SIGALRM problem

[Mike Driscoll]

On Oct 13, 11:45 am, Paul Rubin <http://phr...@NOSPAM.invalid> wrote:
> I'm trying to run a command on a remote host, something like:
>
>    result = os.popen('ssh otherhost mycommand').read()
>
> It is possible that the other host is down, in which case the ssh
> command hangs, so I want my script to time out if this happens:
>
>    def timeout(*x):
>       raise IOError, 'timeout'
>    signal(SIGALRM, timeout)
>    alarm(20)
>
>    result = os.popen('ssh otherhost mycommand').read()
>
> I would expect the above to raise IOError if the ssh doesn't return
> within 20 seconds, but it seems to hang when the other host is down,
> until eventually the tcp connection times out after something like 5
> minutes (which is much longer than I want to wait).
>
> Anyone know if os.popen somehow pre-empts the alarm signal?  If it
> does, I'd consider that a bug.
>
> Thanks
> --Paul

Using some Google-Fu, I found this post:

http://mail.python.org/pipermail/python-list/2003-August/217530.html

It's old, but it looks ok...

Mike