Hi all,
Another newbie question. So you can't use signals on threads but you
can use select. The reason I want to do this in the first place it I
need a timeout. Fundamentally I want to run a command on another
machine, but I need a timeout. I have to do this to a LOT of machines
( > 3000 ) and threading becomes necessary for timeliess. So I created
a function which works with signals ( until you throw threading at it..
) but I can't seem to modify it correctly to use select. Can some
select ( pun intended ) experts out there point out the error of my
way..
Not working RunCmd using select
def runCmd( self, cmd, timeout=None ):
starttime = time.time()
child = popen2.Popen3(cmd)
child.tochild.write("\n")
child.tochild.close()
child.wait()
results = []
results = "".join(child.fromchild.readlines())
endtime = starttime + timeout
r, w, x = select.select(results, [], [], endtime - time.time())
if len(r) == 0:
# We timed out.
prefix = ("TIMED OUT:" + " " * maxlen)[:maxlen]
sys.stdout.write(prefix)
space = ""
os.kill(child.pid,9)
child.fromchild.close()
return results
Working RunCmd using signal
def handler(self, signum, frame):
self.logger.debug("Signal handler called with signal %s" %
signum)
def runCmd( self, cmd, timeout=None ):
self.logger.debug("Initializing function %s - %s" %
(sys._getframe().f_code.co_name,cmd) )
# Set the signal handler and a 5-second alarm
signal.signal(signal.SIGALRM, self.handler)
signal.alarm(timeout)
try:
child = popen2.Popen3(cmd)
child.tochild.write("y\n")
child.tochild.close()
child.wait()
results = "".join(child.fromchild.readlines())
out = child.fromchild.close()
self.logger.debug("command: %s Status: %s PID: %s " % (cmd,
out, child.pid))
if out is None:
out = 0
except:
self.logger.warning( "command: %s failed!" % cmd)
kill = os.kill(child.pid,9)
self.logger.debug( "Killing command %s - Result: %s" %
(cmd, kill))
out = results = None
signal.alarm(0) # Disable the alarm
return out,results
Thanks much - Alternatively if anyone else has a better way to do what
I am trying to get done always looking for better ways. I still want
this to work though..
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