47 lines
1.5 KiB
JavaScript
47 lines
1.5 KiB
JavaScript
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// Generic exclusive file lock, same idiom as calendar.mjs but reusable for any
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// critical section. Used for the global BUILD lock so cron builds (promoteDraft)
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// and Developer Console builds (preview + publish) never run npm/astro
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// concurrently — important on this memory-constrained box.
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import { writeFileSync, openSync, closeSync, unlinkSync, statSync } from "node:fs";
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const sleep = (ms) => new Promise((r) => setTimeout(r, ms));
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/**
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* Acquire an exclusive lockfile, run fn, always release.
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* @param {string} lockPath absolute path to the lockfile
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* @param {() => Promise<T>|T} fn critical section
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* @param {{timeoutMs?: number, staleMs?: number}} [opts]
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* @returns {Promise<T>}
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*/
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export async function withLock(lockPath, fn, { timeoutMs = 300000, staleMs = 15 * 60 * 1000 } = {}) {
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const start = Date.now();
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for (;;) {
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try {
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const fd = openSync(lockPath, "wx"); // exclusive create — fails if it exists
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writeFileSync(lockPath, `${process.pid} ${new Date().toISOString()}`);
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closeSync(fd);
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break;
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} catch {
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try {
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if (Date.now() - statSync(lockPath).mtimeMs > staleMs) {
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unlinkSync(lockPath); // presumed orphaned
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continue;
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}
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} catch {
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/* lock vanished between failed create and stat — retry immediately */
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}
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if (Date.now() - start > timeoutMs) throw new Error(`lock timeout: ${lockPath}`);
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await sleep(200);
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}
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}
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try {
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return await fn();
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} finally {
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try {
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unlinkSync(lockPath);
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} catch {
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/* already gone */
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}
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}
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}
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