Class: Hiera::Backend::Zookeeper_backend

Inherits:
Object
  • Object
show all
Defined in:
lib/hiera/backend/zookeeper_backend.rb

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Zookeeper_backend

ZooKeeper backend for Hiera. Recognizes :server and :datadir config options. If no :server is specified, uses localhost:2181. The node data is expected to be in YAML or JSON (YAML is the default).



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# File 'lib/hiera/backend/zookeeper_backend.rb', line 7

def initialize
  require 'rubygems'
  require 'zookeeper'
  # Set default values
  Config[:zookeeper] = Hash.new() if Config[:zookeeper].nil?
  Config[:zookeeper][:timeout] = 1 if Config[:zookeeper][:timeout].nil?
  Config[:zookeeper][:datadir] = '/hiera' if Config[:zookeeper][:datadir].nil? 
  Config[:zookeeper][:format] = 'yaml' if Config[:zookeeper][:format].nil?
  Config[:zookeeper][:format].downcase!
  if Config[:zookeeper][:server].nil? then
    Config[:zookeeper][:servers] = ['localhost:2181'] if Config[:zookeeper][:servers].nil?
  else
    Hiera.warn("The :server option is deprecated.  Use :servers.  Option :server will go away very soon.") 
    Config[:zookeeper][:servers] = Config[:zookeeper][:server]
  end

  case Config[:zookeeper][:format]
  when 'json'
    require 'json'
  else
    require 'yaml'
  end

  Hiera.debug("Hiera ZooKeeper backend starting")
end

Instance Method Details

#lookup(key, scope, order_override, resolution_type) ⇒ Object 



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# File 'lib/hiera/backend/zookeeper_backend.rb', line 33

def lookup(key, scope, order_override, resolution_type)
  answer = nil
  Hiera.debug("Looking up #{key} in ZooKeeper backend")
  # Establish server(s) to check
  servers = []
  Config[:zookeeper][:servers].shuffle!
  Config[:zookeeper][:servers].each do |s|
    servers.push(Backend.parse_string(s, scope))
  end
  # Establish connection
  zk = nil
  servers.each do |s|
    begin 
      zk = Zookeeper.new(s, Config[:zookeeper][:timeout])
      break if zk.connected?
    rescue => e
      Hiera.debug(e.message)
      next
    end
  end
  # If it did not work, raise that exception!
  if zk.nil? or not zk.connected? then
    raise(ZookeeperExceptions::ZookeeperException, "Could not connect to any zookeeper server in configuration")
  end

  Backend.datasources(scope, order_override) do |source|
    Hiera.debug("Looking for data source #{source}")
    # Determine the zookeeper path to get data from
    datadir = "#{Backend.parse_string(Config[:zookeeper][:datadir], scope)}/#{source}"
    data = zk.get(:path => "#{datadir}/#{key}")
    if data[:stat].exists then
      Hiera.debug("Found #{key} in #{source}")
      case Config[:zookeeper][:format]
      when 'json'
        new_answer = Backend.resolve_answer(JSON.load(data[:data]), resolution_type)
      else
        new_answer = Backend.resolve_answer(YAML.load(data[:data]), resolution_type)
      end
      case resolution_type
      when :array
        raise(Exception, "Hiera type mismatch: expected Array and got #{new_answer.class}") unless new_answer.kind_of?(Array) or new_answer.kind_of?(String)
        answer ||= []
        answer << new_answer
      when :hash
        raise(Exception, "Hiera type mismatch: expected Hash and got #{new_answer.class}") unless new_answer.kind_of?(Hash)
        answer ||= {}
        answer = new_answer.merge(answer)
      else
        answer = new_answer
        break
      end
    end
  end
  zk.close if not zk.nil? and zk.connected?
  return answer
end