Active Job framework in Ruby on Rails

Introduction

Active Job helps you run tasks in the background so your app stays fast. It makes it easy to do things later without slowing down users.

Sending emails after a user signs up without making them wait

Processing image uploads or resizing photos after upload

Running slow database cleanup tasks at night

Sending notifications or messages without delay

Performing API calls to other services without blocking user actions

Syntax

Ruby on Rails

class MyJob < ApplicationJob
  queue_as :default

  def perform(*args)
    # Do the work here
  end
end

Define a job by creating a class that inherits from ApplicationJob.

Use the perform method to write the task you want to run in the background.

Examples

This job sends a welcome email to a user using the mailers queue.

Ruby on Rails

class EmailUserJob < ApplicationJob
  queue_as :mailers

  def perform(user)
    UserMailer.welcome_email(user).deliver_now
  end
end

This job deletes old records using a low priority queue.

Ruby on Rails

class CleanupJob < ApplicationJob
  queue_as :low_priority

  def perform
    OldRecord.where('created_at < ?', 1.month.ago).delete_all
  end
end

Enqueue the job to run later with arguments.

Ruby on Rails

MyJob.perform_later(arg1, arg2)

Sample Program

This job prints a greeting message with the given name. It runs in the background when enqueued.

Ruby on Rails

class GreetUserJob < ApplicationJob
  queue_as :default

  def perform(name)
    puts "Hello, #{name}!"
  end
end

# Enqueue the job
GreetUserJob.perform_later('Alice')

Important Notes

Active Job works with many background systems like Sidekiq, Resque, or Delayed Job.

Use perform_later to run jobs asynchronously and perform_now to run immediately.

Always keep jobs small and focused to avoid long delays.

Summary

Active Job lets you run tasks in the background easily.

Define jobs by subclassing ApplicationJob and writing a perform method.

Use perform_later to enqueue jobs without blocking your app.