Create a Spring Boot Microservice

This tutorial uses the Spring Initializr to create a simple microservice to quickly generate an Entando bundle project.

Prerequisites

• A working instance of Entando
• Verify dependencies with the Entando CLI: ent check-env develop

Step 1: Initialize the Bundle with a Microservice

1. Initialize a new bundle:

ent bundle init your-spring-project

2. From the bundle project root directory, create a new microservice:

cd your-spring-project
ent bundle ms add spring-ms

Step 2: Create the Microservice

1. At the Spring Initialyzr page, start.spring.io (opens new window), create a project with the following configuration:

	Project=Maven
	Language=Java
	Spring Boot version=3.2.3
	Group=com.entando.example
	Artifact=spring-ms 
	Name=spring-ms 
	Description=Demo project for Spring Boot
	Package name=com.entando.example.spring-ms
	Packaging=Jar
	Java=17
	Dependencies:
	         WEB: Spring Web 
	         OPS: Spring Boot Actuator

Click generate.

2. Unzip the package and move the unzipped files and src directory to the microservices/spring-ms/ directory.

3. Create a new directory for the controller:

mkdir microservices/spring-ms/src/main/java/com/entando/example/springms/controller

4. In the controller directory, create TemplateController.java with the following code:

package com.entando.example.springms.controller;
import org.springframework.web.bind.annotation.*;
@RestController
public class TemplateController {
         @CrossOrigin @GetMapping("/api/example")
         public MyResponse getExample() { return new MyResponse("test Data"); }
         public static class MyResponse{
                 private final String payload;
                 public MyResponse(String payload) { this.payload = payload; }
                 public String getPayload() { return payload; }
         }
}

5. To make the microservice compatible with Entando, add the following snippet to the microservices/spring-ms/src/main/resources/application.properties file:

server.port=8081
management.endpoints.web.base-path=/api

6. Run the microservice from the bundle project root directory to test that it works:

ent bundle run spring-ms

• In your browser, access http://localhost:8081/api/example (opens new window) to see {"payload":"test Data"}.
• Then, access http://localhost:8081/api/health (opens new window) to see {"status":"UP"}. In local development, the run command can be used to modify the ports to run multiple microservices, but in production, microservices must run on port 8081.

7. Create microservices/spring-ms/Dockerfile so ent knows how to assemble the Docker image for the service:

FROM openjdk:17
WORKDIR /app
COPY target/*.jar /app/app.jar
CMD ["java", "-jar", "app.jar"]
EXPOSE 8081

Step 3: Build and Install the Bundle

1. Optionally, add an image file in PNG or JPG format named thumbnail for the project.

2. To install your bundle, execute the following commands:

ent bundle pack

ent bundle publish

ent bundle deploy

ent bundle install

3. Test your Spring Boot microservice:

• Retrieve YOUR-HOST-NAME and YOUR-MS-PATH with this command:

ent kubectl describe ingress

YOUR-MS-PATH is listed under path and should be similar to this:

/your-spring-project-83fbf4bf/spring-ms

• Using your values, go to YOUR-HOST-NAME/YOUR-MS-PATH/api/example/ in your browser. It should return {"payload":"test Data"}.

E.g., for a quickstart project,
URL= http://quickstart.192.168.64.34.nip.io/your-spring-project-83fbf4bf/spring-ms/api/example/

Next Steps

• Learn to connect micro frontends to microservices by adding an API Claim.
• Add a configuration micro frontend to your bundle project.