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Dennis van der Stelt
all your batch jobs are belong to us
Dennis van der Stelt
Software Architect
http://dennis.bloggingab...
Dennis van der Stelt
AGENDA
Dennis van der Stelt
NServiceBus
In Particular
Dennis van der Stelt
NServiceBus
It’s not like WCF, which does RPC
But closes to WCF than to BizTalk
Dennis van der Stelt
BUS TOPOLOGY
Dennis van der Stelt
Messaging
What is it and why do I need it?
reduce
coupling
Dennis van der Stelt
SpatialTemporalPlatform
coupling aspects
Dennis van der Stelt
PLATFORM
Also known as ‘interoperability’
http, json, xml, xsd, etc…
Dennis van der Stelt
TEMPORAL
Store Front End Shipping Service
Dennis van der Stelt
TEMPORAL
Store Front End Shipping ServiceShipping Service
Dennis van der Stelt
TEMPORAL
Store Front End Shipping ServiceOrder Queue
Dennis van der Stelt
TEMPORAL
Store Front End Shipping ServiceOrder Queue
Dennis van der Stelt
TEMPORAL
Store Front End Shipping ServiceOrder Queue
Dennis van der Stelt
Messaging
 Reduces spatial coupling
 XML/JSON for platform coupling
 Asynchronous for temporal cou...
demo
Messaging using WCF
Dennis van der Stelt
PERFORMANCE
RPC versus Messaging
Dennis van der Stelt
NServiceBus Sagas
A pattern by relation database community
Dennis van der Stelt
demo
NServiceBus Sagas
Dennis van der Stelt
Sagas Recap
“What have you done” – Within Temptation
Dennis van der Stelt
HANDLING MESSAGES
Behavior like normal message handlers
class MySaga : IHandleMessages<MyMessage>
{
p...
Dennis van der Stelt
STARTING SAGAS
Extends the default IHandleMessages<T>
class MySaga : IAmStartedByMessages<MyMessage>
...
Dennis van der Stelt
STORING STATE
Extends the default IHandleMessages<T>
class MySaga : Saga<MySagaData>,
IAmStartedByMes...
Dennis van der Stelt
CORRELATING MESSAGES TO SAGA INSTANCE
class MySaga : Saga<MySagaData>,
IAmStartedByMessages<MyMessage...
Dennis van der Stelt
REQUESTING TIMEOUTS
Reminders to the Saga itself
class MySaga : Saga<MySagaData>,
IAmStartedByMessage...
Dennis van der Stelt
SENDING MESSAGES
Reminders to the Saga itself
class MySaga : Saga<MySagaData>,
IAmStartedByMessages<M...
Dennis van der Stelt
SAGA STATE
Memento
class MySagaData : IContainSagaData
{
public virtual Guid Id { get; set; }
public ...
Dennis van der Stelt
SAGA STATE
Memento
class MySagaData : IContainSagaData
{
public virtual Guid Id { get; set; }
public ...
Dennis van der Stelt
SAGA STATE
Memento
class MySagaData : IContainSagaData
{
public virtual Guid Id { get; set; }
public ...
Dennis van der Stelt
Death to the batch job
Because we don’t want to depend on operations ;-)
Dennis van der Stelt
Dennis van der Stelt
scheduled tasks
Your CEO had insomnia and was using the system in the
middle of the night. The batch ...
Dennis van der Stelt
BATCH JOB
All customers that ordered $5000 in the last year, get preferred status
DateTime cutoff = D...
Dennis van der Stelt
Tromsø, Norway
Dennis van der Stelt
what if
we can see things before they happen?
Dennis van der Stelt
customer preferred status
Dev: Let's say Steve orders something
for $100. At what point does that
amo...
Dennis van der Stelt
-$300-$100
+$300
DURABLE TIMEOUTS
Our way to predict the future
2015 2016
+$100
Dennis van der Stelt
DURABLE TIMEOUTS
public void Handle(OrderPlaced message)
{
if(this.Data.CustomerId == 0)
this.Data.Cu...
Dennis van der Stelt
DURABLE TIMEOUTS
private void CheckForPreferredStatusChange()
{
if(this.Data.PreferredStatus == false...
Dennis van der Stelt
Best Practices
The silver bullets?
