From 951bad4134c9f6f68371b1937810ccfa7b7ba6e4 Mon Sep 17 00:00:00 2001
From: Hornwitser <github@hornwitser.no>
Date: Wed, 22 Jun 2022 22:16:58 +0200
Subject: [PATCH] Refactor slave code

Move classes from slave.js monolit into their own source files.
---
 packages/slave/slave.js                  | 1762 +---------------------
 packages/slave/src/Instance.js           |  930 ++++++++++++
 packages/slave/src/InstanceConnection.js |   85 ++
 packages/slave/src/Slave.js              |  792 ++++++++++
 test/slave.js                            |   23 +-
 5 files changed, 1820 insertions(+), 1772 deletions(-)
 create mode 100644 packages/slave/src/Instance.js
 create mode 100644 packages/slave/src/InstanceConnection.js
 create mode 100644 packages/slave/src/Slave.js

diff --git a/packages/slave/slave.js b/packages/slave/slave.js
index 586152ec..9c4fb8c6 100755
--- a/packages/slave/slave.js
+++ b/packages/slave/slave.js
@@ -16,998 +16,23 @@
 const fs = require("fs-extra");
 const path = require("path");
 const yargs = require("yargs");
-const events = require("events");
-const pidusage = require("pidusage");
 const setBlocking = require("set-blocking");
-const phin = require("phin");
-const stream = require("stream");
-const util = require("util");
 const version = require("./package").version;
 const winston = require("winston");
 require("winston-daily-rotate-file");
 
 // internal libraries
-const libFileOps = require("@clusterio/lib/file_ops");
-const libFactorio = require("@clusterio/lib/factorio");
 const libLink = require("@clusterio/lib/link");
-const libPlugin = require("@clusterio/lib/plugin");
 const libPluginLoader = require("@clusterio/lib/plugin_loader");
 const libErrors = require("@clusterio/lib/errors");
-const libPrometheus = require("@clusterio/lib/prometheus");
-const libLuaTools = require("@clusterio/lib/lua_tools");
 const libConfig = require("@clusterio/lib/config");
 const libSharedCommands = require("@clusterio/lib/shared_commands");
 const { ConsoleTransport, levels, logger } = require("@clusterio/lib/logging");
 const libLoggingUtils = require("@clusterio/lib/logging_utils");
-const libHelpers = require("@clusterio/lib/helpers");
 
-const finished = util.promisify(stream.finished);
+const Slave = require("./src/Slave");
 
