Improve network graph update logging.

Author: arik-so

lightning/src/routing/gossip.rs

@@ -1553,6 +1553,8 @@ impl<L: Deref> NetworkGraph<L> where L::Target: Logger {
 		let node_id_a = channel_info.node_one.clone();
 		let node_id_b = channel_info.node_two.clone();
 
+		log_gossip!(self.logger, "Adding channel {} between nodes {} and {}", short_channel_id, node_id_a, node_id_b);
+
 		match channels.entry(short_channel_id) {
 			IndexedMapEntry::Occupied(mut entry) => {
 				//TODO: because asking the blockchain if short_channel_id is valid is only optional
@@ -1805,6 +1807,7 @@ impl<L: Deref> NetworkGraph<L> where L::Target: Logger {
 		if !scids_to_remove.is_empty() {
 			let mut nodes = self.nodes.write().unwrap();
 			for scid in scids_to_remove {
+				log_gossip!(self.logger, "Removing channel {}", scid);
 				let info = channels.remove(&scid).expect("We just accessed this scid, it should be present");
 				Self::remove_channel_in_nodes(&mut nodes, &info, scid);
 				self.removed_channels.lock().unwrap().insert(scid, Some(current_time_unix));
@@ -1878,6 +1881,8 @@ impl<L: Deref> NetworkGraph<L> where L::Target: Logger {
 			}
 		}
 
+		log_gossip!(self.logger, "Updating channel {} in direction {}", msg.short_channel_id, msg.flags & 1);
+
 		let mut channels = self.channels.write().unwrap();
 		match channels.get_mut(&msg.short_channel_id) {
 			None => {