when-am-i / files / scripts / lib / server.mts

server.mts

1	// Dev-server lifecycle for the screenshot scripts: reuse a running Vite server
2	// on 5173 if there is one, otherwise start one and stop it when finished.
3
4	import { spawn, type ChildProcess } from 'node:child_process';
5	import http from 'node:http';
6	import path from 'node:path';
7	import { fileURLToPath } from 'node:url';
8
9	const __dirname = path.dirname(fileURLToPath(import.meta.url));
10	export const REPO_ROOT = path.resolve(__dirname, '../..');
11
12	// Port is overridable via SCREENSHOT_PORT so screenshots can be generated
13	// against this checkout even when another Vite server (e.g. a parallel
14	// Conductor workspace) already holds the default 5173. Defaults to 5173.
15	const PORT = process.env.SCREENSHOT_PORT ?? '5173';
16	export const BASE_URL = `http://127.0.0.1:${PORT}/when-am-i/`;
17
18	function isUp(url: string): Promise<boolean> {
19	return new Promise((resolve) => {
20	const req = http.get(url, (res) => {
21	res.resume();
22	resolve(true);
23	});
24	req.on('error', () => resolve(false));
25	req.setTimeout(1000, () => {
26	req.destroy();
27	resolve(false);
28	});
29	});
30	}
31
32	const wait = (ms: number) => new Promise((r) => setTimeout(r, ms));
33
34	export interface DevServer {
35	stop: () => void;
36	}
37
38	export async function startDevServer(): Promise<DevServer> {
39	if (await isUp(BASE_URL)) {
40	console.log(' ℹ️ Reusing the dev server already running on :5173');
41	return { stop: () => {} };
42	}
43
44	console.log(` 🚀 Starting Vite dev server on :${PORT}…`);
45	const proc: ChildProcess = spawn('npx', ['vite', '--port', PORT, '--strictPort'], {
46	cwd: REPO_ROOT,
47	stdio: 'ignore',
48	});
49
50	const start = Date.now();
51	while (Date.now() - start < 30_000) {
52	if (await isUp(BASE_URL)) {
53	console.log(' ✅ Dev server ready');
54	return { stop: () => proc.kill() };
55	}
56	await wait(500);
57	}
58	proc.kill();
59	throw new Error('Dev server did not start within 30s');
60	}