 
-const instanceRconCommandDuration = new libPrometheus.Histogram(
-	"clusterio_instance_rcon_command_duration_seconds",
-	"Histogram of the RCON command duration from request to response.",
-	{ labels: ["instance_id"] }
-);
-
-const instanceRconCommandSize = new libPrometheus.Histogram(
-	"clusterio_instance_rcon_command_size_bytes",
-	"Histogram of the RCON command sizes that are sent.",
-	{
-		labels: ["instance_id", "plugin"],
-		buckets: libPrometheus.Histogram.exponential(16, 2, 12),
-	}
-);
-
-const instanceFactorioCpuTime = new libPrometheus.Gauge(
-	"clusterio_instance_factorio_cpu_time_total",
-	"Factorio CPU time spent in seconds.",
-	{ labels: ["instance_id"] }
-);
-
-const instanceFactorioMemoryUsage = new libPrometheus.Gauge(
-	"clusterio_instance_factorio_resident_memory_bytes",
-	"Factorio resident memory size in bytes.",
-	{ labels: ["instance_id"] }
-);
-
-const instanceFactorioAutosaveSize = new libPrometheus.Gauge(
-	"clusterio_instance_factorio_autosave_bytes",
-	"Size of Factorio server autosave in bytes.",
-	{ labels: ["instance_id"] }
-);
-
-function applyAsConfig(name) {
-	return async function action(instance, value) {
-		if (name === "tags" && value instanceof Array) {
-			// Replace spaces with non-break spaces and delimit by spaces.
-			// This does change the defined tags, but there doesn't seem to
-			// be a way to include a space into a tag from the console.
-			value = value.map(tag => tag.replace(/ /g, "\u00a0")).join(" ");
-		}
-		try {
-			await instance.sendRcon(`/config set ${name} ${value}`);
-		} catch (err) {
-			logger.error(`Error applying server setting ${name} ${err.message}`);
-		}
-	};
-}
-
-const serverSettingsActions = {
-	"afk_autokick_interval": applyAsConfig("afk-auto-kick"),
-	"allow_commands": applyAsConfig("allow-commands"),
-	"autosave_interval": applyAsConfig("autosave-interval"),
-	"autosave_only_on_server": applyAsConfig("autosave-only-on-server"),
-	"description": applyAsConfig("description"),
-	"ignore_player_limit_for_returning_players": applyAsConfig("ignore-player-limit-for-returning-players"),
-	"max_players": applyAsConfig("max-players"),
-	"max_upload_slots": applyAsConfig("max-upload-slots"),
-	"max_upload_in_kilobytes_per_second": applyAsConfig("max-upload-speed"),
-	"name": applyAsConfig("name"),
-	"only_admins_can_pause_the_game": applyAsConfig("only-admins-can-pause"),
-	"game_password": applyAsConfig("password"),
-	"require_user_verification": applyAsConfig("require-user-verification"),
-	"tags": applyAsConfig("tags"),
-	"visibility": async (instance, value) => {
-		for (let scope of ["lan", "public", "steam"]) {
-			try {
-				let enabled = Boolean(value[scope]);
-				await instance.sendRcon(`/config set visibility-${scope} ${enabled}`);
-			} catch (err) {
-				logger.error(`Error applying visibility ${scope} ${err}`);
-			}
-		}
-	},
-};
-
-/**
- * Keeps track of the runtime parameters of an instance
- */
-class Instance extends libLink.Link {
-	constructor(slave, connector, dir, factorioDir, instanceConfig) {
-		super("instance", "slave", connector);
-		libLink.attachAllMessages(this);
-		this._slave = slave;
-		this._dir = dir;
-
-		this.plugins = new Map();
-		this.config = instanceConfig;
-
-		/**
-		 * ID of this instance, equivalenet to `instance.config.get("instance.id")`.
-		 * @constant {number}
-		 */
-		this.id = this.config.get("instance.id");
-
-		this.logger = logger.child({
-			instance_id: this.id,
-			instance_name: this.name,
-		});
-
-		this._configFieldChanged = (group, field, prev) => {
-			let hook = () => libPlugin.invokeHook(this.plugins, "onInstanceConfigFieldChanged", group, field, prev);
-
-			if (group.name === "factorio" && field === "settings") {
-				this.updateFactorioSettings(group.get(field), prev).finally(hook);
-			} else if (group.name === "factorio" && field === "enable_whitelist") {
-				this.updateFactorioWhitelist(group.get(field)).finally(hook);
-			} else {
-				if (group.name === "factorio" && field === "max_concurrent_commands") {
-					this.server.maxConcurrentCommands = group.get(field);
-				}
-				hook();
-			}
-		};
-		this.config.on("fieldChanged", this._configFieldChanged);
-
-		let serverOptions = {
-			logger: this.logger,
-			version: this.config.get("factorio.version"),
-			gamePort: this.config.get("factorio.game_port"),
-			rconPort: this.config.get("factorio.rcon_port"),
-			rconPassword: this.config.get("factorio.rcon_password"),
-			enableWhitelist: this.config.get("factorio.enable_whitelist"),
-			enableAuthserverBans: this.config.get("factorio.enable_authserver_bans"),
-			verboseLogging: this.config.get("factorio.verbose_logging"),
-			stripPaths: this.config.get("factorio.strip_paths"),
-			maxConcurrentCommands: this.config.get("factorio.max_concurrent_commands"),
-		};
-
-		// Valid statuses are stopped, starting, running, stopping, creating_save and exporting_data.
-		this._status = "stopped";
-		this._loadedSave = null;
-		this.server = new libFactorio.FactorioServer(
-			factorioDir, this._dir, serverOptions
-		);
-
-		this.server.on("output", (parsed, line) => {
-			this.logger.log("server", { message: line, instance_id: this.id, parsed });
-
-			libPlugin.invokeHook(this.plugins, "onOutput", parsed, line);
-		});
-
-		this.server.on("error", err => {
-			if (err instanceof libErrors.EnvironmentError) {
-				this.logger.error(err.message);
-			} else {
-				this.logger.error(`${this.name}:\n${err.stack}`);
-			}
-		});
-
-		this.server.on("autosave-finished", name => {
-			this._autosave(name).catch(err => {
-				this.logger.error(`Error handling autosave-finished in instance ${this.name}:\n${err.stack}`);
-			});
-		});
-
-		this.server.on("save-finished", () => {
-			this.sendSaveListUpdate().catch(err => {
-				this.logger.error(`Error handling save-finished in instance ${this.name}:\n${err.stack}`);
-			});
-		});
-
-		this.server.on("ipc-player_event", event => {
-			libLink.messages.playerEvent.send(this, {
-				instance_id: this.id,
-				...event,
-			});
-			libPlugin.invokeHook(this.plugins, "onPlayerEvent", event);
-		});
-	}
-
-	async sendRcon(message, expectEmpty, plugin = "") {
-		let instanceId = String(this.id);
-		let observeDuration = instanceRconCommandDuration.labels(instanceId).startTimer();
-		try {
-			return await this.server.sendRcon(message, expectEmpty);
-		} finally {
-			observeDuration();
-			instanceRconCommandSize.labels(instanceId, plugin).observe(Buffer.byteLength(message, "utf8"));
-		}
-	}
-
-	static async listSaves(savesDir, loadedSave) {
-		let defaultSave = null;
-		if (loadedSave === null) {
-			defaultSave = await libFileOps.getNewestFile(
-				savesDir, (name) => !name.endsWith(".tmp.zip")
-			);
-		}
-
-		let list = [];
-		for (let name of await fs.readdir(savesDir)) {
-			let type;
-			let stat = await fs.stat(path.join(savesDir, name));
-			if (stat.isFile()) {
-				type = "file";
-			} else if (stat.isDirectory()) {
-				type = "directory";
-			} else {
-				type = "special";
-			}
-
-			list.push({
-				name,
-				type,
-				size: stat.size,
-				mtime_ms: stat.mtimeMs,
-				loaded: name === loadedSave,
-				default: name === defaultSave,
-			});
-		}
-
-		return list;
-	}
-
-	async sendSaveListUpdate() {
-		libLink.messages.saveListUpdate.send(this, {
-			instance_id: this.id,
-			list: await Instance.listSaves(this.server.writePath("saves"), this._loadedSave),
-		});
-	}
-
-	async _autosave(name) {
-		let stat = await fs.stat(this.path("saves", `${name}.zip`));
-		instanceFactorioAutosaveSize.labels(String(this.id)).set(stat.size);
-		await this.sendSaveListUpdate();
-	}
-
-	notifyStatus(status) {
-		this._status = status;
-		libLink.messages.instanceStatusChanged.send(this, {
-			instance_id: this.id,
-			status,
-			game_port: this.server && this.server.gamePort || this.config.get("factorio.game_port") || null,
-		});
-	}
-
-	/**
-	 * Current state of the instance
-	 *
-	 * One of stopped, starting, running, stopping, creating_save and exporting_data
-	 *
-	 * @returns {string} instance status.
-	 */
-	get status() {
-		return this._status;
-	}
-
-	notifyExit() {
-		this._loadedSave = null;
-		this.notifyStatus("stopped");
-
-		this.config.off("fieldChanged", this._configFieldChanged);
-
-		// Clear metrics this instance is exporting
-		for (let collector of libPrometheus.defaultRegistry.collectors) {
-			if (
-				collector instanceof libPrometheus.ValueCollector
-				&& collector.metric.labels.includes("instance_id")
-			) {
-				collector.removeAll({ instance_id: String(this.id) });
-			}
-		}
-
-		// Notify plugins of exit
-		for (let pluginInstance of this.plugins.values()) {
-			pluginInstance.onExit();
-		}
-	}
-
-	async _loadPlugin(pluginInfo, slave) {
-		let pluginLoadStarted = Date.now();
-		let InstancePluginClass = await libPluginLoader.loadInstancePluginClass(pluginInfo);
-		let instancePlugin = new InstancePluginClass(pluginInfo, this, slave);
-		this.plugins.set(pluginInfo.name, instancePlugin);
-		await instancePlugin.init();
-		libPlugin.attachPluginMessages(this, instancePlugin);
-
-		this.logger.info(`Loaded plugin ${pluginInfo.name} in ${Date.now() - pluginLoadStarted}ms`);
-	}
-
-	async init(pluginInfos) {
-		this.notifyStatus("starting");
-		try {
-			await this.server.init();
-		} catch (err) {
-			this.notifyExit();
-			await this.sendSaveListUpdate();
-			throw err;
-		}
-
-		// load plugins
-		for (let pluginInfo of pluginInfos) {
-			if (
-				!pluginInfo.instanceEntrypoint
-				|| !this._slave.serverPlugins.has(pluginInfo.name)
-				|| !this.config.group(pluginInfo.name).get("load_plugin")
-			) {
-				continue;
-			}
-
-			try {
-				await this._loadPlugin(pluginInfo, this._slave);
-			} catch (err) {
-				this.notifyExit();
-				await this.sendSaveListUpdate();
-				throw err;
-			}
-		}
-
-		let plugins = {};
-		for (let [name, plugin] of this.plugins) {
-			plugins[name] = plugin.info.version;
-		}
-		libLink.messages.instanceInitialized.send(this, { instance_id: this.id, plugins });
-	}
-
-	/**
-	 * Resolve the effective Factorio server settings
-	 *
-	 * Use the example settings as the basis and override it with all the
-	 * entries from the given settings object.
-	 *
-	 * @param {Object} overrides - Server settings to override.
-	 * @returns {Object}
-	 *     server example settings with the given settings applied over it.
-	 */
-	async resolveServerSettings(overrides) {
-		let serverSettings = await this.server.exampleSettings();
-
-		for (let [key, value] of Object.entries(overrides)) {
-			if (!Object.hasOwnProperty.call(serverSettings, key)) {
-				this.logger.warn(`Server settings does not have the property '${key}'`);
-			}
-			serverSettings[key] = value;
-		}
-
-		return serverSettings;
-	}
-
-	/**
-	 * Write the server-settings.json file
-	 *
-	 * Generate the server-settings.json file from the example file in the
-	 * data directory and override any settings configured in the instance's
-	 * factorio_settings config entry.
-	 */
-	async writeServerSettings() {
-		let serverSettings = await this.resolveServerSettings(this.config.get("factorio.settings"));
-		await libFileOps.safeOutputFile(
-			this.server.writePath("server-settings.json"),
-			JSON.stringify(serverSettings, null, 4)
-		);
-	}
-
-	/**
-	 * Creates a new empty instance directory
-	 *
-	 * Creates the neccessary files for starting up a new instance into the
-	 * provided instance directory.
-	 *
-	 * @param {String} instanceDir -
-	 *     Directory to create the new instance into.
-	 * @param {String} factorioDir - Path to factorio installation.
-	 */
-	static async create(instanceDir, factorioDir) {
-		logger.info(`Creating ${instanceDir}`);
-		await fs.ensureDir(instanceDir);
-		await fs.ensureDir(path.join(instanceDir, "script-output"));
-		await fs.ensureDir(path.join(instanceDir, "saves"));
-	}
-
-	/**
-	 * Prepare instance for starting
-	 *
-	 * Writes server settings, admin/ban/white-lists and links mods.
-	 */
-	async prepare() {
-		this.logger.verbose("Writing server-settings.json");
-		await this.writeServerSettings();
-
-		if (this.config.get("factorio.sync_adminlist")) {
-			this.logger.verbose("Writing server-adminlist.json");
-			libFileOps.safeOutputFile(
-				this.server.writePath("server-adminlist.json"),
-				JSON.stringify([...this._slave.adminlist], null, 4)
-			);
-		}
-
-		if (this.config.get("factorio.sync_banlist")) {
-			this.logger.verbose("Writing server-banlist.json");
-			libFileOps.safeOutputFile(
-				this.server.writePath("server-banlist.json"),
-				JSON.stringify([...this._slave.banlist].map(
-					([username, reason]) => ({ username, reason })
-				), null, 4),
-			);
-		}
-
-		if (this.config.get("factorio.sync_whitelist")) {
-			this.logger.verbose("Writing server-whitelist.json");
-			libFileOps.safeOutputFile(
-				this.server.writePath("server-whitelist.json"),
-				JSON.stringify([...this._slave.whitelist], null, 4)
-			);
-		}
-
-		// eslint-disable-next-line no-use-before-define
-		await symlinkMods(this, "sharedMods");
-	}
-
-	/**
-	 * Prepare a save for starting
-	 *
-	 * Creates a new save if no save is passed and patches it with modules.
-	 *
-	 * @param {String|null} saveName -
-	 *     Save to prepare from the instance saves directory.  Creates a new
-	 *     save if null.
-	 * @returns {String} Name of the save prepared.
-	 */
-	async prepareSave(saveName) {
-		// Use latest save if no save was specified
-		if (saveName === null) {
-			saveName = await libFileOps.getNewestFile(
-				this.path("saves"), (name) => !name.endsWith(".tmp.zip")
-			);
-		}
-
-		// Create save if no save was found.
-		if (saveName === null) {
-			this.logger.info("Creating new save");
-			await this.server.create("world.zip");
-			saveName = "world.zip";
-		}
-
-		// Load a copy if it's autosave to prevent overwriting the autosave
-		if (saveName.startsWith("_autosave")) {
-			this.logger.info("Copying autosave");
-			let now = new Date();
-			let newName = util.format(
-				"%s-%s-%s %s%s %s",
-				now.getUTCFullYear(),
-				(now.getUTCMonth() + 1).toLocaleString("en", { minimumIntegerDigits: 2 }),
-				now.getUTCDate().toLocaleString("en", { minimumIntegerDigits: 2 }),
-				now.getUTCHours().toLocaleString("en", { minimumIntegerDigits: 2 }),
-				now.getUTCMinutes().toLocaleString("en", { minimumIntegerDigits: 2 }),
-				saveName,
-			);
-			await fs.copy(this.path("saves", saveName), this.path("saves", newName));
-			saveName = newName;
-		}
-
-		if (!this.config.get("factorio.enable_save_patching")) {
-			return saveName;
-		}
-
-		// Patch save with lua modules from plugins
-		this.logger.verbose("Patching save");
-
-		// Find plugin modules to patch in
-		let modules = new Map();
-		for (let [pluginName, plugin] of this.plugins) {
-			let pluginPackagePath = require.resolve(path.posix.join(plugin.info.requirePath, "package.json"));
