JackyWhat you need
About 15 minutes
IDE
- Spring Tool Suite (STS)
- IntelliJ
- VSCode
Environment
- Java 17
- Gradle 7.5+ or Maven 3.5+
A little knowledge about dokku and docker Here I use the ready-made Public IP with Ubuntu 22.04 TLS: 64.176.80.xxx
Create a Spring boot 3
Source of web application creation from Spring homepage: https://start.spring.io/
Quick create link: Link
If you use IntelliJ IDE to manage code and compile, you may encounter some errors like this:
No matching variant of org.springframework.boot:spring-boot-gradle-plugin:3.1.2 was found
The workaround is pretty simple:
Ctrl + Alt + S > Build, Execution, Deployment > Gradle > Gradle JVM -> java 17
Add a class HomeController.java in the directory /src/main/java/com/jackynote/dokkudemo/springdokkudemo with the following content, the goal is to see the application page The application can return a request with the complete response:
package com.jackynote.dokkudemo.springdokkudemo;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
@RequestMapping
public class HomeController {
@GetMapping
ResponseEntity<String> getHome() {
return ResponseEntity.accepted().body("Hello world!");
}
}
You can then run the application using the Command line:
./gradlew bootRun
Run the application on the browser at port: http://localhost:8080 and get the results returned from the browser as Hello world
Build the application and package it (jar file), the packaged application will be built in the folder: build/libs and you can find it:
./gradlew build
# Run the jar file to see if it is correct for the debuging environment.
java -jar build/libs/spring-dokku-demo-0.0.1-SNAPSHOT.jar
Deploy the application to Dokku with Dockerfile
To setup Dokku environment, you can read from official website: https://dokku.com/
Create Dockerfile
cd /home/dokku/first-app
vi Dockerfile
And copy the content below or you can write your own script if you already have knowledge of docker and use them proficiently:
FROM openjdk:17
MAINTAINER Andy <jackynote.pro@gmail.com>
RUN mkdir /app
WORKDIR /app/
ADD ./spring-dokku-demo-0.0.1-SNAPSHOT.jar /app/
CMD java -jar spring-dokku-demo-0.0.1-SNAPSHOT.jar
EXPOSE 8080
Push the jar file from the local environment on the prepared server at the directory created for the application using Dokku:
# copy from the project folder to the application folder on the server
scp ~/<Project_Folder>/build/libs/spring-dokku-demo-0.0.1-SNAPSHOT.jar root@64.176.80.xxx:/home/dokku/first-app
root@64.176.80.xxx's password: ...
Deploy Web Application
SSH into the prepared server and execute the following scripts to deploy the application:
# go to the project's folder
cd /home/dokku/first-app
# build app with pushed jar file and generated Dockerfile
docker build -t dokku/first-app .
# some settings like nginx, port mapping from docker to public environment
dokku proxy:set first-app nginx
dokku ports:add first-app http:8080:8080
# deploy application
dokku deploy first-app
After successfully deploying you will get the following successful results:
-----> Deploying web (count=1)
Attempting pre-flight checks (1.)
-----> Executing 1 healthchecks
Running healthcheck name='default' type='uptime' uptime=10
Healthcheck succeeded name='default'
All checks successful (1.)
=====> Start of first-app container output (1.)
. ____ _ __ _ _
/\\\\\\\\ / ___'_ __ _ _(_)_ __ __ _ \\\\ \\\\ \\\\ \\\\
( ( )\\\\___ | '_ | '_| | '_ \\\\/ _` | \\\\ \\\\ \\\\ \\\\
\\\\\\\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\\\\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v3.1.2)
2023-08-22T09:41:22.960Z INFO 6 --- [ main] c.j.d.s.SpringDokkuDemoApplication : Starting SpringDokkuDemoApplication v0.0.1-SNAPSHOT using Java 17.0.2 with PID 6 (/app/spring-dokku-demo-0.0.1-SNAPSHOT.jar started by root in /app)
2023-08-22T09:41:22.967Z INFO 6 --- [ main] c.j.d.s.SpringDokkuDemoApplication : No active profile set, falling back to 1 default profile: "default"
2023-08-22T09:41:25.282Z INFO 6 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)
2023-08-22T09:41:25.306Z INFO 6 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2023-08-22T09:41:25.307Z INFO 6 --- [ main] o.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/10.1.11]
2023-08-22T09:41:25.583Z INFO 6 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2023-08-22T09:41:25.586Z INFO 6 --- [ main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 2495 ms
2023-08-22T09:41:26.906Z INFO 6 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2023-08-22T09:41:26.943Z INFO 6 --- [ main] c.j.d.s.SpringDokkuDemoApplication : Started SpringDokkuDemoApplication in 4.908 seconds (process running for 6.896)
=====> End of first-app container output (1.)
=====> Triggering early nginx proxy rebuild
-----> Running post-deploy
! Detected IPv4 domain name with nginx proxy enabled.
! Ensure the default nginx site is removed before continuing.
-----> Renaming containers
Container type (1) is no longer defined. Removing state
-----> Checking for postdeploy task
No postdeploy task found, skipping
Try accessing the application from the browser via the address: http://64.176.80.xxx:8080/
If you cannot access the application from the internet with a public IP, then it may be necessary to open port 8080 from your server:
sudo ufw allow 80
sudo ufw allow 443
sudo ufw allow 8080
