PyGTK Progress Bar of commands.getstatusoutput.

Question

HI!

I've been trying to get a PyGTK Progress Bar working by tracking the progress of rsync. TO rsync I'm using commands.getstatusoutput.

Does anyone has an idea how to track the progress of rsync and display it on the PyGTK progress bar?

Thank you!

Answer 1

commands.getstatusoutput will not give you the inceremental output you need to power the status bar. Look at other ways of reading output from rsync.

Answer 2

Since there's really no way to programmatically track the progress of rsync, I think your best bet is to "screen scrape" its output and try to "guess" at its progress somehow.

The first thing you should do is use subprocess instead of commands.getstatusoutput because you'll get much more control over screen scraping rsync's stdout to track its progress. One solution might be to execute rsync with the -v option, which will print each file transferred followed by a newline (plus some other cruft that you don't really need). A simple way to guess at the progress of rsync then, would be to do something like:

import subprocess
p = subprocess.Popen(['rsync', '-v', ..other rsync args..], shell=True,
        stdout=subprocess.PIPE, close_fds=True)
while p.stdout.readline():
    ...
    # rsync has just "completed" an operation, i.e. it probably 
    # transferred a file.  now would be a good time to update the 
    # ProgressBar. there are some options here, see below...
    ...
ret = p.wait()
print "Rsync exited with code %d" % ret

This reads the output of rsync -v ... one line at a time, and in the while loop you would update the ProgressBar as appropriate. The question then becomes, what kind of update? ProgressBar really has two modes - one that "pings" back and forth indicating progress towards some indeterminate goal, and one that moves the bar from left to right based on an increment towards a known goal.

You could try to "guess" the number of files rsync will transfer by obtaining a file list before hand (with --list-only or -vn) and use that as the goal, but this is inherently error-prone because you run the risk of the sender's file list changing in between the time you gather the list and when you actually execute rsync. A better solution is probably just to call pulse() on the ProgressBar in the while loop to indicate that things are happening in the background. If you want to display more information, you could read the output of p.stdout.readline() and update a gtk.Label somewhere to indicate which files are being transferred.

(Note: the code above doesn't take into account error conditions when executing rsync, which you should probably do)