$ STANDALONE=false ruby test.rb
connecting to replicaset
/Users/joleary/.rvm/gems/ruby-2.0.0-p643@CS-22855/gems/mongo-2.0.6/lib/mongo/collection/view/iterable.rb:38:in `each': undefined method `select_server' for {:mode=>:secondary}:Hash (NoMethodError)
	from test.rb:13:in `first'
	from test.rb:13:in `<main>'

$ ruby test.rb
connecting to standalone
/Users/joleary/.rvm/gems/ruby-2.0.0-p643@CS-22855/gems/mongo-2.0.6/lib/mongo/collection/view/iterable.rb:38:in `each': undefined method `select_server' for {:mode=>:secondary}:Hash (NoMethodError)
	from test.rb:13:in `first'
	from test.rb:13:in `<main>'

require 'mongo'
Mongo::Logger.logger.level = Logger::INFO
def standalone?
  (ENV.has_key?('STANDALONE') && ENV['STANDALONE'] == 'true') || !ENV.has_key?('STANDALONE')
end

puts "connecting to #{standalone? ? 'standalone' : 'replicaset'}"

config = standalone? ?  {:hosts => ['127.0.0.1:27017'],:options => {:database => 'cookie-store'}} : config = {:hosts => ['127.0.0.1:37017','127.0.0.1:37018','127.0.0.1:37019'],:options => {:database => 'cookie-store', :replica_set => 'replset'}}
c = Mongo::Client.new(config[:hosts], config[:options])
# c[:cookie_jar].find.read(:mode=>:primary).first

puts c[:cookie_jar].find.read(:mode=>:primary).first