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zookeeper

An interface to the Zookeeper distributed configuration server.

== License

Copyright 2008 Phillip Pearson, and 2010 Twitter, Inc. Licensed under the MIT License. See the included LICENSE file. Portions copyright 2008-2010 the Apache Software Foundation, licensed under the Apache 2 license, and used with permission.

== Install

sudo gem install zookeeper

== Usage

Connect to a server:

  require 'rubygems'
  require 'zookeeper'
  z = Zookeeper.new("localhost:2181")

Create, set and read nodes:

  z.create("/bacon", "text to be stored in the new node", 0)
  data, stat = z.get("/bacon")
    # => ["text to be stored in the new node"...]
  
  z.set("/bacon", "an entirely different line of text", stat.version)
  z.set("/bacon", "this won't work", stat.version)
    # CZookeeper::BadVersionError: expected version does not match actual version

  data, stat = z.get("/bacon")
    # => ["an entirely different line of text"...]
  z.delete("/bacon", stat.version)

Create ephemeral and sequence nodes:

  z.create("/parent", "parent node", 0)

  z.create("/parent/test-", 
    "an ordered ephemeral node", 
    Zookeeper::EPHEMERAL | Zookeeper::SEQUENCE)
    # => "/parent/test-0"

  z.create("/parent/test-", 
    "an ordered ephemeral node", 
    Zookeeper::EPHEMERAL | Zookeeper::SEQUENCE)
    # => "/parent/test-1"

Acquire locks:

  z.try_acquire "/parent/lock-", "content for the lock file" do |have_lock|
    puts have_lock ? "we have the lock" : "we don't have the lock"
  end