Deploy SpringBoot web Application(tomcat server) to BTP Kyma runtime

[Jacky_Liu]

One of customers ask if  their existing  application deployed in tomcat server can be deployed into BTP runtimes . I think one option is BTP cloud foundry runtime. I checked the document , BTP cloud foundry has tomcat container. The tutorial Create a Java Application via Cloud Foundry Command Line Interface | Tutorials for SAP Developers give guidance about how. I tried it and if I follow the steps , I can succeed .

Then I think why not build docker image for the application run in Tomcat server and then deply the application into BTP Kyma runtime. I tried with springboot web application run with Tomcat server.

In this blog, I will share the steps :

Prerequisites:

1, Have installed Java JDK

2, Have installed Maven

3, Have installed docker

4, Have installed Intellij IDEA(Optional)

5, Kyma runtime has been activated in your BTP subaccount .

 

Step 1: Creat a SpringBoot application name tomaop

The following is the POM file .

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">

  <modelVersion>4.0.0</modelVersion>

  <parent>

    <groupId>org.springframework.boot</groupId>

    <artifactId>spring-boot-starter-parent</artifactId>

    <version>2.7.8</version>

    <relativePath/> <!-- lookup parent from repository -->

  </parent>

  <groupId>com.sap</groupId>

  <artifactId>tomaop2</artifactId>

  <version>0.0.1-SNAPSHOT</version>

  <name>tomaop2</name>

  <description>Demo project for Spring Boot</description>

  <properties>

    <java.version>11</java.version>

  </properties>

  <dependencies>

    <dependency>

      <groupId>org.springframework.boot</groupId>

      <artifactId>spring-boot-starter-web</artifactId>

    </dependency>

    <dependency>

      <groupId>org.springframework.boot</groupId>

      <artifactId>spring-boot-starter-aop</artifactId>

    </dependency>

    <dependency>

      <groupId>org.springframework.boot</groupId>

      <artifactId>spring-boot-starter-test</artifactId>

      <scope>test</scope>

    </dependency>

  </dependencies>



  <build>

    <plugins>

      <plugin>

        <groupId>org.springframework.boot</groupId>

        <artifactId>spring-boot-maven-plugin</artifactId>

      </plugin>

    </plugins>

  </build>



</project>

The following is the controller class:

package com.sap.tomaop2.controller;

import com.sap.tomaop2.model.Employee;

import com.sap.tomaop2.service.EmployeeService;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.web.bind.annotation.GetMapping;

import org.springframework.web.bind.annotation.RequestParam;

import org.springframework.web.bind.annotation.RestController;



@RestController



public class EmployeeController {



  @Autowired

  private  EmployeeService employeeService;



  @GetMapping(path = "/add/employee")

  public Employee createEmployee(@RequestParam("empId") String empId,@RequestParam("firstName") String firstName,@RequestParam("secondName") String secondName){

   return employeeService.createEmployee(empId,firstName,secondName);

  }

  @GetMapping(path = "/del/employee")

  public String deleteEmployee(@RequestParam("empId") String empId){

    employeeService.deleteEmployee(empId);

    return "The employe " + empId +" has been deleted";

  }

  

}

 

Run the application with the command: mvn  spring-boot:run

Test in browser:

 

Step 2: Buid docker file for the SpringBoot application

Add  google-jib plugin in pom file

Maintain docker account information in Intellij IDEA .

Run the following command to build the application:

mvn compile jib:buildTar

Check the generated tar file :

Load the tar file to Docker with following command:

docker load -i ./target/jib-image.tar

Check the image with the following command:

docker images | find "spring"

Push the image to docker hub with following command:

 

Step 3: Prepare Kyma deployment YAML file:

apiVersion: apps/v1

kind: Deployment

metadata:

  name: tomaop

  labels:

    app: tomaop

spec:

  selector:

    matchLabels:

      app: tomaop

  strategy:

    rollingUpdate:

      maxUnavailable: 1

  replicas: 1

  template:

    metadata:

      labels:

        app: tomaop

    spec:

      containers:

        - image: registry.hub.docker.com/dockeraccount/springbootaop:latest

          imagePullPolicy: Always

          name: tomaop

          ports:

            - name: http

              containerPort: 8080

          env:

            - name: DEBUG

              value: "true"

            - name: RENEWCERT_JOB_CRON

              value: "00 00 */12 * * *"

          resources:

            requests:

              memory: "512Mi"

              cpu: "50m"

            limits:

              memory: "1000Mi"

              cpu: "100m"

---

apiVersion: v1

kind: Service

metadata:

  name: tomaop

  labels:

    app: tomaop

spec:

  ports:

    - name: http

      port: 8080

  selector:

    app: tomaop

Step 4: Deploy the SpringBoot Application to BTP Kyma runtime:

Uload previous step YAML file

 

Step 5:Create API Rule for the service:

Step 6:Test with Chrome:

This is just a simple test, the actual situation is much more complecated with other stuffs like persistance , authorization ,etc .

 

The ends!

Thanks for your time!

Best regards!

Jacky Liu