[almighty] Cache solution for Almighty core

[Alexey Kazakov]

On 11/08/2016 12:41 AM, Thomas Mäder wrote:
> Hi Alexey,
>
> If you're talking about a "cache server" are you talking about a 
> separate process, possibly on a different machine or an in-process 
> service like groupcache?
"Cache server" in this context means a separate process which makes 
sense to keep on a different machine/container. For example Memcashed 
uses TCP to communicate with clients.

Thanks.

>
> How I understand microservices, they DON'T have a shared DB behind 
> them. They have a relatively simple datamodel that is loosely coupled 
> to the other microservices via a well defined API (no peeking at the 
> internals!). Multiple instances of the same service may share a common 
> DB, but not different microservices. As a consequence of this, it 
> doesn't make sense for multiple different services to share the same 
> cache in my opinion. Instead of asking any shared cache service, you 
> might as well ask the original service and let that one take care of 
> caching.
>
> /Thomas
>
> On 11/08/2016 01:15 AM, Alexey Kazakov wrote:
>> 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?
>>
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>