Can i get the user name which is logged into the Metabase.
Covered how to see when users are last logged in the 
Admin Guide on this page: https://metabase.com/docs/latest/administration-guide/04-managing-users.html
Not sure 
if that was what you are asking for?
No i want to now current login name in Metabase. So that accordingly i can apply filters.
Aaaah! … of course 
Then Search here on Discourse:
http://discourse.metabase.com/search?q=username
… and you will see it’s - more or less a #faq - for example: How to use authenticated user’s username as a variable in the SQL string used to create a new question?