return 503 if cluster was not enabled

cluster.go

@@ -77,7 +77,7 @@ type Cluster struct {
 	enabled         atomic.Bool
 	disabled        chan struct{}
 	waitEnable      []chan struct{}
-	shouldEnable    bool
+	shouldEnable    atomic.Bool
 	reconnectCount  int
 	socket          *socket.Socket
 	cancelKeepalive context.CancelFunc
@@ -216,7 +216,7 @@ func (cr *Cluster) Connect(ctx context.Context) bool {
 	})
 	engio.OnDisconnect(func(_ *engine.Socket, err error) {
 		if config.Advanced.ExitWhenDisconnected {
-			if cr.shouldEnable {
+			if cr.shouldEnable.Load() {
 				logErrorf("Cluster disconnected from remote; exit.")
 				os.Exit(0x08)
 			}
@@ -231,7 +231,7 @@ func (cr *Cluster) Connect(ctx context.Context) bool {
 		cr.reconnectCount++
 		logErrorf("Failed to connect to the center server (%d/%d): %v", cr.reconnectCount, maxReconnectCount, err)
 		if cr.reconnectCount >= maxReconnectCount {
-			if cr.shouldEnable {
+			if cr.shouldEnable.Load() {
 				logErrorf("Cluster failed to connect too much times; exit.")
 				os.Exit(0x08)
 			}
@@ -250,7 +250,7 @@ func (cr *Cluster) Connect(ctx context.Context) bool {
 		logInfo("Preparing to connect to center server")
 	})
 	cr.socket.OnConnect(func(*socket.Socket, string) {
-		if cr.shouldEnable {
+		if cr.shouldEnable.Load() {
 			if err := cr.Enable(ctx); err != nil {
 				logErrorf("Cannot enable cluster: %v; exit.", err)
 				os.Exit(0x08)
@@ -304,7 +304,7 @@ func (cr *Cluster) Enable(ctx context.Context) (err error) {
 		return
 	}
 
-	cr.shouldEnable = true
+	cr.shouldEnable.Store(true)
 
 	logInfo("Sending enable packet")
 	resCh, err := cr.socket.EmitWithAck("enable", Map{
@@ -415,7 +415,7 @@ func (cr *Cluster) Disable(ctx context.Context) (ok bool) {
 	cr.mux.Lock()
 	defer cr.mux.Unlock()
 
-	cr.shouldEnable = false
+	cr.shouldEnable.Store(false)
 
 	if !cr.enabled.Load() {
 		logDebug("Extra disable")

handler.go

@@ -280,11 +280,20 @@ func (cr *Cluster) handleDownload(rw http.ResponseWriter, req *http.Request, has
 		return
 	}
 
+	if !cr.shouldEnable.Load() {
+		// do not serve file if cluster is not enabled yet
+		const hint = "Cluster is not enabled yet"
+		rw.Header().Set("Content-Length", strconv.Itoa(len(hint)))
+		rw.WriteHeader(http.StatusServiceUnavailable)
+		rw.Write(([]byte)(hint))
+		return
+	}
+
 	var err error
 	// check if file was indexed in the fileset
 	size, ok := cr.CachedFileSize(hash)
 	if !ok {
-		logInfof("Downloading %s", hash)
+		logInfof("Downloading %s from handler", hash)
 		if err := cr.DownloadFile(req.Context(), hash); err != nil {
 			logErrorf("Could not download %s: %v", hash, err)
 			rw.WriteHeader(http.StatusNotFound)