Hi all

I am implementing a small SaaS with Commanded and one of the areas I am trying Commanded with is counting credits. Every month a free account is going to get some credits which are to be expired within a month if not used.

For tracking it I’ve got a CreditStore aggregate that has buckets of credits with attached expiration time. Adding/using credits is as simple as processing commands AddCredits/UseCredits, but expirations and adding more credits every month (or whatever plan’s timeframe chosen) are more difficult.

Sure I can check credits on demand or via explicit command. E.g. when somebody logs in, I could auto send CheckUpdateCredits and it should work. However, I’d like these monthly expirations/additions happen at roughly correct timing so that I could send notifications like “you’ve got more credits now, go use them” and also have ability to do nice admin reports on what’s the situation right now.

What would be the way to have every single aggregate in the system process some command regularly?

Exact timing is not important, so it’s fine if it happens within an hour or so from the ideal moment. The best I was able to invent is forcing every aggregate have projection with own id and closest expiration time, then some cron-like utility every X minutes to check who needs to be checked and then send lots of CheckUpdateCredits commands to these.

Is this how periodic checks of all aggregates are usually done? Or is these some other [easy] way to schedule processing of all aggregates in the system once in a while?