It is a time of developers complain about performance. Rebel developers, striking from a hidden base, have won their first victory against the evil blocking applications. In this session, attendees will learn about an evolution to a reactive system; we will show how to create a Reactive Application covering tips and tricks of an experience of an evolution the Application and how we evolve to a modern reactive modules; Through the session you are going to get tips, tricks, pros, cons and the reasons for being involved on move forward to non-bloking application and present sample code and explain the security concerns on this evolution. We will be using snippets code based on JAVA, JWT, JWS, Auth0, Spring Boot, Reactor and Webflux deployed on Oracle Cloud.

2. A long time ago in a project far,
far away. . .
REACTIVE
A New Hope
It is a time of developers
complain about performance.
Rebel developers, striking
from a hidden base, have won
their first victory against
the evil blocking applications.
by @betoSalazar

3. Let’s go to
our beginning
blocking
application
by @betoSalazar

4. ParadigmaTradicional
JEE application server (JBoss or WL or WAS)
thebanking.ear
banking-web.war
banking-js.jar
backoffice-web.war
accounts.jar
loans.jar
customers.jar
1 to n modules
Http
Web
Server
JakartaEE (Payara, TomEE, OpenLiberty, Wildfly…..)

5. by @betoSalazar
ParadigmaTradicional
Http
Web
Server
fat jar
accounts.jar
Service
some api
Rest-api-layer

6. Synchronous, blocking communication
by @betoSalazar
Thread 1
{ Thread 2
Thread 3
Thread n
Thread 4
request
response
Block
&
Wait

7. and….our enterprise application going to the cloud….

8. But….I continue in my confort zone
or ……… I think out of the box
by @betoSalazar

9. Reative…. …??????? ….why ?..
by @betoSalazar

10. billons of reasons………………
The era of high volume and high latency
by @betoSalazar

11. Reactive programming
by @betoSalazar
• Non-blocking applications
• Asynchronous
• Event-driven
• Small number of threads to scale vertically (i.e. within
the JVM) rather than horizontally (i.e. through
clustering)
Definition from: Spring Framework Documentation

12. by @betoSalazar
Paradigma Reactive
Database
Subscribe
Server send
Event
Watch streams changes
streams changed
Reactive is propagating changes by using events

13. Non blocking messaging
by @betoSalazar
request
response
{
{
Event loop
asynchronous
subscribe
&
Event from the
In non blocking
Processing
Back pressure

14. Reactive Programming
!=
Reactive System

15. Reactive system
by @betoSalazarImage from: https://medium.com/@ggonchar/reactive-spring-5-and-application-design-impact-159f79678739
React to users
React to failure
& stay available
Components
react to inputs
React to load

16. Reactive Programming
!=
Reactive System
• Impl technyque
• Async dataflow
• Single node or service
• Developer point of view{
• Design principles
• Orchestration of complex systems
• All system
• Architecture point of view{

17. Let’s go to see code
reactive
application
Vs
traditional
application
by @betoSalazar

18. Reactive or Traditional
+
Go to Spring Initializr: https://start.spring.io/

19. Tech stack
by @betoSalazar
● non-blocking applications
● 10's of millions of messages per second
● Scaling-Out to overcome latency and slow
microservices
https://projectreactor.io
https://projectreactor.io/docs/core/release/reference/
https://docs.spring.io/spring/docs/current/spring-framework-reference/web-reactive.html#spring-webflux
● non-blocking HTTP runtimes to the Reactive
Streams API

20. by @betoSalazar
Asynchronous, data stream
map, filter, zip……….. (stream operators)
Time
Time
Event1 Event2 Event3

21. R2DBC
by @betoSalazar
https://github.com/eugenp/tutorials/tree/master/spring-5-data-reactive
https://docs.spring.io/spring-data/r2dbc/docs/current-SNAPSHOT/reference/html/#get-started:first-steps:what
Tech stack

22. by @betoSalazar
Use cases
External Servers Calls High load, multiple consumers
And more:
• Real time data streaming
• Proxy servers, load balancers, Api Gateways
• Server code that serves highly interactive UI
elements (Stocks markets, social media, etc)
https://technology.amis.nl/2020/04/10/spring-blocking-vs-non-blocking-r2dbc-vs-jdbc-and-webflux-vs-web-mvc/
Spring: Blocking vs non-blocking: R2DBC vs JDBC and WebFlux vs Web MVC

23. Let’s go
to secure and
deploy to Cloud
a
reactive
application
by @betoSalazar

24. Secure - OAuth2
by @betoSalazar
● A user can log in with social network credentials like Facebook, Google
● Returns JWT tokens contain the logged in user
● Use the JSON Web Tokens JWT to validate if a user makes request to a REST Endpoints
● Forget about infrastructure (that’s why we are going serverless, after all) as much as possible;
● Use Auth0 and basically forget about the security details that are behind it.
https://auth0.com

25. Save resources on Cloud
by @betoSalazar

26. Reactive systems deploy on Oracle
Application Container Cloud
by @betoSalazar

27. Learnings
● Reactive System != Reactive Programming
● Easy to move forward using Webflux
● Reactive stack of modules: Webflux, Reactor,
R2DBC)
● Save resources at Infra On premise or Cloud
resources
● A new hope to: High load, multiple consumers
by @betoSalazar

28. The code . . .
REACTIVE A NEW HOPE!
Demo & Code blueprints
https://github.com/lasalazarr/reactive-a-new-hope
https://www.oracle.com/technetwork/es/articles/adf/spring-webflux-p1-5131133-esa.html
https://www.oracle.com/technetwork/es/articles/adf/spring-webflux-p2-5139508-esa.html
https://auth0.com/blog/introduction-getting-started-with-spring-webflux-api/ .
by @betoSalazar
Articles . . .

29. THANK YOU !
@betoSalazar