Reactive Guide for Spring MVC - Rossen Stoyanchev

Reactive Guide for Spring MVC by Rossen Stoyanchev at SpringOne Tour 2019

1. Guide to “Reactive”
for Spring MVC
Rossen Stoyanchev

2. About me
Spring Framework since 3.0
Evolution of Spring MVC programming model
Design and creation of WebFlux

3. Ugh, not another “reactive” talk...

4. but seriously,
how do you get on top of it?

5. ... and cut through the learning curve

6. We could talk about concurrency models

7. We can talk about
efficient scale with less (hardware) resources

8. We can talk about
growing asynchronicity in applications,
resilience under load, and so on...

9. All that talk wouldn’t be as effective as
seeing benefits in existing apps

10. Goals for Today
Demonstrate reactive features for Spring MVC applications
Start learning, get experience
For tangible benefits

11. Agenda
RestTemplate vs WebClient
Spring MVC controller reactive handling
Reactive client libraries
Testing

12. Best Practices
Find vertical slices suited for wholesale conversion
Where handling involves waiting for network I/O
More latency, more benefit

13. Best Practices
Avoid block, subscribe, etc. in controllers and services
Instead compose a single, deferred chain
Return Flux/Mono and let Spring MVC handle it

14. Best Practices
Non-blocking code should have a non-blocking API
It’s easy to add a synchronous facade on top
The goal is to enable composing single deferred chain

15. Source code
https://github.com/rstoyanchev/reactive-for-webmvc

16. Q & A