Merge pull request #1423 from AudriusButkevicius/warn

Silence discovery warnings when v6 not available

internal/discover/client_udp.go

@@ -94,7 +94,7 @@ func (d *UDPClient) broadcast(pkt []byte) {
 
 	conn, err := net.ListenUDP(d.url.Scheme, d.listenAddress)
 	for err != nil {
-		l.Warnf("discover %s: broadcast: %v; trying again in %v", d.url, err, d.errorRetryInterval)
+		l.Warnf("discover %s: broadcast listen: %v; trying again in %v", d.url, err, d.errorRetryInterval)
 		select {
 		case <-d.stop:
 			return
@@ -106,7 +106,11 @@ func (d *UDPClient) broadcast(pkt []byte) {
 
 	remote, err := net.ResolveUDPAddr(d.url.Scheme, d.url.Host)
 	for err != nil {
-		l.Warnf("discover %s: broadcast: %v; trying again in %v", d.url, err, d.errorRetryInterval)
+		if d.url.Scheme != "udp6" {
+			l.Warnf("discover %s: broadcast resolve: %v; trying again in %v", d.url, err, d.errorRetryInterval)
+		} else if debug {
+			l.Debugf("discover %s: broadcast resolve: %v; trying again in %v", d.url, err, d.errorRetryInterval)
+		}
 		select {
 		case <-d.stop:
 			return