I recently ran into the issue that the multiprocessing.pool.ThreadPool class is not cancellable in Python 2. It seems that only in Python 3 can you exit a ThreadPool with eg. a KeyboardInterrupt before all tasks are finished.

Since then I've been using this code, which works great across all platforms and Python versions: https://github.com/metachris/pdfx/blob/master/pdfx/threadpoo...