NServiceBus: Fundamentals

~ Anshu Kumar

Event Driven Architecture :
Send command and Publish events.

Asynchronous messaging
A mechanism for Loosely coupled integration of software components. Publisher/subscriber pattern.
Advantage: Scalability, Reliability( Retry)

Service Bus – For Service Endpoint communication.
Allows services to communicate with each other, Have backend messaging implementation.

Service Bus Should not have any business logic, service should be smart enough.

  • One endpoint connected to one queue
  • One service can have multiple endpoint

Service Bus and Enterprise service Bus are different.

NServiceBus
Service Bus implementation in .NET – Open Source.
Not free. Licensing by Particular. Below link to find related documentation.

https://docs.particular.net/

  • Communication between application using messaging.
  • Abstract on backend messaging.
  • Support transport configuration like MSMQ, RabbitMQ, SQLServer

NugetPackages:
NServiceBus
NServiceBus.Host – Run as windows service.
NServiceBus.Testing

Commands:
Messages – In the form of C# Class have data in the form of properties.
Multiple senders
One Receiver
Send Method
Imperative – Create/Use

Heavily relies on DI – Lean version of Autofac Built into Core.
By assembly Scanning – Endpoints depend upon assemblies.

Events:
Messages
One Sender
Multiple Receivers
Publish/Subscriber pattern
Past tense : OrderProcessedEvent

Routing :
For Commands /Events
By 2 Ways -Config File or by Routing API(recommended)

IConfigureThisEndpoint
INeedInitialization

Serialization – Default Xml, Future will change to JSON

Persistence: No Default
NServiceBus Transport Options:

NService Bus provide abstract over transport. Easy to switch transport through configuration.

Messaging Middleware

  • RabbitMQ
  • MSMQ
  • Kafka
  • Azure Service Bus

MSMQ

  • It does not support subscription.
  • Native to windows
  • Decentralize – Every Machine have own local queues.

RabbitMQ

  • Broker style
  • Centralize
  • Exchange and Have a better routing mechanism.

MSQM Vs RabbitMQ – Microservice run on multiple OS. MSMQ limit to windows.

Azure – Storage queues Vs Service Bus(Costly, low latency).