-			let modulePath = path.join(path.dirname(pluginPackagePath), "module");
-			if (!await fs.pathExists(modulePath)) {
-				continue;
-			}
-
-			let moduleJsonPath = path.join(modulePath, "module.json");
-			if (!await fs.pathExists(moduleJsonPath)) {
-				throw new Error(`Module for plugin ${pluginName} is missing module.json`);
-			}
-
-			let module = JSON.parse(await fs.readFile(moduleJsonPath));
-			if (module.name !== pluginName) {
-				throw new Error(`Expected name of module for plugin ${pluginName} to match the plugin name`);
-			}
-
-			module = {
-				version: plugin.info.version,
-				dependencies: { "clusterio": "*" },
-				path: modulePath,
-				load: [],
-				require: [],
-				...module,
-			};
-			modules.set(module.name, module);
-		}
-
-		// Find stand alone modules to load
-		// XXX for now only the included clusterio module is loaded
-		for (let entry of await fs.readdir(path.join(__dirname, "modules"), { withFileTypes: true })) {
-			if (!entry.isFile()) {
-				if (modules.has(entry.name)) {
-					throw new Error(`Module with name ${entry.name} already exists in a plugin`);
-				}
-
-				let moduleJsonPath = path.join(__dirname, "modules", entry.name, "module.json");
-				if (!await fs.pathExists(moduleJsonPath)) {
-					throw new Error(`Module ${entry.name} is missing module.json`);
-				}
-
-				let module = JSON.parse(await fs.readFile(moduleJsonPath));
-				if (module.name !== entry.name) {
-					throw new Error(`Expected name of module ${entry.name} to match the directory name`);
-				}
-
-				module = {
-					path: path.join(__dirname, "modules", entry.name),
-					dependencies: { "clusterio": "*" },
-					load: [],
-					require: [],
-					...module,
-				};
-				modules.set(module.name, module);
-			}
-		}
-
-		await libFactorio.patch(this.path("saves", saveName), [...modules.values()]);
-		return saveName;
-	}
-
-	/**
-	 * Start Factorio server
-	 *
-	 * Launches the Factorio server for this instance with the given save.
-	 *
-	 * @param {String} saveName - Name of save game to load.
-	 */
-	async start(saveName) {
-		this.server.on("rcon-ready", () => {
-			this.logger.verbose("RCON connection established");
-		});
-
-		this.server.on("exit", () => this.notifyExit());
-		this._loadedSave = saveName;
-		await this.server.start(saveName);
-
-		if (this.config.get("factorio.enable_save_patching")) {
-			await this.server.disableAchievements();
-			await this.updateInstanceData();
-		}
-
-		await this.sendSaveListUpdate();
-		await libPlugin.invokeHook(this.plugins, "onStart");
-
-		this.notifyStatus("running");
-	}
-
-	/**
-	 * Start Factorio server by loading a scenario
-	 *
-	 * Launches the Factorio server for this instance with the given
-	 * scenario.
-	 *
-	 * @param {String} scenario - Name of scenario to load.
-	 * @param {?number} seed - seed to use.
-	 * @param {?object} mapGenSettings - MapGenSettings to use.
-	 * @param {?object} mapSettings - MapSettings to use.
-	 */
-	async startScenario(scenario, seed, mapGenSettings, mapSettings) {
-		this.server.on("rcon-ready", () => {
-			this.logger.verbose("RCON connection established");
-		});
-
-		this.server.on("exit", () => this.notifyExit());
-		await this.server.startScenario(scenario, seed, mapGenSettings, mapSettings);
-
-		await libPlugin.invokeHook(this.plugins, "onStart");
-
-		this.notifyStatus("running");
-	}
-
-	/**
-	 * Update instance information on the Factorio side
-	 */
-	async updateInstanceData() {
-		let name = libLuaTools.escapeString(this.name);
-		await this.sendRcon(`/sc clusterio_private.update_instance(${this.id}, "${name}")`, true);
-	}
-
-	async updateFactorioSettings(current, previous) {
-		current = await this.resolveServerSettings(current);
-		previous = await this.resolveServerSettings(previous);
-
-		for (let [key, action] of Object.entries(serverSettingsActions)) {
-			if (current[key] !== undefined && !util.isDeepStrictEqual(current[key], previous[key])) {
-				await action(this, current[key]);
-			}
-		}
-	}
-
-	/**
-	 * Enable or disable the player whitelist
-	 *
-	 * @param {boolean} enable -
-	 *     True to enable the whitelist, False to disable the whitelist.
-	 */
-	async updateFactorioWhitelist(enable) {
-		if (!enable) {
-			await this.sendRcon("/whitelist disable");
-		}
-
-		if (this.config.get("factorio.sync_whitelist")) {
-			await this.sendRcon("/whitelist clear");
-			for (let player of this._slave.whitelist) {
-				await this.sendRcon(`/whitelist ${player}`);
-			}
-		}
-
-		if (enable) {
-			await this.sendRcon("/whitelist enable");
-		}
-	}
-
-	async adminlistUpdateEventHandler(message) {
-		if (!this.config.get("factorio.sync_adminlist")) {
-			return;
-		}
-
-		let { name, admin } = message.data;
-		let command = admin ? `/promote ${name}` : `/demote ${name}`;
-		await this.sendRcon(command);
-	}
-
-	async banlistUpdateEventHandler(message) {
-		if (!this.config.get("factorio.sync_banlist")) {
-			return;
-		}
-
-		let { name, banned, reason } = message.data;
-		let command = banned ? `/ban ${name} ${reason}` : `/unban ${name}`;
-		await this.sendRcon(command);
-	}
-
-	async whitelistUpdateEventHandler(message) {
-		if (!this.config.get("factorio.sync_whitelist")) {
-			return;
-		}
-
-		let { name, whitelisted } = message.data;
-		let command = whitelisted ? `/whitelist add ${name}` : `/whiteliste remove ${name}`;
-		await this.sendRcon(command);
-	}
-
-
-	/**
-	 * Stop the instance
-	 */
-	async stop() {
-		if (this._status === "stopped") {
-			return;
-		}
-		this.notifyStatus("stopping");
-
-		// XXX this needs more thought to it
-		if (this.server._state === "running") {
-			await libPlugin.invokeHook(this.plugins, "onStop");
-			await this.server.stop();
-			await this.sendSaveListUpdate();
-		}
-	}
-
-	async kill() {
-		if (this._status === "stopped") {
-			return;
-		}
-		await this.server.kill(true);
-	}
-
-	async masterConnectionEventEventHandler(message) {
-		await libPlugin.invokeHook(this.plugins, "onMasterConnectionEvent", message.data.event);
-	}
-
-	async prepareMasterDisconnectRequestHandler() {
-		await libPlugin.invokeHook(this.plugins, "onPrepareMasterDisconnect");
-	}
-
-	async getMetricsRequestHandler() {
-		let results = [];
-		if (!["stopped", "stopping"].includes(this._status)) {
-			let pluginResults = await libPlugin.invokeHook(this.plugins, "onMetrics");
-			for (let metricIterator of pluginResults) {
-				for await (let metric of metricIterator) {
-					results.push(libPrometheus.serializeResult(metric));
-				}
-			}
-		}
-
-		let pid = this.server.pid;
-		if (pid) {
-			let stats = await pidusage(pid);
-			instanceFactorioCpuTime.labels(String(this.id)).set(stats.ctime / 1000);
-			instanceFactorioMemoryUsage.labels(String(this.id)).set(stats.memory);
-		}
-
-		return { results };
-	}
-
-	async startInstanceRequestHandler(message) {
-		let saveName = message.data.save;
-		try {
-			await this.prepare();
-			saveName = await this.prepareSave(saveName);
-		} catch (err) {
-			this.notifyExit();
-			await this.sendSaveListUpdate();
-			throw err;
-		}
-
-		try {
-			await this.start(saveName);
-		} catch (err) {
-			await this.stop();
-			throw err;
-		}
-	}
-
-	async loadScenarioRequestHandler(message) {
-		if (this.config.get("factorio.enable_save_patching")) {
-			this.notifyExit();
-			throw new libErrors.RequestError("Load scenario cannot be used with save patching enabled");
-		}
-
-		try {
-			await this.prepare();
-		} catch (err) {
-			this.notifyExit();
-			await this.sendSaveListUpdate();
-			throw err;
-		}
-
-		let { scenario, seed, map_gen_settings, map_settings } = message.data;
-		try {
-			await this.startScenario(scenario, seed, map_gen_settings, map_settings);
-		} catch (err) {
-			await this.stop();
-			throw err;
-		}
-	}
-
-	async listSavesRequestHandler(message) {
-		return {
-			list: await Instance.listSaves(this.server.writePath("saves"), this._loadedSave),
-		};
-	}
-
-	async createSaveRequestHandler(message) {
-		this.notifyStatus("creating_save");
-		try {
-			this.logger.verbose("Writing server-settings.json");
-			await this.writeServerSettings();
-
-			this.logger.verbose("Creating save .....");
-			// eslint-disable-next-line no-use-before-define
-			await symlinkMods(this, "sharedMods");
-
-		} catch (err) {
-			this.notifyExit();
-			await this.sendSaveListUpdate();
-			throw err;
-		}
-
-		this.server.on("exit", () => this.notifyExit());
-		let { name, seed, map_gen_settings, map_settings } = message.data;
-		await this.server.create(name, seed, map_gen_settings, map_settings);
-		await this.sendSaveListUpdate();
-		this.logger.info("Successfully created save");
-	}
-
-	async exportDataRequestHandler() {
-		this.notifyStatus("exporting_data");
-		try {
-			this.logger.verbose("Writing server-settings.json");
-			await this.writeServerSettings();
-
-			this.logger.info("Exporting data .....");
-			// eslint-disable-next-line no-use-before-define
-			await symlinkMods(this, "sharedMods");
-			let zip = await libFactorio.exportData(this.server);
-
-			let content = await zip.generateAsync({ type: "nodebuffer" });
-			let url = new URL(this._slave.config.get("slave.master_url"));
-			url.pathname += "api/upload-export";
-			let response = await phin({
-				url, method: "PUT",
-				data: content,
-				core: { ca: this._slave.tlsCa },
-				headers: {
-					"Content-Type": "application/zip",
-					"x-access-token": this._slave.config.get("slave.master_token"),
-				},
-			});
-			if (response.statusCode !== 200) {
-				throw Error(`Upload failed: ${response.statusCode} ${response.statusMessage}: ${response.body}`);
-			}
-
-		} finally {
-			this.notifyExit();
-		}
-	}
-
-	async stopInstanceRequestHandler() {
-		await this.stop();
-	}
-
-	async killInstanceRequestHandler() {
-		await this.kill();
-	}
-
-	async sendRconRequestHandler(message) {
-		let result = await this.sendRcon(message.data.command);
-		return { result };
-	}
-
-	/**
-	 * Name of the instance
-	 *
-	 * This should not be used for filesystem paths.  See .path() for that.
-	 */
-	get name() {
-		return this.config.get("instance.name");
-	}
-
-	/**
-	 * Return path in instance
-	 *
-	 * Creates a path using path.join with the given parts that's relative to
-	 * the directory of the instance.  For example instance.path("mods")
-	 * returns a path to the mods directory of the instance.  If no parts are
-	 * given it returns a path to the directory of the instance.
-	 *
-	 * @returns {string} path in instance directory.
-	 */
-	path(...parts) {
-		return path.join(this._dir, ...parts);
-	}
-}
-
-/**
- * Searches for instances in the provided directory
- *
- * Looks through all sub-dirs of the provided directory for valid
- * instance definitions and return a mapping of instance id to
- * instanceInfo objects.
- *
- * @param {string} instancesDir - Directory containing instances
- * @returns {Map<integer, Object>}
- *     mapping between instance id and information about this instance.
- */
-async function discoverInstances(instancesDir) {
-	let instanceInfos = new Map();
-	for (let entry of await fs.readdir(instancesDir, { withFileTypes: true })) {
-		if (entry.isDirectory()) {
-			let instanceConfig = new libConfig.InstanceConfig("slave");
-			let configPath = path.join(instancesDir, entry.name, "instance.json");
-
-			try {
-				await instanceConfig.load(JSON.parse(await fs.readFile(configPath)));
-
-			} catch (err) {
-				if (err.code === "ENOENT") {
-					continue; // Ignore folders without config.json
-				}
-
-				logger.error(`Error occured while parsing ${configPath}: ${err.message}`);
-				continue;
-			}
-
-			if (instanceInfos.has(instanceConfig.get("instance.id"))) {
-				logger.warn(`Ignoring instance with duplicate id in folder ${entry.name}`);
-				continue;
-			}
-
-			let instancePath = path.join(instancesDir, entry.name);
-			logger.verbose(`found instance ${instanceConfig.get("instance.name")} in ${instancePath}`);
-			instanceInfos.set(instanceConfig.get("instance.id"), {
-				path: instancePath,
-				config: instanceConfig,
-			});
-		}
-	}
-	return instanceInfos;
-}
-
-class InstanceConnection extends libLink.Link {
-	constructor(connector, slave, instanceId) {
-		super("slave", "instance", connector);
-		this.slave = slave;
-		this.instanceId = instanceId;
-		this.plugins = new Map();
-		this.status = "stopped";
-		libLink.attachAllMessages(this);
-
-		for (let pluginInfo of slave.pluginInfos) {
-			libPlugin.attachPluginMessages(this, { info: pluginInfo });
-		}
-	}
-
-	async forwardRequestToMaster(message, request) {
-		return await request.send(this.slave, message.data);
-	}
-
-	async forwardRequestToInstance(message, request) {
-		let instanceId = message.data.instance_id;
-		let instanceConnection = this.slave.instanceConnections.get(instanceId);
-		if (!instanceConnection) {
-			// Instance is probably on another slave
-			return await this.forwardRequestToMaster(message, request);
-		}
-
-		if (request.plugin && !instanceConnection.plugins.has(request.plugin)) {
-			throw new libErrors.RequestError(`Instance ID ${instanceId} does not have ${request.plugin} plugin loaded`);
-		}
-
-		return await request.send(instanceConnection, message.data);
-	}
-
-
-	async forwardEventToInstance(message, event) {
-		let instanceId = message.data.instance_id;
-		let instanceConnection = this.slave.instanceConnections.get(instanceId);
-		if (!instanceConnection) {
-			// Instance is probably on another slave
-			await this.forwardEventToMaster(message, event);
-			return;
-		}
-		if (event.plugin && !instanceConnection.plugins.has(event.plugin)) { return; }
-
-		event.send(instanceConnection, message.data);
-	}
-
-	async forwardEventToMaster(message, event) {
-		if (!this.slave.connector.hasSession) {
-			return;
-		}
-
-		event.send(this.slave, message.data);
-	}
-
-	async broadcastEventToInstance(message, event) {
-		for (let instanceConnection of this.slave.instanceConnections.values()) {
-			// Do not broadcast back to the source
-			if (instanceConnection === this) { continue; }
-			if (event.plugin && !instanceConnection.plugins.has(event.plugin)) { continue; }
-
-			event.send(instanceConnection, message.data);
-		}
-	}
-
-	async instanceInitializedEventHandler(message, event) {
-		this.plugins = new Map(Object.entries(message.data.plugins));
-	}
-
-	async instanceStatusChangedEventHandler(message, event) {
-		this.status = message.data.status;
-		if (this.status === "stopped") {
-			this.slave.instanceConnections.delete(this.instanceId);
-		}
-		this.forwardEventToMaster(message, event);
-	}
-}
-
 class SlaveConnector extends libLink.WebSocketClientConnector {
 	constructor(slaveConfig, tlsCa, pluginInfos) {
 		super(
@@ -1038,782 +63,6 @@ class SlaveConnector extends libLink.WebSocketClientConnector {
 	}
 }
 
