with_custom_deadletter_configuration.md

Consumer with custom deadletter configuration

Consumer with custom deadletter:

• queue name
• exchange name
• routing key
• queue arguments and type (transient instead of durable)

deadletter_queue_options - Queue options for the deadletter queue as declared in AMQP.Queue.declare/3.

Example

defmodule ConsumerWithCustomDeadletterConfiguration do
  @behaviour GenRMQ.Consumer

  def init() do
    [
      connection: "amqp://guest:guest@localhost:5672",
      queue: "example_queue",
      exchange: "example_exchange",
      routing_key: "routing_key.#",
      prefetch_count: "10",
      deadletter_queue: "custom_deadletter_queue",
      deadletter_exchange: "custom_deadletter_exchange",
      deadletter_routing_key: "custom_deadletter_routing_key",
      deadletter_queue_options: [
        durable: false,
        arguments: [
          {"x-expires", :long, 3_600_000},
          {"x-max-priority", :long, 3}
        ]
      ]
    ]
  end

  def handle_message(%GenRMQ.Message{} = message), do: GenRMQ.Consumer.ack(message)

  def handle_error(%GenRMQ.Message{} = message, _reason), do: GenRMQ.Consumer.reject(message, false)

  def consumer_tag(), do: "consumer-tag"

  def start_link(), do: GenRMQ.Consumer.start_link(__MODULE__, name: __MODULE__)
end

Outcome:

• durable custom_deadletter_exchange exchange created or redeclared
• transient, priority and with ttl custom_deadletter_queue queue created or redeclared and bound to custom_deadletter_exchange exchange
• durable topic example_exchange exchange created or redeclared
• durable example_queue queue created or redeclared and bound to example_exchange exchange
• queue example_queue has a deadletter exchange set to custom_deadletter_exchange
• every handle_message callback will be executed in a separate supervised task. If the task fails handle_error/2 will be called
• on failed rabbitmq connection it will wait for a bit and then reconnect