Project: Message-driver 0.4.0

Publisher: Message Driver

Nacking Redelievered Messages from a consumer

@bunny

You can configure the consumer to nack a re-delievered message. In this example, we use
a dead letter exchange to show how things end up working.

Background

Given

the following broker configuration

MessageDriver::Broker.define do |b|
  # declare a dead letter exchange
  b.destination :rabbit_dlx, "rabbit.dead.letter.exchange", type: :exchange, declare: { type: :fanout }

  # declare a dead letter queue and bind it to the exchange
  b.destination :rabbit_dlq, "rabbit.dead.letter.queue", bindings: [
    { source: "rabbit.dead.letter.exchange" }
  ]

  # declare a work queue that sends dead letters to our dead letter queue
  b.destination :rabbit_work, "rabbit.work", arguments: { :"x-dead-letter-exchange" => "rabbit.dead.letter.exchange" }
end

And

I have no messages on :rabbit_work

And

I have no messages on :rabbit_dlq

And

I have a destination :rabbit_track with no messages on it

Scenarios

Raising an error in an auto_ack consumer

Given

I have a message consumer

MessageDriver::Client.consumer(:manual_redeliver) do |message|
  publish(:rabbit_track, "#{message.body} Attempt")
  raise "oh nos!"
end

And

I create a subscription

MessageDriver::Client.subscribe(:rabbit_work, :manual_redeliver, ack: :auto, retry_redelivered: false)

When

I send the following messages to :rabbit_work

body

Auto Retry 1

Auto Retry 2

And

I let the subscription process

Then

I expect to find no messages on :rabbit_work

And

I expect to find the following 2 messages on :rabbit_dlq

body

Auto Retry 1

Auto Retry 2

And

I expect to find the following 4 messages on :rabbit_track

body

Auto Retry 1 Attempt

Auto Retry 2 Attempt

Auto Retry 1 Attempt

Auto Retry 2 Attempt

Raising an error in a transactional consumer

Given

I have a message consumer

@attempts = 0
MessageDriver::Client.consumer(:transactional_redeliver) do |message|
  publish(:rabbit_track, "#{message.body} Attempt")
  @attempts += 1
  raise "oh nos!"
end

And

I create a subscription

MessageDriver::Client.subscribe(:rabbit_work, :transactional_redeliver, ack: :transactional, retry_redelivered: false)

When

I send the following messages to :rabbit_work

body

Transactional Redeliver 1

Transactional Redeliver 2

Transactional Redeliver 3

Transactional Redeliver 4

Transactional Redeliver 5

And

I let the subscription process

Then

I expect to find no messages on :rabbit_track

Then

I expect to find no messages on :rabbit_work

Then

I expect the following check to pass

expect(@attempts).to eq(10)

Then

I expect to find the following 5 messages on :rabbit_dlq

body

Transactional Redeliver 1

Transactional Redeliver 2

Transactional Redeliver 3

Transactional Redeliver 4

Transactional Redeliver 5

Last published about 7 years ago by soupmatt.

Nacking Redelievered Messages from a consumer

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