clj-kafka

Clojure library for Kafka.

Current build status:

Development is against the unreleased 0.8 branch of Kafka. The protocols for 0.7 and 0.8 are incompatible so this will only work when connecting to a 0.8 cluster.

Installing

Given 0.8 is still unreleased we're pushing SNAPSHOT releases.

Add the following to your Leiningen project.clj:

[clj-kafka "0.1.0-0.8-SNAPSHOT"]

Usage

Producer

Discovery of Kafka brokers from Zookeeper:

(brokers {"zookeeper.connect" "127.0.0.1:2181"}))
;; ({:host "localhost", :jmx_port -1, :port 9999, :version 1})

(use 'clj-kafka.producer)

(def p (producer {"metadata.broker.list" "localhost:9999"
                  "serializer.class" "kafka.serializer.DefaultEncoder"
                  "partitioner.class" "kafka.producer.DefaultPartitioner"}))

(send-message p (keyed-message "test" (.getBytes "this is my message")))

Zookeeper Consumer

The Zookeeper consumer uses broker information contained within Zookeeper to consume messages. This consumer also allows the client to automatically commit consumed offsets so they're not retrieved again.

(use 'clj-kafka.consumer.zk)
(use 'clj-kafka.core)

(def config {"zookeeper.connect" "localhost:2182"
             "group.id" "clj-kafka.consumer"
             "auto.offset.reset" "smallest"
             "auto.commit.enable" "false"})

(with-resource [c (consumer config)]
  shutdown
  (take 2 (messages c ["test"])))

It's also now possible to consume messages from multiple topics at the same time. These are aggregated and returned as a single sequence:

(take 5 (messages c ["test1" "test2"]))

License

Copyright © 2013 Paul Ingles

Distributed under the Eclipse Public License, the same as Clojure.