Machine Head is a small Clojure MQTT client.

1.0.0-beta9 is a development milestone that introduces one breaking API change.

Changes Between 1.0.0-beta8 and 1.0.0-beta9

Subscription API Change

Previously clojurewerkz.machine-head.client/subscribe accepted a list of topics and optionally a list of QoS levels:

(mh/subscribe c ["mh/topics/#" "mh/alt.topics/+"]
                  (fn [^String topic meta ^bytes payload])
                  {:qos [0 1]})

This turns out to be a fairly confusing API.

We’ve changed it to accept a map of topics to QoS levels. While a bit more verbose, this API make it very clear what topic will use what QoS:

(mh/subscribe c {"mh/topics/#" 0 "mh/alt.topics/+" 1}
                  (fn [^String topic meta ^bytes payload] ))

Changes Between 1.0.0-beta7 and 1.0.0-beta8

Clojure 1.6 By Default

The project now depends on org.clojure/clojure version 1.6.0. It is still compatible with Clojure 1.4 and if your project.clj depends on a different version, it will be used, but 1.6 is the default now.

We encourage all users to upgrade to 1.6, it is a drop-in replacement for the majority of projects out there.

Changes Between 1.0.0-beta6 and 1.0.0-beta7

Retain Default Change

When publishing, retain now defaults to false, which is a much more sensible default.

Contributed by Martin Trojer.

Change Log

Machine Head change log is available on GitHub.

Machine Head is a ClojureWerkz Project

Machine Head is part of the group of Clojure libraries known as ClojureWerkz, together with

  • Langohr, a Clojure client for RabbitMQ that embraces the AMQP 0.9.1 model
  • Elastisch, a minimalistic Clojure client for ElasticSearch
  • Monger, a Clojure MongoDB client for a more civilized age
  • Cassaforte, a Cassandra client built around CQL 3
  • Neocons, a feature rich Clojure client for Neo4J REST API

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

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

About the Author

Michael on behalf of the ClojureWerkz Team