The document discusses challenges with monolithic "Big Ball of Mud" architectures and how messaging/event-driven architectures using NServiceBus can help address these. It covers how messaging allows for better encapsulation, separation of concerns, and loose coupling between components. It also discusses strategies for gradually transitioning from a monolith to a messaging system to reduce risk, including using the strangler pattern and automation.

1. Advanced
NServiceBus
Deployment
NSBCon NYC 2014
Kijana Woodard / @kijanawoodard

2. Background
From Dallas, TX
Professional develop since 1996
.net since 1.0
Independent contractor since 2010

3. Around the web
kijanawoodard.com
twitter.com/kijanawoodard
github.com/kijanawoodard
linkedin.com/in/kijanawoodard
particular forum
ravendb forum
ddd/cqrs forum
hypermedia forum

4. Slides are on GitHub
github.com/kijanawoodard/NSBCon-NYC-2014/

5. Mitigation
all
the
way
down

6. Big Ball of Mud
An application which defies modification

7. BBOM Formal Definition
SELECT currentAssignment
FROM workHistory
WHERE originalDeveloper != me

8. Defense Mechanisms
Change control committee
Source control committee

9. BBOM Architecure
- thedailywtf.com Comment On The Enterprise Dependency

10. BBOM Implementation
public class OrderController
{
...
public OrderController(
IOrderRepository orders,
IBillingService billing,
IShippingService shipping)
{
_orders = orders;
_billing = billing;
_shipping = shipping;
}
public HttpStatusCode Post(Order order)
{
_orders.Save(order.OrderDetails);
_billing.Charge(order.BillingDetails);
_shipping.Ship(order.ShippingDetails);
return HttpStatusCode.OK;
}
}

11. Mediator
kijanawoodard.com/introducing-nimbus
lostechies.com/jimmybogard/2014/09/09/tackling-cross-cutting-
concerns-with-a-mediator-pipeline/

12. Decouple through Events

13. Events Implementation
public class OrderController
{
public IBus Bus { get; set; }
public HttpStatusCode Post(ProcessOrder order)
{
Bus.Send(order);
return HttpStatusCode.OK;
}
}
...
public class OrderHandler
: IHandleMessages<ProcessOrder>
{
public IBus Bus { get; set; }
public void Handle(ProcessOrder message)
{
//save order...
Bus.Publish<IOrderAccepted>(x => x.Id = message.Id);
}
}

14. Bliss
Encapsulation
Single Responsibility
Open Closed Principle
Interface Segregation Principle
Dependency Inversion Principle

15. It's almost as if...
OOP to me means only messaging, local
retention and protection and hiding of state-process,
and extreme late-binding of all things.
Alan Kay - 2003

16. What's the Problem?

17. BBOM Solution

18. Events Solution

19. Events Dev UX

20. Friction
Message Conventions
Serialization Format
Persistence Configuration

21. Harder to Deploy
Many Endpoints vs One Application

22. Decreased Legibility
ribbonfarm.com/2010/07/26/a-big-little-idea-called-legibility/

23. Developer's Opinion of
BBOM
- thedailywtf.com Comment On The Enterprise Dependency

24. Executive Summary of
BBOM

25. Executive Summary of
Messaging

26. Combat Friction

27. Don't Call It a Rewrite
public class OrderController
{
...
public OrderController(
IOrderRepository orders,
IBillingService billing,
IShippingService shipping)
{
_orders = orders;
_billing = billing;
_shipping = shipping;
}
public HttpStatusCode Post(Order order)
{
_orders.Save(order.OrderDetails);
_billing.Charge(order.BillingDetails);
_shipping.Ship(order.ShippingDetails);
return HttpStatusCode.OK;
}
}

28. Strangler Pattern
- Entry on Strangler Fig Wikipedia
http://www.martinfowler.com/bliki/StranglerApplication.html

29. Context
Remember that time when we couldn't deploy anything for 6
weeks...
Remember that time when the strategic marketing initiative
was held up due to a Shipping upgrade...

