Question

I have this function trying to print additional ‘.’ every second while it’s copying a big folder (~3GB) from one place to another:

def copy_folder(source, destination):
    print 'copying',
    while shutil.copytree(src=source, dst=destination):
        print '.',
        time.sleep(1)

but when I call the function:

source = 'source_folder'
destination = 'destination_folder'
copy_folder(source=source, destination=destination)

it’s copying perfectly fine the whole folder but it does NOT print ‘.’ at all.

Do I need to use threads?

Answer 1

Threading in Python is pretty simple:

import sys, shutil, time, threading

class CopyThread(threading.Thread):
    def __init__(self, source, destination):
        super(CopyThread, self).__init__()

        self.source = source
        self.destination = destination

    def run(self):
        time.sleep(5)  # Delete me later on, I'm just here to slow things down
        return shutil.copytree(src=self.source, dst=self.destination)

if __name__ == '__main__':
    thread = CopyThread('source_folder', 'destination_folder')
    thread.start()

    while thread.is_alive():
        sys.stdout.write('.')
        sys.stdout.flush()

        time.sleep(1)

    thread.join()

Just subclass threading.Thread and override run(). After that, call .start() on an instance of that class and you have a thread.