unbounce/messenger

A modular inter-service messenger

Messenger

Messenger communicates between the different services and is comprised of a listener and a worker.

Listeners

To create a listener in your application, run rails g messenger:listener <type>. Listeners must implement a listen method.

# Example app/messenger/listeners/something.rb
module Messenger
  module Listeners
    class Something
      include Messenger::Listeners

      def listen

        while true do
          # Get a message
          message = 'something'

          ensure_valid_worker

          @worker.work(message)
        end

      end

    end
  end
end

Another example listener is the SqsListener.

Workers

To create a listener in your application, run rails g messenger:worker <type>. Workers must implement a work method that accepts one parameter.

# Example app/messenger/workers/sidekiq.rb
module Messenger
  module Workers
    class Sidekiq
      include Messenger::Workers

      def work(message)
        BlueCollarWorker.perform_async(message)
      end

    end
  end
end

Installation

Add this line to your application's Gemfile:

gem 'messenger', git: '[email protected]:unbounce/messenger.git'

And then execute:

$ bundle

Configuration

You must set which listener and worker the messenger will use. To create a configuration file in your application, run rails g messenger:install. Set the appropriate type to your listener or worker type. This can be a child of Messenger::Listeners or Messenger::Workers or any other class.

# Example config/initializers/messenger.rb

Messenger.configure do |config|
  config.listener_type = :sqs
  config.worker_type = :sidekiq
end

Tell Rails where to find any listeners or workers you create:

# config/application.rb
config.autoload_paths << "#{Rails.root}/app/messenger"

Usage

The messenger can be run using rake messenger:listen or from the console using:

messenger = Messenger.new
messenger.listen