send email if delayed_job job is failed via exception_notification

dj_plugin.rb

# Usage

# DJ config
require Rails.root.join('lib', 'dj_plugin.rb')
Delayed::Worker.plugins << Delayed::Plugins::EmailNotify


# lib/dj_plugin.rb
require 'exception_notification'

module Delayed::Plugins
  class EmailNotify < ::Delayed::Plugin
    module Notify
      def error(job, exception)
        ExceptionNotifier.notify_exception(exception, email_prefix: '[ERROR] [DJ] ')
        super if defined?(super)
      end
    end

    callbacks do |lifecycle|
      lifecycle.before(:invoke_job) do |job|
        payload = job.payload_object
        payload = payload.object if payload.is_a? Delayed::PerformableMethod
        payload.extend Notify
      end
    end
  end
end