-function checkFilename(name) {
-	// All of these are bad in Windows only, except for /, . and ..
-	// See: https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file
-	const badChars = /[<>:"\/\\|?*\x00-\x1f]/g;
-	const badEnd = /[. ]$/;
-
-	const oneToNine = [1, 2, 3, 4, 5, 6, 7, 8, 9];
-	const badNames = [
-		// Relative path components
-		".", "..",
-
-		// Reserved filenames in Windows
-		"CON", "PRN", "AUX", "NUL",
-		...oneToNine.map(n => `COM${n}`),
-		...oneToNine.map(n => `LPT${n}`),
-	];
-
-	if (typeof name !== "string") {
-		throw new Error("must be a string");
-	}
-
-	if (name === "") {
-		throw new Error("cannot be empty");
-	}
-
-	if (badChars.test(name)) {
-		throw new Error('cannot contain <>:"\\/|=* or control characters');
-	}
-
-	if (badNames.includes(name.toUpperCase())) {
-		throw new Error(
-			"cannot be named any of . .. CON PRN AUX NUL COM1-9 and LPT1-9"
-		);
-	}
-
-	if (badEnd.test(name)) {
-		throw new Error("cannot end with . or space");
-	}
-}
-
-function checkRequestSaveName(name) {
-	try {
-		checkFilename(name);
-	} catch (err) {
-		throw new libErrors.RequestError(`Save name ${err.message}`);
-	}
-}
-
-
-/**
- * Handles running the slave
- *
- * Connects to the master server over the WebSocket and manages intsances.
- */
-class Slave extends libLink.Link {
-	// I don't like God classes, but the alternative of putting all this state
-	// into global variables is not much better.
-	constructor(connector, slaveConfig, tlsCa, pluginInfos) {
-		super("slave", "master", connector);
-		libLink.attachAllMessages(this);
-
-		this.pluginInfos = pluginInfos;
-		for (let pluginInfo of pluginInfos) {
-			libPlugin.attachPluginMessages(this, { info: pluginInfo });
-		}
-
-		this.config = slaveConfig;
-
-		/**
-		 * Certificate authority used to validate TLS connections to the master.
-		 * @type {?string}
-		 */
-		this.tlsCa = tlsCa;
-
-		this.instanceConnections = new Map();
-		this.discoveredInstanceInfos = new Map();
-		this.instanceInfos = new Map();
-
-		this.adminlist = new Set();
-		this.banlist = new Map();
-		this.whitelist = new Set();
-
-		this.connector.on("hello", data => {
-			this.serverVersion = data.version;
-			this.serverPlugins = new Map(Object.entries(data.plugins));
-		});
-
-		this._startup = true;
-		this._disconnecting = false;
-		this._shuttingDown = false;
-
-		this.connector.on("connect", () => {
-			if (this._shuttingDown) {
-				return;
-			}
-
-			this.updateInstances().catch((err) => {
-				if (err instanceof libErrors.SessionLost) {
-					return undefined;
-				}
-
-				logger.fatal(`Unexpected error updating instances:\n${err.stack}`);
-				return this.shutdown();
-			});
-		});
-
-		this.connector.on("close", () => {
-			if (this._shuttingDown) {
-				return;
-			}
-
-			if (this._disconnecting) {
-				this._disconnecting = false;
-				this.connector.connect().catch((err) => {
-					logger.fatal(`Unexpected error reconnecting to master:\n${err.stack}`);
-					return this.shutdown();
-				});
-
-			} else {
-				logger.fatal("Master connection was unexpectedly closed");
-				this.shutdown();
-			}
-		});
-
-		for (let event of ["connect", "drop", "resume", "close"]) {
-			this.connector.on(event, () => {
-				for (let instanceConnection of this.instanceConnections.values()) {
-					libLink.messages.masterConnectionEvent.send(instanceConnection, { event });
-				}
-			});
-		}
-	}
-
-	async _findNewInstanceDir(name) {
-		try {
-			checkFilename(name);
-		} catch (err) {
-			throw new Error(`Instance name ${err.message}`);
-		}
-
-		let instancesDir = this.config.get("slave.instances_directory");
-		return path.join(instancesDir, await libFileOps.findUnusedName(instancesDir, name));
-	}
-
-	async forwardRequestToInstance(message, request) {
-		let instanceId = message.data.instance_id;
-		if (!this.instanceInfos.has(instanceId)) {
-			throw new libErrors.RequestError(`Instance with ID ${instanceId} does not exist`);
-		}
-
-		let instanceConnection = this.instanceConnections.get(instanceId);
-		if (!instanceConnection) {
-			throw new libErrors.RequestError(`Instance ID ${instanceId} is not running`);
-		}
-
-		if (request.plugin && !instanceConnection.plugins.has(request.plugin)) {
-			throw new libErrors.RequestError(`Instance ID ${instanceId} does not have ${request.plugin} plugin loaded`);
-		}
-
-		return await request.send(instanceConnection, message.data);
-	}
-
-	async forwardEventToInstance(message, event) {
-		let instanceId = message.data.instance_id;
-		if (!this.instanceInfos.has(instanceId)) { return; }
-
-		let instanceConnection = this.instanceConnections.get(instanceId);
-		if (!instanceConnection) { return; }
-		if (event.plugin && !instanceConnection.plugins.has(event.plugin)) { return; }
-
-		event.send(instanceConnection, message.data);
-	}
-
-	async broadcastEventToInstance(message, event) {
-		for (let instanceConnection of this.instanceConnections.values()) {
-			if (event.plugin && !instanceConnection.plugins.has(event.plugin)) { continue; }
-
-			event.send(instanceConnection, message.data);
-		}
-	}
-
-	async syncUserListsEventHandler(message) {
-		let updateList = (list, updatedList, prop, event) => {
-			let added = new Set(updatedList);
-			let removed = new Set(list);
-			list.forEach(el => added.delete(el));
-			updatedList.forEach(el => removed.delete(el));
-
-			for (let name of added) {
-				list.add(name);
-				this.broadcastEventToInstance(
-					{ data: { name, [prop]: true }}, event
-				);
-			}
-
-			for (let name of removed) {
-				list.delete(name);
-				this.broadcastEventToInstance(
-					{ data: { name, [prop]: false }}, event
-				);
-			}
-		};
-
-		updateList(this.adminlist, message.data.adminlist, "admin", libLink.messages.adminlistUpdate);
-		updateList(this.whitelist, message.data.whitelist, "whitelisted", libLink.messages.whitelistUpdate);
-
-		let addedOrChanged = new Map(message.data.banlist);
-		let removed = new Set(this.banlist.keys());
-		addedOrChanged.forEach((_, name) => removed.delete(name));
-		this.banlist.forEach((reason, name) => {
-			if (addedOrChanged.get(name) === reason) {
-				addedOrChanged.delete(name);
-			}
-		});
-
-		for (let [name, reason] of addedOrChanged) {
-			this.banlist.set(name, reason);
-			this.broadcastEventToInstance(
-				{ data: { name, banned: true, reason }}, libLink.messages.banlistUpdate
-			);
-		}
-
-		for (let name of removed) {
-			this.banlist.delete(name);
-			this.broadcastEventToInstance(
-				{ data: { name, banned: false, reason: "" }}, libLink.messages.banlistUpdate
-			);
-		}
-	}
-
-	async adminlistUpdateEventHandler(message) {
-		let { name, admin } = message.data;
-		if (admin) {
-			this.adminlist.add(name);
-		} else {
-			this.adminlist.delete(name);
-		}
-	}
-
-	async banlistUpdateEventHandler(message) {
-		let { name, banned, reason } = message.data;
-		if (banned) {
-			this.banlist.set(name, reason);
-		} else {
-			this.banlist.delete(name);
-		}
-	}
-
-	async whitelistUpdateEventHandler(message) {
-		let { name, whitelisted } = message.data;
-		if (whitelisted) {
-			this.whitelist.add(name);
-		} else {
-			this.whitelist.delete(name);
-		}
-	}
-
-	async assignInstanceRequestHandler(message) {
-		let { instance_id, serialized_config } = message.data;
-		let instanceInfo = this.instanceInfos.get(instance_id);
-		if (instanceInfo) {
-			instanceInfo.config.update(serialized_config, true, "master");
-			logger.verbose(`Updated config for ${instanceInfo.path}`);
-
-		} else {
-			instanceInfo = this.discoveredInstanceInfos.get(instance_id);
-			if (instanceInfo) {
-				instanceInfo.config.update(serialized_config, true, "master");
-
-			} else {
-				let instanceConfig = new libConfig.InstanceConfig("slave");
-				await instanceConfig.load(serialized_config, "master");
-
-				// XXX: race condition on multiple simultanious calls
-				let instanceDir = await this._findNewInstanceDir(instanceConfig.get("instance.name"));
-
-				await Instance.create(instanceDir, this.config.get("slave.factorio_directory"));
-				instanceInfo = {
-					path: instanceDir,
-					config: instanceConfig,
-				};
-
-				this.discoveredInstanceInfos.set(instance_id, instanceInfo);
-			}
-
-			this.instanceInfos.set(instance_id, instanceInfo);
-			logger.verbose(`assigned instance ${instanceInfo.config.get("instance.name")}`);
-		}
-
-		// Somewhat hacky, but in the event of a lost session the status is
-		// resent on assigment since the master server sends an assigment
-		// request for all the instances it knows should be on this slave.
-		let instanceConnection = this.instanceConnections.get(instance_id);
-		libLink.messages.instanceStatusChanged.send(this, {
-			instance_id,
-			status: instanceConnection ? instanceConnection.status : "stopped",
-		});
-
-		// save a copy of the instance config
-		let warnedOutput = {
-			_warning: "Changes to this file will be overwritten by the master server's copy.",
-			...instanceInfo.config.serialize(),
-		};
-		await libFileOps.safeOutputFile(
-			path.join(instanceInfo.path, "instance.json"),
-			JSON.stringify(warnedOutput, null, 4)
-		);
-	}
-
-	async unassignInstanceRequestHandler(message) {
-		let instanceId = message.data.instance_id;
-		let instanceInfo = this.instanceInfos.get(instanceId);
-		if (instanceInfo) {
-			let instanceConnection = this.instanceConnections.get(instanceId);
-			if (instanceConnection && ["starting", "running"].includes(instanceConnection.status)) {
-				await libLink.messages.stopInstance.send(instanceConnection, { instance_id: instanceId });
-			}
-
-			this.instanceInfos.delete(instanceId);
-			logger.verbose(`unassigned instance ${instanceInfo.config.get("instance.name")}`);
-		}
-	}
-
-	getRequestInstanceInfo(instanceId) {
-		let instanceInfo = this.instanceInfos.get(instanceId);
-		if (!instanceInfo) {
-			throw new libErrors.RequestError(`Instance with ID ${instanceId} does not exist`);
-		}
-		return instanceInfo;
-	}
-
-	/**
-	 * Initialize and connect an unloaded instance
-	 *
-	 * @param {number} instanceId - ID of instance to initialize.
-	 * @returns {module:slave/slave~InstanceConnection} connection to instance.
-	 */
-	async _connectInstance(instanceId) {
-		let instanceInfo = this.getRequestInstanceInfo(instanceId);
-		if (this.instanceConnections.has(instanceId)) {
-			throw new libErrors.RequestError(`Instance with ID ${instanceId} is running`);
-		}
-
-		let [connectionClient, connectionServer] = libLink.VirtualConnector.makePair();
-		let instanceConnection = new InstanceConnection(connectionServer, this, instanceId);
-		let instance = new Instance(
-			this, connectionClient, instanceInfo.path, this.config.get("slave.factorio_directory"), instanceInfo.config
-		);
-
-		this.instanceConnections.set(instanceId, instanceConnection);
-		await instance.init(this.pluginInfos);
-
-		return instanceConnection;
-	}
-
-	async getMetricsRequestHandler() {
-		let requests = [];
-		for (let instanceConnection of this.instanceConnections.values()) {
-			requests.push(libLink.messages.getMetrics.send(instanceConnection));
-		}
-
-		let results = [];
-		for (let response of await Promise.all(requests)) {
-			results.push(...response.results);
-		}
-
-		for await (let result of libPrometheus.defaultRegistry.collect()) {
-			if (result.metric.name.startsWith("process_")) {
-				results.push(libPrometheus.serializeResult(result, {
-					addLabels: { "slave_id": String(this.config.get("slave.id")) },
-					metricName: result.metric.name.replace("process_", "clusterio_slave_"),
-				}));
-
-			} else {
-				results.push(libPrometheus.serializeResult(result));
-			}
-		}
-
-		return { results };
-	}
-
-	async startInstanceRequestHandler(message, request) {
-		let instanceId = message.data.instance_id;
-		let instanceConnection = await this._connectInstance(instanceId);
-		return await request.send(instanceConnection, message.data);
-	}
-
-	async loadScenarioRequestHandler(message, request) {
-		let instanceId = message.data.instance_id;
-		let instanceConnection = await this._connectInstance(instanceId);
-		return await request.send(instanceConnection, message.data);
-	}
-
-	async listSavesRequestHandler(message, request) {
-		let instanceId = message.data.instance_id;
-		let instanceConnection = this.instanceConnections.get(instanceId);
-		if (instanceConnection) {
-			return await request.send(instanceConnection, message.data);
-		}
-
-		let instanceInfo = this.getRequestInstanceInfo(instanceId);
-		return {
-			list: await Instance.listSaves(path.join(instanceInfo.path, "saves"), null),
-		};
-	}
-
-	async createSaveRequestHandler(message, request) {
-		let instanceId = message.data.instance_id;
-		let instanceConnection = await this._connectInstance(instanceId);
-		await request.send(instanceConnection, message.data);
-	}
-
-	async renameSaveRequestHandler(message) {
-		let { instance_id, old_name, new_name } = message.data;
-		checkRequestSaveName(old_name);
-		checkRequestSaveName(new_name);
-		let instanceInfo = this.getRequestInstanceInfo(instance_id);
-		try {
-			await fs.move(
-				path.join(instanceInfo.path, "saves", old_name),
-				path.join(instanceInfo.path, "saves", new_name),
-				{ overwrite: false },
-			);
-		} catch (err) {
-			if (err.code === "ENOENT") {
-				throw new libErrors.RequestError(`${old_name} does not exist`);
-			}
-			throw err;
-		}
-		await this.sendSaveListUpdate(instance_id, path.join(instanceInfo.path, "saves"));
-	}
-
-	async copySaveRequestHandler(message) {
-		let { instance_id, source, destination } = message.data;
-		checkRequestSaveName(source);
-		checkRequestSaveName(destination);
-		let instanceInfo = this.getRequestInstanceInfo(instance_id);
-		try {
-			await fs.copy(
-				path.join(instanceInfo.path, "saves", source),
-				path.join(instanceInfo.path, "saves", destination),
-				{ overwrite: false, errorOnExist: true },
-			);
-		} catch (err) {
-			if (err.code === "ENOENT") {
-				throw new libErrors.RequestError(`${old_name} does not exist`);
-			}
-			throw err;
-		}
-		await this.sendSaveListUpdate(instance_id, path.join(instanceInfo.path, "saves"));
-	}
-
-	async transferSaveRequestHandler(message) {
-		let { source_save, target_save, copy, instance_id, target_instance_id } = message.data;
-		checkRequestSaveName(source_save);
-		checkRequestSaveName(target_save);
-		let sourceInstanceInfo = this.getRequestInstanceInfo(instance_id);
-		let targetInstanceInfo = this.getRequestInstanceInfo(target_instance_id);
-
-		// For consistency with remote transfer initiated through pullSave the
-		// target is renamed if it already exists.
-		target_save = await libFileOps.findUnusedName(
-			path.join(targetInstanceInfo.path, "saves"), target_save, ".zip"
-		);
-
-		try {
-			if (copy) {
-				await fs.copy(
-					path.join(sourceInstanceInfo.path, "saves", source_save),
-					path.join(targetInstanceInfo.path, "saves", target_save),
-					{ overwrite: true },
-				);
-			} else {
-				await fs.move(
-					path.join(sourceInstanceInfo.path, "saves", source_save),
-					path.join(targetInstanceInfo.path, "saves", target_save),
-					{ overwrite: true },
-				);
-			}
-		} catch (err) {
-			if (err.code === "ENOENT") {
-				throw new libErrors.RequestError(`${source_save} does not exist`);
-			}
-			throw err;
-		}
-		await this.sendSaveListUpdate(instance_id, path.join(sourceInstanceInfo.path, "saves"));
-		await this.sendSaveListUpdate(target_instance_id, path.join(targetInstanceInfo.path, "saves"));
-
-		return { save: target_save };
-	}
-
-	async sendSaveListUpdate(instance_id, savesDir) {
-		let instanceConnection = this.instanceConnections.get(instance_id);
-		let saveList;
-		if (instanceConnection) {
-			saveList = (await libLink.messages.listSaves.send(instanceConnection, { instance_id })).list;
-		} else {
-			saveList = await Instance.listSaves(savesDir, null);
-		}
-
-		libLink.messages.saveListUpdate.send(this, { instance_id, list: saveList });
-	}
-
-	async deleteSaveRequestHandler(message) {
-		let { instance_id, save } = message.data;
-		checkRequestSaveName(save);
-		let instanceInfo = this.getRequestInstanceInfo(instance_id);
-
-		try {
-			await fs.unlink(path.join(instanceInfo.path, "saves", save));
-		} catch (err) {
-			if (err.code === "ENOENT") {
-				throw new libErrors.RequestError(`${save} does not exist`);
-			}
-			throw err;
-		}
-		await this.sendSaveListUpdate(instance_id, path.join(instanceInfo.path, "saves"));
-	}
-
-	async pullSaveRequestHandler(message) {
-		let { instance_id, stream_id, filename } = message.data;
-		checkRequestSaveName(filename);
-		let instanceInfo = this.getRequestInstanceInfo(instance_id);
-
-		let url = new URL(this.config.get("slave.master_url"));
-		url.pathname += `api/stream/${stream_id}`;
-		let response = await phin({
-			url, method: "GET",
-			core: { ca: this.tlsCa },
-			stream: true,
-		});
-
-		if (response.statusCode !== 200) {
-			let content = await libHelpers.readStream(response);
-			throw new libErrors.RequestError(`Stream returned ${response.statusCode}: ${content.toString()}`);
-		}
-
-		let savesDir = path.join(instanceInfo.path, "saves");
-		let tempFilename = filename.replace(/(\.zip)?$/, ".tmp.zip");
-		let writeStream;
-		while (true) {
-			try {
-				writeStream = fs.createWriteStream(path.join(savesDir, tempFilename), { flags: "wx" });
-				await events.once(writeStream, "open");
-				break;
-			} catch (err) {
-				if (err.code === "EEXIST") {
-					tempFilename = await libFileOps.findUnusedName(savesDir, tempFilename, ".tmp.zip");
-				} else {
-					throw err;
-				}
-			}
-		}
-		response.pipe(writeStream);
-		await finished(writeStream);
-
-		filename = await libFileOps.findUnusedName(savesDir, filename, ".zip");
-		await fs.rename(path.join(savesDir, tempFilename), path.join(savesDir, filename));
-
-		await this.sendSaveListUpdate(instance_id, savesDir);
-		return { save: filename };
-	}
-
-	async pushSaveRequestHandler(message) {
-		let { instance_id, stream_id, save } = message.data;
-		checkRequestSaveName(save);
-		let instanceInfo = this.getRequestInstanceInfo(instance_id);
-
-		let content;
-		try {
-			// phin doesn't support streaming requests :(
-			content = await fs.readFile(path.join(instanceInfo.path, "saves", save));
-		} catch (err) {
-			if (err.code === "ENOENT") {
-				throw new libErrors.RequestError(`${save} does not exist`);
-			}
-			throw err;
-		}
-
-		let url = new URL(this.config.get("slave.master_url"));
-		url.pathname += `api/stream/${stream_id}`;
-		phin({
-			url, method: "PUT",
-			core: { ca: this.tlsCa },
-			data: content,
-		}).catch(err => logger.error(`Error pushing save to master:\n${err.stack}`));
-	}
-
-	async exportDataRequestHandler(message, request) {
-		let instanceId = message.data.instance_id;
-		let instanceConnection = await this._connectInstance(instanceId);
-		await request.send(instanceConnection, message.data);
-	}
-
-	async stopInstance(instanceId) {
-		let instanceConnection = this.instanceConnections.get(instanceId);
-		await libLink.messages.stopInstance.send(instanceConnection, { instance_id: instanceId });
-	}
-
-	async deleteInstanceRequestHandler(message) {
-		let instanceId = message.data.instance_id;
-		if (this.instanceConnections.has(instanceId)) {
-			throw new libErrors.RequestError(`Instance with ID ${instanceId} is running`);
-		}
-
-		let instanceInfo = this.discoveredInstanceInfos.get(instanceId);
-		if (!instanceInfo) {
-			throw new libErrors.RequestError(`Instance with ID ${instanceId} does not exist`);
-		}
-
-		this.discoveredInstanceInfos.delete(instanceId);
-		this.instanceInfos.delete(instanceId);
-		await fs.remove(instanceInfo.path);
-	}
-
-	/**
-	 * Discover available instances
-	 *
-	 * Looks through the instances directory for instances and updates
-	 * the slave and master server with the new list of instances.
-	 */
-	async updateInstances() {
-		this.discoveredInstanceInfos = await discoverInstances(this.config.get("slave.instances_directory"));
-		let list = [];
-		for (let [instanceId, instanceInfo] of this.discoveredInstanceInfos) {
-			let instanceConnection = this.instanceConnections.get(instanceId);
-			list.push({
-				serialized_config: instanceInfo.config.serialize("master"),
-				status: instanceConnection ? instanceConnection.status : "stopped",
-			});
-		}
-		await libLink.messages.updateInstances.send(this, { instances: list });
-
-		// Handle configured auto startup instances
-		if (this._startup) {
-			this._startup = false;
-
-			for (let [instanceId, instanceInfo] of this.instanceInfos) {
-				if (instanceInfo.config.get("instance.auto_start")) {
-					try {
-						let instanceConnection = await this._connectInstance(instanceId);
-						await libLink.messages.startInstance.send(instanceConnection, {
-							instance_id: instanceId,
-							save: null,
-						});
-					} catch (err) {
-						logger.error(
-							`Error during auto startup for ${instanceInfo.config.get("instance.name")}:\n${err.stack}`
-						);
-					}
-				}
-			}
-		}
-	}
-
-	async prepareDisconnectRequestHandler(message, request) {
-		for (let instanceConnection of this.instanceConnections.values()) {
-			await libLink.messages.prepareMasterDisconnect.send(instanceConnection);
-		}
-		this._disconnecting = true;
-		this.connector.setClosing();
-		return await super.prepareDisconnectRequestHandler(message, request);
-	}
-
-	/**
-	 * Stops all instances and closes the connection
-	 */
-	async shutdown() {
-		if (this._shuttingDown) {
-			return;
-		}
-		this._shuttingDown = true;
-
-		try {
-			await libLink.messages.prepareDisconnect.send(this);
-		} catch (err) {
-			if (!(err instanceof libErrors.SessionLost)) {
-				logger.error(`Unexpected error preparing disconnect:\n${err.stack}`);
-			}
-		}
-
-		try {
-			for (let instanceId of this.instanceConnections.keys()) {
-				await this.stopInstance(instanceId);
-			}
-			await this.connector.close(1000, "Slave Shutdown");
-
-			// Clear silly interval in pidfile library.
-			pidusage.clear();
-		} catch (err) {
-			setBlocking(true);
-			logger.error(`
-+------------------------------------------------------------+
-| Unexpected error occured while shutting down slave, please |
-| report it to https://github.com/clusterio/clusterio/issues |
-+------------------------------------------------------------+
-${err.stack}`
-			);
-			// eslint-disable-next-line node/no-process-exit
-			process.exit(1);
-		}
-	}
-
-	/**
-	 * True if the connection to the master is connected, not in the dropped
-	 * state,and not in the process of disconnecting.
-	 * @type {boolean}
-	 */
-	get connected() {
-		return !this._disconnecting && this.connector.connected;
-	}
-}
-
-/**
- * Create and update symlinks for shared mods in an instance
- *
- * Creates symlinks for .zip and .dat files that are not present in the
- * instance mods directory but is present in the sharedMods directory,
- * and removes any symlinks that don't point to a file in the instance
- * mods directory.  If the instance mods directory doesn't exist it will
- * be created.
- *
- * Note that on Windows this creates hard links instead of symbolic
- * links as the latter requires elevated privileges.  This unfortunately
- * means the removal of mods from the shared mods dir can't be detected.
- *
- * @param {Instance} instance - Instance to link mods for
- * @param {string} sharedMods - Path to folder to link mods from.
- */
-async function symlinkMods(instance, sharedMods) {
-	await fs.ensureDir(instance.path("mods"));
-
-	// Remove broken symlinks in instance mods.
-	for (let entry of await fs.readdir(instance.path("mods"), { withFileTypes: true })) {
-		if (entry.isSymbolicLink()) {
-			if (!await fs.pathExists(instance.path("mods", entry.name))) {
-				instance.logger.verbose(`Removing broken symlink ${entry.name}`);
-				await fs.unlink(instance.path("mods", entry.name));
-			}
-		}
-	}
-
-	// Link entries that are in sharedMods but not in instance mods.
-	let instanceModsEntries = new Set(await fs.readdir(instance.path("mods")));
-	for (let entry of await fs.readdir(sharedMods, { withFileTypes: true })) {
-		if (entry.isFile()) {
-			if ([".zip", ".dat", ".json"].includes(path.extname(entry.name))) {
-				if (!instanceModsEntries.has(entry.name)) {
-					instance.logger.verbose(`linking ${entry.name} from ${sharedMods}`);
-					let target = path.join(sharedMods, entry.name);
-					let link = instance.path("mods", entry.name);
-
-					/* eslint-disable max-depth */
-					if (process.platform !== "win32") {
-						await fs.symlink(path.relative(path.dirname(link), target), link);
-
-					// On Windows symlinks require elevated privileges, which is
-					// not something we want to have.  For this reason the mods
-					// are hard linked instead.  This has the drawback of not
-					// being able to identify when mods are removed from the
-					// sharedMods directory, or which mods are linked.
-					} else {
-						await fs.link(target, link);
-					}
-					/* eslint-enable max-depth */
-				}
-
-			} else {
-				instance.logger.warn(`Warning: ignoring file '${entry.name}' in sharedMods`);
-			}
-
-		} else {
-			instance.logger.warn(`Warning: ignoring non-file '${entry.name}' in sharedMods`);
-		}
-	}
-}
 
