Fixing shutdown flow

protocol/connections/engine.go

@@ -36,6 +36,8 @@ type engine struct {
 
 	// Required for listen(), inaccessible from identity
 	privateKey ed25519.PrivateKey
+
+	shuttingDown bool
 }
 
 // Engine (ProtocolEngine) encapsulates the logic necessary to make and receive Cwtch connections.
@@ -133,10 +135,10 @@ func (e *engine) eventHandler() {
 func (e *engine) createPeerTemplate() *PeerApp {
 	peerAppTemplate := new(PeerApp)
 	peerAppTemplate.MessageHandler = e.handlePeerMessage
-	peerAppTemplate.OnAcknowledgement = e.peerAck
-	peerAppTemplate.OnAuth = e.peerAuthed
-	peerAppTemplate.OnConnecting = e.peerConnecting
-	peerAppTemplate.OnClose = e.peerDisconnected
+	peerAppTemplate.OnAcknowledgement =  e.ignoreOnShutdown(e.peerAck)
+	peerAppTemplate.OnAuth =  e.ignoreOnShutdown(e.peerAuthed)
+	peerAppTemplate.OnConnecting =  e.ignoreOnShutdown(e.peerConnecting)
+	peerAppTemplate.OnClose =  e.ignoreOnShutdown(e.peerDisconnected)
 	return peerAppTemplate
 }
 
@@ -149,6 +151,7 @@ func (e *engine) listenFn() {
 
 // Shutdown tears down the eventHandler goroutine
 func (e *engine) Shutdown() {
+	e.shuttingDown = true
 	e.service.Shutdown()
 	e.connectionsManager.Shutdown()
 	e.queue.Shutdown()
@@ -159,6 +162,10 @@ func (e *engine) peerWithOnion(onion string) {
 	e.service.Connect(onion, e.createPeerTemplate())
 }
 
+func (e * engine) ignoreOnShutdown(f func(string)) func(string){
+	return func (x string) {if !e.shuttingDown{f(x)} }
+}
+
 func (e *engine) peerAuthed(onion string) {
 	e.eventManager.Publish(event.NewEvent(event.PeerStateChange, map[event.Field]string{
 		event.RemotePeer:      string(onion),