From my knowledge open cloud cannot access the memorystore
But some options you have are
-
you could use the messaging service with open cloud then make the server check if the session is open or closed and make any changes it needs the main problem with this option is making sure not all running server reacts but only 1 server reacts
-
another option is before you open the session save a value into a separate datastore and after the session closes remove that value from the second datastore then check the second datastore with open cloud the problems with this method are that in the small delay between checking the second datastore and updating the main datastore the state might have changed another problem with this method is that if the server crashes or the datastore goes down the players state might not get updated untill they enter your game again this problem could be fixed with a timeout
-
another option is for open cloud to add a list of actions into a separate datastore using updateasync then when the player logs into the game you updateasync the second datastore do the list of actions and empty out the data
Option 3 is my favourite
There use to be APIs like
https://api.roblox.com/users/(userID)/onlinestatus/
To check if a player is online but not sure if there still working