simplify lnrouter API

electrum/lnrouter.py

@@ -310,3 +310,10 @@ class LNPathFinder(Logger):
                                                        node_info=node_info))
             prev_node_id = node_id
         return route
+
+    def find_route(self, nodeA: bytes, nodeB: bytes, invoice_amount_msat: int, *,
+                   path = None, my_channels: Dict[ShortChannelID, 'Channel'] = None) -> Optional[LNPaymentRoute]:
+        if not path:
+            path = self.find_path_for_payment(nodeA, nodeB, invoice_amount_msat, my_channels=my_channels)
+        if path:
+            return self.create_route_from_path(path, nodeA, my_channels=my_channels)

electrum/lnworker.py

@@ -1140,17 +1140,15 @@ class LNWallet(LNWorker):
                 path = full_path[:-len(private_route)]
             else:
                 # find path now on public graph, to border node
-                path = self.network.path_finder.find_path_for_payment(
-                    self.node_keypair.pubkey, border_node_pubkey, amount_msat,
-                    my_channels=scid_to_my_channels)
-            if not path:
-                continue
+                path = None
             try:
-                route = self.network.path_finder.create_route_from_path(
-                    path, self.node_keypair.pubkey,
-                    my_channels=scid_to_my_channels)
+                route = self.network.path_finder.find_route(
+                    self.node_keypair.pubkey, border_node_pubkey, amount_msat,
+                    path=path, my_channels=scid_to_my_channels)
             except NoChannelPolicy:
                 continue
+            if not route:
+                continue
             # we need to shift the node pubkey by one towards the destination:
             private_route_nodes = [edge[0] for edge in private_route][1:] + [invoice_pubkey]
             private_route_rest = [edge[1:] for edge in private_route]
@@ -1186,17 +1184,11 @@ class LNWallet(LNWorker):
             break
         # if could not find route using any hint; try without hint now
         if route is None:
-            if full_path:  # user pre-selected path
-                path = full_path
-            else:  # find path now
-                path = self.network.path_finder.find_path_for_payment(
-                    self.node_keypair.pubkey, invoice_pubkey, amount_msat,
-                    my_channels=scid_to_my_channels)
-            if not path:
+            route = self.network.path_finder.find_route(
+                self.node_keypair.pubkey, invoice_pubkey, amount_msat,
+                path=full_path, my_channels=scid_to_my_channels)
+            if not route:
                 raise NoPathFound()
-            route = self.network.path_finder.create_route_from_path(
-                path, self.node_keypair.pubkey,
-                my_channels=scid_to_my_channels)
             if not is_route_sane_to_use(route, amount_msat, decoded_invoice.get_min_final_cltv_expiry()):
                 self.logger.info(f"rejecting insane route {route}")
                 raise NoPathFound()