Check major version only if it exists

go.mod

@@ -1,9 +1,11 @@
 module meow.tf/astra/gavalink
 
 require (
+	github.com/bwmarrin/discordgo v0.20.3
 	github.com/foxbot/gavalink v0.0.0-20181105223750-6252b1245300
 	github.com/gorilla/websocket v1.4.0
 	github.com/valyala/fastjson v1.4.1
+	golang.org/x/sync v0.0.0-20201207232520-09787c993a3a
 )
 
 go 1.13

go.sum

@@ -1,6 +1,12 @@
+github.com/bwmarrin/discordgo v0.20.3 h1:AxjcHGbyBFSC0a3Zx5nDQwbOjU7xai5dXjRnZ0YB7nU=
+github.com/bwmarrin/discordgo v0.20.3/go.mod h1:O9S4p+ofTFwB02em7jkpkV8M3R0/PUVOwN61zSZ0r4Q=
 github.com/foxbot/gavalink v0.0.0-20181105223750-6252b1245300 h1:/p4AzwhPqvi9V0Ktsd+4jpkTpkLbrns2AyCUrylJFDo=
 github.com/foxbot/gavalink v0.0.0-20181105223750-6252b1245300/go.mod h1:MDlIQ50PLaU0fUW0JcHFOxec8Q17F9byrnGi8ok5vVQ=
 github.com/gorilla/websocket v1.4.0 h1:WDFjx/TMzVgy9VdMMQi2K2Emtwi2QcUQsztZ/zLaH/Q=
 github.com/gorilla/websocket v1.4.0/go.mod h1:E7qHFY5m1UJ88s3WnNqhKjPHQ0heANvMoAMk2YaljkQ=
 github.com/valyala/fastjson v1.4.1 h1:hrltpHpIpkaxll8QltMU8c3QZ5+qIiCL8yKqPFJI/yE=
 github.com/valyala/fastjson v1.4.1/go.mod h1:nV6MsjxL2IMJQUoHDIrjEI7oLyeqK6aBD7EFWPsvP8o=
+golang.org/x/crypto v0.0.0-20181030102418-4d3f4d9ffa16 h1:y6ce7gCWtnH+m3dCjzQ1PCuwl28DDIc3VNnvY29DlIA=
+golang.org/x/crypto v0.0.0-20181030102418-4d3f4d9ffa16/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
+golang.org/x/sync v0.0.0-20201207232520-09787c993a3a h1:DcqTD9SDLc+1P/r1EmRBwnVsrOwW+kk2vWf9n+1sGhs=
+golang.org/x/sync v0.0.0-20201207232520-09787c993a3a/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=

lavalink.go

@@ -1,7 +1,9 @@
 package gavalink
 
 import (
+	"context"
 	"errors"
+	"golang.org/x/sync/errgroup"
 	"log"
 	"net/http"
 	"os"
@@ -65,41 +67,29 @@ func (l *Lavalink) AddNodes(nodeConfigs ...NodeConfig) error {
 		Timeout: 60 * time.Second,
 	}
 
-	wg := &sync.WaitGroup{}
-
-	errCh := make(chan error)
+	eg, ctx := errgroup.WithContext(context.Background())
 
 	for _, c := range nodeConfigs {
+		eg.Go(func() error {
 			n := &Node{
 				config:  c,
 				manager: l,
 				client:  client,
 			}
 
-		wg.Add(1)
-
-		go func(n *Node, wg *sync.WaitGroup, errCh chan error) {
-			defer wg.Done()
-
-			err := n.open()
+			err := n.open(ctx)
 
 			if err != nil {
-				errCh <- err
-				return
+				return err
 			}
 
 			l.nodes = append(l.nodes, n)
-		}(n, wg, errCh)
-	}
 
-	wg.Wait()
-
-	select {
-	case err := <-errCh:
-		return err
-	default:
 			return nil
+		})
 	}
+
+	return eg.Wait()
 }
 
 // RemoveNode removes a node from the manager
@@ -117,12 +107,17 @@ func (l *Lavalink) removeNode(node *Node) error {
 
 	node.stop()
 
+	danglingPlayers := make([]*Player, 0)
+
 	l.playersMu.RLock()
 	for _, player := range l.players {
 		if player.node == node {
+			player.node = nil
+
 			n, err := l.BestNode()
 
