# File actionpack/lib/action_controller/session/mem_cache_store.rb, line 7
 7:         def initialize(app, options = {})
 8:           # Support old :expires option
 9:           options[:expire_after] ||= options[:expires]
10: 
11:           super
12: 
13:           @default_options = {
14:             :namespace => 'rack:session',
15:             :memcache_server => 'localhost:11211'
16:           }.merge(@default_options)
17: 
18:           @pool = options[:cache] || MemCache.new(@default_options[:memcache_server], @default_options)
19:           unless @pool.servers.any? { |s| s.alive? }
20:             raise "#{self} unable to find server during initialization."
21:           end
22:           @mutex = Mutex.new
23: 
24:           super
25:         end