redis_failover.rake

namespace :redis_failover do
  task :monitor_client do
    require 'redis_failover'

    zookeepers = ENV['ZOOKEEPERS']

    if !zookeepers && zookeepers_file = ENV['ZOOKEEPERS_FILE']
      if File.exists?(zookeepers_file)
        zookeepers = File.read(zookeepers_file).chomp
      end
    end

    zookeepers ||= '127.0.0.1:2181'

    unless redis_master_file = ENV['REDIS_MASTER_FILE']
      abort "No REDIS_MASTER_FILE= provided"
    end

    callback = proc do |master, slaves|
      puts "master: #{master.inspect} slaves: #{slaves.inspect}"
      if master && (!File.exists?(redis_master_file) || File.read(redis_master_file) != master)
        File.open(redis_master_file, 'w') do |io|
          io << master
        end
      elsif !master && File.exists?(redis_master_file)
        File.unlink(redis_master_file)
      end
    end

    RedisFailover::Client.new(:zkservers => zookeepers, :safe_mode => false, :master_only => true) do |client|
      client.on_node_change(&callback)
    end

    while true
      sleep 1
    end
  end
end