Redis sorted sets with timestamps for scores

foo.rb

require 'redis'
require 'active_support/time'

redis = Redis.new

# members are added with a score that is a timestamp of when they should expire
redis.zadd('test-sset', 10.minutes.from_now.to_i, 'app1')
# let's add one in the past so we can test some more
redis.zadd('test-sset', 10.minutes.ago.to_i, 'app2')

puts 'all apps'
puts redis.zrange('test-sset', 0, -1) # app1, app2

puts 'active apps'
puts redis.zrangebyscore('test-sset', Time.now.utc.to_i, '+inf') #app1

puts 'expiring old apps'
puts redis.zremrangebyscore('test-sset', '-inf', Time.now.utc.to_i) # returns # of expired elements

puts 'all remaining apps'
puts redis.zrange('test-sset', 0, -1) # app1