Fog-core cache expire policy example.

cache-policies.md

1. Record cache set/fetch time.

Fog::Cache.write_metadata({:last_refreshed => Time.now})

2. Create some custom expirey method

      EXPIRE_TIME = (60 * 60 * 24) # day old cache.
      
      def renew?
        last_refreshed = Fog::Cache.metadata[:last_refreshed]

        if last_refreshed.nil?
          # no metadata, cache is old
          return true
        end

        if (Time.now - last_refreshed) > EXPIRE_TIME
          return true
        else
          return false
        end
      end