Make server port and update interval configurable

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

@@ -4,6 +4,9 @@ import io.prometheus.client.exporter.HTTPServer;
 import net.fabricmc.api.ModInitializer;
 import net.fabricmc.fabric.api.event.lifecycle.v1.ServerLifecycleEvents;
 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.OnlinePlayers;
 
 import java.io.IOException;
@@ -11,13 +14,23 @@ import java.util.Timer;
 
 public class FabricExporter implements ModInitializer {
     private MinecraftServer server;
+    private MainConfig config;
 
     @Override
     public void onInitialize() {
+        try {
+            MainConfig config = new MainConfig("exporter.properties");
+            config.load();
+            this.setConfig(config);
+        } catch (IOException e) {
+            FabricExporter.getLogger().fatal("Unable to load config");
+            e.printStackTrace();
+        }
+
         ServerLifecycleEvents.SERVER_STARTED.register(this::setServer);
 
         try {
-            HTTPServer httpServer = new HTTPServer(1337);
+            new HTTPServer(this.getConfig().getPort());
         } catch (IOException e) {
             e.printStackTrace();
         }
@@ -26,7 +39,11 @@ public class FabricExporter implements ModInitializer {
         metricUpdater.registerMetric(new OnlinePlayers());
 
         Timer timer = new Timer();
-        timer.schedule(metricUpdater, 1000, 1000);
+        timer.schedule(metricUpdater, 1000, this.getConfig().getUpdateInterval());
+    }
+
+    public static Logger getLogger() {
+        return LogManager.getLogger();
     }
 
     public static String getMetricName(String name) {
@@ -40,4 +57,12 @@ public class FabricExporter implements ModInitializer {
     private void setServer(MinecraftServer server) {
         this.server = server;
     }
+
+    public MainConfig getConfig() {
+        return config;
+    }
+
+    public void setConfig(MainConfig config) {
+        this.config = config;
+    }
 }

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

@@ -0,0 +1,47 @@
+package ru.ruscalworld.fabricexporter.config;
+
+import net.fabricmc.loader.api.FabricLoader;
+import org.apache.logging.log4j.LogManager;
+import ru.ruscalworld.fabricexporter.FabricExporter;
+
+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.Properties;
+
+public abstract class Config {
+    private final String fileName;
+
+    public Config(String fileName) {
+        this.fileName = fileName;
+    }
+
+    public void load() throws IOException {
+        Path path = FabricLoader.getInstance().getConfigDir().resolve(this.getFileName());
+        if (!path.toFile().exists()) try {
+            URL url = this.getClass().getClassLoader().getResource("config/" + this.getFileName());
+            assert url != null;
+            File file = new File(url.toURI());
+            byte[] bytes = Files.readAllBytes(file.toPath());
+
+            Files.createFile(path);
+            Files.write(path, bytes);
+        } catch (Exception exception) {
+            exception.printStackTrace();
+            FabricExporter.getLogger().fatal("Unable to save default config");
+        }
+
+        Properties properties = new Properties();
+        properties.load(Files.newInputStream(path));
+        this.parse(properties);
+    }
+
+    public abstract void parse(Properties properties);
+
+    public String getFileName() {
+        return fileName;
+    }
+}

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

@@ -0,0 +1,39 @@
+package ru.ruscalworld.fabricexporter.config;
+
+import ru.ruscalworld.fabricexporter.util.ConvertUtil;
+
+import java.util.Properties;
+
+public class MainConfig extends Config {
+    private int port;
+    private int updateInterval;
+
+    public MainConfig(String name) {
+        super(name);
+    }
+
+    @Override
+    public void parse(Properties properties) {
+        String portString = properties.getProperty("server-port", "25585");
+        this.setPort(ConvertUtil.intToStringOrDefault(portString, 25585));
+
+        String updateIntervalString = properties.getProperty("update-interval", "1000");
+        this.setUpdateInterval(ConvertUtil.intToStringOrDefault(updateIntervalString, 1000));
+    }
+
+    public int getPort() {
+        return port;
+    }
+
+    public void setPort(int port) {
+        this.port = port;
+    }
+
+    public int getUpdateInterval() {
+        return updateInterval;
+    }
+
+    public void setUpdateInterval(int updateInterval) {
+        this.updateInterval = updateInterval;
+    }
+}

src/main/java/ru/ruscalworld/fabricexporter/util/ConvertUtil.java

@@ -0,0 +1,11 @@
+package ru.ruscalworld.fabricexporter.util;
+
+public class ConvertUtil {
+    public static int intToStringOrDefault(String input, int def) {
+        int result = def;
+        try {
+            result = Integer.parseInt(input);
+        } catch (Exception ignored) { }
+        return result;
+    }
+}

src/main/resources/config/exporter.properties

@@ -0,0 +1,2 @@
+server-port=25585
+update-interval=1000