[almighty] Cache solution for Almighty core

[Alexey Kazakov]

Hi all,

At some point we will probably need some universal cache solution which 
we could use different types of objects in almighty core. I'm going to 
spend some time on researching in this area but there are a few 
questions I would like to discuss with the team.
There are some solutions like Memcached or Redis which could be used but 
they require to have a server with the cache service (on a dedicated 
container?) where we could keep WIT, WI and any other artefacts which we 
want to access some value by a key. Some solutions like Memcached are 
pure in-memory some like Redis can be persistent but my biggest concern 
for now is what approaches are best for microservices world.
In monolith world we could have a shared cache server. One DB - one 
cache service. But I'm not sure if it's worth having an internal 
dedicated cache server for each relevant microserver.
Currently we are kinda building a monolith and a cache server could 
work. But how our cache system should evolve when we start 
splitting/introducing microservices in almighty-core? Is there any 
concept of shared cache between microservices or it's always hidden by 
the microservice implementation and the microservice just takes care of 
synchronization of its internal model/DB and uses some internal fully 
independent cache if needed.

Any thoughts?