redis-repl-test.rb

#!/usr/bin/ruby

require 'rubygems'
require 'redis'

REDIS_CMD = "./redis-server"
DIR = "redis-repl-test"
FileUtils.mkdir(DIR) unless File.directory?(DIR)

class Redis
  def slaveof(*args)
    @client.call(:slaveof, *args)
  end
end


class Node
  def initialize(name, port)
    @name = name
    @port = port
  end
  def to_s
    "node #{@name}"
  end
  def client
    Redis.new(:host => "localhost", :port => @port)
  end
  def filename(ext)
    "#{@name.to_s}.#{ext}"
  end
  attr_accessor :port
  def clean_start
    FileUtils.rm(Dir.glob("#{DIR}/#{filename('*')}"))
    start
  end
  def start
    puts "Starting #{self}"
    File.open("#{DIR}/#{filename('conf')}", "w") do |out|
      out.puts "daemonize yes"
      out.puts "pidfile #{filename('pid')}"
      out.puts "port #{@port}"
      out.puts "logfile #{DIR}/#{filename('log')}"
      out.puts "dir #{DIR}/"
      out.puts "dbfilename #{filename('rdb')}"
    end
    system "#{REDIS_CMD} #{DIR}/#{filename('conf')}"
  end

  def stop(sig="TERM")
    File.open("#{DIR}/#{filename("pid")}") do |input|
      input.each do |line|
        puts "Sending sig #{sig} to #{self} (#{line.to_i})"
        Process.kill(sig, line.to_i)
      end
    end
  end

  def follow(master)
    puts "#{self} slaveof #{master}"
    client.slaveof "localhost", master.port
  end
  def unfollow
    puts "#{self} slaveof no one"
    client.slaveof "no", "one"
  end
end

def set(node, key, value)
  result = node.client.set key, value
  puts "Storing '#{key}' => '#{value}' on #{node}"
end

def get(node, key)
  result = node.client.get key
  puts "Get '#{key}' from #{node}: '#{result}'"
end

def failure1
  a = Node.new(:a, 6380)
  b = Node.new(:b, 6381)
  c = Node.new(:c, 6382)
  nodes = [a, b, c]
  nodes.each { |node| node.clean_start }
  sleep 1
  b.follow a
  c.follow b
  sleep 1
  b.stop "KILL"
  set a, "test1", "this will get lost"
  b.start
  sleep 1
  b.follow a
  set a, "test2", "this will get replicated"
  sleep 5
  get b, "test1"
  get c, "test2"
  get c, "test1"
  nodes.each { |node| node.stop }
end

failure1