 async function startSlave() {
 	// argument parsing
@@ -2005,15 +254,6 @@ async function startSlave() {
 	logger.info("Started slave");
 }
 
-module.exports = {
-	// For testing only
-	_Instance: Instance,
-	_checkFilename: checkFilename,
-	_symlinkMods: symlinkMods,
-	_discoverInstances: discoverInstances,
-	_Slave: Slave,
-};
-
 if (module === require.main) {
 	// eslint-disable-next-line no-console
 	console.warn(`
diff --git a/packages/slave/src/Instance.js b/packages/slave/src/Instance.js
new file mode 100644
index 00000000..1b97ded0
--- /dev/null
+++ b/packages/slave/src/Instance.js
@@ -0,0 +1,930 @@
+"use strict";
+const fs = require("fs-extra");
+const path = require("path");
+const pidusage = require("pidusage");
+const phin = require("phin");
+const util = require("util");
+
+// internal libraries
+const libFileOps = require("@clusterio/lib/file_ops");
+const libFactorio = require("@clusterio/lib/factorio");
+const libLink = require("@clusterio/lib/link");
+const libPlugin = require("@clusterio/lib/plugin");
+const libPluginLoader = require("@clusterio/lib/plugin_loader");
+const libErrors = require("@clusterio/lib/errors");
+const libPrometheus = require("@clusterio/lib/prometheus");
+const libLuaTools = require("@clusterio/lib/lua_tools");
+const { logger } = require("@clusterio/lib/logging");
+
+
+const instanceRconCommandDuration = new libPrometheus.Histogram(
+	"clusterio_instance_rcon_command_duration_seconds",
+	"Histogram of the RCON command duration from request to response.",
+	{ labels: ["instance_id"] }
+);
+
+const instanceRconCommandSize = new libPrometheus.Histogram(
+	"clusterio_instance_rcon_command_size_bytes",
+	"Histogram of the RCON command sizes that are sent.",
+	{
+		labels: ["instance_id", "plugin"],
+		buckets: libPrometheus.Histogram.exponential(16, 2, 12),
+	}
+);
+
+const instanceFactorioCpuTime = new libPrometheus.Gauge(
+	"clusterio_instance_factorio_cpu_time_total",
+	"Factorio CPU time spent in seconds.",
+	{ labels: ["instance_id"] }
+);
+
+const instanceFactorioMemoryUsage = new libPrometheus.Gauge(
+	"clusterio_instance_factorio_resident_memory_bytes",
+	"Factorio resident memory size in bytes.",
+	{ labels: ["instance_id"] }
+);
+
+const instanceFactorioAutosaveSize = new libPrometheus.Gauge(
+	"clusterio_instance_factorio_autosave_bytes",
+	"Size of Factorio server autosave in bytes.",
+	{ labels: ["instance_id"] }
+);
+
+function applyAsConfig(name) {
+	return async function action(instance, value) {
+		if (name === "tags" && value instanceof Array) {
+			// Replace spaces with non-break spaces and delimit by spaces.
+			// This does change the defined tags, but there doesn't seem to
+			// be a way to include a space into a tag from the console.
+			value = value.map(tag => tag.replace(/ /g, "\u00a0")).join(" ");
+		}
+		try {
+			await instance.sendRcon(`/config set ${name} ${value}`);
+		} catch (err) {
+			logger.error(`Error applying server setting ${name} ${err.message}`);
+		}
+	};
+}
+
+const serverSettingsActions = {
+	"afk_autokick_interval": applyAsConfig("afk-auto-kick"),
+	"allow_commands": applyAsConfig("allow-commands"),
+	"autosave_interval": applyAsConfig("autosave-interval"),
+	"autosave_only_on_server": applyAsConfig("autosave-only-on-server"),
+	"description": applyAsConfig("description"),
+	"ignore_player_limit_for_returning_players": applyAsConfig("ignore-player-limit-for-returning-players"),
+	"max_players": applyAsConfig("max-players"),
+	"max_upload_slots": applyAsConfig("max-upload-slots"),
+	"max_upload_in_kilobytes_per_second": applyAsConfig("max-upload-speed"),
+	"name": applyAsConfig("name"),
+	"only_admins_can_pause_the_game": applyAsConfig("only-admins-can-pause"),
+	"game_password": applyAsConfig("password"),
+	"require_user_verification": applyAsConfig("require-user-verification"),
+	"tags": applyAsConfig("tags"),
+	"visibility": async (instance, value) => {
+		for (let scope of ["lan", "public", "steam"]) {
+			try {
+				let enabled = Boolean(value[scope]);
+				await instance.sendRcon(`/config set visibility-${scope} ${enabled}`);
+			} catch (err) {
+				logger.error(`Error applying visibility ${scope} ${err}`);
+			}
+		}
+	},
+};
+
+/**
+ * Create and update symlinks for shared mods in an instance
+ *
+ * Creates symlinks for .zip and .dat files that are not present in the
+ * instance mods directory but is present in the sharedMods directory,
+ * and removes any symlinks that don't point to a file in the instance
+ * mods directory.  If the instance mods directory doesn't exist it will
+ * be created.
+ *
+ * Note that on Windows this creates hard links instead of symbolic
+ * links as the latter requires elevated privileges.  This unfortunately
+ * means the removal of mods from the shared mods dir can't be detected.
+ *
+ * @param {Instance} instance - Instance to link mods for
+ * @param {string} sharedMods - Path to folder to link mods from.
+ */
+async function symlinkMods(instance, sharedMods) {
+	await fs.ensureDir(instance.path("mods"));
+
+	// Remove broken symlinks in instance mods.
+	for (let entry of await fs.readdir(instance.path("mods"), { withFileTypes: true })) {
+		if (entry.isSymbolicLink()) {
+			if (!await fs.pathExists(instance.path("mods", entry.name))) {
+				instance.logger.verbose(`Removing broken symlink ${entry.name}`);
+				await fs.unlink(instance.path("mods", entry.name));
+			}
+		}
+	}
+
+	// Link entries that are in sharedMods but not in instance mods.
+	let instanceModsEntries = new Set(await fs.readdir(instance.path("mods")));
+	for (let entry of await fs.readdir(sharedMods, { withFileTypes: true })) {
+		if (entry.isFile()) {
+			if ([".zip", ".dat", ".json"].includes(path.extname(entry.name))) {
+				if (!instanceModsEntries.has(entry.name)) {
+					instance.logger.verbose(`linking ${entry.name} from ${sharedMods}`);
+					let target = path.join(sharedMods, entry.name);
+					let link = instance.path("mods", entry.name);
+
+					/* eslint-disable max-depth */
+					if (process.platform !== "win32") {
+						await fs.symlink(path.relative(path.dirname(link), target), link);
+
+					// On Windows symlinks require elevated privileges, which is
+					// not something we want to have.  For this reason the mods
+					// are hard linked instead.  This has the drawback of not
+					// being able to identify when mods are removed from the
+					// sharedMods directory, or which mods are linked.
+					} else {
+						await fs.link(target, link);
+					}
+					/* eslint-enable max-depth */
+				}
+
+			} else {
+				instance.logger.warn(`Warning: ignoring file '${entry.name}' in sharedMods`);
+			}
+
+		} else {
+			instance.logger.warn(`Warning: ignoring non-file '${entry.name}' in sharedMods`);
+		}
+	}
+}
+
+
+/**
+ * Keeps track of the runtime parameters of an instance
+ * @alias module:slave/src/Instance
+ */
+class Instance extends libLink.Link {
+	constructor(slave, connector, dir, factorioDir, instanceConfig) {
+		super("instance", "slave", connector);
+		libLink.attachAllMessages(this);
+		this._slave = slave;
+		this._dir = dir;
+
+		this.plugins = new Map();
+		this.config = instanceConfig;
+
+		/**
+		 * ID of this instance, equivalenet to `instance.config.get("instance.id")`.
+		 * @constant {number}
+		 */
+		this.id = this.config.get("instance.id");
+
+		this.logger = logger.child({
+			instance_id: this.id,
+			instance_name: this.name,
+		});
+
+		this._configFieldChanged = (group, field, prev) => {
+			let hook = () => libPlugin.invokeHook(this.plugins, "onInstanceConfigFieldChanged", group, field, prev);
+
+			if (group.name === "factorio" && field === "settings") {
+				this.updateFactorioSettings(group.get(field), prev).finally(hook);
+			} else if (group.name === "factorio" && field === "enable_whitelist") {
+				this.updateFactorioWhitelist(group.get(field)).finally(hook);
+			} else {
+				if (group.name === "factorio" && field === "max_concurrent_commands") {
+					this.server.maxConcurrentCommands = group.get(field);
+				}
+				hook();
+			}
+		};
+		this.config.on("fieldChanged", this._configFieldChanged);
+
+		let serverOptions = {
+			logger: this.logger,
+			version: this.config.get("factorio.version"),
+			gamePort: this.config.get("factorio.game_port"),
+			rconPort: this.config.get("factorio.rcon_port"),
+			rconPassword: this.config.get("factorio.rcon_password"),
+			enableWhitelist: this.config.get("factorio.enable_whitelist"),
+			enableAuthserverBans: this.config.get("factorio.enable_authserver_bans"),
+			verboseLogging: this.config.get("factorio.verbose_logging"),
+			stripPaths: this.config.get("factorio.strip_paths"),
+			maxConcurrentCommands: this.config.get("factorio.max_concurrent_commands"),
+		};
+
+		// Valid statuses are stopped, starting, running, stopping, creating_save and exporting_data.
+		this._status = "stopped";
+		this._loadedSave = null;
+		this.server = new libFactorio.FactorioServer(
+			factorioDir, this._dir, serverOptions
+		);
+
+		this.server.on("output", (parsed, line) => {
+			this.logger.log("server", { message: line, instance_id: this.id, parsed });
+
+			libPlugin.invokeHook(this.plugins, "onOutput", parsed, line);
+		});
+
+		this.server.on("error", err => {
+			if (err instanceof libErrors.EnvironmentError) {
+				this.logger.error(err.message);
+			} else {
+				this.logger.error(`${this.name}:\n${err.stack}`);
+			}
+		});
+
+		this.server.on("autosave-finished", name => {
+			this._autosave(name).catch(err => {
+				this.logger.error(`Error handling autosave-finished in instance ${this.name}:\n${err.stack}`);
+			});
+		});
+
+		this.server.on("save-finished", () => {
+			this.sendSaveListUpdate().catch(err => {
+				this.logger.error(`Error handling save-finished in instance ${this.name}:\n${err.stack}`);
+			});
+		});
+
+		this.server.on("ipc-player_event", event => {
+			libLink.messages.playerEvent.send(this, {
+				instance_id: this.id,
+				...event,
+			});
+			libPlugin.invokeHook(this.plugins, "onPlayerEvent", event);
+		});
+	}
+
+	async sendRcon(message, expectEmpty, plugin = "") {
+		let instanceId = String(this.id);
+		let observeDuration = instanceRconCommandDuration.labels(instanceId).startTimer();
+		try {
+			return await this.server.sendRcon(message, expectEmpty);
+		} finally {
+			observeDuration();
+			instanceRconCommandSize.labels(instanceId, plugin).observe(Buffer.byteLength(message, "utf8"));
+		}
+	}
+
+	static async listSaves(savesDir, loadedSave) {
+		let defaultSave = null;
+		if (loadedSave === null) {
+			defaultSave = await libFileOps.getNewestFile(
+				savesDir, (name) => !name.endsWith(".tmp.zip")
+			);
+		}
+
+		let list = [];
+		for (let name of await fs.readdir(savesDir)) {
+			let type;
+			let stat = await fs.stat(path.join(savesDir, name));
+			if (stat.isFile()) {
+				type = "file";
+			} else if (stat.isDirectory()) {
+				type = "directory";
+			} else {
+				type = "special";
+			}
+
+			list.push({
+				name,
+				type,
+				size: stat.size,
+				mtime_ms: stat.mtimeMs,
+				loaded: name === loadedSave,
+				default: name === defaultSave,
+			});
+		}
+
+		return list;
+	}
+
+	async sendSaveListUpdate() {
+		libLink.messages.saveListUpdate.send(this, {
+			instance_id: this.id,
+			list: await Instance.listSaves(this.server.writePath("saves"), this._loadedSave),
+		});
+	}
+
+	async _autosave(name) {
+		let stat = await fs.stat(this.path("saves", `${name}.zip`));
+		instanceFactorioAutosaveSize.labels(String(this.id)).set(stat.size);
+		await this.sendSaveListUpdate();
+	}
+
+	notifyStatus(status) {
+		this._status = status;
+		libLink.messages.instanceStatusChanged.send(this, {
+			instance_id: this.id,
+			status,
+			game_port: this.server && this.server.gamePort || this.config.get("factorio.game_port") || null,
+		});
+	}
+
+	/**
+	 * Current state of the instance
+	 *
+	 * One of stopped, starting, running, stopping, creating_save and exporting_data
+	 *
+	 * @returns {string} instance status.
+	 */
+	get status() {
+		return this._status;
+	}
+
+	notifyExit() {
+		this._loadedSave = null;
+		this.notifyStatus("stopped");
+
+		this.config.off("fieldChanged", this._configFieldChanged);
+
+		// Clear metrics this instance is exporting
+		for (let collector of libPrometheus.defaultRegistry.collectors) {
+			if (
+				collector instanceof libPrometheus.ValueCollector
+				&& collector.metric.labels.includes("instance_id")
+			) {
+				collector.removeAll({ instance_id: String(this.id) });
+			}
+		}
+
+		// Notify plugins of exit
+		for (let pluginInstance of this.plugins.values()) {
+			pluginInstance.onExit();
+		}
+	}
+
+	async _loadPlugin(pluginInfo, slave) {
+		let pluginLoadStarted = Date.now();
+		let InstancePluginClass = await libPluginLoader.loadInstancePluginClass(pluginInfo);
+		let instancePlugin = new InstancePluginClass(pluginInfo, this, slave);
+		this.plugins.set(pluginInfo.name, instancePlugin);
+		await instancePlugin.init();
+		libPlugin.attachPluginMessages(this, instancePlugin);
+
+		this.logger.info(`Loaded plugin ${pluginInfo.name} in ${Date.now() - pluginLoadStarted}ms`);
+	}
+
+	async init(pluginInfos) {
+		this.notifyStatus("starting");
+		try {
+			await this.server.init();
+		} catch (err) {
+			this.notifyExit();
+			await this.sendSaveListUpdate();
+			throw err;
+		}
+
+		// load plugins
+		for (let pluginInfo of pluginInfos) {
+			if (
+				!pluginInfo.instanceEntrypoint
+				|| !this._slave.serverPlugins.has(pluginInfo.name)
+				|| !this.config.group(pluginInfo.name).get("load_plugin")
+			) {
+				continue;
+			}
+
+			try {
+				await this._loadPlugin(pluginInfo, this._slave);
+			} catch (err) {
+				this.notifyExit();
+				await this.sendSaveListUpdate();
+				throw err;
+			}
+		}
+
+		let plugins = {};
+		for (let [name, plugin] of this.plugins) {
+			plugins[name] = plugin.info.version;
+		}
+		libLink.messages.instanceInitialized.send(this, { instance_id: this.id, plugins });
+	}
+
+	/**
+	 * Resolve the effective Factorio server settings
+	 *
+	 * Use the example settings as the basis and override it with all the
+	 * entries from the given settings object.
+	 *
+	 * @param {Object} overrides - Server settings to override.
+	 * @returns {Object}
+	 *     server example settings with the given settings applied over it.
+	 */
+	async resolveServerSettings(overrides) {
+		let serverSettings = await this.server.exampleSettings();
+
+		for (let [key, value] of Object.entries(overrides)) {
+			if (!Object.hasOwnProperty.call(serverSettings, key)) {
+				this.logger.warn(`Server settings does not have the property '${key}'`);
+			}
+			serverSettings[key] = value;
+		}
+
+		return serverSettings;
+	}
+
+	/**
+	 * Write the server-settings.json file
+	 *
+	 * Generate the server-settings.json file from the example file in the
+	 * data directory and override any settings configured in the instance's
+	 * factorio_settings config entry.
+	 */
+	async writeServerSettings() {
+		let serverSettings = await this.resolveServerSettings(this.config.get("factorio.settings"));
+		await libFileOps.safeOutputFile(
+			this.server.writePath("server-settings.json"),
+			JSON.stringify(serverSettings, null, 4)
+		);
+	}
+
+	/**
+	 * Creates a new empty instance directory
+	 *
+	 * Creates the neccessary files for starting up a new instance into the
+	 * provided instance directory.
+	 *
+	 * @param {String} instanceDir -
+	 *     Directory to create the new instance into.
+	 * @param {String} factorioDir - Path to factorio installation.
+	 */
+	static async create(instanceDir, factorioDir) {
+		logger.info(`Creating ${instanceDir}`);
+		await fs.ensureDir(instanceDir);
+		await fs.ensureDir(path.join(instanceDir, "script-output"));
+		await fs.ensureDir(path.join(instanceDir, "saves"));
+	}
+
+	/**
+	 * Prepare instance for starting
+	 *
+	 * Writes server settings, admin/ban/white-lists and links mods.
+	 */
+	async prepare() {
+		this.logger.verbose("Writing server-settings.json");
+		await this.writeServerSettings();
+
+		if (this.config.get("factorio.sync_adminlist")) {
+			this.logger.verbose("Writing server-adminlist.json");
+			libFileOps.safeOutputFile(
+				this.server.writePath("server-adminlist.json"),
+				JSON.stringify([...this._slave.adminlist], null, 4)
+			);
+		}
+
+		if (this.config.get("factorio.sync_banlist")) {
+			this.logger.verbose("Writing server-banlist.json");
+			libFileOps.safeOutputFile(
+				this.server.writePath("server-banlist.json"),
+				JSON.stringify([...this._slave.banlist].map(
+					([username, reason]) => ({ username, reason })
+				), null, 4),
+			);
+		}
+
+		if (this.config.get("factorio.sync_whitelist")) {
+			this.logger.verbose("Writing server-whitelist.json");
+			libFileOps.safeOutputFile(
+				this.server.writePath("server-whitelist.json"),
+				JSON.stringify([...this._slave.whitelist], null, 4)
+			);
+		}
+
+		// eslint-disable-next-line no-use-before-define
+		await symlinkMods(this, "sharedMods");
+	}
+
+	/**
+	 * Prepare a save for starting
+	 *
+	 * Creates a new save if no save is passed and patches it with modules.
+	 *
+	 * @param {String|null} saveName -
+	 *     Save to prepare from the instance saves directory.  Creates a new
+	 *     save if null.
+	 * @returns {String} Name of the save prepared.
+	 */
+	async prepareSave(saveName) {
+		// Use latest save if no save was specified
+		if (saveName === null) {
+			saveName = await libFileOps.getNewestFile(
+				this.path("saves"), (name) => !name.endsWith(".tmp.zip")
+			);
+		}
+
+		// Create save if no save was found.
+		if (saveName === null) {
+			this.logger.info("Creating new save");
+			await this.server.create("world.zip");
+			saveName = "world.zip";
+		}
+
+		// Load a copy if it's autosave to prevent overwriting the autosave
+		if (saveName.startsWith("_autosave")) {
+			this.logger.info("Copying autosave");
+			let now = new Date();
+			let newName = util.format(
+				"%s-%s-%s %s%s %s",
+				now.getUTCFullYear(),
+				(now.getUTCMonth() + 1).toLocaleString("en", { minimumIntegerDigits: 2 }),
+				now.getUTCDate().toLocaleString("en", { minimumIntegerDigits: 2 }),
+				now.getUTCHours().toLocaleString("en", { minimumIntegerDigits: 2 }),
+				now.getUTCMinutes().toLocaleString("en", { minimumIntegerDigits: 2 }),
+				saveName,
+			);
+			await fs.copy(this.path("saves", saveName), this.path("saves", newName));
+			saveName = newName;
+		}
+
+		if (!this.config.get("factorio.enable_save_patching")) {
+			return saveName;
+		}
+
+		// Patch save with lua modules from plugins
+		this.logger.verbose("Patching save");
+
+		// Find plugin modules to patch in
+		let modules = new Map();
+		for (let [pluginName, plugin] of this.plugins) {
+			let pluginPackagePath = require.resolve(path.posix.join(plugin.info.requirePath, "package.json"));
+			let modulePath = path.join(path.dirname(pluginPackagePath), "module");
+			if (!await fs.pathExists(modulePath)) {
+				continue;
+			}
+
+			let moduleJsonPath = path.join(modulePath, "module.json");
+			if (!await fs.pathExists(moduleJsonPath)) {
+				throw new Error(`Module for plugin ${pluginName} is missing module.json`);
+			}
+
+			let module = JSON.parse(await fs.readFile(moduleJsonPath));
+			if (module.name !== pluginName) {
+				throw new Error(`Expected name of module for plugin ${pluginName} to match the plugin name`);
+			}
+
+			module = {
