Fortigate sessions sensors (#10183)

* Adding sensor for sessions

* Adding test data

* Fix index mistake and update test data (#12)

* Update test data for existing fortigate

includes/discovery/sensors/count/fortigate.inc.php

@@ -0,0 +1,48 @@
+<?php
+/*
+ * LibreNMS Dantel Webmon generic sensor
+ *
+ * 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 (at your
+ * option) any later version.  Please see LICENSE.txt at the top level of
+ * the source code distribution for details.
+ *
+ * @package    LibreNMS
+ * @subpackage webui
+ * @link       http://librenms.org
+ * @copyright  2019 LibreNMS
+ * @author     LibreNMS Contributors
+ */
+
+$session_rate = [
+    'Sessions/sec 1m avg' => ['.1.3.6.1.4.1.12356.101.4.1.11', 'fgSysSesRate1'],  //FORTINET-FORTIGATE-MIB::fgSysSesRate1.0
+    'Sessions/sec 10m avg' => ['.1.3.6.1.4.1.12356.101.4.1.12', 'fgSysSesRate10'],  //FORTINET-FORTIGATE-MIB::fgSysSesRate10.0
+    'Sessions/sec 30m avg' => ['.1.3.6.1.4.1.12356.101.4.1.13', 'fgSysSesRate30'],  //FORTINET-FORTIGATE-MIB::fgSysSesRate30.0
+    'Sessions/sec 60m avg' => ['.1.3.6.1.4.1.12356.101.4.1.14', 'fgSysSesRate60'],  //FORTINET-FORTIGATE-MIB::fgSysSesRate60.0
+    'Session count' => ['.1.3.6.1.4.1.12356.101.4.1.8', 'fgSysSesCount'],  //FORTINET-FORTIGATE-MIB::fgSysSesCount.0
+];
+
+foreach ($session_rate as $descr => $oid) {
+    $oid_num = $oid[0];
+    $oid_txt = $oid[1];
+    $result = snmp_getnext($device, $oid_txt, '-Ovq', 'FORTINET-FORTIGATE-MIB');
+    $result = str_replace(' Sessions Per Second', '', $result);
+
+    discover_sensor(
+        $valid['sensor'],
+        'count',
+        $device,
+        $oid_num . '.0',
+        $oid_txt . '.0',
+        'sessions',
+        $descr,
+        1,
+        1,
+        null,
+        null,
+        null,
+        null,
+        $result
+    );
+}