Booting Spring Boot into Heroku

January 17, 2014
spring heroku spring boot deployment

Spring Boot is a new approach from Spring to build web applications. The quote from Spring is that it “takes an opinionated view of building production-ready Spring applications. Spring Boot favors convention over configuration and is designed to get you up and running as quickly as possible.” One of the things I like doing when evaluating a new framework is to ensure that I have an environment to deploy my work. So this post will show you how to get a sample Spring Boot application running on heroku.

To get started, you need a few prerequistes.

JDK 1.7
Maven 3
A Herkou account
Heroku command line tools
Git
An internet connection :)

The very first thing we need to do is create a very simple application that can be deployed.

Firstly, we will create a vanilla maven project with the correct dependencies for Spring Boot setup. Create a new directory (sample-spring-boot) and a pom.xml file inside it. Put the following contents in the 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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.example</groupId>
    <artifactId>myproject</artifactId>
    <version>0.0.1-SNAPSHOT</version>

    <!-- Inherit defaults from Spring Boot -->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>0.5.0.M6</version>
    </parent>

    <!-- Add typical dependencies for a web application -->
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>

    <!-- Package as an executable JAR -->
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

    <!-- Allow access to Spring milestones and snapshots -->
    <!-- (you don't need this if you are using anything after 0.5.0.RELEASE) -->
    <repositories>
        <repository>
            <id>spring-snapshots</id>
            <url>http://repo.spring.io/snapshot</url>
            <snapshots><enabled>true</enabled></snapshots>
        </repository>
        <repository>
            <id>spring-milestones</id>
            <url>http://repo.spring.io/milestone</url>
            <snapshots><enabled>true</enabled></snapshots>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>spring-snapshots</id>
            <url>http://repo.spring.io/snapshot</url>
        </pluginRepository>
        <pluginRepository>
            <id>spring-milestones</id>
            <url>http://repo.spring.io/milestone</url>
        </pluginRepository>
    </pluginRepositories>
</project>

Create a sample controller under src/main/java/SampleController.java. It should have the following contents.

import org.springframework.boot.*;
import org.springframework.boot.autoconfigure.*;
import org.springframework.stereotype.*;
import org.springframework.web.bind.annotation.*;

@Controller
@EnableAutoConfiguration
public class SampleController {

    @RequestMapping("/")
    @ResponseBody
    String home() {
        return "Hello World!";
    }

    public static void main(String[] args) throws Exception {
    	String webPort = System.getenv("PORT");
        if (webPort == null || webPort.isEmpty()) {
            webPort = "8080";
        }
        System.setProperty("server.port", webPort);
        SpringApplication.run(SampleController.class, args);
    }
}

Let’s start up our application to see if everything we have done to date is functional. Run the following command in a shell.
```
$ java -jar target/*.jar
```
You should be able to now go to the http://localhost:8080 via your web browser or use curl to access it.
```
$ curl http://localhost:8080
```
Now let’s create a Procfile so heorku will know how to start our application. So create a file with the name Procfile and put it in the root of your project. Add the following contents to the file.
```
web: java -jar target/*.jar
```
Create a system.properties file that tells heroku to use Java 1.7. It should have the following contents.
```
java.runtime.version=1.7
```

Add your project to a git repository.

$ git init .
$ git add .
$ git commit -m 'initial add'

Assuming you have the heroku command line tools installed, create a heroku application via the following command.
```
$ heroku create
```
Now you should be able to deploy by pushing your code to the heroku remote branch.
```
$ git push heroku master
```
If this has worked your application should now be deployed to heroku.
```
$ heroku open
```

I hope this article has shown you the steps required to deploy a Spring Boot application to herkou. The code for this application can be found here.

Read more