Dennis van der Stelt
Rule #1 : Don’t query data
Never ever, ever, ever query data
- From the saga to another data source
-...
Dennis van der Stelt
Business eventsTimeoutsStarting sagas
out of order
Dennis van der Stelt
ASYNCHRONOUS COMMUNICATION
Order of message delivery
OrderAccepted
OrderAccepted
OrderBilled
Dennis van der Stelt
ASYNCHRONOUS COMMUNICATION
Order of message delivery
OrderAccepted
OrderAccepted
OrderBilled
Dennis van der Stelt
ASYNCHRONOUS COMMUNICATION
Order of message delivery
OrderAccepted
OrderAccepted
OrderBilled
OrderCan...
race conditions do not exist
Dennis van der Stelt
STARTING SAGAS
What business events can start a Saga?
class MySaga : Saga<MySagaData>,
IAmStartedByMe...
Dennis van der Stelt
404 ON SAGAS
What if the Saga was already MarkedAsComplete
public class SagaNotFoundHandler : IHandle...
Dennis van der Stelt
AUTO CORRELATION
Avoids the need for mapping responses
class MySaga : Saga<MySagaData>,
IAmStartedByM...
Dennis van der Stelt
AUTO CORRELATION
Avoids the need for mapping responses
class MySaga : Saga<MySagaData>,
IAmStartedByM...
Dennis van der Stelt
CONCURRENCY
[LockMode(LockModes.Read)]
class ShoppingCartSagaData : IContainSagaData
{
…
[RowVersion]...
Dennis van der Stelt
CONCURRENCY
DELETE FROM ShoppingCartSagaData
WHERE Id = '1C669378-3508-4A20-8EFD-A5C60168893E'
AND Or...
Sagas is business agility
http://bit.ly/nlnsbug
Dennis van der Stelt
Please…
stay in touch!
http://dennis.bloggingabout.net
dennis@bloggingabout.net
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Death of the batch job - NServiceBus Sagas

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Presentation on NServiceBus Sagas
Democode can be found on GitHub : https://github.com/dvdstelt/sagas

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Death of the batch job - NServiceBus Sagas

  1. 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. 2. Dennis van der Stelt AGENDA
  3. 3. Dennis van der Stelt NServiceBus In Particular
  4. 4. Dennis van der Stelt NServiceBus It’s not like WCF, which does RPC But closes to WCF than to BizTalk
  5. 5. Dennis van der Stelt BUS TOPOLOGY
  6. 6. Dennis van der Stelt Messaging What is it and why do I need it?
  7. 7. reduce coupling
  8. 8. Dennis van der Stelt SpatialTemporalPlatform coupling aspects
  9. 9. Dennis van der Stelt PLATFORM Also known as ‘interoperability’ http, json, xml, xsd, etc…
  10. 10. Dennis van der Stelt TEMPORAL Store Front End Shipping Service
  11. 11. Dennis van der Stelt TEMPORAL Store Front End Shipping ServiceShipping Service
  12. 12. Dennis van der Stelt TEMPORAL Store Front End Shipping ServiceOrder Queue
  13. 13. Dennis van der Stelt TEMPORAL Store Front End Shipping ServiceOrder Queue
  14. 14. Dennis van der Stelt TEMPORAL Store Front End Shipping ServiceOrder Queue
  15. 15. Dennis van der Stelt Messaging  Reduces spatial coupling  XML/JSON for platform coupling  Asynchronous for temporal coupling
  16. 16. demo Messaging using WCF
  17. 17. Dennis van der Stelt PERFORMANCE RPC versus Messaging
  18. 18. Dennis van der Stelt NServiceBus Sagas A pattern by relation database community
  19. 19. Dennis van der Stelt
  20. 20. demo NServiceBus Sagas
  21. 21. Dennis van der Stelt Sagas Recap “What have you done” – Within Temptation
  22. 22. Dennis van der Stelt HANDLING MESSAGES Behavior like normal message handlers class MySaga : IHandleMessages<MyMessage> { public void Handle(MyMessage message) { … } }
  23. 23. Dennis van der Stelt STARTING SAGAS Extends the default IHandleMessages<T> class MySaga : IAmStartedByMessages<MyMessage> { public void Handle(MyMessage message) { … } }
  24. 24. 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; } }
  25. 25. 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; } }
  26. 26. 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) { … } }
  27. 27. 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()); } }
  28. 28. 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]
  29. 29. 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; } }
  30. 30. 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; } }
  31. 31. Dennis van der Stelt Death to the batch job Because we don’t want to depend on operations ;-)
  32. 32. Dennis van der Stelt
  33. 33. 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
  34. 34. 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; }
  35. 35. Dennis van der Stelt Tromsø, Norway
  36. 36. Dennis van der Stelt what if we can see things before they happen?
