feat: render threading

scripts/build.ts

@@ -1,6 +1,14 @@
 import { build } from 'esbuild';
+import { readdir } from 'fs/promises';
 
-const FILES = ['bot', 'index'];
+const FILES = [
+  'bot',
+  'index',
+
+  (await readdir('src/workers')).map(
+    (file) => `workers/${file.replace('.ts', '')}`,
+  ),
+];
 
 await build({
   entryPoints: FILES.map((file) => `src/${file}.ts`),

src/core/blitzkrieg/jsxToPngThreaded.ts

@@ -0,0 +1,9 @@
+import jsxToSvg from './jsxToSvg';
+import { svgToPngThreaded } from './svgToPngThreaded';
+
+export default async function jsxToPngThreaded(jsx: JSX.Element) {
+  const svg = await jsxToSvg(jsx);
+  const png = await svgToPngThreaded(svg);
+
+  return png;
+}

src/core/blitzkrieg/svgToPngThreaded.ts

@@ -0,0 +1,42 @@
+import { Worker } from 'worker_threads';
+
+const MAX_WORKERS = 3;
+
+const workers = [...Array(MAX_WORKERS)].map(() => {
+  const worker = new Worker(`${__dirname}/workers/render.cjs`);
+  console.log(`🟡 Launching render worker ${worker.threadId}`);
+  return worker;
+});
+const queue: {
+  svg: string;
+  resolve: (png: Buffer) => void;
+}[] = [];
+
+function manageQueue() {
+  if (queue.length > 0 && workers.length > 0) {
+    const { svg, resolve } = queue.shift()!;
+    const worker = workers.shift()!;
+
+    function cleanup() {
+      workers.push(worker);
+      manageQueue();
+    }
+
+    worker.postMessage(svg);
+    worker.on('message', (png: Uint8Array) => {
+      cleanup();
+      resolve(Buffer.from(png));
+    });
+    worker.on('error', (error) => {
+      cleanup();
+      throw error;
+    });
+  }
+}
+
+export function svgToPngThreaded(svg: string) {
+  return new Promise<Buffer>((resolve) => {
+    queue.push({ svg, resolve });
+    manageQueue();
+  });
+}

src/core/discord/normalizeInteractionReturnable.ts

@@ -6,7 +6,7 @@ import {
   InteractionEditReplyOptions,
 } from 'discord.js';
 import { InteractionReturnable } from '../../events/interactionCreate';
-import jsxToPng from '../blitzkrieg/jsxToPng';
+import jsxToPngThreaded from '../blitzkrieg/jsxToPngThreaded';
 
 export default async function normalizeInteractionReturnable(
   returnable: InteractionReturnable,
@@ -37,7 +37,7 @@ export default async function normalizeInteractionReturnable(
       } else if (item === null) {
         return;
       } else {
-        const image = await jsxToPng(item);
+        const image = await jsxToPngThreaded(item);
         if (!reply.files) reply.files = [];
         reply.files.push(image);
       }

src/events/ready.ts

@@ -1,5 +1,5 @@
 import { Client } from 'discord.js';
 
 export default function ready(client: Client<true>) {
-  console.log(`🟢 Bot ${client.shard?.ids[0]} launched`);
+  console.log(`🟢 Launched bot ${client.shard?.ids[0]}`);
 }

src/index.ts

@@ -2,7 +2,7 @@ import { manager } from './core/discord/manager';
 
 manager.on('shardCreate', (shard) => {
   console.log(`🟡 Launching shard ${shard.id}`);
-  shard.on('ready', () => console.log(`🟢 Shard ${shard.id} launched`));
+  shard.on('ready', () => console.log(`🟢 Launched shard ${shard.id}`));
 });
 
 manager.spawn();

src/workers/render.ts

@@ -0,0 +1,9 @@
+import { parentPort, threadId } from 'worker_threads';
+import svgToPng from '../core/blitzkrieg/svgToPng';
+
+console.log(`🟢 Launched render worker ${threadId}`);
+
+parentPort?.on('message', async (svg: string) => {
+  const png = svgToPng(svg);
+  parentPort?.postMessage(png);
+});