Upgrading

v1.0.0-RC2

Upgrade notes from RC1 to RC2? It looks like I completely blew my commitment to keep API changes to a minimum at this point. This represents one of the largest API changes, of all. I'm seriously excited about it.

• TopicMessage, QueueMessage, ExchangeMessage objects have become Message.topic, Message.queue, Message.exchange, etc.
• ConfirmedMessage has become simply Message, as it is the default.
• UnconfirmedMessage gained a symmetrical Factory function API (UnconfirmedMessage.topic, UnconfirmedMessage.factory, etc.)
• QueueBinding has become Queue, ExchangeBinding has become Exchange.
  • TopicBinding, HeadersBinding, FanoutBinding receive a Queue definition and an Exchange definition, rather than having the parameters for the creation of each flatten.
  • PassiveQueueBinding has become Queue.passive. Queue.passive can receive a Queue definition which will be used to declare the queue in the event that the queue in question doesn't already exist.
  • Exchange.passive has been created, similarly, can receive a non-passive Exchange definition.
  • Exchange definitions are generically typed; if you pass an Exchange[Exchange.Topic.Value] to a HeadersBinding, the compiler will yell at you.
• RecoveryStrategy.limitedRedeliver uses a RabbitMQ queue with dead-letter forwarding options and a TTL to handle message retry. The messages still go to the back of the line, but the consumer is no longer slowed down in failure mode.
• The Directives queue binding DSL has been updated to incorporate the above changes.

v1.0.0-RC1

Overview

• com.spingo.op_rabbit.consumer._ was moved into com.spingo.op_rabbit._; update your imports, accordingly.
• The method of instantiating Subscription has changed, substantially. Subscription is now completely stateless.
• Casting Header values in the Handler DSL has changed, and supports optionalProperty.

Subscription changes

Before, subscriptions were declared and registered like this:

val subscription = new Subscription {
  // A qos of 3 will cause up to 3 concurrent messages to be processed at any given time.
  def config = channel(qos = 3) {
    consume(topic("such-message-queue", List("some-topic.#"))) {
      body(as[Person]) { person =>
        // do work; this body is executed in a separate thread, as provided by the implicit execution context
        ack()
      }
    }
  }
}

rabbitControl ! subscription

subscription.initialized.foreach { _ =>
  println("Initialized!")
  subscription.close()
}

Subscription had a close() method and a closed property. This is no more.

The above is rewritten as follows for v1.0.0-RC1:

val subscription = Subscription {
  // A qos of 3 will cause up to 3 concurrent messages to be processed at any given time.
  def config = channel(qos = 3) {
    consume(topic("such-message-queue", List("some-topic.#"))) {
      body(as[Person]) { person =>
        // do work; this body is executed in a separate thread, as provided by the implicit execution context
        ack()
      }
    }
  }
}

val subscriptionRef = subscription.register(rabbitControl)

subscriptionRef.initialized.foreach { _ =>
  println("Initialized!")
  subscriptionRef.close()
}

Casting header values

Before, HeaderValues were cast using as follows:

property(Header("x-retries")).as(typeOf[Int])

This did not work for optionalProperty; the old way no longer works and the new way is shorter:

property(Header("x-retries").as[Int])
optionalProperty(Header("x-retries").as[Int])