def check_dest(self):
"""Check that the destination is present in the DAG and the graph"""
dest_in_graph = self.dest in self.g
log.debug('Checking for %s in the graph: %s', self.dest, dest_in_graph)
if not dest_in_graph:
log.info('Adding %s in the graph', self.dest)
self.g.add_node(self.dest, data=Node())
new_paths = {}
new_paths_cost = {n: sys.maxint for n in self.g.nodes_iter()}
dest_in_dag = self.dest in self.dag
log.debug('Checking for the presence of %s the the DAG: %s',
self.dest, dest_in_dag)
if not dest_in_dag or not dest_in_graph:
if not dest_in_dag:
sinks = ssu.find_sink(self.dag)
else:
sinks = self.dag.predecessors(self.dest)
for s in sinks:
if not dest_in_dag:
log.info('Adding %s to %s in the dag', self.dest, s)
self.dag.add_edge(s, self.dest)
if not dest_in_graph:
log.info('Adding edge (%s, %s) in the graph',
s, self.dest)
self.g.add_edge(s, self.dest, weight=self.new_edge_weight)
log.debug('Updating spt/cost accordingly')
for n in self.g.nodes_iter():
if n == self.dest:
new_paths[n] = [[n]]
new_paths_cost[n] = 0
continue
if not self.has_path(n, s):
continue
ns_cost = self.cost(n, s) + self.new_edge_weight
if ns_cost < new_paths_cost[n]: # Created a new SP
ns_path = self.path(n, s)
new_paths_cost[n] = ns_cost
new_paths[n] = list(ssu.extend_paths_list(ns_path,
self.dest
))
elif ns_cost == new_paths_cost: # Created ECMP
ns_path = self.path(n, s)
new_paths[n].extend(ssu.extend_paths_list(ns_path,
self.dest
))
for n, p in new_paths.iteritems(): # Incrementally update the SPT
self.register_path(n, self.dest, p, new_paths_cost[n])
def add_dest_to_graphs(self, dest, dag):
if dest not in dag:
for node in ssu.find_sink(dag):
logger.info('Connected %s to %s in the DAG', node, dest)
dag.add_edge(node, dest)
