[Part 2] Executing batch jobs in a multi-container environment using NodeJS and express

This is the second tutorial in a 3-Part series. If you haven’t completed the first tutorial 1, I would recommend going through it first here.

Create a CRON job to be executed at 12 am every day

In this step, we will register a CRON job that executes at 12 am every day. This CRON job will simply console log the time of execution and a static message.

Step 1

Add a new QUEUE_NAME called MIDNIGHT_CRON

export const QUEUE_NAMES = {
  SCHEDULE_JOB: 'scheduleJob',
  MIDNIGHT_CRON: 'midnightCron'
};

Step 2

Add a new processor for CRON

const CRON_EXPRESSIONS = {
  MIDNIGHT: '0 0 * * *'
};

export const QUEUE_PROCESSORS = {
   ...,
  [QUEUE_NAMES.MIDNIGHT_CRON]: (job, done) => {
		console.log({ job, done });
    console.log(`${moment()}::The MIDNIGHT_CRON is being executed at 12:00am`);
    done();
  }
};

Step 3

Register the CRON job in the server/utils/queue.js

export const initQueues = () => {
  ...
  queues[QUEUE_NAMES.MIDNIGHT_CRON].add({}, { repeat: { cron: CRON_EXPRESSIONS.MIDNIGHT } });
};

We will invoke the initQueues method from the server/index.js to initialize the queues on startup. After initializing the queues we will add a CRON job to be executed at 12 am.

You should see the below logs at 12 am!

🚀Feel free to update the regex and execute the CRON sooner than 12 am to test how it works.

Commit your code using the following git commands

git add .
git commit -m 'Add support to run a CRON job at 12 AM everyday'

‍

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Where to go from here

You now have the ability to set up CRON jobs in a multi-container environment.

I hope you enjoyed reading this article as much as I enjoyed writing it. If this piqued your interest stay tuned for the next article in the series where I will take you through how to write GraphQL subscriptions in a multi-container environment using  graphql-redis-subscriptions

If you have any questions or comments, please join the forum discussion on Twitter.