[BUG] There seems to be an atomicity issue while rising domain events in Ordering.Api

In the Ordering service we have a ValidateOrAddBuyerAggregateWhenOrderStartedDomainEventHandler which handles the OrderStartedDomainEvent, after the Buyer is added or updated a call to SaveEntitiesAsync is made to dispatch the domain events and save the changes to the database, after that, a call to PublishThroughEventBusAsync is made. So, if the changes was already saved by calling the SaveEntitiesAsync method no atomicity will be in place or am I missing something? There is even a bigger problem if a chain of domain events are raised because only the last call to PublishThroughEventBusAsync will have atomicity between the current handled aggregate and the event.

[mvelosop]

Hi @arielmoraes,

This was the chosen solution was, at high level:

1. Begin a transaction in the TransactionBehaviour: https://github.com/dotnet-architecture/eShopOnContainers/blob/e05a87658128106fef4e628ccb830bc89325d9da/src/Services/Ordering/Ordering.API/Application/Behaviors/TransactionBehaviour.cs#L40

2. While processing the related commands, add the resulting integration events to a list (an outbox): https://github.com/dotnet-architecture/eShopOnContainers/blob/e05a87658128106fef4e628ccb830bc89325d9da/src/Services/Ordering/Ordering.API/Application/Commands/CreateOrderCommandHandler.cs#L38 There’s a nice detail here, and it’s that the outbox is persisted in the DB, so it’d be easy to implement a “watchdog” microservice that would handle possible failures in the publishing mechanism. This is not implemented in eShopOnContainers.

3. Commit the transaction for all changes when returning from the behavior pipeline: https://github.com/dotnet-architecture/eShopOnContainers/blob/e05a87658128106fef4e628ccb830bc89325d9da/src/Services/Ordering/Ordering.API/Application/Behaviors/TransactionBehaviour.cs#L44

4. Publish all integration events in the outbox: https://github.com/dotnet-architecture/eShopOnContainers/blob/e05a87658128106fef4e628ccb830bc89325d9da/src/Services/Ordering/Ordering.API/Application/Behaviors/TransactionBehaviour.cs#L48

This strategy also handles the atomicity of all changes mentioned in issue https://github.com/dotnet-architecture/eShopOnContainers/issues/721

So I’m closing this issue now, but feel free to comment, will reopen if needed.

[mvelosop]

This issue wasn’t supposed to be closed, wonder who did it 🙄