Journal - Comments

Rinat Abdullin comments on Scalable and Simple CQRS Views in the Cloud

Rinat Abdullin — Wed, 30 May 2012 22:02:07 +0000

Erick, I'm technically implementing a sequence number for the bounded context (all events go through the event store that records them and publishes further afterwards).

So there is an absolute order between events coming from a single aggregate and somewhat relaxed ordering between events from different aggregates (based on the order events arrive to the store). However, since I design my aggregates to be focused and decoupled, this lack of absolutely strict ordering between events from different aggregates - has almost no effect.

Erick comments on Scalable and Simple CQRS Views in the Cloud

Erick — Wed, 30 May 2012 21:06:33 +0000

Rinat,

I've read your posts (CQRS/DDD Group) about views being orthogonal to aggregates and was wondering how you deal with the ordering of events coming to your view handlers.

Right now, I'm sequencing events by aggregate id so my views are tightly bound to the aggregate, but would really like to have the views exist outside of my bound contexts.

I can not easily implement a shared counter (I'm on Google App Engine), so I just lock on the aggregate id and increment the version.

Thanks

Michael L Perry comments on DDD/CQRS Challenge - Integrating Distributed Systems

Michael L Perry — Wed, 23 May 2012 17:33:32 +0000

It's clear that the Cloud Services Integration system subscribes to events from the Subscription system. Since the Subscription architecture is based on Event Sourcing, it should be pretty straight-forward for it to publish those events. Azure service bus seems like a likely candidate for the transport, but other options are available.

The real challenge seems to be the circular dependency of Product 1. The subscription service needs access to its catalog of services so that it can manage subscriptions. But Product 1 needs to consume the Cloud Service Integration API for authentication and authorization. How it publishes its catalog will be a key component of the solution.

I've started an analysis based on historical modeling. More to come.

Antares comments on DDD/CQRS Challenge - Integrating Distributed Systems

Antares — Tue, 22 May 2012 18:16:31 +0000

I think Integration is the separate BC, with its own rules and behaviors

Rinat Abdullin comments on Scalable and Simple CQRS Views in the Cloud

Rinat Abdullin — Sun, 20 May 2012 11:07:53 +0000

Hannes, in this case, it might be simpler to have client host some read models directly. At least, that's one of the approaches that I would've given a try to.

Hannes comments on Scalable and Simple CQRS Views in the Cloud

Hannes — Fri, 18 May 2012 14:09:12 +0000

Thanks for your answer.

That means that the client needs to know which event causes an update on the read model.
I think the client should only care for read model updates.

Rinat Abdullin comments on Scalable and Simple CQRS Views in the Cloud

Rinat Abdullin — Fri, 18 May 2012 14:02:10 +0000

I would just have incoming transactions sent to client via pub/sub as soon as they happen. Then client can use them to keep read models updated in real time

Hannes comments on Scalable and Simple CQRS Views in the Cloud

Hannes — Fri, 18 May 2012 13:53:51 +0000

I am working on a trading application.

On startup the client loads his account history from the read model.
During runtime new incoming transactions should be pushed to the client.

How would you do this?

Rinat Abdullin comments on Dark Visual Studio Theme

Rinat Abdullin — Sat, 12 May 2012 09:29:39 +0000

@Magnus - they are still white. Didn't bother too much with the secondary windows, since they are closed almost always anyway

Magnus Lindhe comments on Dark Visual Studio Theme

Magnus Lindhe — Sat, 12 May 2012 07:01:54 +0000

Have you managed to modify the background color of the Solution Explorer and other window panes like it? Or are they still white?