30. Restore some Legibility

31. Have No Illusions
The Big Ball of Mud will not die easily
- Advanced Life Skills

32. Automate
Automate
Automate

33. Conventions: Web vs Endpoint
Separate configuration repo
Days to Minutes
Smaller, more frequent releases
Confidence
Repeatability

34. Configuration
db alert
local http://localhost:8080 alerts@devnull.example.com
dev http://localhost:8080 alerts@dev.example.com
qa http://qa:8080 alerts@qa.example.com
prod http://p532977:8080 alerts@example.com

35. Don't Do an
"Automation Project"
Over time, layer in...
Build scripts
powershell / msbuild
Team City / Bamboo
Deploy scripts
powershell
Octopus Deploy
Monitoring and Metrics
Service Insight / Control
SCOM
Discussion on DevOPS Experience on devopslive.org

36. Bus Stop
github.com/andreasohlund/BusStop

37. Bus Stop
namespace BusStop.Config
{
public static class MyConvention
{
public static Configure MyMessageConventions(this Configure config)
{
config.DefiningEventsAs(t => t.Namespace != null &&
t.Namespace.EndsWith(".Contracts"));
return config;
}
}
}
github.com/andreasohlund/BusStop

38. Endpoints vs Handlers

39. Before

40. All Together

41. Combined

42. Dev UX

43. Build Artifacts

44. Mix and Match

45. Run
NServiceBus.Host.exe -endpointName=orders

46. Decouple Dev from OPS
Redeploy without recompile
Tie to Platform Tools

47. Pushing Forwards

48. A 2nd Look at Events Impl
public class OrderController
{
public IBus Bus { get; set; }
public HttpStatusCode Post(ProcessOrder order)
{
Bus.Send(order);
return HttpStatusCode.OK;
}
}
...
public class OrderHandler
: IHandleMessages<ProcessOrder>
{
public IBus Bus { get; set; }
public void Handle(ProcessOrder message)
{
//save order...
Bus.Publish<IOrderAccepted>(x => x.Id = message.Id);
}
}

49. One Choice
public class OrderController
{
private IFactory<Duck<Mockable<ProcessOrder>>> _something;
public IBus Bus { get; set; }
public OrderController(IFactory<Duck<Mockable<ProcessOrder>>> something)
{
_something = something;
}
public HttpStatusCode Post(ProcessOrder order)
{
_something.Process(order);
return HttpStatusCode.OK;
}
}
...
public class OrderHandler
: IHandleMessages<ProcessOrder>
{
private IFactory<Duck<Mockable<ProcessOrder>>> _something;
public IBus Bus { get; set; }
public OrderHandler(IFactory<Duck<Mockable<ProcessOrder>>> something)
{
_something = something;
}
public void Handle(ProcessOrder message)
{

50. Exploit Decoupling
public class OrderController
{
private readonly IHandleMessages<ProcessOrder> _handler;
public IBus Bus { get; set; }
public OrderController(IHandleMessages<ProcessOrder> handler)
{
_handler = handler;
}
public HttpStatusCode Post(ProcessOrder order)
{
_handler.Handle(order);
return HttpStatusCode.OK;
}
}
...
public class OrderHandler
: IHandleMessages<ProcessOrder>
{
public IBus Bus { get; set; }
public void Handle(ProcessOrder message)
{
//save order...
Bus.Publish<IOrderAccepted>(x => x.Id = message.Id);
}
}

51. Run

52. Subscriptions

53. Subscribed

54. Direct

55. Future exploration

56. Break Apart the API?
Later....
{
"submit-order" : "http://api.example.com/orders"
}
{
"submit-order" : "http://orders.example.com/"
}
HAL - Hypertext Application Language

57. What about queries?
N fanout queries vs 1 for command
Volatile queues
Could work with proper circuit breakers
Easier configuration with mulitple databases

58. Assembly Neutral
Interfaces
davidfowl.com/assembly-neutral-interfaces/
Consumer Driven Contracts

59. Roslyn
What if source files were distrbuted....

60. THE END

61. Advanced NServiceBus
Deployment
Questions?
slides @ github.com/kijanawoodard/NSBCon-NYC-2014/
kijanawoodard.com
twitter.com/kijanawoodard