# Banter

Simple Publishers and subscribers for Ruby using RabbitMQ

Developed & maintained by The Honest Company. We are always looking for the best talent, find your next opportunity at Honest Careers

Installation

Add this line to your application's Gemfile:

gem 'banter'

And then execute:

$ bundle

Or install it yourself as:

$ gem install banter

You also need to install RabbitMQ

$ brew install rabbitmq

Usage

There are two sides to this gem, publishers and subscribers

Publishers

Publishing to a message is super simple

Banter.publish('user.created', id: 3, name: 'Foo Bar', email: 'foobar@email.com')

Additionally you can setup a context that is passed down to the subscribers. This context can be set up in a before_filter

class ApplicationController < ActionController::Base
    before_filter :setup_pubsub_context

    private

    def setup_pubsub_context
        Banter::Context.setup_context
          unique_id:       request.uuid,
          orig_ip_address: request.remote_ip,
          application:     "my_app/web:#{self.class.name.underscore}/#{action_name}",
          user_id:         current_user.try(:id)
    end
end

Context is automatically cleared up by the gem for a Rails Application. Otherwise, you can call Banter::Context.clear!

Subscribers

You can declare a subscriber class as follows

class UserWelcomeSubscriber < Banter::Subscriber
  subscribe_to "user_created"
  # Message prefix that you're subscribing to. You can also specify options for queue_name and queue_ttl

  def perform(payload)
    # My awesome logic goes here...
  end
end

You also run subscribers in a separate process to consume the message using the provided executable

bundle exec start_subscribers

You can execute bundle exec start_subscribers --help to see all the various options that it providers

Usage: bundle exec start_subscribers [options]
    -P, --pidfile PATH               path to pidfile
    -o, --only [SUBSCRIBERS]         comma separated name of subsriber classes that should be run
    -r, --require [PATH|DIR]         Location of Rails application with workers or file to require
    -n, --name [PROCESS_NAME]        Name of the process
    -v, --version                    Print version and exit

Payload Validations

class UserWelcomeSubscriber < Banter::Subscriber
  subscribe_to "user_created" # The message prefix that you're subscribing to
  validates_payload_with :id_present
  validates_payload_with do |payload|
    payload[:email].present?
  end

  def perform(payload)
    # My awesome logic goes here...
  end

  private

  def id_present(payload)
    payload[:id].present?
  end
end

Dashboards!!!

Banter provides dashboards that can be easily enabled in any Rack application.

For a Rails application

# config/application.rb
config.banter.web_enabled = true

#config/routes.rb
mount Banter::Web::Application => '/banter'

or

#config.routes.rb
  authenticate :admin do
    mount Banter::Web::Application => '/banter'
  end

Dashboards currently use Mongo DB (Mongoid gem) to store data, so the following gems should be added to your gemfile

gem 'mongoid'
gem 'haml'
gem 'sinatra'

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request