[LAD] Python assistance - threads (my favorite)

[fons at kokkinizita.net]

On Thu, Oct 14, 2010 at 03:04:54PM -0700, Patrick Shirkey wrote:

> In a bit of a time crunch. Can anyone tell me how to do this properly?
> 
> I would like to have a threaded timer to run "cmd" after 5 seconds.
> However cmd is normally triggered like this:
> 
> os.system(cmd)
> 
> But there seems to be an issue with calling os.system(cmd) from
> subprocess.popen.
> 
> ==========================
> 
> def do_popen(self, *args):
> 	subprocess.Popen(args[0], shell=True)
> 
> 
> def other function
> 
> 		cmd = 'spd-say -t female2 "' + audioText + '"'
> 		args = shlex.split(cmd)
> 
> 	# Add 5 second delay for first view to allow existing speech processes to
> finish
> 		print "do_speech: ",delay
> 		if delay:
> 			print "do_speech: delayed start"
> 			t = threading.Timer(5.0, self.do_popen(cmd))
> 			t.start()
> 		else :
> 			print "do_speech: immediate start"
> 			self.do_popen(cmd)
> 
> ======================

A bit confusing - you mention os.system() but is not used at all
(nor should it if you use subprocess.Popen(). 

You didn't tell what happens...

I suspect that if you do this in a function the thread 't' will be
destroyed as soon as that function returns. Making 't' global could
help. (no guarantee -- speculating).

Ciao,

-- 
FA

There are three of them, and Alleline.