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We are in the process of migrating a legacy system to nservicebus 5.0. What is generally the best way to migrate our business data to saga data? For example, if we had an OrderCancellationPolicy saga, that only allowed cancellation within 2 days, how would past orders from the legacy system create these new sagas in the correct state?

I see two options. The first being to write some sql script to prepopulate the saga persistence tables (we are using nhibernate persistence). The other being to create some kind of special import message, such as MigrateOrderDataCmd, that contains the data from the legacy order. An import script could send out these messages which the sagas could handle and set the saga data that way.

Any guidance in this area is appreciated.

Tyler Day
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Theoretically I'd go for option two, or a version of it. Imagine your saga being down for a day and messages are piling up in the queue. With messages from a day coming in, you'd want to verify when the message was sent, or add a custom DateTime to the message yourself.

When the saga finally picks up the message, it knows it should not set the timeout two days in the future, but rather the time the message took to be delivered into the saga. That way when you migrate your current state, all messages get a proper timeout set.

On the other hand, if you've got a really large set of running processes, you might want to investigate how to propagate the tables. I have no hands on experience adding records to those tables myself, just changing them. :)

Dennis van der Stelt
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  • OK, thanks for the advice. I just wanted to make sure there wasn't some third option I was overlooking :) – Tyler Day Aug 18 '15 at 02:09