publisher.rb

# frozen_string_literal: true

require 'multi_json'

module Travis
  module Amqp
    class Publisher
      class << self
        def channel
          @channel ||= Amqp.connection.create_channel.tap do
            Amqp.logger.debug 'Created AMQP channel.'
          end
        end
      end

      attr_reader :name, :type, :routing_key, :options

      def initialize(routing_key, options = {})
        @routing_key = routing_key
        @options = options.dup
        @name = @options.delete(:name) || ''
        @type = @options.delete(:type) || 'direct'
      end

      def publish(data, options = {})
        return unless data

        Amqp.logger.warn "Queue #{routing_key} doesn't exist!" if ENV['AMQP_QUEUE_VALIDATION'] && !Amqp.connection.queue_exists?(routing_key)
        data = MultiJson.encode(data)
        exchange.publish(data, deep_merge(default_data, options))
        debug "Published AMQP message to #{routing_key}."
      end

      protected

      def default_data
        { key: routing_key, properties: { message_id: rand(100_000_000_000).to_s } }
      end

      def exchange
        @exchange ||= self.class.channel.exchange(name, type: type.to_sym, durable: true, auto_delete: false)
      end

      def deep_merge(hash, other)
        hash.merge(other, &(merger = proc { |_key, v1, v2|
                              v1.is_a?(Hash) && v2.is_a?(Hash) ? v1.merge(v2, &merger) : v2
                            }))
      end

      def debug(msg)
        Amqp.logger.debug(msg)
      end
    end
  end
end