CQRS - Eventual Consistency

Question

Hi,

I have the following scenario which I need to implement following the CQRS pattern:

1. a user logs in
2. the user enters some insurance details
3. the user ask for a decision to be applied
4. the user views the result of the decision

this seems fairly straightforward, however my problem is between step 3 and 4, on step 3 I send a ApplyForDecision command which will get a decision from a underwriting service, an event with the result of that decision is then sent to the BUS for the read store to later consume it and update the view tables with the decision result.

The problem is on the UI, how do I let the user know that the decision is being applied, since in CQRS the read model is not updated 'straightaway' how do I make the UI show that a decision is in progress and will 'soon' arrive?

I also need to give the user the ability to log out and log back in, since the decision may not have been applied yet, how do I make the UI show the 'pending decision screen'?

Thanks

Answer 1

IMHO the solution would be to let your command emit an "ApplyForDecisionRequested" and an "ApplyForDecisionHandled" event, and update your read model accordingly.