#!/usr/bin/env perl
# -*- perl -*-
# vim: ft=perl

=head1 NAME

snmp__memory_openwrt - Munin plugin to monitor the memory usage of an OpenWrt
device.

=head1 APPLICABLE SYSTEMS

OpenWrt devices which have snmpd installed.

=head1 CONFIGURATION

As a rule SNMP plugins need site specific configuration.  The default
configuration (shown here) will only work on insecure sites/devices.

    [snmp_*]
        env.version 2
        env.community public

In general SNMP is not very secure at all unless you use SNMP version
3 which supports authentication and privacy (encryption).  But in any
case the community string for your devices should not be "public".

Please see 'perldoc Munin::Plugin::SNMP' for further configuration
information.

=head1 INTERPRETATION

The total and used memory on the system.

=head1 MIB INFORMATION

This plugin requires support for the HOST-RESOURCES-MIB (RFC 2790).  It
reports the contents of the hrStorageSize and hrStorageUsed OIDs.

=head1 MAGIC MARKERS

  #%# family=snmpauto
  #%# capabilities=snmpconf

=head1 BUGS

None known.

=head1 AUTHOR

Copyright (C) 2017 Hanson Wong

Based on snmp__memory_openwrt (C) 2008 J.M.Roth

=head1 LICENSE

GPLv2.

=cut

use strict;
use Munin::Plugin::SNMP;

if (defined $ARGV[0] and $ARGV[0] eq 'snmpconf') {
    print "require 1.3.6.1.2.1.25.2.3.1.5.1\n";
    print "require 1.3.6.1.2.1.25.2.3.1.6.1\n";
    exit 0;
}

if (defined $ARGV[0] and $ARGV[0] eq "config") {
    my ($host) = Munin::Plugin::SNMP->config_session();

    print "host_name $host\n" unless ($host eq 'localhost');
    print <<'EOC';
graph_title Memory usage
graph_args --base 1000 -l 0
graph_vlabel kB
graph_category memory
graph_info This graph shows total and used memory on the host.
memsize.label total
memused.label used
memsize.info The total memory.
memused.info The memory in use.
memsize.draw LINE1
memused.draw LINE2
EOC
    exit 0;
}

my $session = Munin::Plugin::SNMP->session();
print "memsize.value ", $session->get_single('1.3.6.1.2.1.25.2.3.1.5.1'), "\n";
print "memused.value ", $session->get_single('1.3.6.1.2.1.25.2.3.1.6.1'), "\n";