Refactor metric updating, implement entity metrics

src/main/java/ru/ruscalworld/fabricexporter/FabricExporter.java

@@ -7,6 +7,7 @@ import net.minecraft.server.MinecraftServer;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import ru.ruscalworld.fabricexporter.config.MainConfig;
+import ru.ruscalworld.fabricexporter.metrics.Entities;
 import ru.ruscalworld.fabricexporter.metrics.OnlinePlayers;
 import ru.ruscalworld.fabricexporter.metrics.TicksPerSecond;
 import ru.ruscalworld.fabricexporter.metrics.MillisPerTick;
@@ -33,6 +34,7 @@ public class FabricExporter implements ModInitializer {
         metricUpdater.registerMetric(new OnlinePlayers());
         metricUpdater.registerMetric(new TicksPerSecond());
         metricUpdater.registerMetric(new MillisPerTick());
+        metricUpdater.registerMetric(new Entities());
 
         ServerLifecycleEvents.SERVER_STARTING.register(this::setServer);
         ServerLifecycleEvents.SERVER_STARTED.register(server -> {

src/main/java/ru/ruscalworld/fabricexporter/MetricUpdater.java

@@ -18,7 +18,7 @@ public class MetricUpdater extends TimerTask {
     public void run() {
         for (Metric metric : this.getMetrics()) {
             try {
-                metric.getGauge().set(metric.getCurrentValue(this.getExporter()));
+                metric.update(this.getExporter());
             } catch (Exception exception) {
                 exception.printStackTrace();
             }

src/main/java/ru/ruscalworld/fabricexporter/metrics/Entities.java

@@ -0,0 +1,35 @@
+package ru.ruscalworld.fabricexporter.metrics;
+
+import net.minecraft.entity.Entity;
+import net.minecraft.entity.EntityType;
+import net.minecraft.server.world.ServerWorld;
+import net.minecraft.util.Identifier;
+import net.minecraft.util.registry.Registry;
+import ru.ruscalworld.fabricexporter.FabricExporter;
+
+import java.util.HashMap;
+
+public class Entities extends Metric {
+    public Entities() {
+        super("entities", "Amount of entities in the world", "world", "group", "type");
+    }
+
+    @Override
+    public void update(FabricExporter exporter) {
+        for (ServerWorld world : exporter.getServer().getWorlds()) {
+            HashMap<String, Integer> currentWorldEntities = new HashMap<>();
+
+            for (Entity entity : world.getEntitiesByType(null, entity -> true)) {
+                String name = Registry.ENTITY_TYPE.getId(entity.getType()).getPath();
+                Integer typeCount = currentWorldEntities.getOrDefault(name, 0);
+                currentWorldEntities.put(name, typeCount + 1);
+            }
+
+            for (String type : currentWorldEntities.keySet()) {
+                Integer count = currentWorldEntities.get(type);
+                EntityType<?> entityType = Registry.ENTITY_TYPE.get(new Identifier(type));
+                this.getGauge().labels(world.getRegistryKey().getValue().getPath(), entityType.getSpawnGroup().getName(), type).set(count);
+            }
+        }
+    }
+}

src/main/java/ru/ruscalworld/fabricexporter/metrics/Metric.java

@@ -6,11 +6,15 @@ import ru.ruscalworld.fabricexporter.FabricExporter;
 public abstract class Metric {
     private final Gauge gauge;
 
-    public Metric(String name, String help) {
-        this.gauge = new Gauge.Builder().name("minecraft_" + name).help(help).create().register();
+    public Metric(String name, String help, String... labels) {
+        this.gauge = new Gauge.Builder()
+                .name("minecraft_" + name)
+                .help(help)
+                .labelNames(labels)
+                .create().register();
     }
 
-    public abstract double getCurrentValue(FabricExporter exporter);
+    public abstract void update(FabricExporter exporter);
 
     public Gauge getGauge() {
         return gauge;

src/main/java/ru/ruscalworld/fabricexporter/metrics/MillisPerTick.java

@@ -11,9 +11,9 @@ public class MillisPerTick extends SparkMetric {
     }
 
     @Override
-    public double getCurrentValue(FabricExporter exporter) {
+    public void update(FabricExporter exporter) {
         GenericStatistic<DoubleAverageInfo, StatisticWindow.MillisPerTick> mspt = this.getSpark().mspt();
-        if (mspt == null) return 0;
-        return mspt.poll(StatisticWindow.MillisPerTick.MINUTES_1).mean();
+        if (mspt == null) this.getGauge().set(0);
+        else this.getGauge().set(mspt.poll(StatisticWindow.MillisPerTick.MINUTES_1).mean());
     }
 }

src/main/java/ru/ruscalworld/fabricexporter/metrics/OnlinePlayers.java

@@ -8,7 +8,7 @@ public class OnlinePlayers extends Metric {
     }
 
     @Override
-    public double getCurrentValue(FabricExporter exporter) {
-        return exporter.getServer().getCurrentPlayerCount();
+    public void update(FabricExporter exporter) {
+        this.getGauge().set(exporter.getServer().getCurrentPlayerCount());
     }
 }

src/main/java/ru/ruscalworld/fabricexporter/metrics/TicksPerSecond.java

@@ -10,9 +10,9 @@ public class TicksPerSecond extends SparkMetric {
     }
 
     @Override
-    public double getCurrentValue(FabricExporter exporter) {
+    public void update(FabricExporter exporter) {
         DoubleStatistic<StatisticWindow.TicksPerSecond> tps = this.getSpark().tps();
-        if (tps == null) return 20;
-        return tps.poll(StatisticWindow.TicksPerSecond.MINUTES_1);
+        if (tps == null) this.getGauge().set(20);
+        else this.getGauge().set(tps.poll(StatisticWindow.TicksPerSecond.MINUTES_1));
     }
 }