Refactor metric registration, add ability to disable metrics in config

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

@@ -16,6 +16,7 @@ public class FabricExporter implements ModInitializer {
     private MinecraftServer server;
     private MainConfig config;
     private HTTPServer httpServer;
+    private MetricRegistry metricRegistry;
 
     @Override
     public void onInitialize() {
@@ -28,18 +29,9 @@ public class FabricExporter implements ModInitializer {
             e.printStackTrace();
         }
 
-        MetricUpdater metricUpdater = new MetricUpdater(this);
+        MetricRegistry metricRegistry = new MetricRegistry(this);
-        metricUpdater.registerMetric(new OnlinePlayers());
+        metricRegistry.registerDefault();
-        metricUpdater.registerMetric(new Entities());
+        this.setMetricRegistry(metricRegistry);
-        metricUpdater.registerMetric(new LoadedChunks());
-        metricUpdater.registerMetric(new TotalLoadedChunks());
-
-        if (this.getConfig().shouldUseSpark()) {
-            metricUpdater.registerMetric(new TicksPerSecond());
-            metricUpdater.registerMetric(new MillisPerTick());
-        }
-
-        Timer timer = new Timer();
 
         ServerLifecycleEvents.SERVER_STARTING.register(this::setServer);
         ServerLifecycleEvents.SERVER_STARTED.register(server -> {
@@ -48,7 +40,7 @@ public class FabricExporter implements ModInitializer {
                 this.setHttpServer(new HTTPServer(port));
                 FabricExporter.getLogger().info("Prometheus exporter server is now listening on port " + port);
 
-                timer.schedule(metricUpdater, 1000, this.getConfig().getUpdateInterval());
+                this.getMetricRegistry().runUpdater();
             } catch (IOException e) {
                 e.printStackTrace();
             }
@@ -56,7 +48,7 @@ public class FabricExporter implements ModInitializer {
 
         ServerLifecycleEvents.SERVER_STOPPING.register(server -> {
             this.getHttpServer().stop();
-            timer.cancel();
+            this.getMetricRegistry().getTimer().cancel();
         });
     }
 
@@ -87,4 +79,12 @@ public class FabricExporter implements ModInitializer {
     public void setHttpServer(HTTPServer httpServer) {
         this.httpServer = httpServer;
     }
+
+    public MetricRegistry getMetricRegistry() {
+        return metricRegistry;
+    }
+
+    private void setMetricRegistry(MetricRegistry metricRegistry) {
+        this.metricRegistry = metricRegistry;
+    }
 }

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

@@ -0,0 +1,67 @@
+package ru.ruscalworld.fabricexporter;
+
+import io.prometheus.client.Collector;
+import ru.ruscalworld.fabricexporter.config.MainConfig;
+import ru.ruscalworld.fabricexporter.metrics.*;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Timer;
+
+public class MetricRegistry {
+    private final FabricExporter exporter;
+    private final List<Metric> metrics = new ArrayList<>();
+    private final Timer timer;
+
+    public MetricRegistry(FabricExporter exporter) {
+        this.exporter = exporter;
+        timer = new Timer();
+    }
+
+    public void runUpdater() {
+        MainConfig config = this.getExporter().getConfig();
+        MetricUpdater metricUpdater = new MetricUpdater(this.getExporter());
+        this.getMetrics().forEach(metricUpdater::registerMetric);
+        this.getTimer().schedule(metricUpdater, 1000, config.getUpdateInterval());
+    }
+
+    public void registerDefault() {
+        this.registerMetric(new OnlinePlayers());
+        this.registerMetric(new Entities());
+        this.registerMetric(new LoadedChunks());
+        this.registerMetric(new TotalLoadedChunks());
+        this.registerMetric(new TicksPerSecond());
+        this.registerMetric(new MillisPerTick());
+    }
+
+    public void registerMetric(Metric metric) {
+        MainConfig config = this.getExporter().getConfig();
+        if (metric instanceof SparkMetric && !config.shouldUseSpark()) return;
+        if (!this.isEnabled(metric.getName())) return;
+
+        metric.getGauge().register();
+        this.metrics.add(metric);
+    }
+
+    public void registerCustomMetric(String name, Collector collector) {
+        if (this.isEnabled(name)) collector.register();
+    }
+
+    public boolean isEnabled(String name) {
+        MainConfig config = this.getExporter().getConfig();
+        String property = "enable-" + name.replace("_", "-");
+        return config.getProperties().getProperty(property, "true").equals("true");
+    }
+
+    public List<Metric> getMetrics() {
+        return metrics;
+    }
+
+    public FabricExporter getExporter() {
+        return exporter;
+    }
+
+    public Timer getTimer() {
+        return timer;
+    }
+}

src/main/java/ru/ruscalworld/fabricexporter/config/Config.java

@@ -1,14 +1,11 @@
 package ru.ruscalworld.fabricexporter.config;
 
 import net.fabricmc.loader.api.FabricLoader;
-import org.apache.logging.log4j.LogManager;
 import ru.ruscalworld.fabricexporter.FabricExporter;
 import ru.ruscalworld.fabricexporter.util.FileUtil;
 
-import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
-import java.net.URL;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.List;
@@ -16,6 +13,7 @@ import java.util.Properties;
 
 public abstract class Config {
     private final String fileName;
+    private Properties properties;
 
     public Config(String fileName) {
         this.fileName = fileName;
@@ -36,12 +34,21 @@ public abstract class Config {
 
         Properties properties = new Properties();
         properties.load(Files.newInputStream(path));
-        this.parse(properties);
+        this.setProperties(properties);
+        this.onLoad();
     }
 
-    public abstract void parse(Properties properties);
+    public abstract void onLoad();
 
     public String getFileName() {
         return fileName;
     }
+
+    public Properties getProperties() {
+        return properties;
+    }
+
+    public void setProperties(Properties properties) {
+        this.properties = properties;
+    }
 }

src/main/java/ru/ruscalworld/fabricexporter/config/MainConfig.java

@@ -14,7 +14,9 @@ public class MainConfig extends Config {
     }
 
     @Override
-    public void parse(Properties properties) {
+    public void onLoad() {
+        Properties properties = this.getProperties();
+
         String portString = properties.getProperty("server-port", "25585");
         this.setPort(ConvertUtil.intToStringOrDefault(portString, 25585));
 

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

@@ -5,13 +5,15 @@ import ru.ruscalworld.fabricexporter.FabricExporter;
 
 public abstract class Metric {
     private final Gauge gauge;
+    private final String name;
 
     public Metric(String name, String help, String... labels) {
+        this.name = name;
         this.gauge = new Gauge.Builder()
                 .name("minecraft_" + name)
                 .help(help)
                 .labelNames(labels)
-                .create().register();
+                .create();
     }
 
     public abstract void update(FabricExporter exporter);
@@ -19,4 +21,8 @@ public abstract class Metric {
     public Gauge getGauge() {
         return gauge;
     }
+
+    public String getName() {
+        return name;
+    }
 }