TL;DR

Langohr is a Clojure RabbitMQ client that embraces AMQP 0.9.1 Model.

1.0.0-beta12 is a development milestone release. We recommend all users to upgrade to it.

Changes between Langohr 1.0.0-beta11 and 1.0.0-beta12

Clojure-friendly Return Values

Previously functions such as langohr.queue/declare returned the underlying RabbitMQ Java client responses. In case a piece of information from the response was needed (e.g. to get the queue name that was generated by RabbitMQ), the only way to obtain it was via the Java interop.

This means developers had to learn about how the Java client works. Such responses are also needlessly unconvenient when inspecting them in the REPL.

Langohr 1.0.0-beta12 makes this much better by returning a data structure that behaves like a regular immutable Clojure map but also provides the same Java interoperability methods for backwards compatibility.

For example, langohr.queue/declare now returns a value that is a map but also provides the same .getQueue method you previously had to use.

Since the responses implement all the Clojure map interfaces, it is possible to use destructuring on them:

1
2
3
4
5
6
7
8

(require '[langohr.core  :as lhc])
(require '[langohr.queue :as lhq])

(let [conn    (lhc/connect)
      channel (lhc/create-channel conn)
      {:keys [queue] :as declare-ok} (lhq/declare channel "" :exclusive true)]
  (println "Response: " declare-ok)
  (println (format "Declared a queue named %s" queue)))

will output

1
2

Response:  {:queue amq.gen-G9bmz19UjHLBjyxhanOG3Q, :consumer-count 0, :message_count 0, :consumer_count 0, :message-count 0}
Declared a queue named amq.gen-G9bmz19UjHLBjyxhanOG3Q

langohr.confirm/add-listener Now Returns Channel

langohr.confirm/add-listener now returns the channel instead of the listener. This way it is more useful with the threading macro (->) that threads channels (a much more common use case).

langohr.exchange/unbind

langohr.exchage/unbind was missing in earlier releases and now added.

langohr.core/closed?

langohr.core/closed? is a new function that complements langohr.core/open?.

langohr.queue/declare-server-named

langohr.queue/declare-server-named is a new convenience function that declares a server-named queue and returns the name RabbitMQ generated:

1
2
3
4
5
6
7

(require '[langohr.core  :as lhc])
(require '[langohr.queue :as lhq])

(let [conn    (lhc/connect)
      channel (lhc/create-channel conn)
      queue   (lhq/declare-server-named channel)]
  (println (format "Declared a queue named %s" queue))

More Convenient TLS Support

Langohr will now correct the port to TLS/SSL if provided :port is 5672 (default non-TLS port) and :ssl is set to true.

Change Log

Langohr change log is available on GitHub.

Langohr is a ClojureWerkz Project

Langohr is part of the group of libraries known as ClojureWerkz, together with

• Elastisch, a minimalistic well documented Clojure client for ElasticSearch
• Welle, a Riak client with batteries included
• Monger, a Clojure MongoDB client for a more civilized age
• Neocons, a client for the Neo4J REST API
• Quartzite, a powerful scheduling library

and several others. If you like Langohr, you may also like our other projects.

Let us know what you think on Twitter or on the Clojure mailing list.

Michael on behalf of the ClojureWerkz Team