Building reliable applications with messaging

Dennis van der Stelt

and building better & more reliable systems


Software Architect

http://dennis.bloggingabout.net/

[email protected]

NServiceBus Community Champ

MESSAGING

@dvdstelt

#blaak

http://bloggingabout.net/blogs/dennis/


YOUR PRESENTER


http://dennis.bloggingabout.net/

Software Architect

Professional Services

Provides coaching & training

About Dennis

Innovative software architect

Almost 20 years of experience in development of

distributed systems. Has a continuous drive to

learn and improve knowledge in different

architectural styles, including quality in software

development. Highly motivated to share his

knowledge via articles, presentations and his

blog.

Awards

NServiceBus Champ

Typemock MVP

Certified Trainer

• Presentations

• Software & Architecture audits

• SOA & Microservices advice

• Unit Testing training

• NServiceBus training


AGENDA


“You know nothing, Jon Snow”

Dennis van der Stelt5

Messaging conceptsWhat is it about & why is it important?


synchronous asynchronousvs


Separation of concerns

Flexibility & Reusability

Scalability

why all the layers?


A monolithic design is characterized by such tight coupling

among modules that they really have no independent existence.

monolithic


MONOLITHIC DESIGN

How does my clean code become a big ball of mud?

Database


COUPLING

Which layer has the

worst coupling?

reduce

coupling


SpatialTemporalPlatform

coupling aspects


PLATFORM

Also known as ‘interoperability’

http, json, xml, xsd, etc…


TEMPORAL

Store Front End Shipping Service


TEMPORAL

Store Front End Shipping ServiceShipping Service


TEMPORAL

Store Front End Shipping ServiceOrder Queue


SPATIAL


SPATIAL.netapplication

.net application

ShipOrder AssignTask


Messaging

Reduces spatial coupling

XML/JSON for platform coupling

Asynchronous for temporal coupling

demo

Messaging using WCF


PERFORMANCE

RPC versus Messaging

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ArchitectureWe do microservices, ‘cause this time

it is the silver bullet!


SERVICE ORIENTATION AT RUNTIME


Don’t do request/reply


Don’t use asynchronous

messaging to query a datastore

for displaying purposes!

Everything has its place.

Messaging isn’t a silver bullet

you use for everything.

demo

NServiceBus Demo


CAP TheoremEric Brewer, PODC Conference 2000


CAP THEOREM

You can only pick 2


CAP THEOREM

You can only pick 2

centralized

system

partition tolerantconsistencyavailability


CAP THEOREM

You can only pick 2

centralized

system


distributed

system



CAP THEOREM

You can only pick 2

centralized

system


distributed

system


when there’s network partition,

which do you sacrifice?


Match the business perspective


But I can’t drop consistency!


Basically Available

BASE

What is BASE?

Soft state

Eventually consistent


Eventual ConsistencyBecause 100% consistency isn’t the only option


Eventual Consistency


Eventual Consistencyyour “enterprise” is already eventual consistent with reality


“Allow things to be inconsistent and find ways to

compensate for mistakes, versus trying to prevent

mistakes altogether.”

EVENTUAL CONSISTENCY

Eric BrewerVP of Infrastructure at Google, Professor at UC Berkeley


Some ideas on messaging


100% synchronized

that‘s eventual consistency.

Udi Dahan in 2010


SagasLong running processes


Death to the batchjob

demo

NServiceBus Saga demo


Asynchronous messaging helps achieve

decoupling at design- & runtime

There’s a lot to think about, designing an

eventual consistent distributed system.

Everyone needs to think about the CAP

Theorem, etc, with or without async messaging

Conclusion


find me.http://dennis.bloggingabout.net

[email protected]

Building reliable applications with messaging

Technology

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