def start_topology(self, tid, client_ip, user):
"""Handles starting up the specified topology id. Returns a 2-tuple.
The first element is None and the second is a string if an error occurs;
otherwise the first element is the topology."""
try:
topo = Topology(tid, self.raw_socket, client_ip, user)
topo.interactors = [] # list of TI connections to this topo
except TopologyCreationException as e:
return (None, str(e))
except db.Topology.DoesNotExist:
return (None, 'topology %d does not exist' % tid)
except db.IPAssignment.DoesNotExist:
return (None, 'topology %d is missing an IP assignment' % tid)
except db.IPBlockAllocation.DoesNotExist:
return (None, 'topology %d is not allocated any IPs' % tid)
except:
msg = 'topology instantiation unexpectedly failed'
log_exception(logging.ERROR, msg)
return (None, msg)
if topo.has_gateway():
self.resolver.register_topology(topo)
with self.topologies_lock:
self.topologies[tid] = topo
self.topologies_changed = True
return (topo, None)
