$re = '/^(?<time>(?:\d{2}:){2}\d{2}\.\d{3} [^\s]*) : (?<message2>[^ \]]*)\] (?<message3>[^ \]]*)\] (?<message4>[^ \]]*)\] (?<message5>[^ \]]*)\] (?<severity>\w+)\s+(?<log2222>.*)/';
$str = '23:02:32.000 17-Oct-2017;04:36:29.744 : [main] [server:] [id:] [yt:] ERROR no.myproject.service.Server - call failed for some reason';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php