Fix a startup race condition in sml

pkg/sml/delegate.go

@@ -54,15 +54,15 @@ func (m *Memberlist[M, S, MP, SP]) MergeRemoteState(buf []byte, join bool) {
 // Cluster implements the EventDelegate interface
 func (m *Memberlist[M, S, MP, SP]) NotifyJoin(n *memberlist.Node) {
 	logrus.Debug("node joined: ", n.Name)
-	go m.updateCache()
+	m.nodeChanges <- struct{}{}
 }
 
 // Node implements the EventDelegate interface
 func (m *Memberlist[M, S, MP, SP]) NotifyLeave(n *memberlist.Node) {
-	go m.updateCache()
+	m.nodeChanges <- struct{}{}
 }
 
 // Node implements the EventDelegate interface
 func (m *Memberlist[M, S, MP, SP]) NotifyUpdate(n *memberlist.Node) {
-	go m.updateCache()
+	m.nodeChanges <- struct{}{}
 }

pkg/sml/memberlist.go

@@ -89,6 +89,7 @@ func (m *Memberlist[M, S, MP, SP]) Run() error {
 			go m.join()
 		case <-m.nodeChanges:
 			logrus.Debug("network topology changed, a node just joined, left or was updated")
+			m.updateCache()
 			for _, node := range m.Nodes() {
 				logrus.Debugf("* %s [%s]\n", node.Name, node.NodeMeta.String())
 			}
@@ -127,11 +128,6 @@ func (m *Memberlist[M, S, MP, SP]) Update() {
 // Update the node cache after a network change, goes through all the
 // nodes and decodes metadata
 func (m *Memberlist[M, S, MP, SP]) updateCache() {
-	// Do not update the node cache until memberlist is setup
-	if m.ml == nil {
-		logrus.Debug("not updating the node cache before memberlist is ready")
-		return
-	}
 	members := m.ml.Members()
 	logrus.Debugf("updating the node cache with %d members", len(members))
 	var cache []Node[M, MP]
@@ -146,7 +142,6 @@ func (m *Memberlist[M, S, MP, SP]) updateCache() {
 		}
 	}
 	m.nodeCache = cache
-	m.nodeChanges <- struct{}{}
 }
 
 // Try and join any anchor that is not currently a cluster member