#!/usr/bin/perl
# nagios: -epn
#
#  Author: Hari Sekhon
#  Date: 2011-08-22 15:56:27 +0000 (Mon, 22 Aug 2011)
#
#  https://github.com/HariSekhon/Nagios-Plugins
#
#  License: see accompanying LICENSE file
#

$DESCRIPTION = "Nagios Plugin to check arbitrary MySQL queries against regex matches or numerical ranges, with perfdata support for graphing

It looks like a similar plugin has now been added to the standard Nagios Plugins collection, although this one still has more features

Only the first row returned is considered for the result so your SQL query should take that in to account

DO NOT ADD a semi-colon to the end of your query in Nagios, although this plugin can handle this fine and it works on the command line, in Nagios the command will end up being prematurely terminated and result in a null critical error that is hard to debug and that this plugin cannot catch since it's raised by the shell before this plugin is executed

Tested on MySQL 5.0, 5.1, 5.5, 5.6, 5.7, 8.0 and MariaDB 5.5, 10.1, 10.2, 10.3
";

# TODO: add retry switch if valid below threshold

$VERSION = "1.2.0";

use strict;
use warnings;
use Time::HiRes;
BEGIN {
    use File::Basename;
    use lib dirname(__FILE__) . "/lib";
}
use HariSekhonUtils;
use DBI;

set_port_default(3306);
set_timeout_max(3600);

my @default_mysql_sockets = ( "/var/lib/mysql/mysql.sock", "/tmp/mysql.sock");
my $mysql_socket;

my $default_message = "query returned";
my $database;
my $epoch;
my $query;
my $field = 1;
my $graph;
my $label;
my $message = $default_message;
my $message_pre;
my $message_printf = 0;
my $message_printf_numeric = 0;
my $no_querytime = 0;
my $output;
my $regex;
my $short;
my $units = "";

env_creds("MYSQL", "MySQL");
env_var("MYSQL_DATABASE", \$database);

%options = (
    %hostoptions,
    %useroptions,
    "d|database=s"  => [ \$database, "MySQL database (\$MYSQL_DATABASE)" ],
    "s|mysql-socket=s" => [ \$mysql_socket,    "MySQL socket file through which to connect (defaults: " . join(", ", @default_mysql_sockets) . ")" ],
    "q|query=s"     => [ \$query,    "MySQL query to execute" ],
    "f|field=s"     => [ \$field,    "Field name / number to check the results of (defaults to '1' for the first field)" ],
    "e|epoch"       => [ \$epoch,    "Subtract result from current time in epoch format from result (useful for timestamp based comparisons)" ],
    "m|message=s"   => [ \$message,  "Message to output after result. Can take a printf string with a single substitution (defaults to '$default_message')" ],
    "n|message-prepend" => [ \$message_pre, "Display message before rather than after result (prepend)" ],
    "o|output=s"    => [ \$output,   "Exact output to expect" ],
    "r|regex=s"     => [ \$regex,    "Regex to match the result against" ],
    "g|graph"       => [ \$graph,    "Perfdata output for graphing" ],
    "l|label=s"     => [ \$label,    "Perfdata label. If not specified uses field name or Undefined if field name doesn't match a known regex of chars" ],
    "U|units=s"     => [ \$units,    "Units of measurement for graphing output (%/s/ms/us/B/KB/MB/TB/c)" ],
    "T|short"       => [ \$short,    "Shorten output, do not output message just result" ],
    "Q|no-querytime" => [ \$no_querytime, "Do not output the mysql query time" ],
    %thresholdoptions,
);
@usage_order = qw/host port user password database mysql-socket query field epoch message message-prepend output regex warning critical graph label units short no-querytime/;

get_options();

if($host){
    $host = validate_host($host) if $host;
    $port = validate_port($port);
} else {
    unless($mysql_socket){
        foreach(@default_mysql_sockets){
            if( -e $_ ){
                vlog2 "found mysql socket '$_'";
                $mysql_socket = $_;
                last;
            }
        }
    }
    unless($mysql_socket){
        usage "host not defined and no mysql socket found, must specify one of --host or --mysql-socket";
    }
    $mysql_socket = validate_filename($mysql_socket, "mysql socket");
}
$user       = validate_user($user);
$password   = validate_password($password) if $password;
$database   = validate_database($database);
$query      = validate_database_query_select_show($query);
$field      = validate_database_fieldname($field);
$regex      = validate_regex($regex) if defined($regex);
$label      = validate_label($label) if($label);
$units      = validate_units($units) if($units);
vlog2("output:    $output") if defined($output);
vlog2("epoch:     on") if $epoch;
validate_thresholds(0, 0, {'positive' => 0});
$message_pre = 1 if($message eq $default_message);
if($message =~ /^[^%]*\%s[^%]*$/){
    $message_printf = 1;
    vlog2("\nenabling printf string format message (only 1 string printf variable detected)");
} elsif($message =~ /^[^%]*\%(?:\d+)?(?:\.\d+)?[fd][^%]*$/){
    $message_printf_numeric = 1;
    vlog2("\nenabling printf numeric format message (only 1 float/int printf variable detected)");
}
$graph = 1 if $label;
$graph = 1 if $units;
if($graph){
    unless($label){
        vlog2("graphing enabled, defaulting label to field: $field");
        $label = "$field";
    }
    $label = validate_label($label);
}

vlog2;
set_timeout();

my $dbh;
if($host){
    vlog2 "connecting to MySQL database on '$host:$port' as '$user'\n";
    $dbh = DBI->connect("DBI:mysql:$database:$host:$port", $user, $password,
                        { Taint      => 1,
                          PrintError => 0,
                          RaiseError => 0 } )
    or quit "CRITICAL", "Couldn't connect to '$host:$port' database '$database' (DBI error: " . DBI->errstr . ")";
} else { # connect through local socket
    vlog2 "connecting to MySQL database via socket '$mysql_socket'\n";
    $dbh = DBI->connect("DBI:mysql:$database", $user, $password, { mysql_socket => $mysql_socket, Taint => 1, PrintError => 0, RaiseError => 0 }) || quit "CRITICAL", "failed to connect to MySQL database through socket: $DBI::errstr";
};
vlog2 "login to database successful\n";

