Semi-Technical events

[Boas Enkler]

Hi

When looking at a booking process. it can be important to react if the ip ofthe user changed. For example the support should see this and some kind of security reviews should be started. 

So i would raise an "IpChangedEvent" on the Booking / Cart Aggregate. But this event seems to be semi technical and I feel unsure wether they should be domain events and also wether the should be handled with eventsourcing.

As i understand eventsourcing and cqrs the events should be business events. Concerning this event  on the one side isn't a visible enduser feature, stakeholders wouldn't talk about this by themself , but on the other side it can be become very important to know that there were possibly two different ips involved.

There are more events similar to this one, they somethimes they include a business action, but sometimes the only result is that the support should be able find out it happened.

So would you consider this kind of events business event and would you declare it as a domain event and there for send it to the aggregates feed?

[@yreynhout]

Is IPChangedEvent of any particular interest to an invariant of the Booking / Cart aggregate? If not, maybe a separate stream? CartIPAddressStream? You can always do the correlation of the cart and cartipaddress stream later on assuming the registered clock times align.