def check_path_request_errors(
self,
source: Address,
target: Address,
value: PaymentAmount,
reachability_state: AddressReachabilityProtocol,
) -> Optional[str]:
"""Checks for basic problems with the path requests. Returns error message or `None`"""
with opentracing.tracer.start_span("check_path_request_errors"):
if (reachability_state.get_address_reachability(source)
is not AddressReachability.REACHABLE):
return "Source not online"
if (reachability_state.get_address_reachability(target)
is not AddressReachability.REACHABLE):
return "Target not online"
if not any(self.G.edges(source)):
return "No channel from source"
if not any(self.G.edges(target)):
return "No channel to target"
source_capacities = [
view.capacity
for _, _, view in self.G.out_edges(source, data="view")
]
if max(source_capacities) < value:
debug_capacities = [
(to_checksum_address(a), to_checksum_address(b),
view.capacity)
for a, b, view in self.G.out_edges(source, data="view")
]
log.debug("Insufficient capacities",
capacities=debug_capacities)
message = (
f"Source does not have a channel with sufficient capacity "
f"(current capacities: {source_capacities} < requested amount: "
f" {value})")
return message
target_capacities = [
view.capacity
for _, _, view in self.G.in_edges(target, data="view")
]
if max(target_capacities) < value:
return "Target does not have a channel with sufficient capacity (%s < %s)" % (
target_capacities,
value,
)
try:
next(
nx.shortest_simple_paths(G=self.G,
source=source,
target=target))
except NetworkXNoPath:
return "No route from source to target"
return None
def prune_graph(graph: DiGraph, reachability_state: AddressReachabilityProtocol) -> DiGraph:
"""Prunes the given `graph` of all channels where the participants are not reachable."""
pruned_graph = DiGraph()
for p1, p2 in graph.edges:
nodes_online = (
reachability_state.get_address_reachability(p1) == AddressReachability.REACHABLE
and reachability_state.get_address_reachability(p2) == AddressReachability.REACHABLE
)
if nodes_online:
pruned_graph.add_edge(p1, p2, view=graph[p1][p2]["view"])
pruned_graph.add_edge(p2, p1, view=graph[p2][p1]["view"])
return pruned_graph