feature: track node load, account for this when selecting a node

lavalink.go

@@ -4,13 +4,14 @@ import (
 	"errors"
 	"log"
 	"os"
+	"sort"
 )
 
 // Log sets the log.Logger gavalink will write to
 var Log *log.Logger
 
 func init() {
-	Log = log.New(os.Stdout, "(gavalink)", 0)
+	Log = log.New(os.Stdout, "(gavalink) ", 0)
 }
 
 // Lavalink manages a connection to Lavalink Nodes
@@ -91,7 +92,11 @@ func (lavalink *Lavalink) BestNode() (*Node, error) {
 	if len(lavalink.nodes) < 1 {
 		return nil, errNoNodes
 	}
-	// TODO: lookup latency
+
+	sort.SliceStable(lavalink.nodes, func(i, j int) bool {
+		return lavalink.nodes[i].load < lavalink.nodes[j].load
+	})
+
 	return &lavalink.nodes[0], nil
 }
 

model.go

@@ -62,27 +62,29 @@ const (
 	opDestroy           = "destroy"
 	opPlayerUpdate      = "playerUpdate"
 	opEvent             = "event"
+	opStats             = "stats"
 	eventTrackEnd       = "TrackEndEvent"
 	eventTrackException = "TrackExceptionEvent"
 	eventTrackStuck     = "TrackStuckEvent"
 )
 
 type message struct {
-	Op          string             `json:"op"`
-	GuildID     string             `json:"guildId,omitempty"`
-	SessionID   string             `json:"sessionId,omitempty"`
-	Event       *VoiceServerUpdate `json:"event,omitempty"`
-	Track       string             `json:"track,omitempty"`
-	StartTime   string             `json:"startTime,omitempty"`
-	EndTime     string             `json:"endTime,omitempty"`
-	Pause       bool               `json:"pause,omitempty"`
-	Position    int                `json:"position,omitempty"`
-	Volume      int                `json:"volume,omitempty"`
-	State       *state             `json:"state,omitempty"`
-	Type        string             `json:"type,omitempty"`
-	Reason      string             `json:"reason,omitempty"`
-	Error       string             `json:"error,omitempty"`
-	ThresholdMs int                `json:"thresholdMs,omitempty"`
+	Op          string            `json:"op"`
+	GuildID     string            `json:"guildId,omitempty"`
+	SessionID   string            `json:"sessionId,omitempty"`
+	Event       VoiceServerUpdate `json:"event,omitempty"`
+	Track       string            `json:"track,omitempty"`
+	StartTime   string            `json:"startTime,omitempty"`
+	EndTime     string            `json:"endTime,omitempty"`
+	Pause       bool              `json:"pause,omitempty"`
+	Position    int               `json:"position,omitempty"`
+	Volume      int               `json:"volume,omitempty"`
+	State       state             `json:"state,omitempty"`
+	Type        string            `json:"type,omitempty"`
+	Reason      string            `json:"reason,omitempty"`
+	Error       string            `json:"error,omitempty"`
+	ThresholdMs int               `json:"thresholdMs,omitempty"`
+	StatCPU     statCPU           `json:"cpu,omitempty"`
 	// TODO: stats
 }
 
@@ -91,6 +93,10 @@ type state struct {
 	Position int `json:"position"`
 }
 
+type statCPU struct {
+	Load float32 `json:"lavalinkLoad"`
+}
+
 // VoiceServerUpdate is a raw Discord VOICE_SERVER_UPDATE event
 type VoiceServerUpdate struct {
 	GuildID  string `json:"guild_id"`

node.go

@@ -29,6 +29,7 @@ type NodeConfig struct {
 // Node wraps a Lavalink Node
 type Node struct {
 	config  NodeConfig
+	load    float32
 	manager *Lavalink
 	wsConn  *websocket.Conn
 }
@@ -84,8 +85,11 @@ func (node *Node) listen() {
 			return
 		}
 		err = node.onEvent(msgType, msg)
-		// TODO: better error handling
-		Log.Println(err)
+		// TODO: better error handling?
+
+		if err != nil {
+			Log.Println(err)
+		}
 	}
 }
 
@@ -124,6 +128,9 @@ func (node *Node) onEvent(msgType int, msg []byte) error {
 		}
 
 		return err
+	case opStats:
+		node.load = m.StatCPU.Load
+		Log.Println("dbg-node", node.config.WebSocket, "load", node.load)
 	default:
 		return errUnknownPayload
 	}
@@ -137,7 +144,7 @@ func (node *Node) CreatePlayer(guildID string, sessionID string, event VoiceServ
 		Op:        opVoiceUpdate,
 		GuildID:   guildID,
 		SessionID: sessionID,
-		Event:     &event,
+		Event:     event,
 	}
 	data, err := json.Marshal(msg)
 	if err != nil {