This document provides an overview of developing microservices for the cloud using Java. It introduces microservices architecture and the WSO2 Microservices Framework for Java (MSF4J). It demonstrates how to develop a simple stock quote microservice using MSF4J annotations and deploy it in standalone and containerized modes. It also covers integrating microservices with Kubernetes and Docker for production deployments in the cloud. Hands-on code samples are provided to illustrate key concepts.

1. Developing Microservices
for Cloud using Java
Senaka Fernando
Solutions Architect, WSO2 (UK)

2. Agenda
• Introduction to Microservices Architecture
• Introduction to WSO2 MSF4J
– Hands-on Sessions
• Introduction to Kubernetes/Docker
• Demonstrating MSF4J deployment with Kubernetes
– Demos

3. Links
• https://github.com/wso2/msf4j/releases/tag/v1.0.0
• https://docs.wso2.com/display/MSF4J100/Running+a
+Basic+Microservice
• http://wso2.com/products/data-analytics-server/
• http://wso2.com/products/identity-server/

4. Microservices Architecture
A method of developing software applications as a
suite of independently deployable, small, modular
services in which each service runs a unique process
and communicates through a well-defined,
lightweight mechanism to serve a business goal.

5. Microservices
h"p://mar)nfowler.com/ar)cles/microservices.html6

6. Inner & Outer Architecture
http://blogs.gartner.com/gary-olliffe/2015/01/30/microservices-guts-on-the-outside/

7. WSO2 Microservices Framework for Java (MSF4J)
• Lightweight & fast runtime
• Use Java annotations as a way of defining microservices APIs as well
as metrics
• Support well known & widely used methods such as JAX-RS
annotations
• Provide simple ways to develop & deploy microservices
• Built-in Metrics & Analytics APIs with out-of-the-box integration with
WSO2 Data Analytics Server (DAS)
• To be used in the WSO2 platform as a way of replacing all admin
services as well as defining other microservices for inter-component
interactions

8. MSF4J Implementation
• Based on the new WSO2 Carbon 5.0 kernel
• Transport is based on Netty 4.0
• Supports streaming
• High performance
• Very small pack size
• Starts within 300ms
• ~25MB memory consumption for the framework

9. MSF4J Performance Comparison

10. MSF4J Memory Consumption Comparison

11. Core Features of MSF4J
• Quick & simple development model using simple annotations
• Lightweight & high performance
• Custom interceptors
• OAuth based security
• Metrics gathering & publishing
• Streaming input & streaming output support
• WSO2 DevStudio based tooling for generating microservices projects
starting from a Swagger API definition
• Comprehensive samples demonstrating how to develop microservices
application

12. MSF4J Flow & Thread Model

13. Developer Experience & Programming
Model

14. Development Model
• Maven Archetype
• IDE/Build Classpath (msf4j-all.jar)
• Tooling (Swagger -> Code)

15. Maven pom.xml

16. Maven Archetype
mvn archetype:generate
-DarchetypeGroupId=org.wso2.msf4j
-DarchetypeArtifactId=msf4j-microservice
-DarchetypeVersion=1.0.0
-DgroupId=org.example
-DartifactId=myservice
-Dversion=1.0.0-SNAPSHOT
-Dpackage=org.example.service

17. Example - StockQuote Microservice

18. Application - Main Class

19. Build and Run !!!
mvn clean install
java -jar stockquote-1.0.0.jar

20. Tooling - WSO2 Developer Studio

21. Types of Deployment
• Standalone, Self contained jar files
• OS / Container images

22. Analytics & Monitoring
Supports annotations
• Timed – measures execution
• Metered – measures rate of events
• Counted – counts the total invocations
• HTTPMonitored – monitors HTTP requests

23. Analytics & Monitoring

24. Service Metrics - Console Output

26. Security
• Security is done via a central server issuing JWT or
OAuth tokens.
• The OAuth2SecurityInterceptor verifies the token
before accessing the resources.

27. MSF4J Hands-on Sessions

28. Hello World!
• Build the sample - wso2msf4j-dist-1.0.0/samples/
helloworld
mvn clean install
• Run the sample
java -jar helloworld-*.jar
• Test the sample
curl http://localhost:8080/hello/
wso2

29. Fat JAR samples
• Refer the sample -
https://docs.wso2.com/display/
MSF4J100/Developing+a+Microservice+in
+Fat+JAR+Mode

30. Download WSO2 Data Analytics Server
• http://wso2.com/products/data-
analytics-server

31. HTTP Monitoring with Data Analytics
• Refer the sample -
https://docs.wso2.com/display/
MSF4J100/Using+Metrics+and+HTTP
+Monitoring+Interceptors

32. Simple File Server
• Refer the sample -
https://docs.wso2.com/display/
MSF4J100/Handling+Files

33. Download WSO2 Identity Server
• http://wso2.com/products/identity-
server

34. Security for Microservices
• Refer the sample -
https://docs.wso2.com/display/
MSF4J100/Securing+Microservices

35. Your First MS - Maven Build
mvn archetype:generate -
DarchetypeGroupId=org.wso2.msf4j -
DarchetypeArtifactId=msf4j-microservice
-DarchetypeVersion=1.0.0

36. Your First MS - Write a StudentService
• API -
– GET /student/getAll - get all students
– GET /student/get/{id} - get student with {id}
– POST /add - add a student
• Intercept requests
• Monitoring

37. Your First MS - Annotations
• JAX-RS HTTP resource methods - @GET @POST
@PUT @DELETE
• Content-negotiation - @Produces @Consumes
• Service lifecycle - @PreDestroy
@PostDestroy

38. Production Deployment with
Kubernetes and Docker

39. Virtual Machines vs Containers

40. What is Docker
• Container Virtualization
• Build, pack, ship and run applications as containers
• Build once, run in many places
• Isolated

41. Docker Filesystem

42. StockQuote Service Dockerfile

43. Kubernetes
• Kubernetes is an open source orchestration system
for Docker containers
• Docker -> Container lifecycle management
• Kubernetes -> Orchestration and container cluster
management
“Kubernetes, I need 5 Tomcat and one
MySQL server running at all times.”

44. Kubernetes in a Nutshell

45. Kubernetes UI

46. PetStore sample

47. Petstore sample

48. Petstore sample

49. Petstore sample - deployment view

50. CONTACT US !