Spring Boot Application as a Service

In this post, we will explore the option to run Spring Boot Application as a Service.

 

Introduction

Spring Boot provides different options to build, package and run applications.In this article, we will cover different options to run Spring Boot application as a service.We are covering the following points in this article.

• Unix/Linux Services.
• Microsoft Windows Services.

 

1. Build as Standard Jar

Spring Boot provides the feature to package your application as jar or war file.If we choose to create a jar package for a web application using Spring Boot, it will include all required dependencies in the jar along with embedded servlet container.Let’s take a look at project setup, packaging and running our application.

 

1.1 Maven Configurations

<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 http://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <packaging>jar</packaging>
   <!-- Inherit defaults from Spring Boot -->
   <parent>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-parent</artifactId>
      <version>2.0.1.RELEASE</version>
   </parent>
   <dependencies>....</dependencies>
   <build>
      <plugins>
         <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
            <configuration>
               <executable>true</executable>
            </configuration>
         </plugin>
      </plugins>
   </build>
</project>

This is a standard configuration for the Spring Boot application except <executable>true</executable>, this will help in

• Add MANIFEST.MF file in the JAR.This file contains a Main-Class entry that specifies which class defines the main method for your application.
• We can also use <start-class> properties in the POM.xml if using spring-boot-starter-parent pom.

 

1.2 Build and Run Spring Boot Application

To create deployment packet for our application, run following maven command

mvn clean package

When you run above command, Maven will create executable jar on the target folder.We may find following output on the successful build

INFO] --- maven-jar-plugin:3.0.2:jar (default-jar) @ restdemo ---
[INFO] Building jar: /Users/restdemo/target/restdemo-0.0.1-SNAPSHOT.jar
[INFO] 
[INFO] --- spring-boot-maven-plugin:2.0.0.RELEASE:repackage (default) @ restdemo ---
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 7.247 s
[INFO] Finished at: 2018-04-13T22:57:33-07:00
[INFO] Final Memory: 35M/310M
[INFO] ------------------------------------------------------------------------

To run the executable jar, use the following command

$ java -jar /Users/restdemo/target/restdemo-0.0.1-SNAPSHOT.jar

 

2. Spring Boot Unix/Linux Services

We can install and run Spring Boot application as Unix services by using init.d or systemd.

 

2.1 Installation as an init.d Service

To install Spring Boot application as init.d service, we only need to create a symlink.Let’s assume that our application is in the following location /var/rest-app

$ sudo ln -s /var/rest-app/restdemo.jar /etc/init.d/rest-app

Let’s understand what we did in the above command.

• We created a symbolic link to our executable JAR file.
• Make sure to use full path while creating a symbolic link else this may not work as expected.

Once completed, we use standard Linux way to start, stop our application

$ service rest-app start

• Use the application’s PID by using /var/run/<appname>/<appname>.pid to track application.
• Use /var/log/<appname>.log to check application specific error logs.

[pullquote align=”normal”]Make sure to secure init.d Service.Please follow OS specific security guide to secure your application. [/pullquote]

 

2.2. Systemd Service

Systemd is the latest and being used by many modern Linux distributions.Setting up systemd services is really easy.Let’s assume that we have installed our Spring Boot application on /var/rest-app.To create systemd service.

• Create a script with name your-app.service (rest-app.service).
• We should place this script in /etc/systemd/system directory.

Here is the sample content of the script

[Unit]
Description=Spring Boot REST Application
After=syslog.target

[Service]
User=javadevjournal
ExecStart=/var/rest-app/restdemo.jar
SuccessExitStatus=200

[Install]
WantedBy=multi-user.target

Please note that user that runs the application, the PID file, and the console log file managed by systemd itself and be configured by using proper fields in the ‘service’ script.

 

3. Microsoft Windows

Let’s have a look at the different options to run Spring Boot application on Microsoft Windows as a Windows service.

 

3.1. Windows Service Wrapper

A Spring Boot application can be started as a Windows service by using <a class="link" href="https://github.com/kohsuke/winsw" target="_blank" rel="nofollow noopener">winsw</a>.WinSW is an executable binary, which can be used to wrap and manage a custom process as a Windows service.We need to follow these steps to create Windows Service Wrapper for Spring Boot application.

• Download winsw.
• Rename the winsw.exe to DemoREST.exe.
• As the second step, we create a DemoREST.xml configuration XML file to define our Window service.

<?xml version="1.0" encoding="UTF-8"?>
<service>
   <id>demo-rest-service</id>
   <name>DemoREST</name>
   <description>Demo REST Spring Boot as a service.</description>
   <executable>java</executable>
   <arguments>-Xrs -Xmx512m -jar "%BASE%\demo.jar" --httpPort=8080</arguments>
   <logmode>rotate</logmode>
</service>

[pullquote align=”normal”]Make sure to rename winsw.exe to DemoREST.exe so its name matches with the DemoREST.xml configuration file [/pullquote]

To install our application as Window service, run following command

DemoREST.exe install

Once finished, you may use other commands like uninstall, start, stop etc for your application.

 

[pullquote align=”normal”]The Java Service Wrapper makes it possible to install a Java Application as a Windows Service.For more details read [/pullquote]

 

4. Alternatives

Apart from the options covered on this article, there are few other alternates worth looking at

• Apache Common Daemon
• Java Service Wrapper
• Procrun

 

Summary

In this article, we learned how to run Spring Boot Application as a Service on Linux and Window system.Services provide us more flexibility to manage and monitor our application status.