promises, link

lib/generate-pool.ts

@@ -0,0 +1,81 @@
+import { createRequire } from "node:module";
+import os from "node:os";
+import path from "node:path";
+import type { IdDrawStyle } from "./id-config";
+
+export type WorkerFont = {
+  path: string;
+  family: string;
+};
+
+export type GenerateTask = {
+  text: string;
+  outPath: string;
+};
+
+const nodeRequire = createRequire(path.join(process.cwd(), "package.json"));
+
+function spawnWorker(workerPath: string, workerData: unknown) {
+  const threads = nodeRequire("node:worker_threads") as typeof import("node:worker_threads");
+  return new threads.Worker(workerPath, { workerData });
+}
+
+function workerCount(taskCount: number): number {
+  const cpus =
+    typeof os.availableParallelism === "function"
+      ? os.availableParallelism()
+      : os.cpus().length;
+  return Math.max(1, Math.min(cpus, 8, taskCount));
+}
+
+function splitTasks<T>(items: T[], parts: number): T[][] {
+  const chunks: T[][] = Array.from({ length: parts }, () => []);
+  items.forEach((item, index) => {
+    chunks[index % parts]?.push(item);
+  });
+  return chunks.filter((chunk) => chunk.length > 0);
+}
+
+export async function generatePngsInWorkers(options: {
+  imagePath: string;
+  fonts: WorkerFont[];
+  style: IdDrawStyle;
+  tasks: GenerateTask[];
+  onProgress: (completed: number, total: number) => void;
+}): Promise<void> {
+  const { imagePath, fonts, style, tasks, onProgress } = options;
+  if (tasks.length === 0) return;
+
+  const workerPath = path.join(process.cwd(), "workers", "generate-id.cjs");
+  const chunks = splitTasks(tasks, workerCount(tasks.length));
+  let completed = 0;
+
+  await Promise.all(
+    chunks.map(
+      (chunk) =>
+        new Promise<void>((resolve, reject) => {
+          const worker = spawnWorker(workerPath, {
+            imagePath,
+            fonts,
+            style,
+            tasks: chunk,
+          });
+
+          worker.on("message", (message: { type?: string }) => {
+            if (message?.type !== "progress") return;
+            completed += 1;
+            onProgress(completed, tasks.length);
+          });
+
+          worker.once("error", reject);
+          worker.once("exit", (code) => {
+            if (code === 0) {
+              resolve();
+              return;
+            }
+            reject(new Error(`Image worker stopped with code ${code}`));
+          });
+        }),
+    ),
+  );
+}