#12 Helidon 2.2 – Fast, Secure & Lightweight microservices framework

Helidon framework (Open sourced by Oracle ) to develop fast, lightweight and secure microservices

Microservices – also known as the microservice architecture – is an architectural style that structures an application as a collection of loosely coupled services, which implement business capabilities. The microservice architecture enables the continuous delivery/deployment of large, complex applications. It also enables an organization to evolve its technology stack. There are many framework used for writing microservices like Spring boot, Micronauts, micronaut, Quarkus and Helidon. In this article we will talk about Helidon framework and how we can write an effective, fast and lightweight microservice using Oracle Helidon.

What is Helidon ?

Helidon is a microservices framework developed by Oracle internal projects under the name J4C(Java for Cloud). Now Helidon framework has been open sourced by Oracle.

Helidon SE and Helidon MP

Currently there are two programming model supported by this framework – Helidon SE and Helidon MP. Helidon SE is designed for microservices that support reactive programming model. Helidon MP is designed to support Eclipse MicroProfile runtime that allow Jakarta EE community to run portable microservices.

Helidon architecture and how Helidon SE & Helidon MP fit together

The relationship between Helidon SE and Helidon MP is shown in the architecture diagram

Helidon SE quickstart

Prerequisite

• Maven
• Java > 11

1. Run following command from cmd/bash

mvn -U archetype:generate -DinteractiveMode=false -DarchetypeGroupId=io.helidon.archetypes -DarchetypeArtifactId=helidon-quickstart-se -DarchetypeVersion=2.2.2 -DgroupId=com.teknonauts.examples -DartifactId=helidon-example-se -Dpackage=com.teknonauts.examples.helidon.se

2. It will generate project: helidon-example-se. Import this project as an existing maven project in your workspace. Structure will look like this

3. Understand main method in Main.java

WebServer server = WebServer.builder(createRouting(config))
                .config(config.get("server"))
                .addMediaSupport(JsonpSupport.create())
                .build();

        // Try to start the server. If successful, print some info and arrange to
        // print a message at shutdown. If unsuccessful, print the exception.
        server.start()
                .thenAccept(ws -> {
                    System.out.println(
                            "WEB server is up! http://localhost:" + ws.port() + "/greet");
                    ws.whenShutdown().thenRun(()
                            -> System.out.println("WEB server is DOWN. Good bye!"));
                })
                .exceptionally(t -> {
                    System.err.println("Startup failed: " + t.getMessage());
                    t.printStackTrace(System.err);
                    return null;
                });

4. Now run the main method and check the services –

http://localhost:8080/greet

http://localhost:8080/greet/{name}

5. You can also run below command to generate jar and run the server

mvn package
java -jar target/helidon-example-se.jar

6. Build and Run Docker Image

docker build -t helidon-example-se .
docker run --rm -p 8080:8080 helidon-example-se:latest

Helidon MP quickstart

Prerequisite

• Maven,
• Java > 11

1. Run following command from cmd/bash

mvn -U archetype:generate -DinteractiveMode=false -DarchetypeGroupId=io.helidon.archetypes -DarchetypeArtifactId=helidon-quickstart-mp -DarchetypeVersion=2.2.2 -DgroupId=com.teknonauts.examples -DartifactId=helidon-example-mp -Dpackage=com.teknonauts.examples.helidon.mp

2. It will generate project: helidon-example-mp. Import this project as an existing maven project in your workspace. Structure will look like this

3. Package the project with below command

mvn package

4. Run the below command to start the server

java -jar target/helidon-example-mp.jar

5. Observe below API and related code

http://localhost:8080/greet

http://localhost:8080/greet/{name}

6. Health Matrics

Health 
curl -s -X GET http://localhost:8080/health

Matrics in Prometheus format 
curl -s -X GET http://localhost:8080/metrics 

7. Build and Run docker image

docker build -t helidon-example-mp .
docker run --rm -p 8080:8080 helidon-example-mp:latest

Conclusion Helidon SE vs Helidon MP

Helidon SE	Helidon MP
Helidon SE gives you full transparency and puts you in control.	Helidon MP is built on top of the Helidon libraries and provides platform definition that is familiar to enterprise Java developers.
Microframework model with a very small footprint and limited functionality (~7 MB)	Eclipse MicroProfile implementation; slightly larger footprint than SE (~13 MB)
Functional style is reactive non-blocking	Declarative style with dependency injection
Transparent “no magic” development experience; pure java application development with no annotations and no dependency injections	Jakarta EE microprofile development experience; all Jakarta components (CDI, JAX-RS, JSON-P/B)
Learn more about Helidon SE.	Learn more about Helidon MP.

Helidon SE & Helidon MP example code available on our git page

https://github.com/teknonauts/helidon

Next topic to cover

In this article I have covered basics of helidon framework and how to create simple project in both categories. Below are the two topics I will cover in next post of this series

• GraalVM and its benefit. GraalVM support in Helidon framework
• Non-blocking Database client in Helidon

Reference

• Helidon.io
• Example from baeldung
• Microprofile.io — https://microprofile.io/

Explore more at Teknonauts.com