How To Implement Resque In Rails

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If you want to use a job, you can use Resque in Rails. You should require the “resque” gem in your Gemfile.

gem "resque"

Then you can create a new job by subclassing the Resque::Job class.

require "resque"

class MyJob < Resque::Job
  def self.perform
    p "Doing some work..."
  end
end

Enqueue a Job

Once you’ve defined your job, you can enqueue it using the Resque.enqueue method.

Resque.enqueue(MyJob)

You can also pass arguments to your job if you need to.

Resque.enqueue(MyJob, "arg1", "arg2")

These arguments will be available inside the perform method as method arguments.

require "resque"

class MyJob < Resque::Job
  def self.perform(arg1, arg2)
    p "Doing some work with #{arg1} & #{arg2}..."
  end
end

Resque.enqueue(MyJob, "arg1", "arg2")

Run a Job Now

When you enqueue a Resque job, it will be added to a queue and executed as soon as a worker is available.

But sometimes, you might want to run a job immediately instead of waiting for a worker.

This can be done using the Resque class and the #perform method.

require "resque"

class MyJob < Resque::Job
  def self.perform
    p "Doing some work..."
  end
end

MyJob.perform

Execute a Job in a Separate Thread

You can execute it in a separate thread if you don’t want to wait for the job to finish.

This can be done using the Thread class.

require "resque"

class MyJob < Resque::Job
  def self.perform
    p "Doing some work..."
  end
end

Thread.new { MyJob.perform }

Execute a Job at a Specific Time

If you want to execute a job at a specific time, you can use the Resque.enqueue_at method.

Resque.enqueue_at(Time.now + 10.seconds, MyJob)

Scheduling Jobs with Cron

You can use crontab to schedule your jobs.

You need to add a new line in your crontab file to do this.

30 21 * * * rake resque:schedule

This will run the rake resque:schedule command every day at 9:30 PM.

Scheduling Jobs with the Whenever Gem

The Whenever gem makes it easy to schedule jobs using cron.

It also has a friendly DSL for setting up your appointments.

First, you need to add the whenever gem to your Gemfile.

gem "whenever"

Then you need to create the config/schedule.rb file.

require "resque/scheduler"

set :environment, :development

env :PATH, ENV['PATH']

job_type :job, "cd :path && :environment_variable=:environment bundle exec rake :task --silent :output"

every 1.day, :at => '2:30 am' do
  job "resque:schedule"
end

Finally, you need to run the whenever --update-crontab command to generate the crontab file and schedule your jobs.

Passing Variables to Your Job

If you want to pass variables to your job, you need to overwrite the perform method.

require "resque"

class MyJob < Resque::Job
  def self.perform(name, age)
    p "Hi #{name}, you are #{age}"
  end
end

Resque.enqueue(MyJob, "John", 21)

Running a Job in the Background

Resque also has a perform_in and perform_at method, which can run a job in the background.

require "resque"

class MyJob < Resque::Job
  def self.perform
    p "Doing some work..."
  end
end

Resque.enqueue_in(10.seconds, MyJob)
Resque.enqueue_at(Time.now + 10.seconds, MyJob)

With perform_in the job will be executed in 10 seconds, and with perform _at the job will be completed at the specified time.

You can also pass arguments to these methods.

require "resque"

class MyJob < Resque::Job
  def self.perform(name, age)
    p "Hi #{name}, you are #{age}"
  end
end

Resque.enqueue_in(10.seconds, MyJob, "John", 30)
Resque.enqueue_at(Time.now + 10.seconds, MyJob, "John", 30)

Running a Job on a Specific Queue

If you want to run a job on a specific queue, you can use the Resque.enqueue_to method.

require "resque"

class MyJob < Resque::Job
  def self.perform
    p "Doing some work..."
  end
end

Resque.enqueue_to("some_queue", MyJob)

You can also pass arguments to this method.

require "resque"

class MyJob < Resque::Job
  def self.perform(name, age)
    p "Hi #{name}, you are #{age}"
  end
end

Resque.enqueue_to("some_queue", MyJob, "John", 30)

Conclusion

In this article, you’ve learned how to enqueue, schedule, and run jobs using the Resque gem.