Use localNode to store the local node name

Also rename setupDelegate to SetLocalNode, so that
main can call SetLocalNode then Update().

cluster/cluster.go

@@ -19,10 +19,9 @@ const KeyLen = 32
 
 // Cluster represents a running cluster configuration
 type Cluster struct {
-	LocalName string // used to avoid LocalNode(); should not change
 	ml        *memberlist.Memberlist
 	mlConfig  *memberlist.Config
-	localNode common.Node
+	localNode *common.Node
 	state     *state
 	events    chan memberlist.NodeEvent
 }
@@ -56,18 +55,22 @@ func New(init bool, clusterKey []byte, bindAddr string, bindPort int, useIPAsNam
 	}
 
 	cluster := Cluster{
-		LocalName: ml.LocalNode().Name,
-		ml:        ml,
-		mlConfig:  mlConfig,
+		ml:       ml,
+		mlConfig: mlConfig,
 		// The big channel buffer is a work-around for https://github.com/hashicorp/memberlist/issues/23
 		// More than this many simultaneous events will deadlock cluster.members()
 		events: make(chan memberlist.NodeEvent, 100),
 		state:  state,
 	}
-	cluster.setupDelegate()
+	cluster.SetLocalNode(&common.Node{})
 	return &cluster, nil
 }
 
+// Name provides the current cluster name
+func (c *Cluster) Name() string {
+	return c.localNode.Name
+}
+
 // Join tries to join the cluster by contacting provided addresses
 // Provided addresses are passed as is, if no address is provided, known
 // cluster nodes are contacted instead.
@@ -95,12 +98,8 @@ func (c *Cluster) Leave() {
 	c.ml.Shutdown() //nolint: errcheck
 }
 
-// Update takes a new local node configuration into account
-// If the node is already joined, update also gossips the new local node
-// configuration
-func (c *Cluster) Update(localNode common.Node) {
-	c.localNode = localNode
-	c.setupDelegate()
+// Update gossips the local node configuration, propagating any change
+func (c *Cluster) Update() {
 	c.ml.UpdateNode(1 * time.Second) // we currently do not update after creation
 }
 
@@ -112,7 +111,7 @@ func (c *Cluster) Members() <-chan []common.Node {
 	go func() {
 		for {
 			event := <-c.events
-			if event.Node.Name == c.LocalName {
+			if event.Node.Name == c.localNode.Name {
 				// ignore events about ourselves
 				continue
 			}
@@ -127,7 +126,7 @@ func (c *Cluster) Members() <-chan []common.Node {
 
 			nodes := make([]common.Node, 0)
 			for _, n := range c.ml.Members() {
-				if n.Name == c.LocalName {
+				if n.Name == c.localNode.Name {
 					continue
 				}
 				nodes = append(nodes, common.Node{
@@ -144,10 +143,15 @@ func (c *Cluster) Members() <-chan []common.Node {
 	return changes
 }
 
-func (c *Cluster) setupDelegate() {
-	delegate := delegateNode{&c.localNode}
-	c.mlConfig.Conflict = &delegate
-	c.mlConfig.Delegate = &delegate
+// SetLocalNode takes a new local node configuration into account
+// It also sets this node as the memberlist.Delegate implementation
+func (c *Cluster) SetLocalNode(localNode *common.Node) {
+	c.localNode = localNode
+	c.localNode.Name = c.ml.LocalNode().Name
+	// wrap in a delegateNode instance for memberlist.Delegate implementation
+	delegate := &delegateNode{c.localNode}
+	c.mlConfig.Conflict = delegate
+	c.mlConfig.Delegate = delegate
 	c.mlConfig.Events = &memberlist.ChannelEventDelegate{Ch: c.events}
 }
 

main.go

@@ -50,11 +50,12 @@ func main() {
 	}
 
 	// Assign a local node address and propagate it to the cluster
-	wgstate.AssignOverlayAddr((*net.IPNet)(config.OverlayNet), cluster.LocalName)
-	localNode := common.Node{}
+	wgstate.AssignOverlayAddr((*net.IPNet)(config.OverlayNet), cluster.Name())
+	localNode := &common.Node{}
 	localNode.OverlayAddr = wgstate.OverlayAddr
 	localNode.PubKey = wgstate.PubKey.String()
-	cluster.Update(localNode)
+	cluster.SetLocalNode(localNode)
+	cluster.Update()
 
 	// Join the cluster
 	nodec := cluster.Members() // avoid deadlocks by starting before join