memodis

semi-transparent memoization; backed by redis;

writes are sent to the master, reads are sent to an approriate slave.

Two features:

  1. Memodis#memoize
  2. Memodis::DistCache

Example

def fib(num)
return num if num < 2
fib(num - 1) + fib(num - 2)
end

puts "Before memoize: "
puts fib(33) => 3524578 # after ~ 7 seconds

extend Memodis
memoize :fib, Memodis::DistCache.new({
:key_gen => lambda { |k| "fib(#{k})" },
:decoder => :integer,
:expires => (10 * 60),
:master  => '127.0.0.1:16379 127.0.0.1:16380'.split,
:slaves  => '127.0.0.1:16389 127.0.0.1:16390 
             127.0.0.1:16391 127.0.0.1:16392
             127.0.0.1:16393 127.0.0.1:16394'.split
})

puts "After memoize: "
puts fib(33) => 3524578 # after ~ 0.03   seconds
puts fib(33) => 3524578 # after ~ 0.0001 seconds
puts fib(33) => 3524578 # after ~ 0.0001 seconds

Background

  1. http://blog.grayproductions.net/articles/caching_and_memoization
  2. http://code.google.com/p/redis & http://github.com/ezmobius/redis-rb

Important Moving Parts

  1. http://code.google.com/p/redis/wiki/GetCommand
  2. http://code.google.com/p/redis/wiki/SetCommand
  3. http://code.google.com/p/redis/wiki/SetnxCommand

Note on Patches/Pull Requests

  • Fork the project.
  • Make your feature addition or bug fix.
  • Add tests for it. This is important so I don't break it in a future version unintentionally.
  • Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)
  • Send me a pull request. Bonus points for topic branches.

Copyright (c) 2010 [email protected]. See LICENSE for details.