Using moto DynamoDB for production in-memory caching

[kflathers-chwy]

I would have posted this as a discussion if it were available, so apologies upfront if this is not the right space to ask my question.

I am trying to implement an in-memory caching solution that operates very similarly to DynamoDB. I have a DynamoDB global table that I need to protect with a caching solution, and because of various reason, DAX is not an option.

My thoughts were to use moto's DynamoDB module to effectively act as this in-memory cache, similar to how you can do the same with sqlite. Is this a really bad idea? Moto appears to have all the bells and whistles I need, and it works amazing for our unit tests. Just wanted some feedback if this was a red flag usage of moto, or it sounds ok.

[bblommers]

I would have posted this as a discussion if it were available, so apologies upfront if this is not the right space to ask my question.

We have discussions now! Been meaning to enable it for this repo for ages, so this was a good reason to finally get it done.

My thoughts were to use moto's DynamoDB module to effectively act as this in-memory cache,

I would have two concerns with that approach: responsibility and performance.

Responsibility: because you're essentially outsourcing the responsibility for a core component.
Moto may work perfectly today, but it may break things tomorrow/in a next release. Obviously we try to not do that, but if it happens, and you're using Moto in production, you would have to be 110% certain that your own tests will catch any problems/change in behaviour.

Performance: because Moto is not made with performance in mind. It works for unit tests, but the volume/requests-per-second in production are presumably much higher.

I understand that the DynamoDB parsing logic can be valuable though. If you extract that into it's own module/repo/project, with a separate release-cycle from Moto, then I don't see a problem with it. It gives you full control over the component, both in terms of new changes and in terms of any performance improvements that are required.