How to copy a file in Python with a progress bar?

Question

When copying large files using shutil.copy(), you get no indication of how the operation is progressing..

I have put together something that works - it uses a simple ProgressBar class (which simple returns a simple ASCII progress bar, as a string), and a loop of open().read() and .write() to do the actual copying. It displays the progress bar using sys.stdout.write("\r%s\r" % (the_progress_bar)) which is a little hackish, but it works.

You can see the code (in context) on github here

Is there any built-in module that will do this better? Is there any improvements that can be made to this code?

Answer 1

Two things:

• I would make the default block size a lot larger than 512. I would start with 16384 and perhaps more.
• For modularity, it might be better to have the copy_with_prog function not output the progress bar itself, but call a callback function so the caller can decide how to display the progress.

Perhaps something like this:

def copy_with_prog(src, dest, callback = None):
    while True:
        # copy loop stuff
        if callback:
            callback(pos, total)

prog = ProgressBar(...)
copy_with_prog(src, dest, lambda pos, total: prog.update(pos, total))

Answer 2

Overkill? Perhaps. But on almost any system, Linux, Mac, and With a quick wxWidgets install on Windows, you can have the real deal, with pause and cancel buttons in a gui setup. Macs ship with wxWidgets these days, and it's a common package on Linux.

A single file is very quick (it will immediately finish and look broken) so you might consider creating a fileSet job that ticks along once per file instead of once per block. Enjoy!

-Jim Carroll

"""
Threaded Jobs.

Any class that does a long running process can inherit
from ThreadedJob.  This enables running as a background
thread, progress notification, pause and cancel.  The
time remaining is also calculated by the ThreadedJob class.
"""
import wx.lib.newevent
import thread
import exceptions
import time

(RunEvent, EVT_RUN) = wx.lib.newevent.NewEvent()
(CancelEvent, EVT_CANCEL) = wx.lib.newevent.NewEvent()
(DoneEvent, EVT_DONE) = wx.lib.newevent.NewEvent()
(ProgressStartEvent, EVT_PROGRESS_START) = wx.lib.newevent.NewEvent()
(ProgressEvent, EVT_PROGRESS) = wx.lib.newevent.NewEvent()

class InterruptedException(exceptions.Exception):
    def __init__(self, args = None):
        self.args = args
    #
#

class ThreadedJob:
    def __init__(self):
        # tell them ten seconds at first
        self.secondsRemaining = 10.0
        self.lastTick = 0

        # not running yet
        self.isPaused = False
        self.isRunning = False
        self.keepGoing = True

    def Start(self):
        self.keepGoing = self.isRunning = True
        thread.start_new_thread(self.Run, ())

        self.isPaused = False
    #

    def Stop(self):
        self.keepGoing = False
    #

    def WaitUntilStopped(self):
        while self.isRunning:
            time.sleep(0.1)
            wx.SafeYield()
        #
    #

    def IsRunning(self):
        return self.isRunning
    #

    def Run(self):
        # this is overridden by the
        # concrete ThreadedJob
        print "Run was not overloaded"
        self.JobFinished()

        pass
    #

    def Pause(self):
        self.isPaused = True
        pass
    #

    def Continue(self):
        self.isPaused = False
        pass
    #

    def PossibleStoppingPoint(self):
        if not self.keepGoing:
            raise InterruptedException("process interrupted.")
        wx.SafeYield()

        # allow cancel while paused
        while self.isPaused:
            if not self.keepGoing:
                raise InterruptedException("process interrupted.")

            # don't hog the CPU
            time.sleep(0.1)
        #
    #

    def SetProgressMessageWindow(self, win):
        self.win = win
    #

    def JobBeginning(self, totalTicks):

        self.lastIterationTime = time.time()
        self.totalTicks = totalTicks

        if hasattr(self, "win") and self.win:
            wx.PostEvent(self.win, ProgressStartEvent(total=totalTicks))
        #
    #

    def JobProgress(self, currentTick):
        dt = time.time() - self.lastIterationTime
        self.lastIterationTime = time.time()
        dtick = currentTick - self.lastTick
        self.lastTick = currentTick

        alpha = 0.92
        if currentTick > 1:
            self.secondsPerTick = dt * (1.0 - alpha) + (self.secondsPerTick * alpha)
        else:
            self.secondsPerTick = dt
        #

