subprocess seems to "detach" / ignore wait() | | |
Hi there,
it seems that child.wait() is ignored when
print "Server running [PID %s]"%(child.pid)
fpid.write(child.pid)
are between the process creation child = Popen(cmd.split(),
stderr=flog) and child.wait().
It seems to be a bug, doesn't it ?
Mathieu
(I'm running x11vnv with args in the cmd string on FreeBSD 8.0/CURRENT)
flog = open(logfile, 'w')
fpid = open(pidfile, 'w')
try:
child = Popen(cmd.split(), stderr=flog)
print "Server running [PID %s]"%(child.pid)
fpid.write(child.pid)
child.wait()
except KeyboardInterrupt:
print "INT sent to vnc server"
finally:
fpid.close()
flog.close()
os.remove(pidfile)
os.remove(logfile)
sys.exit(0)
| | | | re: subprocess seems to "detach" / ignore wait()
On Wed, 20 Aug 2008 15:09:11 +0200, Mathieu Prevot wrote: Quote:
flog = open(logfile, 'w')
fpid = open(pidfile, 'w')
try:
child = Popen(cmd.split(), stderr=flog)
print "Server running [PID %s]"%(child.pid)
fpid.write(child.pid)
What happens if you change:
fpid.write(child.pid)
into:
fpid.write('%d\n' % (child.pid))
I think that the problem here is that fpid.write() fails silently
(probably TypeError), because it takes string as its first argument,
not integer.
--
Regards,
Wojtek Walczak, http://tosh.pl/gminick/ | | | | re: subprocess seems to "detach" / ignore wait()
En Wed, 20 Aug 2008 12:22:16 -0300, Wojtek Walczak <gminick@bzt.bztescribió: Quote:
On Wed, 20 Aug 2008 15:09:11 +0200, Mathieu Prevot wrote:
> Quote:
> child = Popen(cmd.split(), stderr=flog)
> print "Server running [PID %s]"%(child.pid)
> fpid.write(child.pid)
>
I think that the problem here is that fpid.write() fails silently
(probably TypeError), because it takes string as its first argument,
not integer.
Exactly, but it doesn't fail "silently" (that would be a bug). The exception is raised, but due to the finally clause ending in sys.exit(0), it has no chance of being handled.
This is the original code, for reference:
flog = open(logfile, 'w')
fpid = open(pidfile, 'w')
try:
child = Popen(cmd.split(), stderr=flog)
print "Server running [PID %s]"%(child.pid)
fpid.write(child.pid)
child.wait()
except KeyboardInterrupt:
print "INT sent to vnc server"
finally:
fpid.close()
flog.close()
os.remove(pidfile)
os.remove(logfile)
sys.exit(0)
--
Gabriel Genellina | | | | re: subprocess seems to "detach" / ignore wait()
2008/8/20 Gabriel Genellina <gagsl-py2@yahoo.com.ar>: Quote:
En Wed, 20 Aug 2008 12:22:16 -0300, Wojtek Walczak <gminick@bzt.bztescribió:
> Quote:
>On Wed, 20 Aug 2008 15:09:11 +0200, Mathieu Prevot wrote:
>> Quote:
>> child = Popen(cmd.split(), stderr=flog)
>> print "Server running [PID %s]"%(child.pid)
>> fpid.write(child.pid)
>>
>I think that the problem here is that fpid.write() fails silently
>(probably TypeError), because it takes string as its first argument,
>not integer.
>
Exactly, but it doesn't fail "silently" (that would be a bug). The exception is raised, but due to the finally clause ending in sys.exit(0), it has no chance of being handled.
This is the original code, for reference:
>
flog = open(logfile, 'w')
fpid = open(pidfile, 'w')
try:
child = Popen(cmd.split(), stderr=flog)
print "Server running [PID %s]"%(child.pid)
fpid.write(child.pid)
child.wait()
except KeyboardInterrupt:
print "INT sent to vnc server"
finally:
fpid.close()
flog.close()
os.remove(pidfile)
os.remove(logfile)
sys.exit(0)
>
--
Gabriel Genellina
Indeed, I got TypeError: argument 1 must be string or read-only
character buffer, not int
and Wojtek's code works. So what is the right thing to do so my script
returns 1 or 0 depending on its state and success ?
