From d685aefab3d753489f0477df5cefd70d8f6906bc Mon Sep 17 00:00:00 2001
From: Deluan <deluan@navidrome.org>
Date: Sat, 12 Dec 2020 23:04:50 -0500
Subject: [PATCH] Don't ever stop the `listen` go routine

---
 server/events/sse.go | 24 +++++++++++++-----------
 1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/server/events/sse.go b/server/events/sse.go
index c6371ad5b..e18cb0379 100644
--- a/server/events/sse.go
+++ b/server/events/sse.go
@@ -53,9 +53,6 @@ type broker struct {
 
 	// Closed client connections
 	unsubscribing clientsChan
-
-	// Client connections registry
-	clients map[client]struct{}
 }
 
 func NewBroker() Broker {
@@ -64,7 +61,6 @@ func NewBroker() Broker {
 		publish:       make(messageChan, 100),
 		subscribing:   make(clientsChan, 1),
 		unsubscribing: make(clientsChan, 1),
-		clients:       make(map[client]struct{}),
 	}
 
 	// Set it running - listening and broadcasting events
@@ -160,13 +156,15 @@ func (b *broker) listen() {
 	keepAlive := time.NewTicker(keepAliveFrequency)
 	defer keepAlive.Stop()
 
+	clients := map[client]struct{}{}
+
 	for {
 		select {
 		case c := <-b.subscribing:
 			// A new client has connected.
 			// Register their message channel
-			b.clients[c] = struct{}{}
-			log.Debug("Client added to event broker", "numClients", len(b.clients), "newClient", c.String())
+			clients[c] = struct{}{}
+			log.Debug("Client added to event broker", "numClients", len(clients), "newClient", c.String())
 
 			// Send a serverStart event to new client
 			c.channel <- b.preparePackage(&ServerStart{serverStart})
@@ -175,20 +173,24 @@ func (b *broker) listen() {
 			// A client has detached and we want to
 			// stop sending them messages.
 			close(c.channel)
-			delete(b.clients, c)
-			log.Debug("Removed client from event broker", "numClients", len(b.clients), "client", c.String())
+			delete(clients, c)
+			log.Debug("Removed client from event broker", "numClients", len(clients), "client", c.String())
 
 		case event := <-b.publish:
 			// We got a new event from the outside!
 			// Send event to all connected clients
-			for c := range b.clients {
+			for c := range clients {
 				log.Trace("Putting event on client's queue", "client", c.String(), "event", event)
 				// Use non-blocking send. If cannot send, terminate the client's connection
 				select {
 				case c.channel <- event:
 				default:
-					log.Warn("Could not send message to client", "client", c.String(), "event", event)
-					c.done <- struct{}{}
+					log.Warn("Could not send event to client", "client", c.String(), "event", event)
+					select {
+					case c.done <- struct{}{}:
+					default:
+						log.Warn("Could not ask client to end", "client", c.String())
+					}
 				}
 			}