Less-dynamic module system (#62)

config/defaults.yml

@@ -18,9 +18,11 @@ exit_on_module_load_error: true
 # passwords
 password_rounds: 8
 
-# please note that modules are loaded in the given order. below are
-# given sensible defaults, but you are welcome to use your own values.
+# below are sensible defaults, but you are welcome to use your own values.
 modules: {}
+# modules/housekeep.js: {}
+### updating the database from foreign sources; `sources.yml` contains
+### the module-specific configuration
 ### reading from and saving to a disk file
 # modules/disk.js:
 #   enabled: true
@@ -30,13 +32,6 @@ modules: {}
 ##### prophylactic. 3600_000 (every hour) is good; 86400_000 (every
 ##### full day) is, for all intents and purposes, good too
 #   backup_interval: 1800_000
-### refreshing a few variables after loading the database
-# modules/housekeep.js: {}
-### updating the database from foreign sources; `sources.yml` contains
-### the module-specific configuration
-# modules/update.js:
-#   enabled: true
-#   update_interval: 300_000
 ### removing sufficiently downvoted entries
 # modules/cleanup.js:
 #   enabled: true
@@ -49,3 +44,7 @@ modules: {}
 # modules/announce.js:
 #   enabled: true
 #   hook: 'https://discordapp.com/api/webooks/here/goes/your/webhook'
+### refreshing a few variables after loading the database
+# modules/update.js:
+#   enabled: true
+#   update_interval: 300_000

core/api.ts

@@ -182,6 +182,20 @@ actions.vote = guard(
 		e.votes[uname] = i.vote;
 		e.score += i.vote - old_vote;
 		ret(good({ entry: present(e, uname) }));
+
+		const cleanup = config.modules['modules/cleanup.js'];
+		if (cleanup.enabled) {
+			const culpable = !cleanup.users || cleanup.users.includes(e.user);
+			const bad = e.score <= cleanup.vote_threshold;
+			if (culpable && bad) {
+				call(
+					{ action: 'remove', id: e.id },
+					() => console.log(`-- ${e.head} weeded out`),
+					e.user,
+				);
+			}
+		}
+
 		emitter.emit('vote', e, uname);
 	},
 );

core/commons.ts

@@ -217,7 +217,21 @@ export interface ToaduaConfig {
 	 */
 	password_rounds: number;
 
-	modules: Record<string, object>;
+	modules: {
+		'modules/disk.js'?: {
+			enabled: boolean;
+			save_interval: number;
+			backup_interval: number;
+		};
+		'modules/housekeep.js'?: Record<string, never>;
+		'modules/update.js'?: { enabled: boolean; save_interval: number };
+		'modules/cleanup.js'?: {
+			enabled: boolean;
+			vote_threshold: number;
+			users?: string[];
+		};
+		'modules/announce.js'?: { enabled: boolean; hook: string };
+	};
 }
 
 const toaduaPath = getToaduaPath();

core/server.ts

@@ -7,6 +7,11 @@ import * as fs from 'node:fs';
 import * as argparse from 'argparse';
 import * as commons from './commons.js';
 
+import { HousekeepModule } from '../modules/housekeep.js';
+import { DiskModule } from '../modules/disk.js';
+import { UpdateModule } from '../modules/update.js';
+import { AnnounceModule } from '../modules/announce.js';
+
 const argparser = new argparse.ArgumentParser({
 	description: 'Toaq dictionary',
 	add_help: true,
@@ -36,6 +41,7 @@ console.log(`starting up v${VERSION}...`);
 import * as http from 'node:http';
 import * as api from './api.js';
 import type { Socket } from 'node:net';
+import type { EventEmitter } from 'node:stream';
 
 const fourohfour = static_handler('frontend/404.html', 'text/html', 404);
 const routes = {
@@ -169,37 +175,64 @@ function handler(r, s_) {
 	}
 }
 
-const modules: Record<string, any> = {};
+class ToaduaModules {
+	private housekeep?: HousekeepModule;
+	private disk?: DiskModule;
+	private announce?: AnnounceModule;
+	private update?: UpdateModule;
 
-async function load_modules(data: commons.ToaduaConfig): Promise<void> {
-	for (const path of Object.keys(data.modules)) {
-		if (!modules[path]) {
-			try {
-				modules[path] = { ...(await import(`./../${path}`)), path };
-			} catch (e) {
-				if (config.exit_on_module_load_error) throw e;
-				console.log(`error when loading module '${path}': ${e.stack}`);
-				delete modules[path];
-			}
+	constructor(
+		private store: commons.Store,
+		private config: commons.ToaduaConfig,
+		private emitter: EventEmitter,
+	) {
+		const housekeepConfig = config.modules['modules/housekeep.js'];
+		if (housekeepConfig) {
+			this.housekeep = new HousekeepModule();
 		}
-	}
-	for (const path in modules) {
-		const new_options = data.modules[path];
-		// note that when an entry in the module table is removed,
-		// `new_options === undefined`. this is all right
-		if (JSON.stringify(new_options) !== JSON.stringify(modules[path].options)) {
-			modules[path].options = new_options;
-			console.log(`changing state for module '${path}'`);
-			try {
-				modules[path].state_change.call(new_options);
-			} catch (e) {
-				console.log(`error for module '${path}': ${e.stack}`);
-			}
+
+		const diskConfig = config.modules['modules/disk.js'];
+		if (diskConfig) {
+			this.disk = new DiskModule(
+				diskConfig.save_interval,
+				diskConfig.backup_interval,
+			);
+		}
+
+		const announceConfig = config.modules['modules/announce.js'];
+		if (announceConfig) {
+			this.announce = new AnnounceModule(
+				announceConfig.enabled,
+				announceConfig.hook,
+			);
 		}
+
+		const updateConfig = config.modules['modules/update.js'];
+		if (updateConfig) {
+			this.update = new UpdateModule(
+				updateConfig.enabled,
+				updateConfig.save_interval,
+				this.announce,
+			);
+		}
+	}
+
+	public up(): void {
+		this.housekeep?.up(this.store, this.config);
+		this.disk?.up(this.store);
+		this.announce?.up(this.emitter);
+		this.update?.up(this.store);
+	}
+
+	public down(): void {
+		// The other modules don't need to do anything special when Toadua is
+		// going down:
+		this.disk?.down(this.store);
 	}
 }
 
-await load_modules(config);
+const modules = new ToaduaModules(commons.store, config, commons.emitter);
+modules.up();
 
 const server = http.createServer(handler);
 const connections: Socket[] = [];
@@ -223,15 +256,7 @@ function bye(error) {
 	for (const connection of connections) {
 		connection.destroy();
 	}
-	for (const [path, _] of Object.entries(modules).reverse()) {
-		try {
-			_.state_change.call(null);
-		} catch (e) {
-			console.log(
-				`ignoring state change error for module '${path}': ${e.stack}`,
-			);
-		}
-	}
+	modules.down();
 	process.exitCode = 0;
 }