[pygtk] Non-blocking subprocess.Popen stop GUI

[Lobais]

Hi Bou,
I created this PyGtk class a little while ago, to do exactly what you
describe: Do advanced stuff in a thread, and report seamless back to
gtk using signals.
There "recipe" also contains an example, but please tell me if you
need more info.
http://code.activestate.com/recipes/521881/

Regards, Thomas

On Sun, Aug 30, 2009 at 5:26 PM, Bou Baris<boubaris at gmail.com> wrote:
> I'm a new user of PyGTK.
> I'm writing with Python and PyGTK a little software for decoding MKV
> video files using external tool MKV TOOL UNIX. It's a simple graphical
> front-end to ffmpeg and MKVTOOLNIX.
> I use Ubuntu 9.04 shipped with Python 2.6.2 and PyGTK 2.x
>
> I've a problem (obviously).
>
> I've made a non blocking function (using subprocess.Popen and select)
> for calling the external program MKVEXTRACT. When works, 'mkvextract'
> reports its progress state as a percentage:
> Progress: 0%
> Progress: 1%
> Progress: 2%
> ....
>
> I want read 'mkvextract' stdout in a real-time (non-blocking) fashion,
> decode progress number from string 'Progress: xx%' and control a PyGTK
> ProgressBar.
>
>
> This is the code and non-blocking is working (printing the progress to
> console it's ok).
> The problem is that when code run, I see in terminal the percentage
> number decoded correctly (printed from my code, not by 'mkvextract',
> see code below)  but progress bar isn't moving.
> Really ALL GUI is blocked.
> It's look that Popen block GUI job until 'mkvextraxt' end.
> When Popen/mkvextract ends its job, GUI restart to normal behaviour
> and I see the progress bar to 100%
>
>
> def mkv_dts_extraction(self,dtstrack,pgbar=None):
>
>      command=[ 'mkvextract', \
>                        'tracks', \
>                         self.INPUTFILE, \
>                         dtstrack + ':' + self.DTSFILENAME ]
>
>         # start subprocess
>         proc = subprocess.Popen(command,stdout=subprocess.PIPE)
>
>         # set non-blocking mode
>         outfile = proc.stdout
>         outfd = outfile.fileno()
>         file_flags = fcntl.fcntl(outfd, fcntl.F_GETFL)
>         fcntl.fcntl(outfd, fcntl.F_SETFL, file_flags | os.O_NDELAY)
>
>         # use 'select' for reading
>         while True:
>             ready = select.select([outfd],[],[]) # wait for input
>             if outfd in ready[0]:
>                 outchunk = outfile.read()
>                 if outchunk == '' :
>                     break
>             select.select([],[],[],.1) # give a little time for buffers to fill
>
>             perc =
> re.compile("Progress:\s+(\d+)",re.IGNORECASE).findall(outchunk)
>             if len(perc) > 0:
>                 completed = int(perc[len(perc)-1]) / 100.00  # take
> last 'Progress' number
>
>                 print completed  # this print WORKS: in terminal I can
> see the percentage growing
>
>                 # progress bar DON'T WORK : GUI is blocked
>                 pgbar.set_fraction(completed)
>                 pgbar.show()
>
>         err = proc.wait()
>
>         return True
> _______________________________________________
> pygtk mailing list   pygtk at daa.com.au
> http://www.daa.com.au/mailman/listinfo/pygtk
> Read the PyGTK FAQ: http://faq.pygtk.org/
>



-- 
Mvh. Thomas