Best practices on managing event schemas?

[elsurudo]

Being a relational guy at heart, I'm a bit uneasy about the fact that data and metadata are basically JSON blobs by default.

I wasn't able to find any best practices in the docs around managing/validating that event schemas are actually valid. Is this a problem I should worry about? Any tips?

Also, what about event versioning? If my schema changes, aren't I going to run into trouble eventually when reading older events?

[pjurewicz]

Hello @elsurudo, nice to meet you!

There are many ways to implement events schema validation. It's out of scope of Rails Event Store itself.
However, an example of dry-types based event schema is presented in the ecommerce, our demo app
Another one implementation, usingclassy_hash, has been described in Domain-Driven Rails book.

When it comes to versioning and schema changes, please check out these 2 blogposts:
https://blog.arkency.com/4-strategies-when-you-need-to-change-a-published-event/
https://blog.arkency.com/upcasting-events-in-railseventstore/
I believe they cover this topic in details.

[elsurudo]

Hi @pjurewicz, nice to meet you too and thanks for the answer :)

In the meantime I've found the exact file in the ecommerce sample and used that as an example, since I was thinking of Dry::Struct myself for this.

And thanks for the tips about event changes. I've heard of upcasting and while it makes sense in theory, I can't help but imagine an app accumulating a bunch of cruft over time due to this. But perhaps this is a growing pain I need to get over to get more used to this paradigm?