How to setup LRU Cache

I want to setup an LRU Cache that persists data across requests. I guess set_shared_data/get_shared_data can be used for normal cache, but how to use an LRU cache? 
Also, have a couple of queries regarding storing key-value pairs using set_shared_data:
- Is there any TTL for the data?
- How to manage size of the data since there is no function to delete the values once set?