Files
Gerhard Scheikl 01b4734477 security hardening
2026-05-31 09:35:31 +02:00

119 lines
4.2 KiB
TypeScript

import pLimit from "p-limit";
import type { WebhookReservation } from "./dedupe.server";
/**
* Background runner for webhook side-effects.
*
* Shopify expects a 200 response within ~5 seconds, otherwise it considers
* the delivery failed and retries it. Heavy automation work (PDF render,
* Shopify Files upload, SMTP send) routinely exceeded that budget, which
* caused duplicate invoice emails before we added the dedupe table.
*
* Returning the response immediately and finishing the work afterwards keeps
* Shopify happy. Two problems with a naive `void work()`:
*
* 1. DoS / resource exhaustion — an order burst would spawn unbounded
* concurrent PDF renders + SMTP sends. We cap concurrency with a small
* in-process queue (`p-limit`); excess tasks queue instead of piling up.
* 2. Data loss on restart — `void work()` is invisible to shutdown, so a
* container stop (SIGTERM) killed in-flight invoice work mid-send. We
* track in-flight tasks and drain them (bounded) on SIGTERM/SIGINT.
*
* Reserve/commit dedupe (see dedupe.server.ts) is integrated here: on success
* we `commit()` the reservation (permanently deduped); on failure we
* `release()` it so Shopify's retry re-runs the work instead of being dropped
* as a duplicate.
*/
const CONCURRENCY = Math.max(1, Number(process.env.WEBHOOK_CONCURRENCY) || 4);
const DRAIN_TIMEOUT_MS = Math.max(
1000,
Number(process.env.WEBHOOK_DRAIN_TIMEOUT_MS) || 25_000,
);
const limit = pLimit(CONCURRENCY);
const inFlight = new Set<Promise<unknown>>();
let draining = false;
export function runWebhookInBackground(
description: string,
work: () => Promise<unknown>,
reservation?: WebhookReservation | null,
): void {
if (draining) {
// The process is shutting down. We still enqueue so the drain awaits this
// task — the server has already stopped listening, so this is at most the
// tail end of the last accepted request.
console.warn(`[webhook-queue] enqueuing task during shutdown drain: ${description}`);
}
const task = limit(async () => {
try {
await work();
await reservation?.commit();
} catch (err) {
console.error(`background webhook task '${description}' failed:`, err);
// Drop the dedupe reservation so Shopify's retry re-runs the work.
try {
await reservation?.release();
} catch (releaseErr) {
console.error(
`background webhook task '${description}': failed to release dedupe reservation:`,
releaseErr,
);
}
}
});
inFlight.add(task);
void task.finally(() => inFlight.delete(task));
}
/**
* Stop accepting new work (best-effort) and await in-flight + queued tasks,
* bounded by `timeoutMs`, so a container stop drains invoice work instead of
* killing it mid-send. Idempotent.
*/
export async function drainWebhookQueue(timeoutMs = DRAIN_TIMEOUT_MS): Promise<void> {
draining = true;
if (inFlight.size === 0) return;
console.log(
`[webhook-queue] draining ${inFlight.size} in-flight webhook task(s) (timeout ${timeoutMs}ms)...`,
);
let timer: ReturnType<typeof setTimeout> | undefined;
const timeout = new Promise<void>((resolve) => {
timer = setTimeout(resolve, timeoutMs);
if (typeof timer.unref === "function") timer.unref();
});
await Promise.race([Promise.allSettled([...inFlight]), timeout]);
if (timer) clearTimeout(timer);
if (inFlight.size > 0) {
console.warn(
`[webhook-queue] drain timed out with ${inFlight.size} task(s) still running`,
);
} else {
console.log("[webhook-queue] drain complete");
}
}
// Bridge for the custom server (server.js), which loads only the bundled
// build and cannot import this module directly. It awaits this drain before
// calling process.exit during graceful shutdown.
type DrainGlobal = typeof globalThis & {
__linumiqWebhookDrain?: typeof drainWebhookQueue;
};
(globalThis as DrainGlobal).__linumiqWebhookDrain = drainWebhookQueue;
// Safety net for runtimes that don't go through server.js (e.g. `shopify app
// dev`): stop accepting work and best-effort drain. The custom server awaits
// the same (idempotent) drain before exiting.
for (const signal of ["SIGTERM", "SIGINT"] as const) {
process.once(signal, () => {
void drainWebhookQueue();
});
}