Crons Convex Component

This Convex component provides functionality for registering and managing cron jobs at runtime. Convex comes with built-in support for cron jobs but they must be statically defined at deployment time. This library allows for dynamic registration of cron jobs at runtime.

It supports intervals in ms as well as cron schedules with the same format as the unix cron command:

 *  *  *  *  *  *
 ┬  ┬  ┬  ┬  ┬  ┬
 │  │  │  │  │  |
 │  │  │  │  │  └── day of week (0 - 7, 1L - 7L) (0 or 7 is Sun)
 │  │  │  │  └───── month (1 - 12)
 │  │  │  └──────── day of month (1 - 31, L)
 │  │  └─────────── hour (0 - 23)
 │  └────────────── minute (0 - 59)
 └───────────────── second (0 - 59, optional)

Installation

Most developers will want to install this via an npm package:

npm install @convex-dev/crons

Usage

See example/convex/example.ts for a simple example of how to use this library.

The component must first be defined in convex.config.ts:

import { defineApp } from "convex/server";
import crons from "@convex-dev/crons/convex.config.js";

const app = defineApp();
app.use(crons, { name: "crons" });

export default app;

and can then be used from Convex functions via the Crons wrapper class:

const crons = new Crons(components.crons);

// ...

if ((await crons.get(ctx, { name: "daily" })) === null) {
  await crons.register(
    ctx,
    { kind: "cron", cronspec: "0 0 * * *" },
    internal.example.logStuff,
    { message: "daily cron" },
    "daily"
  );
}

If you'd like to statically define cronjobs like in the built-in crons.ts Convex feature you can do so via an init script that idempotently registers a cron with a given name. e.g., in an init.ts file that gets run on every deploy via convex dev --run init.

Design

The design of this component is based on the Cronvex demo app that's described in this Stack post.