Is there any recommended way how can we configure projection handlers to generate the read models for the event sourced grains? about orleans

[smfields]

Another option to consider is using a mechanism built-in to your storage provider. For instance, if you store your events in EventStoreDB then it can create the projections for you.

I didn't look closely at the sample you linked, but you have to be careful about persisting state and publishing events in separate actions. When you do that, there's a chance, however small, that something happens between when you save to the database and when you publish the event that causes the event to never get published.

Event sourcing can sidestep this issue by making the persistence of the state and the publishing of the event a single atomic action, but only when you use a supported event store.

[smfields]

@AlexandrIalticenco you're also welcome to look into Orleans.EventSourcing.EventStorage. It's a library I'm working on to add support for using an external event store with Orleans event sourcing.

The package I linked is for the base library that you could build your own storage on top of, but I've already got other packages made for common event stores like:

• EventStoreDB
• MartenDB

It's still a bit of a work in progress, but it does have nuget packages published if you want to start using it, or you can use it as inspiration for your own solution.

[AlexandrIalticenco]

Actually I found the answer on my question here https://github.com/pmorelli92/Orleans.Tournament?tab=readme-ov-file#cqrs-projections-event-sourcing-and-eventual-consistency.

There is a really nice diagram describing the whole flow I need (copying from there if it can be useful for anyone).

[AlexandrIalticenco]

@smfields thank you for your response. Yes, the sample I linked has exactly the problem you are talking about "You have to be careful about persisting state and publishing events in separate actions."

We are considering now to apply the solution you described by using custom log consistency storage provider.