+				version: plugin.info.version,
+				dependencies: { "clusterio": "*" },
+				path: modulePath,
+				load: [],
+				require: [],
+				...module,
+			};
+			modules.set(module.name, module);
+		}
+
+		// Find stand alone modules to load
+		// XXX for now only the included clusterio module is loaded
+		let modulesDirectory = path.join(__dirname, "..", "modules");
+		for (let entry of await fs.readdir(modulesDirectory, { withFileTypes: true })) {
+			if (!entry.isFile()) {
+				if (modules.has(entry.name)) {
+					throw new Error(`Module with name ${entry.name} already exists in a plugin`);
+				}
+
+				let moduleJsonPath = path.join(modulesDirectory, entry.name, "module.json");
+				if (!await fs.pathExists(moduleJsonPath)) {
+					throw new Error(`Module ${entry.name} is missing module.json`);
+				}
+
+				let module = JSON.parse(await fs.readFile(moduleJsonPath));
+				if (module.name !== entry.name) {
+					throw new Error(`Expected name of module ${entry.name} to match the directory name`);
+				}
+
+				module = {
+					path: path.join(modulesDirectory, entry.name),
+					dependencies: { "clusterio": "*" },
+					load: [],
+					require: [],
+					...module,
+				};
+				modules.set(module.name, module);
+			}
+		}
+
+		await libFactorio.patch(this.path("saves", saveName), [...modules.values()]);
+		return saveName;
+	}
+
+	/**
+	 * Start Factorio server
+	 *
+	 * Launches the Factorio server for this instance with the given save.
+	 *
+	 * @param {String} saveName - Name of save game to load.
+	 */
+	async start(saveName) {
+		this.server.on("rcon-ready", () => {
+			this.logger.verbose("RCON connection established");
+		});
+
+		this.server.on("exit", () => this.notifyExit());
+		this._loadedSave = saveName;
+		await this.server.start(saveName);
+
+		if (this.config.get("factorio.enable_save_patching")) {
+			await this.server.disableAchievements();
+			await this.updateInstanceData();
+		}
+
+		await this.sendSaveListUpdate();
+		await libPlugin.invokeHook(this.plugins, "onStart");
+
+		this.notifyStatus("running");
+	}
+
+	/**
+	 * Start Factorio server by loading a scenario
+	 *
+	 * Launches the Factorio server for this instance with the given
+	 * scenario.
+	 *
+	 * @param {String} scenario - Name of scenario to load.
+	 * @param {?number} seed - seed to use.
+	 * @param {?object} mapGenSettings - MapGenSettings to use.
+	 * @param {?object} mapSettings - MapSettings to use.
+	 */
+	async startScenario(scenario, seed, mapGenSettings, mapSettings) {
+		this.server.on("rcon-ready", () => {
+			this.logger.verbose("RCON connection established");
+		});
+
+		this.server.on("exit", () => this.notifyExit());
+		await this.server.startScenario(scenario, seed, mapGenSettings, mapSettings);
+
+		await libPlugin.invokeHook(this.plugins, "onStart");
+
+		this.notifyStatus("running");
+	}
+
+	/**
+	 * Update instance information on the Factorio side
+	 */
+	async updateInstanceData() {
+		let name = libLuaTools.escapeString(this.name);
+		await this.sendRcon(`/sc clusterio_private.update_instance(${this.id}, "${name}")`, true);
+	}
+
+	async updateFactorioSettings(current, previous) {
+		current = await this.resolveServerSettings(current);
+		previous = await this.resolveServerSettings(previous);
+
+		for (let [key, action] of Object.entries(serverSettingsActions)) {
+			if (current[key] !== undefined && !util.isDeepStrictEqual(current[key], previous[key])) {
+				await action(this, current[key]);
+			}
+		}
+	}
+
+	/**
+	 * Enable or disable the player whitelist
+	 *
+	 * @param {boolean} enable -
+	 *     True to enable the whitelist, False to disable the whitelist.
+	 */
+	async updateFactorioWhitelist(enable) {
+		if (!enable) {
+			await this.sendRcon("/whitelist disable");
+		}
+
+		if (this.config.get("factorio.sync_whitelist")) {
+			await this.sendRcon("/whitelist clear");
+			for (let player of this._slave.whitelist) {
+				await this.sendRcon(`/whitelist ${player}`);
+			}
+		}
+
+		if (enable) {
+			await this.sendRcon("/whitelist enable");
+		}
+	}
+
+	async adminlistUpdateEventHandler(message) {
+		if (!this.config.get("factorio.sync_adminlist")) {
+			return;
+		}
+
+		let { name, admin } = message.data;
+		let command = admin ? `/promote ${name}` : `/demote ${name}`;
+		await this.sendRcon(command);
+	}
+
+	async banlistUpdateEventHandler(message) {
+		if (!this.config.get("factorio.sync_banlist")) {
+			return;
+		}
+
+		let { name, banned, reason } = message.data;
+		let command = banned ? `/ban ${name} ${reason}` : `/unban ${name}`;
+		await this.sendRcon(command);
+	}
+
+	async whitelistUpdateEventHandler(message) {
+		if (!this.config.get("factorio.sync_whitelist")) {
+			return;
+		}
+
+		let { name, whitelisted } = message.data;
+		let command = whitelisted ? `/whitelist add ${name}` : `/whiteliste remove ${name}`;
+		await this.sendRcon(command);
+	}
+
+
+	/**
+	 * Stop the instance
+	 */
+	async stop() {
+		if (this._status === "stopped") {
+			return;
+		}
+		this.notifyStatus("stopping");
+
+		// XXX this needs more thought to it
+		if (this.server._state === "running") {
+			await libPlugin.invokeHook(this.plugins, "onStop");
+			await this.server.stop();
+			await this.sendSaveListUpdate();
+		}
+	}
+
+	async kill() {
+		if (this._status === "stopped") {
+			return;
+		}
+		await this.server.kill(true);
+	}
+
+	async masterConnectionEventEventHandler(message) {
+		await libPlugin.invokeHook(this.plugins, "onMasterConnectionEvent", message.data.event);
+	}
+
+	async prepareMasterDisconnectRequestHandler() {
+		await libPlugin.invokeHook(this.plugins, "onPrepareMasterDisconnect");
+	}
+
+	async getMetricsRequestHandler() {
+		let results = [];
+		if (!["stopped", "stopping"].includes(this._status)) {
+			let pluginResults = await libPlugin.invokeHook(this.plugins, "onMetrics");
+			for (let metricIterator of pluginResults) {
+				for await (let metric of metricIterator) {
+					results.push(libPrometheus.serializeResult(metric));
+				}
+			}
+		}
+
+		let pid = this.server.pid;
+		if (pid) {
+			let stats = await pidusage(pid);
+			instanceFactorioCpuTime.labels(String(this.id)).set(stats.ctime / 1000);
+			instanceFactorioMemoryUsage.labels(String(this.id)).set(stats.memory);
+		}
+
+		return { results };
+	}
+
+	async startInstanceRequestHandler(message) {
+		let saveName = message.data.save;
+		try {
+			await this.prepare();
+			saveName = await this.prepareSave(saveName);
+		} catch (err) {
+			this.notifyExit();
+			await this.sendSaveListUpdate();
+			throw err;
+		}
+
+		try {
+			await this.start(saveName);
+		} catch (err) {
+			await this.stop();
+			throw err;
+		}
+	}
+
+	async loadScenarioRequestHandler(message) {
+		if (this.config.get("factorio.enable_save_patching")) {
+			this.notifyExit();
+			throw new libErrors.RequestError("Load scenario cannot be used with save patching enabled");
+		}
+
+		try {
+			await this.prepare();
+		} catch (err) {
+			this.notifyExit();
+			await this.sendSaveListUpdate();
+			throw err;
+		}
+
+		let { scenario, seed, map_gen_settings, map_settings } = message.data;
+		try {
+			await this.startScenario(scenario, seed, map_gen_settings, map_settings);
+		} catch (err) {
+			await this.stop();
+			throw err;
+		}
+	}
+
+	async listSavesRequestHandler(message) {
+		return {
+			list: await Instance.listSaves(this.server.writePath("saves"), this._loadedSave),
+		};
+	}
+
+	async createSaveRequestHandler(message) {
+		this.notifyStatus("creating_save");
+		try {
+			this.logger.verbose("Writing server-settings.json");
+			await this.writeServerSettings();
+
+			this.logger.verbose("Creating save .....");
+			// eslint-disable-next-line no-use-before-define
+			await symlinkMods(this, "sharedMods");
+
+		} catch (err) {
+			this.notifyExit();
+			await this.sendSaveListUpdate();
+			throw err;
+		}
+
+		this.server.on("exit", () => this.notifyExit());
+		let { name, seed, map_gen_settings, map_settings } = message.data;
+		await this.server.create(name, seed, map_gen_settings, map_settings);
+		await this.sendSaveListUpdate();
+		this.logger.info("Successfully created save");
+	}
+
+	async exportDataRequestHandler() {
+		this.notifyStatus("exporting_data");
+		try {
+			this.logger.verbose("Writing server-settings.json");
+			await this.writeServerSettings();
+
+			this.logger.info("Exporting data .....");
+			// eslint-disable-next-line no-use-before-define
+			await symlinkMods(this, "sharedMods");
+			let zip = await libFactorio.exportData(this.server);
+
+			let content = await zip.generateAsync({ type: "nodebuffer" });
+			let url = new URL(this._slave.config.get("slave.master_url"));
+			url.pathname += "api/upload-export";
+			let response = await phin({
+				url, method: "PUT",
+				data: content,
+				core: { ca: this._slave.tlsCa },
+				headers: {
+					"Content-Type": "application/zip",
+					"x-access-token": this._slave.config.get("slave.master_token"),
+				},
+			});
+			if (response.statusCode !== 200) {
+				throw Error(`Upload failed: ${response.statusCode} ${response.statusMessage}: ${response.body}`);
+			}
+
+		} finally {
+			this.notifyExit();
+		}
+	}
+
+	async stopInstanceRequestHandler() {
+		await this.stop();
+	}
+
+	async killInstanceRequestHandler() {
+		await this.kill();
+	}
+
+	async sendRconRequestHandler(message) {
+		let result = await this.sendRcon(message.data.command);
+		return { result };
+	}
+
+	/**
+	 * Name of the instance
+	 *
+	 * This should not be used for filesystem paths.  See .path() for that.
+	 */
+	get name() {
+		return this.config.get("instance.name");
+	}
+
+	/**
+	 * Return path in instance
+	 *
+	 * Creates a path using path.join with the given parts that's relative to
+	 * the directory of the instance.  For example instance.path("mods")
+	 * returns a path to the mods directory of the instance.  If no parts are
+	 * given it returns a path to the directory of the instance.
+	 *
+	 * @returns {string} path in instance directory.
+	 */
+	path(...parts) {
+		return path.join(this._dir, ...parts);
+	}
+}
+
+module.exports = Instance;
+
+// For testing only
+module.exports._symlinkMods = symlinkMods;
diff --git a/packages/slave/src/InstanceConnection.js b/packages/slave/src/InstanceConnection.js
new file mode 100644
index 00000000..74aa12c4
--- /dev/null
+++ b/packages/slave/src/InstanceConnection.js
@@ -0,0 +1,85 @@
+"use strict";
+const libLink = require("@clusterio/lib/link");
+const libPlugin = require("@clusterio/lib/plugin");
+const libErrors = require("@clusterio/lib/errors");
+
+
+class InstanceConnection extends libLink.Link {
+	constructor(connector, slave, instanceId) {
+		super("slave", "instance", connector);
+		this.slave = slave;
+		this.instanceId = instanceId;
+		this.plugins = new Map();
+		this.status = "stopped";
+		libLink.attachAllMessages(this);
+
+		for (let pluginInfo of slave.pluginInfos) {
+			libPlugin.attachPluginMessages(this, { info: pluginInfo });
+		}
+	}
+
+	async forwardRequestToMaster(message, request) {
+		return await request.send(this.slave, message.data);
+	}
+
+	async forwardRequestToInstance(message, request) {
+		let instanceId = message.data.instance_id;
+		let instanceConnection = this.slave.instanceConnections.get(instanceId);
+		if (!instanceConnection) {
+			// Instance is probably on another slave
+			return await this.forwardRequestToMaster(message, request);
+		}
+
+		if (request.plugin && !instanceConnection.plugins.has(request.plugin)) {
+			throw new libErrors.RequestError(`Instance ID ${instanceId} does not have ${request.plugin} plugin loaded`);
+		}
+
+		return await request.send(instanceConnection, message.data);
+	}
+
+
+	async forwardEventToInstance(message, event) {
+		let instanceId = message.data.instance_id;
+		let instanceConnection = this.slave.instanceConnections.get(instanceId);
+		if (!instanceConnection) {
+			// Instance is probably on another slave
+			await this.forwardEventToMaster(message, event);
+			return;
+		}
+		if (event.plugin && !instanceConnection.plugins.has(event.plugin)) { return; }
+
+		event.send(instanceConnection, message.data);
+	}
+
+	async forwardEventToMaster(message, event) {
+		if (!this.slave.connector.hasSession) {
+			return;
+		}
+
+		event.send(this.slave, message.data);
+	}
+
+	async broadcastEventToInstance(message, event) {
+		for (let instanceConnection of this.slave.instanceConnections.values()) {
+			// Do not broadcast back to the source
+			if (instanceConnection === this) { continue; }
+			if (event.plugin && !instanceConnection.plugins.has(event.plugin)) { continue; }
+
+			event.send(instanceConnection, message.data);
+		}
+	}
+
+	async instanceInitializedEventHandler(message, event) {
+		this.plugins = new Map(Object.entries(message.data.plugins));
+	}
+
+	async instanceStatusChangedEventHandler(message, event) {
+		this.status = message.data.status;
+		if (this.status === "stopped") {
+			this.slave.instanceConnections.delete(this.instanceId);
+		}
+		this.forwardEventToMaster(message, event);
+	}
+}
+
+module.exports = InstanceConnection;
diff --git a/packages/slave/src/Slave.js b/packages/slave/src/Slave.js
new file mode 100644
index 00000000..6cc88d1f
--- /dev/null
+++ b/packages/slave/src/Slave.js
@@ -0,0 +1,792 @@
+"use strict";
+const fs = require("fs-extra");
+const path = require("path");
+const yargs = require("yargs");
+const events = require("events");
+const pidusage = require("pidusage");
+const setBlocking = require("set-blocking");
+const phin = require("phin");
+const stream = require("stream");
+const util = require("util");
+
+// internal libraries
+const libFileOps = require("@clusterio/lib/file_ops");
+const libLink = require("@clusterio/lib/link");
+const libPlugin = require("@clusterio/lib/plugin");
+const libErrors = require("@clusterio/lib/errors");
+const libPrometheus = require("@clusterio/lib/prometheus");
+const libConfig = require("@clusterio/lib/config");
+const { logger } = require("@clusterio/lib/logging");
+const libHelpers = require("@clusterio/lib/helpers");
+
+const Instance = require("./Instance");
+const InstanceConnection = require("./InstanceConnection");
+
+const finished = util.promisify(stream.finished);
+
+
+function checkFilename(name) {
+	// All of these are bad in Windows only, except for /, . and ..
+	// See: https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file
+	const badChars = /[<>:"\/\\|?*\x00-\x1f]/g;
+	const badEnd = /[. ]$/;
+
+	const oneToNine = [1, 2, 3, 4, 5, 6, 7, 8, 9];
+	const badNames = [
+		// Relative path components
+		".", "..",
+
+		// Reserved filenames in Windows
+		"CON", "PRN", "AUX", "NUL",
+		...oneToNine.map(n => `COM${n}`),
+		...oneToNine.map(n => `LPT${n}`),
+	];
+
+	if (typeof name !== "string") {
+		throw new Error("must be a string");
+	}
+
+	if (name === "") {
+		throw new Error("cannot be empty");
+	}
+
+	if (badChars.test(name)) {
+		throw new Error('cannot contain <>:"\\/|=* or control characters');
+	}
+
+	if (badNames.includes(name.toUpperCase())) {
+		throw new Error(
+			"cannot be named any of . .. CON PRN AUX NUL COM1-9 and LPT1-9"
+		);
+	}
+
+	if (badEnd.test(name)) {
+		throw new Error("cannot end with . or space");
+	}
+}
+
+function checkRequestSaveName(name) {
+	try {
+		checkFilename(name);
+	} catch (err) {
+		throw new libErrors.RequestError(`Save name ${err.message}`);
+	}
+}
+
+/**
+ * Searches for instances in the provided directory
+ *
+ * Looks through all sub-dirs of the provided directory for valid
+ * instance definitions and return a mapping of instance id to
+ * instanceInfo objects.
+ *
+ * @param {string} instancesDir - Directory containing instances
+ * @returns {Map<integer, Object>}
+ *     mapping between instance id and information about this instance.
+ */
+async function discoverInstances(instancesDir) {
+	let instanceInfos = new Map();
+	for (let entry of await fs.readdir(instancesDir, { withFileTypes: true })) {
+		if (entry.isDirectory()) {
+			let instanceConfig = new libConfig.InstanceConfig("slave");
+			let configPath = path.join(instancesDir, entry.name, "instance.json");
+
+			try {
+				await instanceConfig.load(JSON.parse(await fs.readFile(configPath)));
+
+			} catch (err) {
+				if (err.code === "ENOENT") {
+					continue; // Ignore folders without config.json
+				}
+
+				logger.error(`Error occured while parsing ${configPath}: ${err.message}`);
+				continue;
+			}
+
+			if (instanceInfos.has(instanceConfig.get("instance.id"))) {
+				logger.warn(`Ignoring instance with duplicate id in folder ${entry.name}`);
+				continue;
+			}
+
+			let instancePath = path.join(instancesDir, entry.name);
+			logger.verbose(`found instance ${instanceConfig.get("instance.name")} in ${instancePath}`);
+			instanceInfos.set(instanceConfig.get("instance.id"), {
+				path: instancePath,
+				config: instanceConfig,
+			});
+		}
+	}
+	return instanceInfos;
+}
+
+/**
+ * Handles running the slave
+ *
+ * Connects to the master server over the WebSocket and manages intsances.
+ */
+class Slave extends libLink.Link {
+	// I don't like God classes, but the alternative of putting all this state
+	// into global variables is not much better.
+	constructor(connector, slaveConfig, tlsCa, pluginInfos) {
+		super("slave", "master", connector);
+		libLink.attachAllMessages(this);
+
+		this.pluginInfos = pluginInfos;
+		for (let pluginInfo of pluginInfos) {
+			libPlugin.attachPluginMessages(this, { info: pluginInfo });
+		}
+
+		this.config = slaveConfig;
+
+		/**
+		 * Certificate authority used to validate TLS connections to the master.
+		 * @type {?string}
+		 */
+		this.tlsCa = tlsCa;
+
+		this.instanceConnections = new Map();
+		this.discoveredInstanceInfos = new Map();
+		this.instanceInfos = new Map();
+
+		this.adminlist = new Set();
+		this.banlist = new Map();
+		this.whitelist = new Set();
+
+		this.connector.on("hello", data => {
+			this.serverVersion = data.version;
+			this.serverPlugins = new Map(Object.entries(data.plugins));
+		});
+
+		this._startup = true;
+		this._disconnecting = false;
+		this._shuttingDown = false;
+
+		this.connector.on("connect", () => {
+			if (this._shuttingDown) {
+				return;
+			}
+
+			this.updateInstances().catch((err) => {
+				if (err instanceof libErrors.SessionLost) {
+					return undefined;
+				}
+
+				logger.fatal(`Unexpected error updating instances:\n${err.stack}`);
+				return this.shutdown();
+			});
+		});
+
+		this.connector.on("close", () => {
+			if (this._shuttingDown) {
+				return;
+			}
+
+			if (this._disconnecting) {
+				this._disconnecting = false;
+				this.connector.connect().catch((err) => {
+					logger.fatal(`Unexpected error reconnecting to master:\n${err.stack}`);
+					return this.shutdown();
+				});
+
+			} else {
+				logger.fatal("Master connection was unexpectedly closed");
+				this.shutdown();
+			}
+		});
+
+		for (let event of ["connect", "drop", "resume", "close"]) {
+			this.connector.on(event, () => {
+				for (let instanceConnection of this.instanceConnections.values()) {
+					libLink.messages.masterConnectionEvent.send(instanceConnection, { event });
+				}
+			});
+		}
+	}
+
+	async _findNewInstanceDir(name) {
+		try {
+			checkFilename(name);
+		} catch (err) {
+			throw new Error(`Instance name ${err.message}`);
+		}
+
+		let instancesDir = this.config.get("slave.instances_directory");
+		return path.join(instancesDir, await libFileOps.findUnusedName(instancesDir, name));
