ruby-rabbit-rpc-client.rb

require 'securerandom'

require 'bundler'
Bundler.require(:default)

class RPCClient
  def initialize
    @var_store = {}
    @connection = Bunny.new
    start_connection!
  end

  def send(request)
    p "Sending message <<#{request}>>"
    request_key = SecureRandom.hex(4)
    @exchange.publish(request, headers: { 'X-Request-Key' => request_key })
    var = Concurrent::MVar.new
    @var_store[request_key] = var
    var.take
  end

  def shutdown
    @connection.close
  end

  private

  def start_connection!
    @connection.start

    @channel = @connection.create_channel
    @exchange = @channel.direct('rpcc-rb')

    @rpc_request_queue = @channel.queue('rpc_request')
    @rpc_response_queue = @channel.queue('rpc_response')

    @rpc_request_queue.bind('rpcc-rb')
    @rpc_response_queue.subscribe do |_dlvr, props, body|
      headers = props[:headers]
      response_for = headers['X-Response-For']
      @var_store.delete(response_for).put(body)
    end
  end
end

client = RPCClient.new

t1 = Thread.new do
  reply = client.send('Hello from handler 1')
  p "[1] Received message <<#{reply}>>"
end

t2 = Thread.new do
  reply = client.send('Hello from handler 2')
  p "[2] Received message <<#{reply}>>"
end

t1.join
t2.join

client.shutdown