Mathieu | | | | re: subprocess seems to "detach" / ignore wait()
2008/8/21 Mathieu Prevot <mathieu.prevot@ens.fr>: Quote:
2008/8/20 Gabriel Genellina <gagsl-py2@yahoo.com.ar>: Quote:
>En Wed, 20 Aug 2008 12:22:16 -0300, Wojtek Walczak <gminick@bzt.bztescribió:
>> Quote:
>>On Wed, 20 Aug 2008 15:09:11 +0200, Mathieu Prevot wrote:
>>>
>>> child = Popen(cmd.split(), stderr=flog)
>>> print "Server running [PID %s]"%(child.pid)
>>> fpid.write(child.pid)
>>>
>>I think that the problem here is that fpid.write() fails silently
>>(probably TypeError), because it takes string as its first argument,
>>not integer.
>>
>Exactly, but it doesn't fail "silently" (that would be a bug). The exception is raised, but due to the finally clause ending in sys.exit(0), it hasno chance of being handled.
>This is the original code, for reference:
>>
>flog = open(logfile, 'w')
>fpid = open(pidfile, 'w')
>try:
> child = Popen(cmd.split(), stderr=flog)
> print "Server running [PID %s]"%(child.pid)
> fpid.write(child.pid)
> child.wait()
>except KeyboardInterrupt:
> print "INT sent to vnc server"
>finally:
> fpid.close()
> flog.close()
> os.remove(pidfile)
> os.remove(logfile)
> sys.exit(0)
>>
>--
>Gabriel Genellina
>
>
Indeed, I got TypeError: argument 1 must be string or read-only
character buffer, not int
and Wojtek's code works. So what is the right thing to do so my script
returns 1 or 0 depending on its state and success ?
PS: BTW how can I detach my process ie have an equivalent to
`myscript.py&` from the python script ?
Thanks,
Mathieu | | | | re: subprocess seems to "detach" / ignore wait()
En Thu, 21 Aug 2008 02:46:06 -0300, Mathieu Prevot <mathieu.prevot@ens.frescribió: Quote: Quote:
>So what is the right thing to do so my script
>returns 1 or 0 depending on its state and success ?
I use something like this:
def main(argv):
try:
try:
do_things()
return 0
finally:
do_cleanup()
except:
log_exception()
return 1
if __name__=='__main__':
import sys
sys.exit(main(sys.argv)) Quote:
PS: BTW how can I detach my process ie have an equivalent to
`myscript.py&` from the python script ?
There are a few recipes in the Python CookBook at http://code.activestate.com/recipes/langs/python/
--
Gabriel Genellina | | | | re: subprocess seems to "detach" / ignore wait()
2008/8/21 Gabriel Genellina <gagsl-py2@yahoo.com.ar>: Quote:
En Thu, 21 Aug 2008 02:46:06 -0300, Mathieu Prevot <mathieu.prevot@ens.frescribió:
> Quote: Quote:
>>So what is the right thing to do so my script
>>returns 1 or 0 depending on its state and success ?
>
I use something like this:
>
def main(argv):
try:
try:
do_things()
return 0
finally:
do_cleanup()
except:
log_exception()
return 1
>
if __name__=='__main__':
import sys
sys.exit(main(sys.argv))
> Quote:
>PS: BTW how can I detach my process ie have an equivalent to
>`myscript.py&` from the python script ?
>
There are a few recipes in the Python CookBook at http://code.activestate..com/recipes/langs/python/ The return from main()... it was my thought too.
Thank you Gabriel :)
Mathieu |  |
| | |  /bytes/about
We are a network of experts and professionals in IT and software development that help one another with answers to tough questions and share insights.
Get the best answers to your questions from over 226,419 network members.
|