        if dtick > 0:
            self.secondsPerTick /= dtick

        self.secondsRemaining = self.secondsPerTick * (self.totalTicks - 1 - currentTick) + 1

        if hasattr(self, "win") and self.win:
            wx.PostEvent(self.win, ProgressEvent(count=currentTick))
        #
    #

    def SecondsRemaining(self):
        return self.secondsRemaining
    #

    def TimeRemaining(self):

        if 1: #self.secondsRemaining > 3:
            minutes = self.secondsRemaining // 60
            seconds = int(self.secondsRemaining % 60.0)
            return "%i:%02i" % (minutes, seconds)
        else:
            return "a few"
    #

    def JobFinished(self):
        if hasattr(self, "win") and self.win:
            wx.PostEvent(self.win, DoneEvent())
        #

        # flag we're done before we post the all done message
        self.isRunning = False
    #
#

class EggTimerJob(ThreadedJob):
    """ A sample Job that demonstrates the mechanisms and features of the Threaded Job"""
    def __init__(self, duration):
        self.duration = duration
        ThreadedJob.__init__(self)
    #

    def Run(self):
        """ This can either be run directly for synchronous use of the job,
        or started as a thread when ThreadedJob.Start() is called.

        It is responsible for calling JobBeginning, JobProgress, and JobFinished.
        And as often as possible, calling PossibleStoppingPoint() which will 
        sleep if the user pauses, and raise an exception if the user cancels.
        """
        self.time0 = time.clock()
        self.JobBeginning(self.duration)

        try:
            for count in range(0, self.duration):
                time.sleep(1.0)
                self.JobProgress(count)
                self.PossibleStoppingPoint()
            #
        except InterruptedException:
            # clean up if user stops the Job early
            print "canceled prematurely!"
        #

        # always signal the end of the job
        self.JobFinished()
        #
    #

    def __str__(self):
        """ The job progress dialog expects the job to describe its current state."""
        response = []
        if self.isPaused:
            response.append("Paused Counting")
        elif not self.isRunning:
            response.append("Will Count the seconds")
        else:
            response.append("Counting")
        #
        return " ".join(response)
    #
#

class FileCopyJob(ThreadedJob):
    """ A common file copy Job. """

    def __init__(self, orig_filename, copy_filename, block_size=32*1024):

        self.src = orig_filename
        self.dest = copy_filename
        self.block_size = block_size
        ThreadedJob.__init__(self)
    #

    def Run(self):
        """ This can either be run directly for synchronous use of the job,
        or started as a thread when ThreadedJob.Start() is called.

        It is responsible for calling JobBeginning, JobProgress, and JobFinished.
        And as often as possible, calling PossibleStoppingPoint() which will 
        sleep if the user pauses, and raise an exception if the user cancels.
        """
        self.time0 = time.clock()

        try:
            source = open(self.src, 'rb')

            # how many blocks?
            import os
            (st_mode, st_ino, st_dev, st_nlink, st_uid, st_gid, st_size, st_atime, st_mtime, st_ctime) = os.stat(self.src)
            num_blocks = st_size / self.block_size
            current_block = 0

            self.JobBeginning(num_blocks)

            dest = open(self.dest, 'wb')

            while 1:
                copy_buffer = source.read(self.block_size)
                if copy_buffer:
                    dest.write(copy_buffer)
                    current_block += 1
                    self.JobProgress(current_block)
                    self.PossibleStoppingPoint()
                else:
                    break

            source.close()
            dest.close()

        except InterruptedException:
            # clean up if user stops the Job early
            dest.close()
            # unlink / delete the file that is partially copied
            os.unlink(self.dest)
            print "canceled, dest deleted!"
        #

        # always signal the end of the job
        self.JobFinished()
        #
    #

    def __str__(self):
        """ The job progress dialog expects the job to describe its current state."""
        response = []
        if self.isPaused:
            response.append("Paused Copy")
        elif not self.isRunning:
            response.append("Will Copy a file")
        else:
            response.append("Copying")
        #
        return " ".join(response)
    #
#

class JobProgress(wx.Dialog):
    """ This dialog shows the progress of any ThreadedJob.

