Lang lopende processen bestaan in de meeste systemen. Veelal geëvolueerd naar nachtelijke batch processen, welke langdurig draaien en grote hoeveelheden data aggregeren en wijzigen. Of verborgen in grote hoeveelheden classes die te lang staan te stampen op eigenlijk heel eenvoudige processen. Dat moet toch anders kunnen? We zullen kijken naar een process manager welke zowel de functionele als technische implementatie van lang lopende processen vereenvoudigt. Hoe we beter met de business kunnen communiceren over de te implementeren bedrijfsprocessen, hoe we nieuwe mogelijkheden vinden om deze processen binnen je systeem te implementeren en een eind te maken aan die verschrikkelijk batch processen.

1. Dennis van der Stelt
all your batch jobs are belong to us
Dennis van der Stelt
Software Architect
http://dennis.bloggingabout.net/
dennis@bloggingabout.net
Particular Software engineer
death of the batch job
@dvdstelt
#nservicebus

2. Dennis van der Stelt
AGENDA

3. Dennis van der Stelt
NServiceBus
In Particular

4. Dennis van der Stelt
NServiceBus
It’s not like WCF, which does RPC
But closer to WCF than to BizTalk

5. Dennis van der Stelt
BUS TOPOLOGY

6. Dennis van der Stelt
Messaging
What is it and why do I need it?

7. Dennis van der Stelt
SpatialTemporalPlatform
coupling aspects

8. demo
Quick NServiceBus Demo

9. Dennis van der Stelt
NServiceBus Sagas
A pattern by relation database community

10. Dennis van der Stelt

11. Dennis van der Stelt
PROCESS MANAGER
process managerInitiating message

12. demo
NServiceBus Sagas

13. Dennis van der Stelt
Sagas Recap
“What have you done” – Within Temptation

14. Dennis van der Stelt
HANDLING MESSAGES
Behavior like normal message handlers
class MySaga : IHandleMessages<MyMessage>
{
public void Handle(MyMessage message)
{
…
}
}

15. Dennis van der Stelt
STARTING SAGAS
Extends the default IHandleMessages<T>
class MySaga : IAmStartedByMessages<MyMessage>
{
public void Handle(MyMessage message)
{
…
}
}

16. Dennis van der Stelt
STORING STATE
Extends the default IHandleMessages<T>
class MySaga : Saga<MySagaData>,
IAmStartedByMessages<MyMessage>
{
public void Handle(MyMessage message)
{
this.Saga.Data.MyStateProperty = Message.MyProperty;
}
}

17. Dennis van der Stelt
CORRELATING MESSAGES TO SAGA INSTANCE
class MySaga : Saga<MySagaData>,
IAmStartedByMessages<MyMessage>
{
protected override void ConfigureHowToFindSaga(SagaPropertyMapper<MySagaData> mapper)
{
mapper.ConfigureMapping<MyMessage>(m => m.MyProperty).ToSaga(s => s.MyStateProperty);
}
public void Handle(MyMessage message)
{
this.Saga.Data.MyStateProperty = Message.MyProperty;
}
}

18. Dennis van der Stelt
REQUESTING TIMEOUTS
Reminders to the Saga itself
class MySaga : Saga<MySagaData>,
IAmStartedByMessages<MyMessage>,
IHandleTimeouts<MyTimeout>
{
public void Handle(MyMessage message)
{
this.Saga.Data.MyStateProperty = Message.MyProperty;
RequestTimeout<MyTimeout>(TimeSpan.FromSeconds(10));
}
public void Timeout(MyTimeout state)
{
…
}
}

19. Dennis van der Stelt
SENDING MESSAGES
Reminders to the Saga itself
class MySaga : Saga<MySagaData>,
IAmStartedByMessages<MyMessage>
{
public void Handle(MyMessage message)
{
this.Saga.Data.MyStateProperty = Message.MyProperty;
this.Bus.Send(new MyCommand());
this.Bus.Publish(new MyEvent());
}
}

20. Dennis van der Stelt
SAGA STATE
Memento
class MySagaData : IContainSagaData
{
public virtual Guid Id { get; set; }
public virtual string Originator { get; set; }
public virtual string OriginalMessageId { get; set; }
[Unique]
public virtual Guid MySagaId { get; set; }
}
ALTER TABLE [dbo].[MySagaData]
ADD UNIQUE NONCLUSTERED
([MySagaId] ASC) ON [PRIMARY]