+	}
+
+	async forwardRequestToInstance(message, request) {
+		let instanceId = message.data.instance_id;
+		if (!this.instanceInfos.has(instanceId)) {
+			throw new libErrors.RequestError(`Instance with ID ${instanceId} does not exist`);
+		}
+
+		let instanceConnection = this.instanceConnections.get(instanceId);
+		if (!instanceConnection) {
+			throw new libErrors.RequestError(`Instance ID ${instanceId} is not running`);
+		}
+
+		if (request.plugin && !instanceConnection.plugins.has(request.plugin)) {
+			throw new libErrors.RequestError(`Instance ID ${instanceId} does not have ${request.plugin} plugin loaded`);
+		}
+
+		return await request.send(instanceConnection, message.data);
+	}
+
+	async forwardEventToInstance(message, event) {
+		let instanceId = message.data.instance_id;
+		if (!this.instanceInfos.has(instanceId)) { return; }
+
+		let instanceConnection = this.instanceConnections.get(instanceId);
+		if (!instanceConnection) { return; }
+		if (event.plugin && !instanceConnection.plugins.has(event.plugin)) { return; }
+
+		event.send(instanceConnection, message.data);
+	}
+
+	async broadcastEventToInstance(message, event) {
+		for (let instanceConnection of this.instanceConnections.values()) {
+			if (event.plugin && !instanceConnection.plugins.has(event.plugin)) { continue; }
+
+			event.send(instanceConnection, message.data);
+		}
+	}
+
+	async syncUserListsEventHandler(message) {
+		let updateList = (list, updatedList, prop, event) => {
+			let added = new Set(updatedList);
+			let removed = new Set(list);
+			list.forEach(el => added.delete(el));
+			updatedList.forEach(el => removed.delete(el));
+
+			for (let name of added) {
+				list.add(name);
+				this.broadcastEventToInstance(
+					{ data: { name, [prop]: true }}, event
+				);
+			}
+
+			for (let name of removed) {
+				list.delete(name);
+				this.broadcastEventToInstance(
+					{ data: { name, [prop]: false }}, event
+				);
+			}
+		};
+
+		updateList(this.adminlist, message.data.adminlist, "admin", libLink.messages.adminlistUpdate);
+		updateList(this.whitelist, message.data.whitelist, "whitelisted", libLink.messages.whitelistUpdate);
+
+		let addedOrChanged = new Map(message.data.banlist);
+		let removed = new Set(this.banlist.keys());
+		addedOrChanged.forEach((_, name) => removed.delete(name));
+		this.banlist.forEach((reason, name) => {
+			if (addedOrChanged.get(name) === reason) {
+				addedOrChanged.delete(name);
+			}
+		});
+
+		for (let [name, reason] of addedOrChanged) {
+			this.banlist.set(name, reason);
+			this.broadcastEventToInstance(
+				{ data: { name, banned: true, reason }}, libLink.messages.banlistUpdate
+			);
+		}
+
+		for (let name of removed) {
+			this.banlist.delete(name);
+			this.broadcastEventToInstance(
+				{ data: { name, banned: false, reason: "" }}, libLink.messages.banlistUpdate
+			);
+		}
+	}
+
+	async adminlistUpdateEventHandler(message) {
+		let { name, admin } = message.data;
+		if (admin) {
+			this.adminlist.add(name);
+		} else {
+			this.adminlist.delete(name);
+		}
+	}
+
+	async banlistUpdateEventHandler(message) {
+		let { name, banned, reason } = message.data;
+		if (banned) {
+			this.banlist.set(name, reason);
+		} else {
+			this.banlist.delete(name);
+		}
+	}
+
+	async whitelistUpdateEventHandler(message) {
+		let { name, whitelisted } = message.data;
+		if (whitelisted) {
+			this.whitelist.add(name);
+		} else {
+			this.whitelist.delete(name);
+		}
+	}
+
+	async assignInstanceRequestHandler(message) {
+		let { instance_id, serialized_config } = message.data;
+		let instanceInfo = this.instanceInfos.get(instance_id);
+		if (instanceInfo) {
+			instanceInfo.config.update(serialized_config, true, "master");
+			logger.verbose(`Updated config for ${instanceInfo.path}`);
+
+		} else {
+			instanceInfo = this.discoveredInstanceInfos.get(instance_id);
+			if (instanceInfo) {
+				instanceInfo.config.update(serialized_config, true, "master");
+
+			} else {
+				let instanceConfig = new libConfig.InstanceConfig("slave");
+				await instanceConfig.load(serialized_config, "master");
+
+				// XXX: race condition on multiple simultanious calls
+				let instanceDir = await this._findNewInstanceDir(instanceConfig.get("instance.name"));
+
+				await Instance.create(instanceDir, this.config.get("slave.factorio_directory"));
+				instanceInfo = {
+					path: instanceDir,
+					config: instanceConfig,
+				};
+
+				this.discoveredInstanceInfos.set(instance_id, instanceInfo);
+			}
+
+			this.instanceInfos.set(instance_id, instanceInfo);
+			logger.verbose(`assigned instance ${instanceInfo.config.get("instance.name")}`);
+		}
+
+		// Somewhat hacky, but in the event of a lost session the status is
+		// resent on assigment since the master server sends an assigment
+		// request for all the instances it knows should be on this slave.
+		let instanceConnection = this.instanceConnections.get(instance_id);
+		libLink.messages.instanceStatusChanged.send(this, {
+			instance_id,
+			status: instanceConnection ? instanceConnection.status : "stopped",
+		});
+
+		// save a copy of the instance config
+		let warnedOutput = {
+			_warning: "Changes to this file will be overwritten by the master server's copy.",
+			...instanceInfo.config.serialize(),
+		};
+		await libFileOps.safeOutputFile(
+			path.join(instanceInfo.path, "instance.json"),
+			JSON.stringify(warnedOutput, null, 4)
+		);
+	}
+
+	async unassignInstanceRequestHandler(message) {
+		let instanceId = message.data.instance_id;
+		let instanceInfo = this.instanceInfos.get(instanceId);
+		if (instanceInfo) {
+			let instanceConnection = this.instanceConnections.get(instanceId);
+			if (instanceConnection && ["starting", "running"].includes(instanceConnection.status)) {
+				await libLink.messages.stopInstance.send(instanceConnection, { instance_id: instanceId });
+			}
+
+			this.instanceInfos.delete(instanceId);
+			logger.verbose(`unassigned instance ${instanceInfo.config.get("instance.name")}`);
+		}
+	}
+
+	getRequestInstanceInfo(instanceId) {
+		let instanceInfo = this.instanceInfos.get(instanceId);
+		if (!instanceInfo) {
+			throw new libErrors.RequestError(`Instance with ID ${instanceId} does not exist`);
+		}
+		return instanceInfo;
+	}
+
+	/**
+	 * Initialize and connect an unloaded instance
+	 *
+	 * @param {number} instanceId - ID of instance to initialize.
+	 * @returns {module:slave/slave~InstanceConnection} connection to instance.
+	 */
+	async _connectInstance(instanceId) {
+		let instanceInfo = this.getRequestInstanceInfo(instanceId);
+		if (this.instanceConnections.has(instanceId)) {
+			throw new libErrors.RequestError(`Instance with ID ${instanceId} is running`);
+		}
+
+		let [connectionClient, connectionServer] = libLink.VirtualConnector.makePair();
+		let instanceConnection = new InstanceConnection(connectionServer, this, instanceId);
+		let instance = new Instance(
+			this, connectionClient, instanceInfo.path, this.config.get("slave.factorio_directory"), instanceInfo.config
+		);
+
+		this.instanceConnections.set(instanceId, instanceConnection);
+		await instance.init(this.pluginInfos);
+
+		return instanceConnection;
+	}
+
+	async getMetricsRequestHandler() {
+		let requests = [];
+		for (let instanceConnection of this.instanceConnections.values()) {
+			requests.push(libLink.messages.getMetrics.send(instanceConnection));
+		}
+
+		let results = [];
+		for (let response of await Promise.all(requests)) {
+			results.push(...response.results);
+		}
+
+		for await (let result of libPrometheus.defaultRegistry.collect()) {
+			if (result.metric.name.startsWith("process_")) {
+				results.push(libPrometheus.serializeResult(result, {
+					addLabels: { "slave_id": String(this.config.get("slave.id")) },
+					metricName: result.metric.name.replace("process_", "clusterio_slave_"),
+				}));
+
+			} else {
+				results.push(libPrometheus.serializeResult(result));
+			}
+		}
+
+		return { results };
+	}
+
+	async startInstanceRequestHandler(message, request) {
+		let instanceId = message.data.instance_id;
+		let instanceConnection = await this._connectInstance(instanceId);
+		return await request.send(instanceConnection, message.data);
+	}
+
+	async loadScenarioRequestHandler(message, request) {
+		let instanceId = message.data.instance_id;
+		let instanceConnection = await this._connectInstance(instanceId);
+		return await request.send(instanceConnection, message.data);
+	}
+
+	async listSavesRequestHandler(message, request) {
+		let instanceId = message.data.instance_id;
+		let instanceConnection = this.instanceConnections.get(instanceId);
+		if (instanceConnection) {
+			return await request.send(instanceConnection, message.data);
+		}
+
+		let instanceInfo = this.getRequestInstanceInfo(instanceId);
+		return {
+			list: await Instance.listSaves(path.join(instanceInfo.path, "saves"), null),
+		};
+	}
+
+	async createSaveRequestHandler(message, request) {
+		let instanceId = message.data.instance_id;
+		let instanceConnection = await this._connectInstance(instanceId);
+		await request.send(instanceConnection, message.data);
+	}
+
+	async renameSaveRequestHandler(message) {
+		let { instance_id, old_name, new_name } = message.data;
+		checkRequestSaveName(old_name);
+		checkRequestSaveName(new_name);
+		let instanceInfo = this.getRequestInstanceInfo(instance_id);
+		try {
+			await fs.move(
+				path.join(instanceInfo.path, "saves", old_name),
+				path.join(instanceInfo.path, "saves", new_name),
+				{ overwrite: false },
+			);
+		} catch (err) {
+			if (err.code === "ENOENT") {
+				throw new libErrors.RequestError(`${old_name} does not exist`);
+			}
+			throw err;
+		}
+		await this.sendSaveListUpdate(instance_id, path.join(instanceInfo.path, "saves"));
+	}
+
+	async copySaveRequestHandler(message) {
+		let { instance_id, source, destination } = message.data;
+		checkRequestSaveName(source);
+		checkRequestSaveName(destination);
+		let instanceInfo = this.getRequestInstanceInfo(instance_id);
+		try {
+			await fs.copy(
+				path.join(instanceInfo.path, "saves", source),
+				path.join(instanceInfo.path, "saves", destination),
+				{ overwrite: false, errorOnExist: true },
+			);
+		} catch (err) {
+			if (err.code === "ENOENT") {
+				throw new libErrors.RequestError(`${old_name} does not exist`);
+			}
+			throw err;
+		}
+		await this.sendSaveListUpdate(instance_id, path.join(instanceInfo.path, "saves"));
+	}
+
+	async transferSaveRequestHandler(message) {
+		let { source_save, target_save, copy, instance_id, target_instance_id } = message.data;
+		checkRequestSaveName(source_save);
+		checkRequestSaveName(target_save);
+		let sourceInstanceInfo = this.getRequestInstanceInfo(instance_id);
+		let targetInstanceInfo = this.getRequestInstanceInfo(target_instance_id);
+
+		// For consistency with remote transfer initiated through pullSave the
+		// target is renamed if it already exists.
+		target_save = await libFileOps.findUnusedName(
+			path.join(targetInstanceInfo.path, "saves"), target_save, ".zip"
+		);
+
+		try {
+			if (copy) {
+				await fs.copy(
+					path.join(sourceInstanceInfo.path, "saves", source_save),
+					path.join(targetInstanceInfo.path, "saves", target_save),
+					{ overwrite: true },
+				);
+			} else {
+				await fs.move(
+					path.join(sourceInstanceInfo.path, "saves", source_save),
+					path.join(targetInstanceInfo.path, "saves", target_save),
+					{ overwrite: true },
+				);
+			}
+		} catch (err) {
+			if (err.code === "ENOENT") {
+				throw new libErrors.RequestError(`${source_save} does not exist`);
+			}
+			throw err;
+		}
+		await this.sendSaveListUpdate(instance_id, path.join(sourceInstanceInfo.path, "saves"));
+		await this.sendSaveListUpdate(target_instance_id, path.join(targetInstanceInfo.path, "saves"));
+
+		return { save: target_save };
+	}
+
+	async sendSaveListUpdate(instance_id, savesDir) {
+		let instanceConnection = this.instanceConnections.get(instance_id);
+		let saveList;
+		if (instanceConnection) {
+			saveList = (await libLink.messages.listSaves.send(instanceConnection, { instance_id })).list;
+		} else {
+			saveList = await Instance.listSaves(savesDir, null);
+		}
+
+		libLink.messages.saveListUpdate.send(this, { instance_id, list: saveList });
+	}
+
+	async deleteSaveRequestHandler(message) {
+		let { instance_id, save } = message.data;
+		checkRequestSaveName(save);
+		let instanceInfo = this.getRequestInstanceInfo(instance_id);
+
+		try {
+			await fs.unlink(path.join(instanceInfo.path, "saves", save));
+		} catch (err) {
+			if (err.code === "ENOENT") {
+				throw new libErrors.RequestError(`${save} does not exist`);
+			}
+			throw err;
+		}
+		await this.sendSaveListUpdate(instance_id, path.join(instanceInfo.path, "saves"));
+	}
+
+	async pullSaveRequestHandler(message) {
+		let { instance_id, stream_id, filename } = message.data;
+		checkRequestSaveName(filename);
+		let instanceInfo = this.getRequestInstanceInfo(instance_id);
+
+		let url = new URL(this.config.get("slave.master_url"));
+		url.pathname += `api/stream/${stream_id}`;
+		let response = await phin({
+			url, method: "GET",
+			core: { ca: this.tlsCa },
+			stream: true,
+		});
+
+		if (response.statusCode !== 200) {
+			let content = await libHelpers.readStream(response);
+			throw new libErrors.RequestError(`Stream returned ${response.statusCode}: ${content.toString()}`);
+		}
+
+		let savesDir = path.join(instanceInfo.path, "saves");
+		let tempFilename = filename.replace(/(\.zip)?$/, ".tmp.zip");
+		let writeStream;
+		while (true) {
+			try {
+				writeStream = fs.createWriteStream(path.join(savesDir, tempFilename), { flags: "wx" });
+				await events.once(writeStream, "open");
+				break;
+			} catch (err) {
+				if (err.code === "EEXIST") {
+					tempFilename = await libFileOps.findUnusedName(savesDir, tempFilename, ".tmp.zip");
+				} else {
+					throw err;
+				}
+			}
+		}
+		response.pipe(writeStream);
+		await finished(writeStream);
+
+		filename = await libFileOps.findUnusedName(savesDir, filename, ".zip");
+		await fs.rename(path.join(savesDir, tempFilename), path.join(savesDir, filename));
+
+		await this.sendSaveListUpdate(instance_id, savesDir);
+		return { save: filename };
+	}
+
+	async pushSaveRequestHandler(message) {
+		let { instance_id, stream_id, save } = message.data;
+		checkRequestSaveName(save);
+		let instanceInfo = this.getRequestInstanceInfo(instance_id);
+
+		let content;
+		try {
+			// phin doesn't support streaming requests :(
+			content = await fs.readFile(path.join(instanceInfo.path, "saves", save));
+		} catch (err) {
+			if (err.code === "ENOENT") {
+				throw new libErrors.RequestError(`${save} does not exist`);
+			}
+			throw err;
+		}
+
+		let url = new URL(this.config.get("slave.master_url"));
+		url.pathname += `api/stream/${stream_id}`;
+		phin({
+			url, method: "PUT",
+			core: { ca: this.tlsCa },
+			data: content,
+		}).catch(err => logger.error(`Error pushing save to master:\n${err.stack}`));
+	}
+
+	async exportDataRequestHandler(message, request) {
+		let instanceId = message.data.instance_id;
+		let instanceConnection = await this._connectInstance(instanceId);
+		await request.send(instanceConnection, message.data);
+	}
+
+	async stopInstance(instanceId) {
+		let instanceConnection = this.instanceConnections.get(instanceId);
+		await libLink.messages.stopInstance.send(instanceConnection, { instance_id: instanceId });
+	}
+
+	async deleteInstanceRequestHandler(message) {
+		let instanceId = message.data.instance_id;
+		if (this.instanceConnections.has(instanceId)) {
+			throw new libErrors.RequestError(`Instance with ID ${instanceId} is running`);
+		}
+
+		let instanceInfo = this.discoveredInstanceInfos.get(instanceId);
+		if (!instanceInfo) {
+			throw new libErrors.RequestError(`Instance with ID ${instanceId} does not exist`);
+		}
+
+		this.discoveredInstanceInfos.delete(instanceId);
+		this.instanceInfos.delete(instanceId);
+		await fs.remove(instanceInfo.path);
+	}
+
+	/**
+	 * Discover available instances
+	 *
+	 * Looks through the instances directory for instances and updates
+	 * the slave and master server with the new list of instances.
+	 */
+	async updateInstances() {
+		this.discoveredInstanceInfos = await discoverInstances(this.config.get("slave.instances_directory"));
+		let list = [];
+		for (let [instanceId, instanceInfo] of this.discoveredInstanceInfos) {
+			let instanceConnection = this.instanceConnections.get(instanceId);
+			list.push({
+				serialized_config: instanceInfo.config.serialize("master"),
+				status: instanceConnection ? instanceConnection.status : "stopped",
+			});
+		}
+		await libLink.messages.updateInstances.send(this, { instances: list });
+
+		// Handle configured auto startup instances
+		if (this._startup) {
+			this._startup = false;
+
+			for (let [instanceId, instanceInfo] of this.instanceInfos) {
+				if (instanceInfo.config.get("instance.auto_start")) {
+					try {
+						let instanceConnection = await this._connectInstance(instanceId);
+						await libLink.messages.startInstance.send(instanceConnection, {
+							instance_id: instanceId,
+							save: null,
+						});
+					} catch (err) {
+						logger.error(
+							`Error during auto startup for ${instanceInfo.config.get("instance.name")}:\n${err.stack}`
+						);
+					}
+				}
+			}
+		}
+	}
+
+	async prepareDisconnectRequestHandler(message, request) {
+		for (let instanceConnection of this.instanceConnections.values()) {
+			await libLink.messages.prepareMasterDisconnect.send(instanceConnection);
+		}
+		this._disconnecting = true;
+		this.connector.setClosing();
+		return await super.prepareDisconnectRequestHandler(message, request);
+	}
+
+	/**
+	 * Stops all instances and closes the connection
+	 */
+	async shutdown() {
+		if (this._shuttingDown) {
+			return;
+		}
+		this._shuttingDown = true;
+
+		try {
+			await libLink.messages.prepareDisconnect.send(this);
+		} catch (err) {
+			if (!(err instanceof libErrors.SessionLost)) {
+				logger.error(`Unexpected error preparing disconnect:\n${err.stack}`);
+			}
+		}
+
+		try {
+			for (let instanceId of this.instanceConnections.keys()) {
+				await this.stopInstance(instanceId);
+			}
+			await this.connector.close(1000, "Slave Shutdown");
+
+			// Clear silly interval in pidfile library.
+			pidusage.clear();
+		} catch (err) {
+			setBlocking(true);
+			logger.error(`
++------------------------------------------------------------+
+| Unexpected error occured while shutting down slave, please |
+| report it to https://github.com/clusterio/clusterio/issues |
++------------------------------------------------------------+
+${err.stack}`
+			);
+			// eslint-disable-next-line node/no-process-exit
+			process.exit(1);
+		}
+	}
+
+	/**
+	 * True if the connection to the master is connected, not in the dropped
+	 * state,and not in the process of disconnecting.
+	 * @type {boolean}
+	 */
+	get connected() {
+		return !this._disconnecting && this.connector.connected;
+	}
+}
+
+module.exports = Slave;
+
+// For testing only
+module.exports._checkFilename = checkFilename;
+module.exports._discoverInstances = discoverInstances;
+module.exports._Slave = Slave;
+
diff --git a/test/slave.js b/test/slave.js
index adc75d41..7603f803 100644
--- a/test/slave.js
+++ b/test/slave.js
@@ -5,7 +5,8 @@ const fs = require("fs-extra");
 
