Connecting to a newer node triggers autoupgrade check (fixes #1177)

cmd/syncthing/main.go

@@ -1259,28 +1259,35 @@ func standbyMonitor() {
 }
 
 func autoUpgrade() {
-	var skipped bool
+	timer := time.NewTimer(0)
-	interval := time.Duration(cfg.Options().AutoUpgradeIntervalH) * time.Hour
+	sub := events.Default.Subscribe(events.DeviceConnected)
 	for {
-		if skipped {
+		select {
-			time.Sleep(interval)
+		case event := <-sub.C():
-		} else {
+			data, ok := event.Data.(map[string]string)
-			skipped = true
+			if !ok || data["clientName"] != "syncthing" || upgrade.CompareVersions(data["clientVersion"], Version) != upgrade.Newer {
+				continue
+			}
+			l.Infof("Connected to device %s with a newer version (current %q < remote %q). Checking for upgrades.", data["id"], Version, data["clientVersion"])
+		case <-timer.C:
 		}
 
 		rel, err := upgrade.LatestRelease(IsBeta)
 		if err == upgrade.ErrUpgradeUnsupported {
+			events.Default.Unsubscribe(sub)
 			return
 		}
 		if err != nil {
 			// Don't complain too loudly here; we might simply not have
 			// internet connectivity, or the upgrade server might be down.
 			l.Infoln("Automatic upgrade:", err)
+			timer.Reset(time.Duration(cfg.Options().AutoUpgradeIntervalH) * time.Hour)
 			continue
 		}
 
 		if upgrade.CompareVersions(rel.Tag, Version) != upgrade.Newer {
 			// Skip equal, older or majorly newer (incompatible) versions
+			timer.Reset(time.Duration(cfg.Options().AutoUpgradeIntervalH) * time.Hour)
 			continue
 		}
 
@@ -1288,8 +1295,10 @@ func autoUpgrade() {
 		err = upgrade.To(rel)
 		if err != nil {
 			l.Warnln("Automatic upgrade:", err)
+			timer.Reset(time.Duration(cfg.Options().AutoUpgradeIntervalH) * time.Hour)
 			continue
 		}
+		events.Default.Unsubscribe(sub)
 		l.Warnf("Automatically upgraded to version %q. Restarting in 1 minute.", rel.Tag)
 		time.Sleep(time.Minute)
 		stop <- exitUpgrading

internal/events/events.go

@@ -187,6 +187,10 @@ func (s *Subscription) Poll(timeout time.Duration) (Event, error) {
 	}
 }
 
+func (s *Subscription) C() <-chan Event {
+	return s.events
+}
+
 type BufferedSubscription struct {
 	sub  *Subscription
 	buf  []Event

internal/model/model.go

@@ -577,8 +577,21 @@ func (m *Model) ClusterConfig(deviceID protocol.DeviceID, cm protocol.ClusterCon
 	} else {
 		m.deviceVer[deviceID] = cm.ClientName + " " + cm.ClientVersion
 	}
+
+	event := map[string]string{
+		"id":            deviceID.String(),
+		"clientName":    cm.ClientName,
+		"clientVersion": cm.ClientVersion,
+	}
+
+	if conn, ok := m.rawConn[deviceID].(*tls.Conn); ok {
+		event["addr"] = conn.RemoteAddr().String()
+	}
+
 	m.pmut.Unlock()
 
+	events.Default.Log(events.DeviceConnected, event)
+
 	l.Infof(`Device %s client is "%s %s"`, deviceID, cm.ClientName, cm.ClientVersion)
 
 	var changed bool