A simple AMQ "Factory" setup using Bunny. Opinionated for one of my projects

require 'bunny'

module AMQFactory

class << self

attr_accessor :connection

#
# Public API
#

##
# Create a durable fanout exchange
#
# @param [String] name Name of the exchange
#
# @api public
#
def create_exchange(name)
  with_channel { |channel| channel.fanout name, durable: true }
end

##
# Remove exchange
#
# @param [String] name Name of the exchange
#
# @api public
#
def teardown_exchange(name)
  with_channel do |channel|
    xchg = channel.fanout name, durable: true
    xchg.delete
  end
end

##
# Create a durable queue that is bound to an exchange
#
# @param [String] name Name of the queue
# @param [String] xchg_name Name of the exchange
#
# @api public
#
def create_queue(name, xchg_name)
  with_channel do |channel|
    xchg = channel.fanout xchg_name, durable: true
    queue = channel.queue name, durable: true

    queue.bind xchg
  end
end

##
# Remove a queue
#
# @param [String] name Name of the queue
#
# @api public
#
def teardown_queue(name)
  with_channel do |channel|
    queue = channel.queue name, durable: true
    queue.delete
  end
end

##
# Bind one exchange to another
#
# @param [String] source_name Name of the exchange to bind to
# @param [String] receiver_name Name of the receiving exchange
#
# @api public
#
def bind_exchange(source_name, receiver_name)
  with_channel do |channel|
    receiver = channel.fanout receiver_name, durable: true
    receiver.bind source_name
  end
end

##
# Unbind one exchange from another
#
# @param [String] source_name Name of the source exchange
# @param [String] receiver_name Name of the exchange to unbind
#
# @api public
#
def unbind_exchange(source_name, receiver_name)
  with_channel do |channel|
    receiver = channel.fanout receiver_name, durable: true
    receiver.unbind source_name
  end
end

##
# Publish a message to an exchange
#
# @param [Object] message Any payload that can receive +to_json+
# @param [String] xchg_name Name of the exchange to publish to
# @param [Hash] opts Any options to send to Bunny/RMQ with payload
#
# @api public
#
def publish(message, xchg_name, opts = {})
  with_channel do |channel|
    xchg = channel.fanout xchg_name, durable: true
    xchg.publish message.to_json, opts
  end
end

private

##
# Create a Bunny::Session connection to RMQ
#
# @return [Bunny::Session] Connection
# @api private
#
def connect
  @connection = Bunny.new   # pass in configuration params
  @connection.start
end

##
# Wrapper for code requiring the use of a [Bunny::Channel] instance
#
# @return [BunnyMock::Session] Connection
# @api private
#
def with_channel
  connect unless @connection && @connection.open?
  @connection.with_channel { |c| yield c }
end

end end