How can I get the current user when dealing with a Django InlineFormset

And the long story in short. Just use the session variable when the user logs in.

def login(request):
  #your code here
  request.session['userID']=the_user_id
  .
  .
  #rest of your code

Now you can use this id in any view or template. Like

#in any other view

def myview(request):
  user_id=request.session['userID']
  #rest of your code

#in template

You can directly use the userID in templates like

{{request.session.userID}}

OR

you can make a global variable in DOM for javascript use

<script>
window.userID={{request.session.userID}};
//use userID variable anywhere in DOM
</script>