Parse string to date and have difference between 2 dates

[Badger]

@Pierre_What_s_Up_Sca

match => [ "dateLog", "MMM d H:mm:ss yyyy" ]

That would match if dateLog were something like "Feb 16 14:30:09 2018", but you said it is formatted as "Fri Feb 16 14:30:09 CET 2018". So you need to modify the pattern to include items to match the "Fri" and "CET". The pattern has to match every part of the date string.