Remove unconditional debug logging

There were some unconditional debug logging in serf.
Removed them and made then go through logrus writers
based on what error level the log string contains.

Signed-off-by: Jana Radhakrishnan <mrjana@docker.com>

libnetwork/drivers/overlay/ov_serf.go

@@ -47,7 +47,7 @@ func (d *driver) serfInit() error {
 	config.UserCoalescePeriod = 1 * time.Second
 	config.UserQuiescentPeriod = 50 * time.Millisecond
 
-	config.LogOutput = logrus.StandardLogger().Out
+	config.LogOutput = &logWriter{}
 
 	s, err := serf.Create(config)
 	if err != nil {
@@ -89,12 +89,12 @@ func (d *driver) notifyEvent(event ovNotify) {
 		event.nid, event.eid)
 
 	if err := d.serfInstance.UserEvent(eName, []byte(ePayload), true); err != nil {
-		fmt.Printf("Sending user event failed: %v\n", err)
+		logrus.Errorf("Sending user event failed: %v\n", err)
 	}
 }
 
 func (d *driver) processEvent(u serf.UserEvent) {
-	fmt.Printf("Received user event name:%s, payload:%s\n", u.Name,
+	logrus.Debugf("Received user event name:%s, payload:%s\n", u.Name,
 		string(u.Payload))
 
 	var dummy, action, vtepStr, nid, eid, ipStr, maskStr, macStr string
@@ -107,11 +107,11 @@ func (d *driver) processEvent(u serf.UserEvent) {
 		fmt.Printf("Failed to scan value string: %v\n", err)
 	}
 
-	fmt.Printf("Parsed data = %s/%s/%s/%s/%s/%s\n", nid, eid, vtepStr, ipStr, maskStr, macStr)
+	logrus.Debugf("Parsed data = %s/%s/%s/%s/%s/%s\n", nid, eid, vtepStr, ipStr, maskStr, macStr)
 
 	mac, err := net.ParseMAC(macStr)
 	if err != nil {
-		fmt.Printf("Failed to parse mac: %v\n", err)
+		logrus.Errorf("Failed to parse mac: %v\n", err)
 	}
 
 	if d.serfInstance.LocalMember().Addr.String() == vtepStr {
@@ -122,18 +122,18 @@ func (d *driver) processEvent(u serf.UserEvent) {
 	case "join":
 		if err := d.peerAdd(nid, eid, net.ParseIP(ipStr), net.IPMask(net.ParseIP(maskStr).To4()), mac,
 			net.ParseIP(vtepStr), true); err != nil {
-			fmt.Printf("Peer add failed in the driver: %v\n", err)
+			logrus.Errorf("Peer add failed in the driver: %v\n", err)
 		}
 	case "leave":
 		if err := d.peerDelete(nid, eid, net.ParseIP(ipStr), net.IPMask(net.ParseIP(maskStr).To4()), mac,
 			net.ParseIP(vtepStr), true); err != nil {
-			fmt.Printf("Peer delete failed in the driver: %v\n", err)
+			logrus.Errorf("Peer delete failed in the driver: %v\n", err)
 		}
 	}
 }
 
 func (d *driver) processQuery(q *serf.Query) {
-	fmt.Printf("Received query name:%s, payload:%s\n", q.Name,
+	logrus.Debugf("Received query name:%s, payload:%s\n", q.Name,
 		string(q.Payload))
 
 	var nid, ipStr string
@@ -193,7 +193,7 @@ func (d *driver) startSerfLoop(eventCh chan serf.Event, notifyCh chan ovNotify,
 			}
 
 			if err := d.serfInstance.Leave(); err != nil {
-				fmt.Printf("failed leaving the cluster: %v\n", err)
+				logrus.Errorf("failed leaving the cluster: %v\n", err)
 			}
 
 			d.serfInstance.Shutdown()