Reactive Microservice with MicroProfile presentation at Community Day, EclipseCon Europe 2019. Speaker: Emily Jiang

1. Reactive Microservices with
Eclipse MicroProfile
Emily Jiang
Java Champion
STSM, IBM
Liberty Microservice Architect, Advocate
Senior Lead for MicroProfile and CDI
@emilyfhjiang

2. 2
Why Reactive?

3. 3
Synchronous calls

4. Two microservices...
BA

5. Two microservices...
BA
data/client/test/hello data/service/hello
“hello” “hello”

6. data/client/test/hello data/service/hello
“hello” “hello”
… Interacting using synchronous calls

7. 7
Asynchronous calls

8. Asynchronous calls (because it’s trendy)

9. Microservices are like kids...
Need mudguards
(a)
(b)
(c)

10. (a)
(b)
(c)
MicroProfile Fault-Tolerance

11. Sorry, I’m out of context...
I’ve lost my thread locals!
(User, Transaction, Correlation
Id…)

12. MicroProfile Context Propagation
Restore the
context
Capture the
context

13. MicroProfile Context Propagation

14. Most asynchronous things
AREN’T non-blocking.

15. You need
asynchrony + non-blocking
to use resources
efficiently

16. … Is this what you want?
Non-Blocking IOAsynchronous,
Fault-Tolerance
Context
Propagation

17. … And they lived together happily ever after.
???
!!!

18. 19
Reactive

19. 20
What Reactive?

20. System eXtensions
Programming
Manifesto
Streams
Asynchrony
Back-Pressure
Resilience
Elasticity
Spreadsheets
Actor
Data Flows
Observable
Events
Messages ReactorRX JavaResponsiveness
Fibers
Non-Blocking
MicroProfile
Spring
RSocket
Reactive all the things ???

21. 22
System eXtensions
Programming
Manifesto
Streams
Asynchrony
Back-Pressure
Resilience
Elasticity
Spreadsheets
Actor
Data Flows
Observable
Events
Messages ReactorRX JavaResponsiveness
Fibers
Non-Blocking
MicroProfile
Spring
RSocket
Reactive all the things ???

22. 23
Reactive Programming
Data
Streams
Propagation
of changes

23. 24
Reactive Extensions
Data
Streams
Propagation
of changes

24. 25
Reactive Streams
Data
Streams
Propagatio
n of
changes
Back
Pressure
Protocol

25. 26
Reactive Streams - Java 9+ edition
Observable Stream of <T>
Stream Observer
On new item
On failure
On completion

26. 27
Reactive Streams - Java 9+ edition
The contract between the
observer and the stream
Stop the observation
Request items

27. 28
Reactive Streams - How does that work?
Subscriber Publisher
(1)subscribe
(2) onSubscribe(sub)

28. 29
Reactive Streams - How does that work?
Subscriber Publisher
(3) request(x)
(4) onNext(i1)
(5) onNext(i2)
(6) onComplete()

29. 30
Reactive Streams - How does that work?
Subscriber Processor Publisher
subscribe
request(x)
subscribe
request(x)

30. 31
http://www.reactivemanifesto.org/
Reactive Systems

31. 32
How Reactive?

32. Applying reactive to microservices
Temporal
decoupling
Back-Pressure
Protocol

33. Using messages to achieve decoupling
BA
Sent to virtual addresses
Can be durable (temporal
decoupling)
Use non-blocking IO

34. Messaging / Streaming
MicroProfile
Application Code
Container Host / Operating System
Async HTTP Messaging
MicroProfile
Application Code
Container Host / Operating System
MicroProfile Reactive Messaging
MicroProfile
Reactive Messaging

35. 36
MicroProfile Reactive Messaging

36. 37
MicroProfile Reactive Messaging
Connector
configuration
(protocol specific)

37. 38
MicroProfile Reactive Messaging
Reactive
Streams

38. Reactive architecture
BA
Decoupling, Elasticity, Resilience,
Back-Pressure, Asynchrony, Non-Blocking

39. https://github.com/Emily-Jiang/reactive-service-a
https://github.com/Emily-Jiang/reactive-service-b
40
Example

40. Thank you
41
Emily Jiang
STSM, Liberty Microservice Architect and Advocate
Java Champion
—
emijiang@uk.ibm.com