Kinsky: Clojure Kafka client library

Kinsky is a somewhat opinionated client library for Apache Kafka in Clojure.

Kinsky provides the following:

• Kakfa 0.10.0.x compatibility
• Adequate data representation of Kafka types.
• Default serializer and deserializer implementations such as JSON, EDN and a keyword serializer for keys.
• A core.async facade for producers and consumers.
• Documentation

Usage

   [[spootnik/kinsky "0.1.22"]]

Documentation

• API Documentation

Changelog

0.1.23

• Fixed ConcurrentModificationException when async consumer created with topic

0.1.22

• Update to latest Kafka clients
• Typo fix

0.1.21

• Update to latest Kafka clients
• Provide duplex channels to bridge control and record channels in consumers

0.1.16

• Stability and bugfix release
• Lots of input from @jmgrov, @scott-abernethy, and @henriklundahl. Thanks!

Examples

The examples assume the following require forms:

(:require [kinsky.client      :as client]
          [kinsky.async       :as async]
          [clojure.core.async :as a :refer [go <! >!]])

Production

(let [p (client/producer {:bootstrap.servers "localhost:9092"}
                         (client/keyword-serializer)
                         (client/edn-serializer))]
  (client/send! p "account" :account-a {:action :login}))

Async facade:

(let [ch (async/producer {:bootstrap.servers "localhost:9092"} :keyword :edn)]
   (go
     (>! ch {:topic "account" :key :account-a :value {:action :login}})
     (>! ch {:topic "account" :key :account-a :value {:action :logout}})))

Consumption

(let [c (client/consumer {:bootstrap.servers "localhost:9092"
                          :group.id          "mygroup"}
                         (client/keyword-deserializer)
                         (client/edn-deserializer))]
  (client/subscribe! c "account")
  (client/poll! c 100))

Async facade:

(let [ch     (async/consumer {:bootstrap.servers "localhost:9092"
                              :group.id (str (java.util.UUID/randomUUID))}
                             (client/string-deserializer)
                             (client/string-deserializer))
      topic  "tests"]
						  
  (a/go-loop []
    (when-let [record (a/<! ch)]
      (println (pr-str record))
      (recur)))
  (a/put! ch {:op :partitions-for :topic topic})
  (a/put! ch {:op :subscribe :topic topic})
  (a/put! ch {:op :commit})
  (a/put! ch {:op :pause :topic-partitions [{:topic topic :partition 0}
                                             {:topic topic :partition 1}
                                             {:topic topic :partition 2}
                                             {:topic topic :partition 3}]})
  (a/put! ch {:op :resume :topic-partitions [{:topic topic :partition 0}
                                              {:topic topic :partition 1}
                                              {:topic topic :partition 2}
                                              {:topic topic :partition 3}]})
  (a/put! ch {:op :stop}))

Examples

Fusing two topics

  (let [popts {:bootstrap.servers "localhost:9092"}
        copts (assoc popts :group.id "consumer-group-id")
        c-ch  (kinsky.async/consumer copts :string :string)
        p-ch  (kinsky.async/producer popts :string :string)]

    (a/go
      ;; fuse topics
	  (a/>! c-ch {:op :subscribe :topic "test1"})
      (let [transit (a/chan 10 (map #(assoc % :topic "test2")))]
        (a/pipe c-ch transit)
        (a/pipe transit p-ch))))