killbill-plugin-framework-ruby

Framework to write Killbill plugins in Ruby.

There are various types of plugins one can write for Killbill:

1. notifications plugins, which listen to external bus events and can react to it
2. payment plugins, which are used to issue payments against a payment gateway

Both types of plugin can interact with Killbill directly via killbill-library APIs and expose HTTP endpoints.

How to write a Notification plugin

require 'killbill'

class MyNotificationPlugin < Killbill::Plugin::Notification
  # Overriding this method is optional, only if you need to do some initialization work
  def start_plugin
    puts "MyNotificationPlugin plugin starting"
    super
    puts "MyNotificationPlugin plugin started"
  end

  # Invoked each time an event is received
  def on_event(event)
    puts "Received Killbill event #{event}"
  end

  # Overriding this method is optional, only if you need to do some tear down work
  def stop_plugin
    puts "MyNotificationPlugin plugin stopping"
    super
    puts "MyNotificationPlugin plugin stopped"
  end
end

Make sure to create the corresponding killbill.properties file:

mainClass=MyNotificationPlugin
pluginType=NOTIFICATION

How to write a Payment plugin

require 'killbill'

class MyPaymentPlugin < Killbill::Plugin::Payment
  def start_plugin
    puts "MyPaymentPlugin plugin starting"
    super
    puts "MyPaymentPlugin plugin started"
  end

  def authorize_payment(kb_account_id, kb_payment_id, kb_payment_transaction_id, kb_payment_method_id, amount, currency, properties, context)
  end

  def capture_payment(kb_account_id, kb_payment_id, kb_payment_transaction_id, kb_payment_method_id, amount, currency, properties, context)
  end

  def purchase_payment(kb_account_id, kb_payment_id, kb_payment_transaction_id, kb_payment_method_id, amount, currency, properties, context)
  end

  def void_payment(kb_account_id, kb_payment_id, kb_payment_transaction_id, kb_payment_method_id, properties, context)
  end

  def credit_payment(kb_account_id, kb_payment_id, kb_payment_transaction_id, kb_payment_method_id, amount, currency, properties, context)
  end

  def refund_payment(kb_account_id, kb_payment_id, kb_payment_transaction_id, kb_payment_method_id, amount, currency, properties, context)
  end

  def get_payment_info(kb_account_id, kb_payment_id, properties, context)
  end

  def search_payments(search_key, offset, limit, properties, context)
  end

  def add_payment_method(kb_account_id, kb_payment_method_id, payment_method_props, set_default, properties, context)
  end

  def delete_payment_method(kb_account_id, kb_payment_method_id, properties, context)
  end

  def get_payment_method_detail(kb_account_id, kb_payment_method_id, properties, context)
  end

  def set_default_payment_method(kb_account_id, kb_payment_method_id, properties, context)
  end

  def get_payment_methods(kb_account_id, refresh_from_gateway, properties, context)
  end

  def search_payment_methods(search_key, offset, limit, properties, context)
  end

  def reset_payment_methods(kb_account_id, payment_methods, properties, context)
  end

  def build_form_descriptor(kb_account_id, descriptor_fields, properties, context)
  end

  def process_notification(notification, properties, context)
  end

  # Overriding this method is optional, only if you need to do some tear down work
  def stop_plugin
    puts "MyPaymentPlugin plugin stopping"
    super
    puts "MyPaymentPlugin plugin stopped"
  end
end

Make sure to create the corresponding killbill.properties file:

mainClass=MyPaymentPlugin
pluginType=PAYMENT

How to write a Payment plugin integrated with ActiveMerchant

Use the plugin generator:

./script/generate active_merchant gateway_name /path/to/dir

Replace gateway_name with the snake case of your ActiveMerchant gateway (e.g. yandex, stripe, paypal, etc.).

This will generate a tree of files ready to be plugged into Kill Bill. To package the plugin, run:

rake killbill:clean ; rake build ; rake killbill:package

Most of the work consists of filling in the blank in api.rb (payment plugin API for ActiveMerchant gateways) and application.rb (sinatra application for ActiveMerchant integrations). Check the Stripe plugin for an example.

In case the templates behind the generator change and you want to upgrade your plugin, you can re-run the above generate command on top of your existing code. For each file, you'll be prompted whether you want to overwrite it, show a diff, etc.

How to expose HTTP endpoints

Killbill exports a Rack handler that interfaces directly with the container in which killbill-server runs (e.g. Jetty).

This basically means that Killbill will understand native Rack config.ru files placed in the root of your plugin, e.g. (using Sinatra):

require 'sinatra'

get "/plugins/myPlugin/ping" do
  status 200
  "pong"
end
run Sinatra::Application

Rake tasks

The killbill gem also ships helpful Rake tasks to package Killbill-ready plugins.

To access these tasks, add the following to your Rakefile:

# Install tasks to package the plugin for Killbill
require 'killbill/rake_task'
Killbill::PluginHelper.install_tasks

# (Optional) Install tasks to build and release your plugin gem
require 'bundler/setup'
Bundler::GemHelper.install_tasks

You can verify these tasks are available by running rake -T.

To build the artifacts into pkg/:

# Cleanup output directories
rake killbill:clean
# Build your plugin gem in the pkg/ directory
rake build
# Build the Killbill plugin in the pkg/ directory
# The <plugin_name>-<plugin-version>/ directory is used as a staging directory
rake killbill:package

For quick testing of your plugin, you can use the deploy task:

# Deploy the plugin in /var/tmp/bundles
rake killbill:deploy
# Deploy the plugin and clobber a previous version if needed
rake killbill:deploy[true]
# You can also specify a custom plugins directory as such
rake killbill:deploy[false,/path/to/bundles]

To debug packaging issues, pass true as the third (optional) parameter:

rake killbill:deploy[false,/path/to/bundles,true]