 const libLink = require("@clusterio/lib/link");
 const libConfig = require("@clusterio/lib/config");
-const slave = require("@clusterio/slave/slave");
+const Instance = require("@clusterio/slave/src/Instance");
+const Slave = require("@clusterio/slave/src/Slave");
 
 describe("Slave testing", function() {
 	before(function() {
@@ -18,7 +19,7 @@ describe("Slave testing", function() {
 			let instanceConfig = new libConfig.InstanceConfig("slave");
 			await instanceConfig.init();
 			instanceConfig.set("instance.name", "foo");
-			instance = new slave._Instance({}, new libLink.VirtualConnector(), "dir", "factorioDir", instanceConfig);
+			instance = new Instance({}, new libLink.VirtualConnector(), "dir", "factorioDir", instanceConfig);
 		});
 
 		describe(".name", function() {
@@ -39,11 +40,11 @@ describe("Slave testing", function() {
 
 	describe("checkFilename()", function() {
 		it("should allow a basic name", function() {
-			slave._checkFilename("file");
+			Slave._checkFilename("file");
 		});
 
 		function check(item, msg) {
-			assert.throws(() => slave._checkFilename(item), new Error(msg));
+			assert.throws(() => Slave._checkFilename(item), new Error(msg));
 		}
 
 		it("should throw on non-string", function() {
@@ -100,14 +101,14 @@ describe("Slave testing", function() {
 			let instanceConfig = new libConfig.InstanceConfig("slave");
 			await instanceConfig.init();
 			instanceConfig.set("instance.name", "test");
-			instance = new slave._Instance(
+			instance = new Instance(
 				{}, new libLink.VirtualConnector(), path.join(testDir, "instance"), "factorioDir", instanceConfig
 			);
 			await fs.outputFile(instance.path("mods", "mod_i.zip"), "i");
 		});
 
 		it("should link mods and data files", async function() {
-			await slave._symlinkMods(instance, path.join(testDir, "shared"));
+			await Instance._symlinkMods(instance, path.join(testDir, "shared"));
 
 			assert.equal(await fs.readFile(instance.path("mods", "mod_a.zip"), "utf-8"), "a");
 			assert.equal(await fs.readFile(instance.path("mods", "mod_b.zip"), "utf-8"), "b");
@@ -118,14 +119,14 @@ describe("Slave testing", function() {
 
 		it("should ignore directories", async function() {
 			await fs.ensureDir(path.join(testDir, "shared", "dir"));
-			await slave._symlinkMods(instance, path.join(testDir, "shared"));
+			await Instance._symlinkMods(instance, path.join(testDir, "shared"));
 
 			assert(!await fs.exists(instance.path("mods", "dir"), "utf-8"), "dir was unxpectedly linked");
 		});
 
 		it("should ignore files", async function() {
 			await fs.outputFile(path.join(testDir, "shared", "file"), "f");
-			await slave._symlinkMods(instance, path.join(testDir, "shared"));
+			await Instance._symlinkMods(instance, path.join(testDir, "shared"));
 
 			assert(!await fs.exists(instance.path("mods", "file"), "utf-8"), "dir was unxpectedly linked");
 		});
@@ -137,7 +138,7 @@ describe("Slave testing", function() {
 			}
 
 			await fs.unlink(path.join(testDir, "shared", "mod_a.zip"));
-			await slave._symlinkMods(instance, path.join(testDir, "shared"));
+			await Instance._symlinkMods(instance, path.join(testDir, "shared"));
 
 			await assert.rejects(fs.lstat(instance.path("mods", "mod_a.zip")), { code: "ENOENT" });
 			assert.equal(await fs.readFile(instance.path("mods", "mod_b.zip"), "utf-8"), "b");
@@ -150,7 +151,7 @@ describe("Slave testing", function() {
 	describe("discoverInstances()", function() {
 		it("should discover test instance", async function() {
 			let instancePath = path.join("test", "file", "instances");
-			let instanceInfos = await slave._discoverInstances(instancePath);
+			let instanceInfos = await Slave._discoverInstances(instancePath);
 
 			let referenceConfig = new libConfig.InstanceConfig("slave");
 			await referenceConfig.init();
@@ -178,7 +179,7 @@ describe("Slave testing", function() {
 					broadcastEventToInstance(message, event) {
 						this.broadcasts.push(message["data"]);
 					},
-					syncUserListsEventHandler: slave._Slave.prototype.syncUserListsEventHandler,
+					syncUserListsEventHandler: Slave.prototype.syncUserListsEventHandler,
 					syncLists(adminlist, banlist, whitelist) {
 						return this.syncUserListsEventHandler({ "data": {
 							"adminlist": adminlist,