In modern software development, automating routine tasks is crucial for maintaining system health and efficiency. One of the ways to achieve this automation is by using cron jobs. Cron jobs are scheduled tasks that run at specific intervals on Unix-like operating systems. In this blog, we will explore how to write and schedule cron jobs in Micronaut, a popular Java framework for building microservices and serverless applications.

Prerequisites:

Before diving into the details, make sure you have the following prerequisites in place:

1. Micronaut Installed: Ensure you have Micronaut installed on your development machine. If not, you can easily install it by following the official documentation.
2. Basic Micronaut Project: Create a basic Micronaut project.

Writing a Cron Job in Micronaut:

Now, let’s get started with writing a cron job in Micronaut.

Create a New Micronaut Bean:

To create a cron job, we’ll start by creating a new Micronaut bean. This bean will contain the logic we want to execute at specified intervals.

package com.example.event

import io.micronaut.scheduling.annotation.Scheduled
import jakarta.inject.Singleton

@Singleton
class CronJob {

    @Scheduled(cron = "* * * * *") // Specify your cron expression here
    fun executeScheduledTask() {
        // Your task logic goes here
        println("Cron job executed at every minute")
    }
}

1. In the code above, we define a CronJob bean with a method annotated with @Scheduled. The cron attribute allows you to specify the cron expression that defines when the method should be executed. In this example, the method runs every day at 1 AM.
2. Customize Your Cron Expression:Customize the cron attribute to match your desired schedule. Cron expressions can be quite flexible, allowing you to specify precise timings for your tasks. You can find numerous online tools to help you generate the perfect cron expression for your needs.

Read Also: Integrating RabbitMQ in Micronaut: A Step-by-Step Guide

Having a locking mechanism in place for a scheduled job is crucial because when dealing with multiple instances, each instance can trigger the cron job independently.

Code: https://github.com/cw-bhanunadar/Micronaut-playground/pull/5

Conclusion:

In this blog, we’ve explored how to create and schedule cron jobs in Micronaut applications. Automating tasks using cron jobs is a powerful way to keep your applications running smoothly and efficiently. Micronaut’s built-in support for scheduling tasks makes it a great choice for developing applications that require periodic background processing.