# Functions

The ./src/index.js file includes global register, bootstrap and destroy functions that can be used to add dynamic and logic-based configurations.

# Register

Path — ./src/index.js.

The register lifecycle function is an asynchronous function that runs before the application is initialized. It can be used to:

# Bootstrap

Path — ./src/index.js

The bootstrap lifecycle function is called at every server start.

It can be used to:

  • create an admin user if there isn't one.
  • fill the database with some necessary data.
  • load some environment variables.

The bootstrap function can be synchronous or asynchronous.

Synchronous

module.exports = () => {
  // some sync code
};

Return a promise

module.exports = () => {
  return new Promise(/* some code */);
};

Asynchronous

module.exports = async () => {
  await someSetup();
};

# Destroy

The destroy function is an asynchronous function that runs before the application gets shut down.

It can be used to gracefully stop services that are running or clean up plugin actions (e.g. close connections, remove listeners, etc.).

# CRON tasks

CRON tasks allow you to schedule jobs (arbitrary functions) for execution at specific dates, with optional recurrence rules. It only uses a single timer at any given time (rather than reevaluating upcoming jobs every second/minute).

This feature is powered by the node-schedule (opens new window) package.

✋ CAUTION

Make sure the enabled cron config is set to true in ./config/server.js file.

The cron format consists of:

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

To define a CRON job, add your logic like below:

// path: ./config/functions/cron.js

module.exports = {
  /**
   * Simple example.
   * Every monday at 1am.
   */

  '0 0 1 * * 1': () => {
    // Add your own logic here (e.g. send a queue of email, create a database backup, etc.).
  },
};

If your CRON task is required to run based on a specific timezone then you can configure the task like below:

module.exports = {
  /**
   * CRON task with timezone example.
   * Every monday at 1am for Asia/Dhaka timezone.
   * List of valid timezones: https://en.wikipedia.org/wiki/List_of_tz_database_time_zones#List
   */

  '0 0 1 * * 1': {
    task: () => {
      // Add your own logic here (e.g. send a queue of email, create a database backup, etc.).
    },
    options: {
      tz: 'Asia/Dhaka',
    },
  },
};

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