-			if err != nil {
+			if err != nil || n == nil {
+				danglingPlayers = append(danglingPlayers, player)
 				continue
 			}
 
@@ -131,6 +126,12 @@ func (l *Lavalink) removeNode(node *Node) error {
 	}
 	l.playersMu.RUnlock()
 
+	if len(danglingPlayers) > 0 {
+		for _, player := range danglingPlayers {
+			player.Destroy()
+		}
+	}
+
 	// temp var for easier reading
 	n := l.nodes
 	z := len(n) - 1

node.go

@@ -1,6 +1,7 @@
 package gavalink
 
 import (
+	"context"
 	"encoding/json"
 	"fmt"
 	"github.com/valyala/fastjson"
@@ -15,16 +16,21 @@ import (
 
 // NodeConfig configures a Lavalink Node
 type NodeConfig struct {
+	// Node identifier (uuid, hostname, etc)
+	Identifier string
+
 	// REST is the host where Lavalink's REST server runs
 	//
 	// This value is expected without a trailing slash, e.g. like
 	// `http://localhost:2333`
 	REST string
+
 	// WebSocket is the host where Lavalink's WebSocket server runs
 	//
 	// This value is expected without a trailing slash, e.g. like
 	// `http://localhost:8012`
 	WebSocket string
+
 	// Password is the expected Authorization header for the Node
 	Password string
 }
@@ -68,13 +74,14 @@ type FrameStats struct {
 }
 
 // Opens the connection to the Lavalink server
-func (node *Node) open() error {
+func (node *Node) open(ctx context.Context) error {
 	header := http.Header{}
 
-	header.Set("User-Agent", gavalinkUserAgent())
 	header.Set("Authorization", node.config.Password)
 	header.Set("Num-Shards", strconv.Itoa(node.manager.shards))
 	header.Set("User-Id", node.manager.userID)
+	header.Set("Client-Name", "Gavalink")
+	header.Set("User-Agent", gavalinkUserAgent())
 
 	if node.manager.capabilities != nil {
 		v := make([]string, 0)
@@ -92,14 +99,16 @@ func (node *Node) open() error {
 		header.Set("Capabilities", strings.Join(v, ";"))
 	}
 
-	ws, resp, err := websocket.DefaultDialer.Dial(node.config.WebSocket, header)
+	ws, resp, err := websocket.DefaultDialer.DialContext(ctx, node.config.WebSocket, header)
 
 	if err != nil {
 		return err
 	}
 
+	// TODO: This isn't officially required, so we ignore it for now if it's empty.
 	vstr := resp.Header.Get("Lavalink-Major-Version")
 
+	if vstr != "" {
 		v, err := strconv.Atoi(vstr)
 
 		if err != nil {
@@ -109,6 +118,7 @@ func (node *Node) open() error {
 		if v < 3 {
 			return errInvalidVersion
 		}
+	}
 
 	node.wsConn = ws
 	go node.listen()
@@ -136,7 +146,7 @@ func (node *Node) listen() {
 		if err != nil {
 			Log.Println(err)
 			// try to reconnect
-			oerr := node.open()
+			oerr := node.open(context.Background())
 
 			if oerr != nil {
 				Log.Println("node", node.config.WebSocket, "failed and could not reconnect, destroying.", err, oerr)

player.go

@@ -184,22 +184,23 @@ func (player *Player) Forward(sessionID string, event VoiceServerUpdate) error {
 func (player *Player) ChangeNode(node *Node) error {
 	player.node = node
 
-	player.Forward(player.sessionID, player.lastVoiceServerUpdate)
+	if err := player.Forward(player.sessionID, player.lastVoiceServerUpdate); err != nil {
+		return err
+	}
 
 	return player.PlayAt(player.track, player.position, 0)
 }
 
 // Destroy will destroy this player
 func (player *Player) Destroy() error {
+	if player.node != nil && player.node.wsConn != nil {
 		msg := basicMessage{
 			Op:      opDestroy,
 			GuildID: player.guildID,
 		}
 
-	err := player.node.wsConn.WriteJSON(msg)
-
-	if err != nil {
-		return err
+		// We don't actually care if this goes through, since the node/connection may be invalid anyway.
+		player.node.wsConn.WriteJSON(msg)
 	}
 
 	player.manager.playersMu.Lock()