feat: enhance AFK bot with dynamic username configuration and logging improvements

afk.js

@@ -2,15 +2,34 @@ const mineflayer = require("mineflayer");
 const fs = require("fs");
 const path = require("path");
 
+function getRuntimeUsername() {
+  const fromArg = process.argv[2];
+  if (typeof fromArg === "string" && fromArg.trim()) return fromArg.trim();
+
+  const fromEnv = process.env.BOT_USERNAME;
+  if (typeof fromEnv === "string" && fromEnv.trim()) return fromEnv.trim();
+
+  return "AFKBot";
+}
+
+function toSafeFilePart(value) {
+  return String(value).replace(/[^a-zA-Z0-9_-]/g, "_");
+}
+
+const runtimeUsername = getRuntimeUsername();
+
 // Configuration
 const BOT_CONFIG = {
   host: "java.donutsmp.net",
-  username: "AFKBot",
+  username: runtimeUsername,
   auth: "microsoft",
   version: "1.21.1",
 };
 
-const LOG_FILE = path.join(__dirname, "afk.log");
+const LOG_FILE = path.join(
+  __dirname,
+  `afk-${toSafeFilePart(runtimeUsername)}.log`,
+);
 const TELEPORT_DETECT_REGEX = /you teleported to\b/i;
 
