lnpeer: add get_channel_by_id, for small speed-up

electrum/lnpeer.py

@@ -107,7 +107,8 @@ class Peer(Logger):
         if not (message_name.startswith("update_") or is_commitment_signed):
             return
         assert channel_id
-        chan = self.channels[channel_id]
+        chan = self.get_channel_by_id(channel_id)
+        assert chan
         chan.hm.store_local_update_raw_msg(raw_msg, is_commitment_signed=is_commitment_signed)
         if is_commitment_signed:
             # saving now, to ensure replaying updates works (in case of channel reestablishment)
@@ -139,10 +140,17 @@ class Peer(Logger):
 
     @property
     def channels(self) -> Dict[bytes, Channel]:
-        # FIXME this iterates over all channels in lnworker,
-        #       so if we just want to lookup a channel by channel_id, it's wasteful
         return self.lnworker.channels_for_peer(self.pubkey)
 
+    def get_channel_by_id(self, channel_id: bytes) -> Optional[Channel]:
+        # note: this is faster than self.channels.get(channel_id)
+        chan = self.lnworker.get_channel_by_id(channel_id)
+        if not chan:
+            return None
+        if chan.node_id != self.pubkey:
+            return None
+        return chan
+
     def diagnostic_name(self):
         return self.lnworker.__class__.__name__ + ', ' + self.transport.name()
 
@@ -158,7 +166,7 @@ class Peer(Logger):
             self.ordered_message_queues[chan_id].put_nowait((message_type, payload))
         else:
             if message_type != 'error' and 'channel_id' in payload:
-                chan = self.channels.get(payload['channel_id'])
+                chan = self.get_channel_by_id(payload['channel_id'])
                 if chan is None:
                     raise Exception('Got unknown '+ message_type)
                 args = (chan, payload)

electrum/lnworker.py

@@ -504,6 +504,9 @@ class LNWallet(LNWorker):
         with self.lock:
             return self._channels.copy()
 
+    def get_channel_by_id(self, channel_id: bytes) -> Optional[Channel]:
+        return self._channels.get(channel_id, None)
+
     @ignore_exceptions
     @log_exceptions
     async def sync_with_local_watchtower(self):
@@ -691,7 +694,8 @@ class LNWallet(LNWorker):
 
     def channels_for_peer(self, node_id):
         assert type(node_id) is bytes
-        return {x: y for (x, y) in self.channels.items() if y.node_id == node_id}
+        return {chan_id: chan for (chan_id, chan) in self.channels.items()
+                if chan.node_id == node_id}
 
     def channel_state_changed(self, chan):
         self.save_channel(chan)

electrum/tests/test_lnpeer.py

@@ -170,6 +170,7 @@ class MockLNWallet(Logger, NetworkRetryManager[LNPeerAddr]):
     try_force_closing = LNWallet.try_force_closing
     get_first_timestamp = lambda self: 0
     on_peer_successfully_established = LNWallet.on_peer_successfully_established
+    get_channel_by_id = LNWallet.get_channel_by_id
 
 
 class MockTransport: