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How to Create a Cron Job

In this document, you’ll learn how to create a cron job in Medusa.

Overview

Medusa allows you to create cron jobs that run at specific times during your server’s lifetime. For example, you can synchronize your inventory with an Enterprise Resource Planning (ERP) system once a day.

This guide explains how to create a cron job on your Medusa server. The cron job in this example will simply change the status of draft products to Copy to Clipboard.

Prerequisites

Medusa Components

It is assumed that you already have a Medusa server installed and set up. If not, you can follow the quickstart guide to get started.

Redis

Redis is required for cron jobs to work. Make sure you install Redis and configure it with your Medusa server.

1. Create a File

Each cron job should reside in a TypeScript or JavaScript file under the Copy to Clipboard directory.

Start by creating the Copy to Clipboard directory. Then, inside that directory, create the JavaScript or TypeScript file that you’ll add the cron job in. You can use any name for the file.

For the example in this tutorial, you can create the file Copy to Clipboard.

2. Create Cron Job

To create a cron job, add the following code in the file you created, which is Copy to Clipboard in this example:

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const publishJob = async (container, options) => {
const eventBus = container.resolve("eventBusService");
eventBus.createCronJob("publish-products", {}, "0 0 * * *", async () => {
//job to execute
const productService = container.resolve("productService");
const draftProducts = await productService.list({
status: 'draft'
});

for (const product of draftProducts) {
await productService.update(product.id, {
status: 'published'
});
}
})
}

export default publishJob;
Copy to Clipboard

This file should export a function that accepts a Copy to Clipboard and Copy to Clipboard parameters. Copy to Clipboard is the dependency container that you can use to resolve services, such as the EventBusService. Copy to Clipboard are the plugin’s options if this cron job is created in a plugin.

You then resolve the Copy to Clipboard and use the Copy to Clipboard method to create the cron job. This method accepts four parameters:

  • The first parameter is a unique name to give to the cron job. In the example above, you use the name Copy to Clipboard;
  • The second parameter is an object which can be used to pass data to the job;
  • The third parameter is the cron job expression pattern. In this example, it will execute the cron job once a day at 12 AM.
  • The fourth parameter is the function to execute. This is where you add the code to execute once the cron job runs. In this example, you retrieve the draft products using the ProductService and update the status of each of these products to Copy to Clipboard.

You can see examples of cron job expression patterns on crontab guru.

Pass Data to the Cron Job

To pass data to your cron job, you can add them to the object passed as a second parameter under the Copy to Clipboard property. This is helpful if you use one function to handle multiple cron jobs.

For example:

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eventBus.createCronJob("publish-products", {
data: {
productId
}
}, "0 0 * * *", async (job) => {
console.log(job.data); // {productId: 'prod_124...'}
//...
});
Copy to Clipboard

3. Run Medusa Server

Cron Jobs only run while the Medusa server is running.

In your terminal run the following command to run your Medusa server:

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npm run start
Copy to Clipboard

This builds your code under the Copy to Clipboard directory into the Copy to Clipboard directory, then runs the Medusa server.

If the cron job was registered successfully, you should see a message similar to this logged on your Medusa server:

Report Incorrect CodeReport Incorrect CodeReport Incorrect CodeCopy to Clipboard
Registering publish-products
Copy to Clipboard

Where Copy to Clipboard is the unique name you provided to the cron job.

Once it is time to run your cron job based on the cron job expression pattern, the cron job will run and you can see it logged on your Medusa server.

For example, the above cron job will run at 12 AM and, when it runs, you can see the following logged on your Medusa server:

info:    Processing cron job: publish-products
Copy to Clipboard

If you log anything in the cron job, for example using Copy to Clipboard, or if any errors are thrown, it’ll also be logged on your Medusa server.

To test the previous example out instantly, you can change the cron job expression pattern passed as the third parameter to Copy to Clipboard to Copy to Clipboard. This will run the cron job every minute.

What’s Next