metroctl: display labels for nodes

Change-Id: I78c0c5b37d10989539bfe5f13b0afdc3fc8a2a7a
Reviewed-on: https://review.monogon.dev/c/monogon/+/3102
Reviewed-by: Tim Windelschmidt <tim@monogon.tech>
Tested-by: Jenkins CI
diff --git a/metropolis/cli/metroctl/table_node.go b/metropolis/cli/metroctl/table_node.go
index 4af9f2c..9c79489 100644
--- a/metropolis/cli/metroctl/table_node.go
+++ b/metropolis/cli/metroctl/table_node.go
@@ -57,5 +57,13 @@
 	tshs := n.TimeSinceHeartbeat.GetSeconds()
 	res.Add("heartbeat", fmt.Sprintf("%ds", tshs))
 
+	if l := n.Labels; l != nil {
+		var labels []string
+		for _, pair := range l.Pairs {
+			labels = append(labels, fmt.Sprintf("%s:%s", pair.Key, pair.Value))
+		}
+		res.Add("labels", strings.Join(labels, ","))
+	}
+
 	return res
 }