instance method get_server_for_key

# File activesupport/lib/active_support/vendor/memcache-client-1.5.1/memcache.rb, line 540
  def get_server_for_key(key)
    raise ArgumentError, "illegal character in key #{key.inspect}" if
      key =~ /\s/
    raise ArgumentError, "key too long #{key.inspect}" if key.length > 250
    raise MemCacheError, "No servers available" if @servers.empty?
    return @servers.first if @servers.length == 1

    hkey = hash_for key

    20.times do |try|
      server = @buckets[hkey % @buckets.nitems]
      return server if server.alive?
      hkey += hash_for "#{try}#{key}"
    end

    raise MemCacheError, "No servers available"
  end