# Usage:
#       ./zbx_linux_io.pl <no args specified> - returns a list of available devices in JSON.
#       ./zbx_linux_io.pl $DEVICE_NAME OPTION - returns a I/O statistics of given device in JSON. OPTIONs: rps, wps, util.


use warnings;
use strict;

# Get io statistics
my @iostat_system = qx(iostat -x -p -k);

# Get all block devices and its partitions
my @lsblk_system = qx(lsblk -l);

# Array to store partitions
my @partitions;

# Hash to store Zabbix data
my %disk_data;

# Removing all except disk partitions
@lsblk_system = grep /part/, @lsblk_system;

# Removing empty lines from iostat output
@iostat_system = grep /\S/, @iostat_system;

# Filtering out all fields except partition name
foreach (@lsblk_system) {
# Converting spaces or tabs to comma
        s/\s+/,/g;
# Getting partition name
        my ($partition) = split (/,/, $_);
        push @partitions, $partition;
}

foreach my $partition (@partitions) {
        foreach my $io (@iostat_system) {
                $io =~ s/\s+/,/g;
                $io =~ s/p(\d)/$1/;
                if ($io =~ /$partition/) {
                        my ($device, $rrqms, $wrqms, $rs, $ws, $rkBs, $wkBs, $avgrqsz, $avgqusz, $await, $rawait, $wawait, $svctm, $util) = split (/,/, $io);
                        $disk_data{$device}{rps}        = $rs;
                        $disk_data{$device}{wps}        = $ws;
                        $disk_data{$device}{util}       = $util;
                }
        }
}

if (! @ARGV) {
        my $JSON =  "{ \"data\": [\n" . join(",\n", map { "\t".'{ "{#DEVICE_NAME}": "'.$_.'" }' } sort keys %disk_data) . "\n]}\n";
        print $JSON;
} elsif ((defined $ARGV[0]) && (defined $ARGV[1])) {
        print "$disk_data{$ARGV[0]}{$ARGV[1]}\n"
}