Outboxer

Background

Outboxer is an ActiveRecord implementation of the transactional outbox pattern for PostgreSQL and MySQL databases.

Setup

1. add gem to gemfile

gem 'outboxer'

2. install gem

bundle install

3. generate schema

bin/rails g outboxer:schema

4. migrate schema

bin/rake db:migrate

5. seed database

bin/rake outboxer:db:seed

6. generate publisher

sidekiq

bin/rails g outboxer:sidekiq_publisher

custom

bin/rails g outboxer:publisher

7. queue message after model creation

# your existing model

class Event < ActiveRecord::Base
  after_create do |event|
    Outboxer::Message.queue(messageable: event)
  end
end

8. publish message out of band

Sidekiq

Outboxer::Publisher.publish do |message|
  case message[:messageable_type]
  when 'Event'
    EventCreatedJob.perform_async({ 'id' => message[:messageable_id] })
  end
end

Bunny

Outboxer::Publisher.publish do |message|
  case message[:messageable_type]
  when 'Event'
    queue.publish(JSON.generate({ 'id' => message[:messageable_id] }), persistent: true)
  end
end

Custom

Outboxer::Publisher.publish do |message|
  case message[:messageable_type]
  when 'Event'
    # publish message here

    logger.info "Outboxer published message #{message[:id]} for "\
      "#{message[:messageable_type]}::#{message[:messageable_id]}"
  end
end

9. run publisher

bin/outboxer_publisher

10. open rails console

bin/rails c

11. create event

Event.create!

12. Observe published message

Confirm the message has been published out of band

Management

Outboxer provides a sidekiq like UI to help manage your messages

Publishers

Messages

rails

config/routes.rb

require 'outboxer/web'

Rails.application.routes.draw do
  mount Outboxer::Web, at: '/outboxer'
end

rack

config.ru

require 'outboxer/web'

map '/outboxer' do
  run Outboxer::Web
end

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/fast-programmer/outboxer.

License

This gem is available as open source under the terms of the GNU Lesser General Public License v3.0.

outboxer

Runtime