Perl by Philipp Gruber <pg@flupps.net>

=head1 MAGIC MARKERS

  #%# family=auto

  #%# capabilities=autoconf

=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 3 of the License, or

    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, see <http://www.gnu.org/licenses/>.

=cut

use warnings;

use strict;

use Munin::Plugin;

use POSIX qw(setsid);

my $PLUGIN_NAME = "du";

my $CACHEFILE="$Munin::Plugin::pluginstatedir/du.cache";

my $TEMPFILE="$Munin::Plugin::pluginstatedir/du.tmp";

my $LOCKFILE="$Munin::Plugin::pluginstatedir/du.lock";

my $TIMEFILE="$Munin::Plugin::pluginstatedir/du.time";

##### autoconf

if( (defined $ARGV[0]) && ($ARGV[0] eq "autoconf") ) {

    print "yes\n";

    ## Done !

    munin_exit_done();

}

## In the parent, it's just a regular munin plugin which reads a file with the infos

##### config

if( (defined $ARGV[0]) && ($ARGV[0] eq "config") ) {

    print "graph_title Directory usage\n";

    print "graph_args --base 1024 -l 1\n";

    print "graph_vlabel Bytes\n";

    print "graph_category disk\n";

    print "graph_total total\n";

    print "graph_info This graph shows the size of several directories\n";

    my $foo = 0;

    open (FILE, "<", $CACHEFILE) or munin_exit_fail();

    while(defined (my $bar = <FILE>)) {

        if ($bar =~ m/(\d+)\s+(.+)/) {

            my $dir = $2;

            clean_path(\$dir);

            print "$dir.label $dir\n";

            if ($foo++) {

                print "$dir.draw STACK\n";

            } else {

                print "$dir.draw AREA\n";

            }

        }

    }

    close(FILE);

    ## Done !

    munin_exit_done();

}

##### fetch

open (FILE, "<", $CACHEFILE) or munin_exit_fail();

while(defined (my $foo = <FILE>)) {

    if ($foo =~ m/(\d+)\s+(.+)/) {

        my ($field, $value) = ($2, $1);

        clean_path(\$field);

        print $field, ".value ", $value, "\n";

    }

}

close(FILE);

daemonize();

#

##

### PUBLIC FONCTIONS

###############################################################################

## Used to create the fork

sub daemonize {

    chdir '/'               or die "Can't chdir to /: $!";

    defined(my $pid = fork) or die "Can't fork: $!";

    munin_exit_done() if $pid;

    open STDIN, '/dev/null' or die "Can't read /dev/null: $!";

    open STDOUT, '>/dev/null' or die "Can't write to /dev/null: $!";

    open STDERR, '>&STDOUT' or die "Can't dup stdout: $!";

    setsid                  or die "Can't start a new session: $!";

    ## In the child, let's get the du infos if necessary

    if (cache_is_too_old() && du_not_running()) {

        my $dirs = $ENV{dirs};

        system("touch $LOCKFILE; du -sb $dirs > $TEMPFILE; cat $TEMPFILE > $CACHEFILE; rm $LOCKFILE; date +%s > $TIMEFILE;");

    }

    exit;

} ## daemonize

## Used to remove the beginning of the paths if wanted

sub clean_path {

    my ($path) = @_;

    if (defined $ENV{suppr}) {

        my $pattern = $ENV{suppr};

        $$path =~ s#^($pattern)##;

    }

} ## clean_path

## Do you really need I told you what this functions are going to check ?

sub cache_is_too_old {

    return 1 if (! -e $TIMEFILE);

    my ($time) = `cat $TIMEFILE`;

    chomp $time;

    return 1 if ( (time - $time) > ($ENV{interval}*60) );

    return 0;

} ## cache_is_too_old

sub du_not_running {

    if (-e $LOCKFILE) {

        my ($time) = `cat $TIMEFILE`;

        chomp $time;

        if ( (time - $time) > ($ENV{interval}*60*60) ) {

            # The cache is really old (60xinterval) => Maybe the lockfile wasn't properly deleted.

            # Let's delete it.

            system("rm $LOCKFILE;");

            return 1;

        } else {

	        return 0;

        }

    } else {

        return 1;

    }

}

sub munin_exit_done {

    __munin_exit(0);

} ## sub munin_exit_done

sub munin_exit_fail {

    __munin_exit(1);

} ## sub munin_exit_fail

#

##

### INTERNALS FONCTIONS

###############################################################################

sub __munin_exit {

    my $exitcode = shift;

    exit($exitcode) if(defined $exitcode);

    exit(1);

} ## sub __munin_exit