cmd/devp2p: reduce output of node crawler (ethereum#26674)

Our discovery crawler spits out a huge amount of logs, most of which is pretty non-interesting. This change moves the very verbose output to Debug, and adds a 8-second status log message giving the general idea about what's going on.

cmd/devp2p/crawl.go

@@ -36,6 +36,14 @@ type crawler struct {
 	revalidateInterval time.Duration
 }
 
+const (
+	nodeRemoved = iota
+	nodeSkipRecent
+	nodeSkipIncompat
+	nodeAdded
+	nodeUpdated
+)
+
 type resolver interface {
 	RequestENR(*enode.Node) (*enode.Node, error)
 }
@@ -63,19 +71,39 @@ func (c *crawler) run(timeout time.Duration) nodeSet {
 	var (
 		timeoutTimer = time.NewTimer(timeout)
 		timeoutCh    <-chan time.Time
+		statusTicker = time.NewTicker(time.Second * 8)
 		doneCh       = make(chan enode.Iterator, len(c.iters))
 		liveIters    = len(c.iters)
 	)
 	defer timeoutTimer.Stop()
+	defer statusTicker.Stop()
 	for _, it := range c.iters {
 		go c.runIterator(doneCh, it)
 	}
 
+	var (
+		added   int
+		updated int
+		skipped int
+		recent  int
+		removed int
+	)
 loop:
 	for {
 		select {
 		case n := <-c.ch:
-			c.updateNode(n)
+			switch c.updateNode(n) {
+			case nodeSkipIncompat:
+				skipped++
+			case nodeSkipRecent:
+				recent++
+			case nodeRemoved:
+				removed++
+			case nodeAdded:
+				added++
+			default:
+				updated++
+			}
 		case it := <-doneCh:
 			if it == c.inputIter {
 				// Enable timeout when we're done revalidating the input nodes.
@@ -89,6 +117,10 @@ loop:
 			}
 		case <-timeoutCh:
 			break loop
+		case <-statusTicker.C:
+			log.Info("Crawling in progress",
+				"added", added, "updated", updated, "removed", removed,
+				"ignored(recent)", recent, "ignored(incompatible)", skipped)
 		}
 	}
 
@@ -113,22 +145,25 @@ func (c *crawler) runIterator(done chan<- enode.Iterator, it enode.Iterator) {
 	}
 }
 
-func (c *crawler) updateNode(n *enode.Node) {
+// updateNode updates the info about the given node, and returns a status
+// about what changed
+func (c *crawler) updateNode(n *enode.Node) int {
 	node, ok := c.output[n.ID()]
 
 	// Skip validation of recently-seen nodes.
 	if ok && time.Since(node.LastCheck) < c.revalidateInterval {
-		return
+		return nodeSkipRecent
 	}
 
 	// Request the node record.
 	nn, err := c.disc.RequestENR(n)
 	node.LastCheck = truncNow()
+	status := nodeUpdated
 	if err != nil {
 		if node.Score == 0 {
 			// Node doesn't implement EIP-868.
 			log.Debug("Skipping node", "id", n.ID())
-			return
+			return nodeSkipIncompat
 		}
 		node.Score /= 2
 	} else {
@@ -137,18 +172,20 @@ func (c *crawler) updateNode(n *enode.Node) {
 		node.Score++
 		if node.FirstResponse.IsZero() {
 			node.FirstResponse = node.LastCheck
+			status = nodeAdded
 		}
 		node.LastResponse = node.LastCheck
 	}
 
 	// Store/update node in output set.
 	if node.Score <= 0 {
-		log.Info("Removing node", "id", n.ID())
+		log.Debug("Removing node", "id", n.ID())
 		delete(c.output, n.ID())
-	} else {
-		log.Info("Updating node", "id", n.ID(), "seq", n.Seq(), "score", node.Score)
-		c.output[n.ID()] = node
+		return nodeRemoved
 	}
+	log.Debug("Updating node", "id", n.ID(), "seq", n.Seq(), "score", node.Score)
+	c.output[n.ID()] = node
+	return status
 }
 
 func truncNow() time.Time {