add connected sockets metric

src/main/java/xyz/mcutils/backend/service/MetricService.java

@@ -9,10 +9,7 @@ import org.springframework.stereotype.Service;
 import xyz.mcutils.backend.common.Timer;
 import xyz.mcutils.backend.repository.MetricsRepository;
 import xyz.mcutils.backend.service.metric.Metric;
-import xyz.mcutils.backend.service.metric.metrics.RequestsPerRouteMetric;
+import xyz.mcutils.backend.service.metric.metrics.*;
-import xyz.mcutils.backend.service.metric.metrics.TotalPlayerLookupsMetric;
-import xyz.mcutils.backend.service.metric.metrics.TotalRequestsMetric;
-import xyz.mcutils.backend.service.metric.metrics.TotalServerLookupsMetric;
 import xyz.mcutils.backend.service.metric.metrics.process.CpuUsageMetric;
 import xyz.mcutils.backend.service.metric.metrics.process.MemoryMetric;
 
@@ -49,6 +46,7 @@ public class MetricService {
         registerMetric(new CpuUsageMetric());
         registerMetric(new TotalPlayerLookupsMetric());
         registerMetric(new TotalServerLookupsMetric());
+        registerMetric(new ConnectedSocketsMetric());
 
         // Load the metrics from Redis
         loadMetrics();

src/main/java/xyz/mcutils/backend/service/metric/metrics/ConnectedSocketsMetric.java

@@ -0,0 +1,21 @@
+package xyz.mcutils.backend.service.metric.metrics;
+
+import xyz.mcutils.backend.service.metric.impl.IntegerMetric;
+import xyz.mcutils.backend.websocket.MetricsWebSocketHandler;
+
+public class ConnectedSocketsMetric extends IntegerMetric {
+
+    public ConnectedSocketsMetric() {
+        super("connected_sockets");
+    }
+
+    @Override
+    public boolean isCollector() {
+        return true;
+    }
+
+    @Override
+    public void collect() {
+        setValue(MetricsWebSocketHandler.SESSIONS.size());
+    }
+}

src/main/java/xyz/mcutils/backend/websocket/MetricsWebSocketHandler.java

@@ -22,14 +22,14 @@ import java.util.concurrent.TimeUnit;
 @Log4j2(topic = "WebSocket/Metrics")
 public class MetricsWebSocketHandler extends TextWebSocketHandler {
     private final long interval = TimeUnit.SECONDS.toMillis(5);
-    public final List<WebSocketSession> sessions = new ArrayList<>();
+    public static final List<WebSocketSession> SESSIONS = new ArrayList<>();
 
     private final MetricService metricService;
 
     public MetricsWebSocketHandler(MetricService metricService) {
         this.metricService = metricService;
         Timer.scheduleRepeating(() -> {
-            for (WebSocketSession session : sessions) {
+            for (WebSocketSession session : SESSIONS) {
                 sendMetrics(session);
             }
         }, interval, interval);
@@ -59,13 +59,13 @@ public class MetricsWebSocketHandler extends TextWebSocketHandler {
         log.info("WebSocket connection established with session id: {}", session.getId());
 
         sendMetrics(session);
-        sessions.add(session);
+        SESSIONS.add(session);
     }
 
     @Override
     public void afterConnectionClosed(WebSocketSession session, @NotNull CloseStatus status) {
         log.info("WebSocket connection closed with session id: {}", session.getId());
 
-        sessions.remove(session);
+        SESSIONS.remove(session);
     }
 }