 // Logging

afk_parent.js

@@ -0,0 +1,183 @@
+const { spawn } = require("child_process");
+const fs = require("fs");
+const path = require("path");
+
+// Add all bot usernames here.
+const USERNAMES = ["ZareMate", "Tomek"];
+
+const AFK_SCRIPT = path.join(__dirname, "afk.js");
+const OUTPUT_MODE = (
+  process.env.PARENT_OUTPUT_MODE || "prefixed"
+).toLowerCase();
+const SPLIT_LOGS_ENABLED = process.env.PARENT_SPLIT_LOGS === "1";
+const RESTART_MIN_MS = 2 * 60 * 1000;
+const RESTART_MAX_MS = 5 * 60 * 1000;
+
+const ALREADY_ONLINE_TEXT = "You are already online, try restarting your game.";
+const TIMEOUT_REGEX = /timeout|timed out|ETIMEDOUT|ECONNRESET|socket hang up/i;
+
+let isShuttingDown = false;
+
+function toSafeFilePart(value) {
+  return String(value).replace(/[^a-zA-Z0-9_-]/g, "_");
+}
+
+function writeSplitLog(logFile, line) {
+  if (!logFile) return;
+  const timestamp = new Date().toISOString();
+  fs.appendFileSync(logFile, `[${timestamp}] ${line}\n`);
+}
+
+function withUsernamePrefix(username, line) {
+  const prefix = `[${username}] `;
+  if (line.startsWith(prefix)) return line;
+  return `${prefix}${line}`;
+}
+
+function randomRestartDelayMs() {
+  return (
+    RESTART_MIN_MS +
+    Math.floor(Math.random() * (RESTART_MAX_MS - RESTART_MIN_MS + 1))
+  );
+}
+
+function shouldRestartFromState(state) {
+  if (state.sawKick) return true;
+  if (state.sawTimeout) return true;
+  if (state.sawAlreadyOnline) return true;
+  return false;
+}
+
+function updateRestartSignalsFromLine(state, line) {
+  if (!line) return;
+
+  if (line.includes("Kicked:")) {
+    state.sawKick = true;
+  }
+  if (TIMEOUT_REGEX.test(line)) {
+    state.sawTimeout = true;
+  }
+  if (line.includes(ALREADY_ONLINE_TEXT)) {
+    state.sawAlreadyOnline = true;
+  }
+}
+
+function startBot(state) {
+  const { username } = state;
+  const shouldPrefix = OUTPUT_MODE !== "raw";
+  const logFile = SPLIT_LOGS_ENABLED
+    ? path.join(__dirname, `afk-parent-${toSafeFilePart(username)}.log`)
+    : null;
+
+  state.sawKick = false;
+  state.sawTimeout = false;
+  state.sawAlreadyOnline = false;
+  state.child = null;
+
+  const child = spawn(process.execPath, [AFK_SCRIPT, username], {
+    cwd: __dirname,
+    stdio: shouldPrefix ? ["inherit", "pipe", "pipe"] : "inherit",
+  });
+  state.child = child;
+
+  console.log(`[parent] started ${username} (pid=${child.pid})`);
+
+  child.on("exit", (code, signal) => {
+    const reason = signal ? `signal ${signal}` : `code ${code}`;
+    console.log(`[parent] ${username} exited (${reason})`);
+
+    if (isShuttingDown) return;
+    if (!shouldRestartFromState(state)) return;
+
+    const delay = randomRestartDelayMs();
+    const seconds = Math.round(delay / 1000);
+    console.log(`[parent] scheduling restart for ${username} in ${seconds}s`);
+
+    if (state.restartTimer) clearTimeout(state.restartTimer);
+    state.restartTimer = setTimeout(() => {
+      if (isShuttingDown) return;
+      startBot(state);
+    }, delay);
+  });
+
+  child.on("error", (err) => {
+    console.error(`[parent] failed to start ${username}: ${err.message}`);
+  });
+
+  if (shouldPrefix) {
+    let stdoutBuffer = "";
+    let stderrBuffer = "";
+
+    child.stdout.on("data", (chunk) => {
+      const text = stdoutBuffer + chunk.toString("utf8");
+      const lines = text.split(/\r?\n/);
+      stdoutBuffer = lines.pop() || "";
+      for (const line of lines) {
+        if (!line) continue;
+        updateRestartSignalsFromLine(state, line);
+        const rendered = withUsernamePrefix(username, line);
+        process.stdout.write(`${rendered}\n`);
+        writeSplitLog(logFile, `stdout: ${line}`);
+      }
+    });
+
+    child.stderr.on("data", (chunk) => {
+      const text = stderrBuffer + chunk.toString("utf8");
+      const lines = text.split(/\r?\n/);
+      stderrBuffer = lines.pop() || "";
+      for (const line of lines) {
+        if (!line) continue;
+        updateRestartSignalsFromLine(state, line);
+        const rendered = withUsernamePrefix(username, line);
+        process.stderr.write(`${rendered}\n`);
+        writeSplitLog(logFile, `stderr: ${line}`);
+      }
+    });
+
+    child.on("close", () => {
+      if (stdoutBuffer) {
+        updateRestartSignalsFromLine(state, stdoutBuffer);
+        const rendered = withUsernamePrefix(username, stdoutBuffer);
+        process.stdout.write(`${rendered}\n`);
+        writeSplitLog(logFile, `stdout: ${stdoutBuffer}`);
+      }
+      if (stderrBuffer) {
+        updateRestartSignalsFromLine(state, stderrBuffer);
+        const rendered = withUsernamePrefix(username, stderrBuffer);
+        process.stderr.write(`${rendered}\n`);
+        writeSplitLog(logFile, `stderr: ${stderrBuffer}`);
+      }
+    });
+  }
+
+  return child;
+}
+
+const botStates = USERNAMES.map((username) => ({
+  username,
+  child: null,
+  restartTimer: null,
+  sawKick: false,
+  sawTimeout: false,
+  sawAlreadyOnline: false,
+}));
+
+for (const state of botStates) {
+  startBot(state);
+}
+
+function shutdownAll() {
+  isShuttingDown = true;
+  console.log("[parent] shutdown requested");
+  for (const state of botStates) {
+    if (state.restartTimer) {
+      clearTimeout(state.restartTimer);
+      state.restartTimer = null;
+    }
+    const child = state.child;
+    if (child && !child.killed) child.kill("SIGINT");
+  }
+}
+
+process.on("SIGINT", shutdownAll);
+process.on("SIGTERM", shutdownAll);

package.json

@@ -7,7 +7,9 @@
   "type": "commonjs",
   "main": "index.js",
   "scripts": {
-    "test": "echo \"Error: no test specified\" && exit 1"
+    "test": "echo \"Error: no test specified\" && exit 1",
+    "afk": "node afk.js",
+    "afk:parent": "node afk_parent.js"
   },
   "dependencies": {
     "dotenv": "^17.3.1",