README.md

etcd-clojure


A Clojure library to interact with an etcd server.

Why etcd and not Zookeeper? Well Zookeeper is a bloated terrifying piece of software while etcd is tiny, fast, efficient.

Why this project at all? Googling for etcd & clojure returned zero results. Now there are a bunch of alternatives, pick up your favourite from etcd clients matrix.

Usage

This library now supports V2 of the etcd API.

The default server endpoint is http://127.0.0.1 running on port 4001, however you can 'connect' to any server by using the connect! function:

(connect! "196.0.0.1")

(connect! "196.0.0.1" 4001)

(connect! "196.0.0.1" 4001 7001)

Getting the etcd version

(version)

Key Space Operations

Setting the value of a key, with optional time to live

(set "key" "value")

(set "key" "value" :ttl 5)

Get the value of a key

(get "key")

Waiting for a change

(defn callback[arg] (println (str "Key change: " arg)))

(get "key" :wait true :callback callback)

Changing the value of a key

(set "key" "someothervalue")

Deleting a key

(delete "key")

Where callback can be for example:

(defn callback[arg] (println arg))

Atomically Creating In-Order Keys

(create-in-order "key"

Atomic Compare-and-Swap

This reflects the example on the etcd api page

(set "foo" "one")
(set "foo" "three" :prev-exist false)
(set "foo" "two" :prev-value "one")

Atomic Compare-and-Delete

This reflects the example on the etcd api page

(set "foo" "one")
(delete "foo" :prev-value "two")
(delete "foo" :prev-index 1)

Listing a directory

(list "/directory")

Listing a directory in order

(list-in-order "/directory")

Creating a directory

(create-dir "/directory")

Deleting a directory

(delete-dir "/directory")

Deleting a value:

(delete "key")

Leader Stats

(stats)

Self Stats

(self-stats)

Store Stats

(store-stats)

List machines in the cluster

(members)

TODO

• connect to cluster
• failover and recovery
• SSL (looks tricky - might need to change clj-http)

License

Apache 2.0