Serverless CQRS in Azure!

Toon Vanhoutte

https://be.linkedin.com/pub/toon-vanhoutte/6/276/84b

Toon Vanhoutte

Serverless CQRS in Azure!

Nice to meet you

Toon Vanhoutte

Lead Architect @ Codit Belgium

Microsoft Azure MVP

@toonvanhoutte

toonvanhoutte.wordpress.com

www.linkedin.com/in/toon-vanhoutte

Who we are

Customers Entities

2000 Belgium

2004 France

2013 Portugal

2016 Switzerland

2016 UK

2016 The Netherlands

2017 Malta

150worldwide

The thing we do

Agenda

• An Introduction to CQRS

• Serverless Technologies in Azure

• Use Case: Optimize a Webshop

• Conclusion

6

An introduction to CQRS

CRUD ArchitectureProven and simple design

Command Query Responsibility SegregationDealing with complex domain models

Command Query Responsibility SegregationDealing with high performing applications

Commands vs Queries

Write

Reliable

Sync / Async

Transactional

Persistent

Commands Queries

Read

Volatile

Sync

Non Transactional

In Memory

Fast Fast

Serverless in Azure

Pizza as a Service

14

Serverless Technology Options

Azure Functions

“Code triggered by events”

Azure Logic Apps

“Workflows triggered by events”

Azure Event Grid

“Serverless event routing service”

Azure Service Bus

“Reliable messaging platform”

Pricing Model

Security

Runtime

Monitoring

Deployment

State

Networking

Connectivity

Exception Handling

Developer experience

Azure Functions Azure Logic Apps

Azure Functions Azure Logic Apps

Preferred option for

complex synchronous

request/response calls.

Preferred option for

asynchronous fire-and-

forget messaging.

Azure Functions

perfectly extends

Azure Logic Apps.

Command

Query

Report

TransferNotification

MeasurementAssignment

Job

UpdateRequest Trace

Handover

Azure Service Bus Azure Event Grid

© Clemens Vasters

Azure Service Bus Azure Event Grid

Command

Query

ReportTransfer

Notification

MeasurementAssignment

Job

Update

Request

Trace

Handover

Passing Intents Reporting Facts

Mess

ag

ing Eve

ntin

g

Discrete

Series

© Clemens Vasters

Azure Service Bus Azure Event Grid

Passing Intents Reporting Facts

Mess

ag

ing Eve

ntin

g

Discrete

Series

“PriceUpdated”

“OpportunityWon”

“InvoiceBooked”

Temperature stream

Telemetry data

Audit trail

“CreateOrder”

“BookHotel”

“UpdateStock”

© Clemens Vasters

Use Case

Pizza Antonio

Find out how CQRS will save

Antonio’s business!

Pizza Antonio

Website

€ 10€ 12€ 11

Submit

Query

Command

Pizza Antonio

Query

Co

mm

and

GetProducts

CreateOrder

SQ

L D

ata

base

Very good pizza’s

Customers get errors when ordering pizza during peak hours

Pizza Antonio

Query

Co

mm

and

GetProducts

CreateOrder

SQ

L D

ata

base

Customers don’t get any errors anymore

The orders don’t make it to the database, so no pizza

Pizza Antonio

Query

Co

mm

and

GetProducts

CreateOrder

SQ

L D

ata

base

All orders make it to the database

Polling during quiet hours is rather expensive, so more expensive pizza’s

Pizza Antonio

Query

Co

mm

and

GetProducts

CreateOrder

SQ

L D

ata

base

Cheaper polling mechanism, so again sharper prices

No flexible way to send order confirmations through email

Pizza Antonio

Query

Co

mm

and

GetProducts

CreateOrder

SQ

L D

ata

base

Flexible extension points for e.g. emails

Two different URL’s and security keys for the website

Pizza Antonio

Query

Co

mm

and

SQ

L D

ata

base

GetProducts

CreateOrder

Azu

re F

unct

ion P

roxy

Uniform API for website

Loading products on the website is extremely slow during peak hours

Pizza Antonio

Query

Co

mm

and

SQ

L D

ata

base

GetProducts

CreateOrder

Azu

re F

unct

ion P

roxy

Fast responsive times on the website

No flexible way to update products on external food delivery services

Pizza Antonio

Query

Co

mm

and

GetProducts

CreateOrder

SQ

L D

ata

base

Azu

re F

unct

ion P

roxy

Pizza Antonio

Query

Co

mm

and

GetProducts

CreateOrder

SQ

L D

ata

base

Azu

re F

unct

ion P

roxy

Antonio happy

Customers happy

Conclusion

CQRS is a proven design pattern!It exists in many different variations

Azure Function Proxy

SQL Database

QueryCommand

Sentinet

SQL Database

QueryCommand

Azure API Mgmt

SQL Database

QueryCommand

Cache

Lessons learned

Azure Functions Azure Event Grid

Consumption plan results

in cold starts, also for

function proxies!

Solution:

• Keep it warm (5 min)

• App Service Plan

• Pre-compiled

functions

Event Grid puts

responsibility for

sequencing at receive side!

Solution:

• Use it wisely

• Consider Azure Service

Bus if sequencing is

required

Architectural Advise on CQRSDo not overengineer!

Performance

Flexibility

Scalability

Advantages

Idempotence

Resiliency

Eventual Consistency

Challenges

Complexity

Maintenance

Monitoring

Disadvantages

Apply CQRS carefully on specific parts of the solution!

Thank you!Keep in touch.

@toonvanhoutte

toonvanhoutte.wordpress.com

www.linkedin.com/in/toon-vanhoutte