RequestQueue

This is a utility for deduping work on a per-request basis. It works like this:

1. When the request starts, create a queue.
2. Add some work to the queue by calling RequestQueue.enqueue(some_job).
3. Before the request ends, you'll have opportunity to dedupe the work.

Add this line to your application's Gemfile:

gem 'request_queue'

And then execute:

$ bundle

Or install it yourself as:

$ gem install request_queue

A a job can be any callable, so for example:

job = proc { puts 'Hello' }

RequestQueue.enqueue(job)
RequestQueue.enqueue(job)

This would output 'Hello' once at the end of the request.

Because RequestQueue accepts any callable, you can also use an object.

class Job
  def initialize(message)
    @message = message
  end

  def call
    puts @message
  end
end

job = Job.new('Hello')
RequestQueue.enqueue(job)
RequestQueue.enqueue(job)

Sometimes, you need a little more control over the deduping.

class Job
  def self.filter(jobs)
    jobs.uniq_by(&:message)
  end

  attr_reader :message

  def initialize(message)
    @message = message
  end

  def call
    puts message
  end
end

RequestQueue.enqueue Job.new('Hello')
RequestQueue.enqueue Job.new('Hello')

In this example, the job instances are unique, so they wouldn't be automatically deduped. But, when the class of a message responds to filter, it will be called and give you the opportunity to provide custom dedupe logic.

When testing, sometimes you want a little more control. As such, RequestQueue offers multiple queue backends:

• :default - Runs jobs at the end of the request.
• :fake - Never runs jobs, and allows you to inspect the queue with RequestQueue.queue.queue.
• :inline - Runs jobs immediately and never adds them to the queue.

To change the queueing backend, you can just give the backend name as an argument to process.

RequestQueue.process :inline do
  # ...
end

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/Ray Zane/request_queue.

The gem is available as open source under the terms of the MIT License.