  37. 37. 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!
  38. 38. Dennis van der Stelt -$300-$100 +$300 DURABLE TIMEOUTS Our way to predict the future 2015 2016 +$100
  39. 39. Dennis van der Stelt DURABLE TIMEOUTS public void Handle(OrderPlaced message) { if(this.Data.CustomerId == 0) 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(); }
  40. 40. 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); } }
  41. 41. Dennis van der Stelt Best Practices The silver bullets?
  42. 42. 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
  43. 43. Dennis van der Stelt Business eventsTimeoutsStarting sagas out of order
  44. 44. Dennis van der Stelt ASYNCHRONOUS COMMUNICATION Order of message delivery OrderAccepted OrderAccepted OrderBilled
  45. 45. Dennis van der Stelt ASYNCHRONOUS COMMUNICATION Order of message delivery OrderAccepted OrderAccepted OrderBilled
  46. 46. Dennis van der Stelt ASYNCHRONOUS COMMUNICATION Order of message delivery OrderAccepted OrderAccepted OrderBilled OrderCancelled How to solve?
  47. 47. race conditions do not exist
  48. 48. 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(); } }
  49. 49. Dennis van der Stelt 404 ON SAGAS What if the Saga was already MarkedAsComplete public class SagaNotFoundHandler : IHandleSagaNotFound { IBus bus; public SagaNotFoundHandler(IBus bus) { this.bus = bus; } public void Handle(object message) { bus.Reply(new SagaDisappearedMessage()); } }
  50. 50. Dennis van der Stelt AUTO CORRELATION Avoids the need for mapping responses class MySaga : Saga<MySagaData>, IAmStartedByMessages<MyMessage>, IHandleMessages<Response> { protected override void ConfigureHowToFindSaga(SagaPropertyMapper<MySagaData> mapper) { mapper.ConfigureMapping<MyMessage>(m => m.MyProperty).ToSaga(s => s.MyStateProperty); // Mapping for Respose not needed! } } public class RequestHandler : IHandleMessages<Request> { public void Handle(Request message) { Bus.Reply(new Response()); } }
  51. 51. Dennis van der Stelt AUTO CORRELATION Avoids the need for mapping responses class MySaga : Saga<MySagaData>, IAmStartedByMessages<MyMessage>, IHandleMessages<MyTimeout> { public void Timeout(MyTimeout state) { if (state.RasiedAtUtc == … } } public class MyTimeout { public DateTime RaisedAtUtc { get; set; } = DateTime.UtcNow; } Can be a POCO No `virtual` as it’s serialized to string format
  52. 52. Dennis van der Stelt CONCURRENCY [LockMode(LockModes.Read)] class ShoppingCartSagaData : IContainSagaData { … [RowVersion] public virtual int RowVersion { get; set; } [Unique] public virtual Guid CartId { get; set; } }
  53. 53. Dennis van der Stelt CONCURRENCY DELETE FROM ShoppingCartSagaData WHERE Id = '1C669378-3508-4A20-8EFD-A5C60168893E' AND Originator is null AND OriginalMessageId = 'd6436b7-eb17-4de5-8b92-a5c60168888c' AND CartId = '49784AF0-0854-4FF9-B8CD-E57CC8EE6CFC‘ AND … AND … AND … DELETE FROM ShoppingCartSagaData WHERE Id = '1C669378-3508-4A20-8EFD-A5C60168893E' AND RowVersion = 1
  54. 54. Sagas is business agility
  55. 55. http://bit.ly/nlnsbug
  56. 56. Dennis van der Stelt Please… stay in touch! http://dennis.bloggingabout.net dennis@bloggingabout.net

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