#!/usr/bin/perl

use DBI;
use Time::Local;
use FileHandle;
use strict;
our $dbh;
my ($p_file,$p_offset,$p_warn,$p_crit,$p_sqlhost,$p_sqlport,$p_sqluser,$p_sqlpass,$p_dbname);

$p_sqlhost = '127.0.0.1';
$p_sqlport = '3306';
$p_sqluser = 'root';
$p_sqlpass = '';
$p_dbname = 'dnsdatadb';
$p_offset = 1800;
$p_warn = 10;
$p_crit = 300;
$p_file = "/var/tmp/replcheck";

if ( $ARGV[0] eq "-help" || $ARGV[0] eq "--help" ){
    help();
    exit(1);
}

my %par;

if ( $ARGV[0] ne "" ){
    my $chk = @ARGV;
    for ( my $i = 0; $i < $chk; $i = $i + 2 ){
        if ($ARGV[$i] =~ /^\-/ ){
            my $key = $ARGV[$i];
            $key =~ s/^\-//ig;
            my $j = $i + 1;
            $par{$key} = $ARGV[$j];
        }
    }
}

#while( my ($key,$value) = each %par){
#    print "$key => $value\n";
#}

$p_sqlhost = $par{'sqlhost'} if ($par{'sqlhost'} ne "" );
$p_sqlport = $par{'sqlport'} if ($par{'sqlport'} ne "" );
$p_sqluser = $par{'sqluser'} if ($par{'sqluser'} ne "" );
$p_sqlpass = $par{'sqlpass'} if ($par{'sqlpass'} ne "" );
$p_dbname = $par{'sqldb'} if ($par{'sqldb'} ne "" );
$p_offset = $par{'offset'} if ($par{'offset'} ne "" );
$p_warn = $par{'warn'} if ($par{'warn'} ne "" );
$p_crit = $par{'crit'} if ($par{'crit'} ne "" );
$p_file = $par{'file'} if ($par{'file'} ne "" );

connect_db($p_sqlhost,$p_sqlport,$p_sqluser,$p_sqlpass,$p_dbname);

if ( $p_crit < $p_warn ){
    print "Critical alert offset cannot be less than warning alert offset\n";
    exit(1);
}

my $pointer = $p_file;
my $logpos = get_mysql_status(0);
my $sec_to_master = get_mysql_status(1);

if ( $sec_to_master > $p_warn ){
    print "Warning! The parameter \"seconds behind master\" greater than $p_warn ($sec_to_master)\n";
    exit(1);
}
elsif ( $sec_to_master > $p_crit ){
    print "CRITICAL! The parameter \"seconds behind master\" greater than $p_crit sec ($sec_to_master)\n";
    exit(2);
}

my $chk_step = $p_offset;

my $time = time();
my $timeleft;

if ( -e $pointer ){
    open (LOG,"$pointer") || error("Cannot open file");
    my @strs = <LOG>;
    close(LOG);
    my ($logtime,$chkpos) = split( /-/, $strs[0]);
    chomp($chkpos);
    my $chktime = $time - $chk_step;
    my $timefut = $logtime + $chk_step;
    $timeleft = $timefut - $time;
    if ( $logtime < $chktime ){
        if ( $chkpos != $logpos ){
            #print "Different - $chkpos - $logpos\n";
        }
        else {
            #print "The same! $chkpos - $logpos\n";
            error("No changes during $chk_step seconds");
        }
        put_result($pointer, $logpos, $time);
        print "OK\n";
        exit(0);
    }
}
else {
    #print "There is no logfile. Creating...\n";
    put_result($pointer, $logpos, $time);
}

print "Waiting for next check... $timeleft seconds left\n";
exit(0);

sub error {
    my $reason = shift;
    print "CRITICAL - $reason\n";
    exit(2);
}

sub put_result {
    my $pointer = shift;
    my $logpos = shift;
    my $time = shift;
    open (FILE, ">$pointer") || error("Cannot open logfile");
    print FILE "$time-$logpos\n";
    close(FILE);
}

sub get_mysql_status {
    my $request = shift;
    my $res;
    my $sth = $dbh->prepare("show slave status");
    $sth->execute;
    my $result = $sth->fetchrow_hashref();
#    print "$result->{'Exec_Master_Log_Pos'}\n";
    if ( $request == 1 ){
        $res = $result->{'Seconds_Behind_Master'};
    }
    else {
        $res = $result->{'Exec_Master_Log_Pos'};
    }
return($res);
}

sub connect_db{
my ($db_base, $db_host, $db_user, $db_pass, $db_enc);

my $db_host = shift;
my $db_port = shift;
my $db_user = shift;
my $db_pass = shift;
my $db_name = shift;

$db_enc = 'utf8';

my $dsn = "DBI:mysql:$db_name:$db_host:$db_port";
$dbh = DBI->connect($dsn, $db_user, $db_pass) || error("MySQL error");
my $sth = $dbh->do("set names \'$db_enc\'");

}
sub help {

my $script = $0;
print <<"[END]";

The script $script made as NRPE plugin. It\'s checking MySQL slave status and generates the correspondent status message.
The command line should be the next:

        $script [option1] [value1] [option2] [value2] ... [optionN] [valueN]

You can specify the next options in command line running the script:

-offset [seconds]  - Option that specifies the frequency of comparing of "Exec_Master_Log_Pos" values. If the values stays the same after this time, you get CRITICAL status.
                     Default value: 1800 (30 min)
-warn [seconds]    - Option that specifies the value of "Seconds_Behind_Master" when the script start returning of WARNING status.
                     Default value: 10
-crit [seconds]    - Option that specifies the value of "Seconds_Behind_Master" when the script start returning CRITICAL status.
                     Default value: 300
-sqlhost [address] - MySQL server address
                     Default value: localhost
-sqlport [port]    - MySQL server port
                     Default value: 3306
-sqluser [username]- MySQL username
                     Deafult: root
-sqlpass [password]- MySQL password
                     Default: <none>
-sqldb [name]      - Database name
                     Default: dnsdatadb
-file [/path/file] - File to store time and "Exec_Master_Log_Pos" values.
                     Default: /var/tmp/replcheck
-help                Show this help

Sample:

        $script -offset 1800 -warn 10 -crit 300 -sqlhost localhost -sqlport 3306 -sqluser root -sqlpass password -sqldb dnsdatadb -file /var/tmp/replcheck
        $script -offset 1800 -warn 10 -crit 300 -sqlhost localhost
        $script -sqlhost localhost -sqlport 3306 -sqluser root -sqlpass password


[END]

exit;
}