Class: ZeevexCluster::Election

Inherits:
Base
  • Object
show all
Defined in:
lib/zeevex_cluster/election.rb

Instance Attribute Summary

Attributes inherited from Base

#nodename, #options

Instance Method Summary collapse

Methods inherited from Base

#ensure_master, #run_if_master

Methods included from Util::Logging

#logger

Constructor Details

#initialize(options = {}) ⇒ Election

Returns a new instance of Election.

Raises:

  • (ArgumentError) 


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# File 'lib/zeevex_cluster/election.rb', line 7

def initialize(options = {})
  super
  raise ArgumentError, 'Must specify :cluster_name' unless options[:cluster_name]

  if options[:hooks]
    add_hooks(options[:hooks])
  end

  unless (@strategy = options[:strategy])
    stype = options[:strategy_type] || 'cas'
    @strategy = ZeevexCluster::Strategy.create(stype,
                                               {:nodename         => options.fetch(:nodename, Socket.gethostname),
                                                :cluster_name     => options[:cluster_name],
                                                :logger           => options[:logger]}.
                                                   merge(options[:backend_options]))
  end
  @strategy.add_hook_observer Proc.new { |*args| hook_observer(*args) }

  after_initialize
end

Instance Method Details

#campaign! ⇒ Object 



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# File 'lib/zeevex_cluster/election.rb', line 57

def campaign!
  @strategy.start unless @strategy.started?
  # stop sitting out the election
  @strategy.resign 0
end

#can_view? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/zeevex_cluster/election.rb', line 92

def can_view?
  member? || observing? || @strategy.respond_to?(:can_view?) ? @strategy.can_view? : false
end

#join ⇒ Object 



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# File 'lib/zeevex_cluster/election.rb', line 70

def join
  return if member?
  @member = true
  @strategy.start unless @strategy.started?
end

#leave ⇒ Object 



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# File 'lib/zeevex_cluster/election.rb', line 76

def leave
  return unless member?
  resign! if master?
  @strategy.stop if @strategy.started?
ensure
  @member = false
end

#make_master! ⇒ Object

Make this node the master, returning true if successful. No-op for now.



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# File 'lib/zeevex_cluster/election.rb', line 39

def make_master!
  return unless member?
  if @strategy.steal_election!
    true
  else
    false
  end
end

#master ⇒ Object

Return name of master node



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# File 'lib/zeevex_cluster/election.rb', line 66

def master
  can_view? && @strategy.master_node && @strategy.master_node[:nodename]
end

#master? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/zeevex_cluster/election.rb', line 32

def master?
  member? && @strategy.am_i_master?
end

#member? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/zeevex_cluster/election.rb', line 84

def member?
  @strategy.member?
end

#members ⇒ Object 



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# File 'lib/zeevex_cluster/election.rb', line 88

def members
  can_view? && (@strategy.respond_to?(:members) ? @strategy.members : [@nodename])
end

#observe ⇒ Object 



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# File 'lib/zeevex_cluster/election.rb', line 101

def observe
  @strategy.observe
  {:master => master, :members => members}
end

#observing? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/zeevex_cluster/election.rb', line 96

def observing?
  # TODO: make this smarter
  @strategy.respond_to?(:observing?) ? @strategy.observing? : true
end

#resign!(delay = nil) ⇒ Object

Resign from mastership; returns false if this is the only node.

No-op for now.



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# File 'lib/zeevex_cluster/election.rb', line 53

def resign!(delay = nil)
  @strategy.resign delay
end

#strategy ⇒ Object 



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# File 'lib/zeevex_cluster/election.rb', line 28

def strategy
  @strategy
end