Allow num_oid to use OCTET STRING indexes (#10410)

* make index available as OCTET STRING converted to OID
* codeclimate

includes/discovery/functions.inc.php

@@ -1047,6 +1047,9 @@ function discovery_process(&$valid, $device, $sensor_type, $pre_cache)
                 $skippedFromYaml = YamlDiscovery::canSkipItem($value, $index, $data, $sensor_options, $pre_cache);
                 if ($skippedFromYaml === false && is_numeric($value)) {
                     $oid = str_replace('{{ $index }}', $index, $data['num_oid']);
+                    // if index is a string, we need to convert it to OID
+                    // strlen($index) as first number, and each letter converted to a number, separated by dots
+                    $oid = str_replace('{{ $index_string }}', strlen($index) . '.' . implode(".", unpack("c*", $index)), $oid);
 
                     // process the description
                     $descr = YamlDiscovery::replaceValues('descr', $index, null, $data, $pre_cache);