    It can be shown Modally if the main application needs to suspend
    operation, or it can be shown Modelessly for background progress
    reporting.

    app = wx.PySimpleApp()
    job = EggTimerJob(duration = 10)
    dlg = JobProgress(None, job)
    job.SetProgressMessageWindow(dlg)
    job.Start()
    dlg.ShowModal()


    """
    def __init__(self, parent, job):
        self.job = job

        wx.Dialog.__init__(self, parent, -1, "Progress", size=(350,200))

        # vertical box sizer
        sizeAll = wx.BoxSizer(wx.VERTICAL)

        # Job status text
        self.JobStatusText = wx.StaticText(self, -1, "Starting...")
        sizeAll.Add(self.JobStatusText, 0, wx.EXPAND|wx.ALL, 8)

        # wxGague
        self.ProgressBar = wx.Gauge(self, -1, 10, wx.DefaultPosition, (250, 15))
        sizeAll.Add(self.ProgressBar, 0, wx.EXPAND|wx.ALL, 8)

        # horiz box sizer, and spacer to right-justify
        sizeRemaining = wx.BoxSizer(wx.HORIZONTAL)
        sizeRemaining.Add((2,2), 1, wx.EXPAND)

        # time remaining read-only edit
        # putting wide default text gets a reasonable initial layout.
        self.remainingText = wx.StaticText(self, -1, "???:??")
        sizeRemaining.Add(self.remainingText, 0, wx.LEFT|wx.RIGHT|wx.ALIGN_CENTER_VERTICAL, 8)

        # static text: remaining
        self.remainingLabel = wx.StaticText(self, -1, "remaining")
        sizeRemaining.Add(self.remainingLabel, 0, wx.ALL|wx.ALIGN_CENTER_VERTICAL, 8)

        # add that row to the mix
        sizeAll.Add(sizeRemaining, 1, wx.EXPAND)

        # horiz box sizer & spacer
        sizeButtons = wx.BoxSizer(wx.HORIZONTAL)
        sizeButtons.Add((2,2), 1, wx.EXPAND|wx.ADJUST_MINSIZE)

        # Pause Button
        self.PauseButton = wx.Button(self, -1, "Pause")
        sizeButtons.Add(self.PauseButton, 0, wx.ALL, 4)
        self.Bind(wx.EVT_BUTTON, self.OnPauseButton, self.PauseButton)

        # Cancel button
        self.CancelButton = wx.Button(self, wx.ID_CANCEL, "Cancel")
        sizeButtons.Add(self.CancelButton, 0, wx.ALL, 4)
        self.Bind(wx.EVT_BUTTON, self.OnCancel, self.CancelButton)

        # Add all the buttons on the bottom row to the dialog
        sizeAll.Add(sizeButtons, 0, wx.EXPAND|wx.ALL, 4)

        self.SetSizer(sizeAll)
        #sizeAll.Fit(self)
        sizeAll.SetSizeHints(self)

        # jobs tell us how they are doing
        self.Bind(EVT_PROGRESS_START, self.OnProgressStart)
        self.Bind(EVT_PROGRESS, self.OnProgress)
        self.Bind(EVT_DONE, self.OnDone)

        self.Layout()
    #

    def OnPauseButton(self, event):
        if self.job.isPaused:
            self.job.Continue()
            self.PauseButton.SetLabel("Pause")
            self.Layout()
        else:
            self.job.Pause()
            self.PauseButton.SetLabel("Resume")
            self.Layout()
        #
    #

    def OnCancel(self, event):
        self.job.Stop()
    #

    def OnProgressStart(self, event):
        self.ProgressBar.SetRange(event.total)
        self.statusUpdateTime = time.clock()
    #

    def OnProgress(self, event):
        # update the progress bar
        self.ProgressBar.SetValue(event.count)

        self.remainingText.SetLabel(self.job.TimeRemaining())

        # update the text a max of 20 times a second
        if time.clock() - self.statusUpdateTime > 0.05:
            self.JobStatusText.SetLabel(str(self.job))
            self.statusUpdateTime = time.clock()
            self.Layout()
        #
    #

    # when a job is done
    def OnDone(self, event):
        self.ProgressBar.SetValue(0)
        self.JobStatusText.SetLabel("Finished")
        self.Destroy()
    #
#

if __name__ == "__main__":
    app = wx.PySimpleApp()
    #job = EggTimerJob(duration = 10)
    job = FileCopyJob("VeryBigFile.mp4", "/tmp/test_junk.mp4", 1024*1024*10)
    dlg = JobProgress(None, job)
    job.SetProgressMessageWindow(dlg)
    job.Start()
    dlg.ShowModal()
#