21. Dennis van der Stelt
SAGA STATE
Memento
class MySagaData : IContainSagaData
{
public virtual Guid Id { get; set; }
public virtual string Originator { get; set; }
public virtual string OriginalMessageId { get; set; }
[Unique]
public virtual Guid MySagaId { get; set; }
public virtual IList<Product> Products { get; set; }
}
public class Product
{
public virtual Guid ProductId { get; set; }
}

22. Dennis van der Stelt
SAGA STATE
Memento
class MySagaData : IContainSagaData
{
public virtual Guid Id { get; set; }
public virtual string Originator { get; set; }
public virtual string OriginalMessageId { get; set; }
[Unique]
public virtual Guid MySagaId { get; set; }
public virtual IList<Product> Products { get; set; }
}
public class Product
{
public virtual Guid ProductId MyUniqueId { get; set; }
}

23. Dennis van der Stelt
Death to the batch job
Because we don’t want to depend on operations ;-)

24. Dennis van der Stelt

25. Dennis van der Stelt
scheduled tasks
Your CEO had insomnia and was using the system in the
middle of the night. The batch job failed somewhere in
the middle of updating 74 million records…
You need to figure out which row it failed on (how?),
why it failed, correct the issue, then start the job again
from where it left off, because if you have to start from
the beginning, it won't get done before peak hours in
the morning.
because that sounds better than batch job

26. Dennis van der Stelt
BATCH JOB
All customers that ordered $5000 in the last year, get preferred status
DateTime cutoff = DateTime.Today.AddDays(-365);
foreach(var customer in customers)
{
var orderTotal = customer.Orders
.Where(o => o.OrderDate > cutoff)
.Sum(order => order.OrderValue);
customer.Prefered = orderTotal > 5000;
}

27. Dennis van der Stelt
Tromsø, Norway

28. Dennis van der Stelt
what if
we can see things before they happen?

29. Dennis van der Stelt
customer preferred status
Dev: Let's say Steve orders something
for $100. At what point does that
amount no longer count toward Steve's
preferred status?
BA: That's easy, after 365 days!

30. Dennis van der Stelt
-$300-$100
+$300
DURABLE TIMEOUTS
Our way to predict the future
2015 2016
+$100

31. Dennis van der Stelt
DURABLE TIMEOUTS
public void Handle(OrderPlaced message)
{
this.Data.CustomerId = message.CustomerId;
this.Data.RunningTotal += message.Amount;
this.RequestTimeout<OrderExpired>(TimeSpan.FromDays(365),
timeout => timeout.Amount = message.Amount);
CheckForPreferredStatusChange();
}
public void Handle(OrderExpired message)
{
this.Data.RunningTotal -= message.Amount;
CheckForPreferredStatusChange();
}

32. Dennis van der Stelt
DURABLE TIMEOUTS
private void CheckForPreferredStatusChange()
{
if(this.Data.PreferredStatus == false && this.Data.RunningTotal >= 5000)
{
this.Bus.Publish<CustomerHasBecomePreferred>(
evt => evt.CustomerId = this.Data.CustomerId);
}
else if(this.Data.PreferredStatus == true && this.Data.RunningTotal < 5000)
{
this.Bus.Publish<CustomerHasBecomeNonPreferred(
evt => evt.CustomerId = this.Data.CustomerId);
}
}

33. Dennis van der Stelt
Best Practices
The silver bullets?

34. Dennis van der Stelt
Rule #1 : Don’t query data
Never ever, ever, ever query data
- From the saga to another data source
- Owned by saga with a 3rd party tool

35. race conditions do not exist

36. Dennis van der Stelt
STARTING SAGAS
What business events can start a Saga?
class MySaga : Saga<MySagaData>,
IAmStartedByMessages<MyMessage>,
IAmStartedByMessages<YourMessage>,
IAmStartedByMessages<AnotherMesssage>
{
public void Handle(MyMessage message)
{
…
if (VerifyState())
MarkAsComplete();
}
}

37. sagas bring agility

38. Dennis van der Stelt
Please…
stay in touch!
http://dennis.bloggingabout.net
dennis@bloggingabout.net