memcache_lock.rb

require 'memcache'

CACHE = Memcache.new(:servers => [ 'localhost:11211' ], :namespace => 'test')

def lock(name, secs=60, &block)
	return !! CACHE.add("lock:#{name}", '1', secs)
end

def unlock(name)
	CACHE.delete("lock:#{name}")
end

if lock('tryit', 5)
	puts 'running...'
	loop do
		puts '.'
		sleep 1
		lock('tryit', 5)
	end
else
	puts "couldn't get lock"
end