Added tracking of stats

.gitignore

@@ -1,2 +1,3 @@
 /.idea/
 *.iml
+/logs/

LavalinkClient/src/main/java/lavalink/client/io/Lavalink.java

@@ -56,6 +56,10 @@ public IPlayer getPlayer(String guildId) {
         return players.computeIfAbsent(guildId, __ -> new LavalinkPlayer(socket, guildId));
     }
 
+    public RemoteStats getLastStats() {
+        return socket.stats;
+    }
+
     public void shutdown() {
         socket.close();
     }

LavalinkClient/src/main/java/lavalink/client/io/LavalinkSocket.java

@@ -30,6 +30,7 @@ public class LavalinkSocket extends WebSocketClient {
 
     private static final int TIMEOUT_MS = 5000;
     private final Lavalink lavalink;
+    RemoteStats stats;
 
     LavalinkSocket(Lavalink lavalink, URI serverUri, Draft protocolDraft, Map<String, String> headers) {
         super(serverUri, protocolDraft, headers, TIMEOUT_MS);
@@ -102,6 +103,9 @@ public void onMessage(String message) {
                 ((LavalinkPlayer) lavalink.getPlayer(json.getString("guildId")))
                         .provideState(json.getJSONObject("state"));
                 break;
+            case "stats":
+                stats = new RemoteStats(json);
+                break;
             case "event":
                 try {
                     handleEvent(json);

LavalinkClient/src/main/java/lavalink/client/io/RemoteStats.java

@@ -0,0 +1,118 @@
+package lavalink.client.io;
+
+import org.json.JSONObject;
+
+public class RemoteStats {
+
+    private int players;
+    private int playingPlayers;
+    private long uptime;
+
+    // In bytes
+    private int memFree;
+    private int memUsed;
+    private int memAllocated;
+    private int memReservable;
+
+    private int cpuCores;
+    private double systemLoad;
+    private double lavalinkLoad;
+
+    private int avgFramesSentPerMinute = -1;
+    private int avgFramesNulledPerMinute = -1;
+    private int avgFramesDeficitPerMinute = -1;
+
+    RemoteStats(JSONObject json) {
+        players = json.getInt("players");
+        playingPlayers = json.getInt("playingPlayers");
+        uptime = json.getLong("uptime");
+
+        memFree = json.getJSONObject("memory").getInt("free");
+        memUsed = json.getJSONObject("memory").getInt("used");
+        memAllocated = json.getJSONObject("memory").getInt("allocated");
+        memReservable = json.getJSONObject("memory").getInt("reservable");
+
+        cpuCores = json.getJSONObject("cpu").getInt("cores");
+        systemLoad = json.getJSONObject("cpu").getDouble("systemLoad");
+        lavalinkLoad = json.getJSONObject("cpu").getDouble("lavalinkLoad");
+
+        JSONObject frames = json.optJSONObject("frameStats");
+
+        if (frames != null) {
+            avgFramesSentPerMinute = frames.getInt("sent");
+            avgFramesNulledPerMinute = frames.getInt("nulled");
+            avgFramesDeficitPerMinute = frames.getInt("deficit");
+        }
+    }
+
+    public int getPlayers() {
+        return players;
+    }
+
+    public int getPlayingPlayers() {
+        return playingPlayers;
+    }
+
+    public long getUptime() {
+        return uptime;
+    }
+
+    public int getMemFree() {
+        return memFree;
+    }
+
+    public int getMemUsed() {
+        return memUsed;
+    }
+
+    public int getMemAllocated() {
+        return memAllocated;
+    }
+
+    public int getMemReservable() {
+        return memReservable;
+    }
+
+    public int getCpuCores() {
+        return cpuCores;
+    }
+
+    public double getSystemLoad() {
+        return systemLoad;
+    }
+
+    public double getLavalinkLoad() {
+        return lavalinkLoad;
+    }
+
+    public int getAvgFramesSentPerMinute() {
+        return avgFramesSentPerMinute;
+    }
+
+    public int getAvgFramesNulledPerMinute() {
+        return avgFramesNulledPerMinute;
+    }
+
+    public int getAvgFramesDeficitPerMinute() {
+        return avgFramesDeficitPerMinute;
+    }
+
+    @Override
+    public String toString() {
+        return "RemoteStats{" +
+                "players=" + players +
+                ", playingPlayers=" + playingPlayers +
+                ", uptime=" + uptime +
+                ", memFree=" + memFree +
+                ", memUsed=" + memUsed +
+                ", memAllocated=" + memAllocated +
+                ", memReservable=" + memReservable +
+                ", cpuCores=" + cpuCores +
+                ", systemLoad=" + systemLoad +
+                ", lavalinkLoad=" + lavalinkLoad +
+                ", avgFramesSentPerMinute=" + avgFramesSentPerMinute +
+                ", avgFramesNulledPerMinute=" + avgFramesNulledPerMinute +
+                ", avgFramesDeficitPerMinute=" + avgFramesDeficitPerMinute +
+                '}';
+    }
+}

LavalinkClient/src/test/java/lavalink/client/io/RemoteStatsTest.java

@@ -0,0 +1,24 @@
+package lavalink.client.io;
+
+import org.json.JSONObject;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+class RemoteStatsTest {
+
+    private static final Logger log = LoggerFactory.getLogger(RemoteStatsTest.class);
+
+    @Test
+    void remoteStatsTest() {
+        JSONObject json = new JSONObject("{\"playingPlayers\":0,\"op\":\"stats\",\"memory\":{\"reservable\":1892155392,\"used\":67111552,\"free\":137885056,\"allocated\":204996608},\"players\":0,\"cpu\":{\"cores\":4,\"systemLoad\":0,\"lavalinkLoad\":0},\"uptime\":15754}");
+        RemoteStats stats = new RemoteStats(json);
+
+        Assertions.assertEquals(-1, stats.getAvgFramesSentPerMinute());
+        Assertions.assertEquals(-1, stats.getAvgFramesNulledPerMinute());
+        Assertions.assertEquals(-1, stats.getAvgFramesDeficitPerMinute());
+        log.info(stats + "");
+    }
+
+}

LavalinkServer/src/main/java/lavalink/server/io/StatsTask.java

@@ -4,21 +4,27 @@
 import lavalink.server.player.AudioLossCounter;
 import lavalink.server.player.Player;
 import org.json.JSONObject;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import oshi.SystemInfo;
 import oshi.hardware.HardwareAbstractionLayer;
 import oshi.software.os.OSProcess;
 import oshi.software.os.OperatingSystem;
 
 public class StatsTask implements Runnable {
 
+    private static final Logger log = LoggerFactory.getLogger(StatsTask.class);
+
     private SocketContext context;
 
-    public StatsTask(SocketContext context) {
+    StatsTask(SocketContext context) {
         this.context = context;
     }
 
     @Override
     public void run() {
+        log.info("Sending stats");
+
         JSONObject out = new JSONObject();
         out.put("op", "stats");
         out.put("players", context.getPlayers().size());