# TODO: add multi record support
sub execute_query{
    my $sql = $_[0];
    defined($dbh) or quit "CRITICAL", "database handle no longer valid while attempting to prepare query ($sql)";
    #DBI->trace("SQL");
    my $sth = $dbh->prepare($sql) or quit "CRITICAL", "failed to prepare query: " . $dbh->errstr . " ($sql)";
    vlog2 "query: $sql";
    my $start = Time::HiRes::time;
    $sth->execute or quit "CRITICAL", "Couldn't execute query: " . $sth->errstr . " (\"$sql\")";
    my $stop  = Time::HiRes::time;
    my $query_time = sprintf("%.4f", $stop - $start);
    vlog2 "query executed in $query_time secs";
    if($sth->rows == 0){
        quit "CRITICAL", "no rows returned by query \"$sql\"";
    }
    my $result;
    if($field =~ /^\d+$/){
        my @data = $sth->fetchrow_array();
        if ($verbose >= 3){
            # Data::Dumper makes this ugly as it dumps this out to dozens of lines of $VAR<N> = 'Y';
            # deferred import of Data::Dumper to here so you don't need to have Data::Dumper installed if not running in debug mode / verbose >= 3
            use Data::Dumper;
            vlog3 "Result Row array:\n" . Dumper(@data);
            # looks nicer and more concise but not as clear in quickly determining field numbers
            #my $row_str = "Result row:  ";
            #vlog3 "Result row:  " . Dumper(@data);
            #foreach(@data){
            #    $row_str .= "$_ " if $_;
            #}
            #vlog3 $row_str
        }
        defined($data[$field-1]) or quit "CRITICAL", "couldn't find field $field in result from query \"$sql\"";
        $result = $data[$field-1];
    } else {
        my $data;
        $data = $sth->fetchrow_hashref();
        if($verbose >= 3){
            # deferred import of Data::Dumper to here so you don't need to have Data::Dumper installed if not running in debug mode / verbose >= 3
            use Data::Dumper;
            vlog3 "Result Row:  " . Dumper($data);
        }
        unless(defined($$data{$field})){
            my $errstr = "couldn't find '$field' field in result from query \"$sql\" (fields returned: ";
            foreach(sort keys %$data){
                $errstr .= "'$_', ";
            }
            $errstr =~ s/, $/)/;
            quit "CRITICAL", $errstr;
        }
        $result = $$data{$field};
    }
    $sth->finish();
    vlog3 "result: $result";
    return ($result, $query_time);
}

my ($result, $query_time) = execute_query($query);
defined($result) or quit "CRITICAL", "no result was received from '$database' database on '$host:$port'";
vlog2;

my $time;
if($epoch){
    isFloat($result) or quit "CRITICAL", "cannot diff result from current epoch time, result is not a number (result: '$result')";
    $time = time;
    vlog3 "epoch time: $time";
    $result = $time - $result;
    vlog2 "result diff: $result";
}

$status = "OK";
if($message_printf){
    $msg   .= sprintf($message, $result);
} elsif($message_printf_numeric and isFloat($result)){
    $msg   .= sprintf($message, $result);
} else {
    $msg   .= "$message " if ($message_pre and not $short);
    $msg   .= "'$result'";
    $msg   .= " $message" unless ($message_pre or $short);
}

if(defined($regex)){
    if($result =~ /$regex/){
        vlog2 "result matched regex $regex\n";
    } else {
        quit "CRITICAL", "$msg (expected regex: '$regex')";
    }
}

if(defined($output)){
    if($result eq $output){
        vlog2 "result matched expected output";
    } else {
        quit "CRITICAL", "$msg (expected: '$output')";
    }
}

if($thresholds{"defined"}){
    #$result =~ /^\d+(?:\.\d+)?$/ or quit "CRITICAL", "result did not match expected thresholds, was not in numeric format (result: '$result')";
    #isFloat($result)
    # Allow for negative numbers
    isFloat($result, 1)
        or quit "CRITICAL", "result did not match expected thresholds, was not in numeric format (result: '$result')";
    check_thresholds($result);
}

$msg .= " | ";
if ($graph and isFloat($result, 1)) {
    $msg .= "'$label'=$result";
    if($units){
        $msg .= $units;
    }
    if($thresholds{"warning"}{"upper"} or $thresholds{"critical"}{"upper"}){
        $msg .= ";" . ( $thresholds{"warning"}{"upper"} ? $thresholds{"warning"}{"upper"} : "" );
        $msg .= ";" . ( $thresholds{"critical"}{"upper"} ? $thresholds{"critical"}{"upper"} : "" );
    }
    $msg .= " ";
}
$msg .= "mysql_query_time=${query_time}s" unless $no_querytime;

vlog2;
quit $status, $msg;