autopilot/prefattach: trace log score process

autopilot/prefattach.go

@@ -107,6 +107,8 @@ func (p *PrefAttachment) NodeScores(g ChannelGraph, chans []Channel,
 	}
 
 	medianChanSize := Median(allChans)
+	log.Tracef("Found channel median %v for preferential score heuristic",
+		medianChanSize)
 
 	// Count the number of large-ish channels for each particular node in
 	// the graph.
@@ -143,11 +145,14 @@ func (p *PrefAttachment) NodeScores(g ChannelGraph, chans []Channel,
 		// early.
 		nID := NodeID(n.PubKey())
 		if _, ok := nodes[nID]; !ok {
+			log.Tracef("Node %x not among nodes to score, "+
+				"ignoring", nID[:])
 			return nil
 		}
 
 		// Otherwise we'll record the number of channels.
 		nodeChanNum[nID] = nodeChans
+		log.Tracef("Counted %v channels for node %x", nodeChans, nID[:])
 
 		return nil
 	}); err != nil {
@@ -158,6 +163,7 @@ func (p *PrefAttachment) NodeScores(g ChannelGraph, chans []Channel,
 	// preferences, so we return, indicating all candidates get a score of
 	// zero.
 	if maxChans == 0 {
+		log.Tracef("No channels in the graph")
 		return nil, nil
 	}
 
@@ -171,18 +177,19 @@ func (p *PrefAttachment) NodeScores(g ChannelGraph, chans []Channel,
 	candidates := make(map[NodeID]*NodeScore)
 	for nID, nodeChans := range nodeChanNum {
 
-		_, ok := existingPeers[nID]
-
-		switch {
-
 		// If the node is among or existing channel peers, we don't
 		// need another channel.
-		case ok:
+		if _, ok := existingPeers[nID]; ok {
+			log.Tracef("Node %x among existing peers for pref "+
+				"attach heuristic, giving zero score", nID[:])
 			continue
+		}
 
 		// If the node had no large channels, we skip it, since it
 		// would have gotten a zero score anyway.
-		case nodeChans <= 0:
+		if nodeChans <= 0 {
+			log.Tracef("Skipping node %x with channel count %v",
+				nID[:], nodeChans)
 			continue
 		}
 
@@ -190,6 +197,9 @@ func (p *PrefAttachment) NodeScores(g ChannelGraph, chans []Channel,
 		// channels in the graph, scaled such that the highest-degree
 		// node will be given a score of 1.0.
 		score := float64(nodeChans) / float64(maxChans)
+		log.Tracef("Giving node %x a pref attach score of %v",
+			nID[:], score)
+
 		candidates[nID] = &NodeScore{
 			NodeID: nID,
 			Score:  score,