def monitor( self, hosts=None, timeoutms=-1 ):
"""Monitor a set of hosts (or all hosts by default),
and return their output, a line at a time.
hosts: (optional) set of hosts to monitor
timeoutms: (optional) timeout value in ms
returns: iterator which returns host, line"""
if hosts is None:
hosts = self.hosts
poller = select.poll()
Node = hosts[ 0 ] # so we can call class method fdToNode
for host in hosts:
poller.register( host.stdout )
while True:
ready = poller.poll( timeoutms )
for fd, event in ready:
host = Node.fdToNode( fd )
if event & select.POLLIN:
line = host.readline()
if line is not None:
yield host, line
# Return if non-blocking
if not ready and timeoutms >= 0:
yield None, None
