Welcome to the FAQ website covering document topics in Canada.
I have work permit, which expires on 12th Aug. Till then I’m planning to visit Europe for vacations for few weeks. Still I will have the same job in Canada and planning to extend the validity of my work permit for few months. Can I re-enter Canada on 4th Aug? Should I apply for some documents before my vacations?
You should be able to re-enter however you can expect questions about your intentions if you haven’t gotten an extension. (This assumes you have a valid eTA/visa to get to Canada in the first place.)