AMQP Ruby Client

The recommended Ruby client is amqp-client.rb. It has no dependencies, reconnects on its own, and recovers consumers after a reconnect. Install it with:

gem install amqp-client

Publish and consume

The example reads the broker URL from BROKER_URL and falls back to a local LavinMQ at amqp://guest:guest@localhost.

Save the connection helper as amqp.rb:

require "amqp-client"

module Amqp
  def self.client
    AMQP::Client.new(ENV.fetch("BROKER_URL", "amqp://guest:guest@localhost")).start
  end
end

Save the publisher as publisher.rb:

require_relative "amqp"

module Publisher
  # Messages are persistent and wait for a publisher confirm by default
  def self.publish(client, queue, message)
    client.queue(queue).publish(message)
    puts " [x] Sent #{message.inspect}"
  end
end

if __FILE__ == $PROGRAM_NAME
  client = Amqp.client
  Publisher.publish(client, "hello", "Hello world!")
  client.stop
end

Save the consumer as worker.rb in the same directory:

require_relative "amqp"

module Worker
  # The message is acked when the block returns, and requeued if it raises
  def self.consume(client, queue, &handler)
    client.queue(queue).subscribe(prefetch: 10) do |msg|
      handler.call(msg.body)
    end
  end
end

if __FILE__ == $PROGRAM_NAME
  client = Amqp.client
  Worker.consume(client, "hello") { |message| puts " [x] Received #{message.inspect}" }
  puts " [*] Waiting for messages. To exit press CTRL+C"
  begin
    sleep
  rescue Interrupt
    client.stop
  end
end

Run ruby worker.rb in one terminal and ruby publisher.rb in another.

The full, runnable example lives in ruby/amqp-client in cloudamqp/examples, and CI tests it against LavinMQ.

Good to know

• Messages get acked after the block returns. If the block raises, the client rejects the message and LavinMQ requeues it. A message can arrive twice after a reconnect, so keep handlers idempotent.
• Set a prefetch limit. subscribe defaults to a prefetch of 1. Raise it, as in subscribe(prefetch: 10), for higher throughput without buffering more than a consumer can handle.
• Use amqps:// for TLS. The client verifies the server certificate and hostname.

The amqp-client.rb README covers codecs, RPC and the low-level API.

Other Ruby clients

• Bunny, a widely used synchronous client
• Kicks (formerly Sneakers), a background job framework