Auto Ack

Overview

Auto-ack is the fire-and-forget receive mode for queues: the broker marks a message as consumed the instant it hands it to your client, instead of waiting for your code to settle it. Reach for it when the work is idempotent, low-value, or cheap to lose — a metrics ping, a cache warm, a best-effort notification — and you'd rather not carry the bookkeeping of explicit acknowledgment for every message.

It works by setting auto_ack: true on the QueuePollRequest passed to the downstream receiver's poll. With it enabled, delivery and acknowledgment happen as one atomic step on the broker side, so there's no separate ack call and no in-flight "pending" state for the message to sit in.

Gotchas: if your consumer crashes or raises after poll returns but before it finishes processing, that message is gone for good — auto-ack gives you no chance to nack or requeue it, unlike Ack & Reject. It's an at-most-once model, so never use it for messages where losing one silently would matter. And because acknowledgment happens on delivery, max_items and wait_timeout are your only throttles — there's no visibility-timeout window to tune.

Prerequisites

• KubeMQ server running on localhost:50000
• Ruby SDK installed (gem install kubemq)

Code

require 'kubemq'

address = ENV.fetch('KUBEMQ_ADDRESS', 'localhost:50000')
channel = 'ruby-queues.auto-ack'

begin
  client = KubeMQ::QueuesClient.new(address: address, client_id: 'qstream-autoack-example')
  puts "Connected to #{address}"

  3.times do |i|
    msg = KubeMQ::Queues::QueueMessage.new(channel: channel, metadata: "item-#{i}", body: "data-#{i}")
    client.send_queue_message(msg)
  end
  puts 'Pre-sent 3 messages'

  receiver = client.create_downstream_receiver
  request = KubeMQ::Queues::QueuePollRequest.new(
    channel: channel,
    max_items: 5,
    wait_timeout: 5,
    auto_ack: true
  )
  response = receiver.poll(request)

  puts "Polled #{response.messages.size} messages (auto-acked):"
  response.messages.each { |m| puts "  #{m.metadata}: #{m.body}" }
rescue KubeMQ::Error => e
  puts "KubeMQ error: #{e.message}"
ensure
  receiver&.close
  client&.close
  puts 'Done'
end

How It Works

• Setting auto_ack: true on QueuePollRequest automatically acknowledges messages on receipt.
• No need to call ack on individual messages — useful for fire-and-forget processing.
• Review timeouts, channel names, and client IDs before running against shared environments.

Related

• Pattern overview
• Ruby SDK Reference
• Ack/Reject
• Stream Receive