[JAVA] I tried Heroku, which can publish web applications for free

Overview

I felt that I was a long way behind the times, so I tried to get back even a little, so I tried Heroku, which can publish web applications for free, and summarized when I tried Getting Started on Heroku with Java on the official website & memorandum

[Official website (English)] 　Getting Started on Heroku with Java

What you can do when Getting Started is complete

• Web applications can be published for free (with restrictions *)

• You can use DB (PostgreSQL) for free

• Free frame is 550 hours / month Automatically sleeps if there is no operation for 30 minutes (no access, etc.) (If there is access, it will take the first time, but it will start automatically) See below for details 　Free Dyno Hours

Getting Started Approximate working time to complete

2 hours (I did it while putting it together, so if I just did it, it would be much less impressive)

Reference book

If the English documentation is painful, the only thing about Heroku? The following of Japanese books may be helpful It has the same contents as Getting Started, DB, files, response time at startup, and is full of useful information for beginners. Introduction to Heroku for Professionals Application Development and Operation Using Platform Cloud

My skills

• Java, Maven
• Heroku, git beginner

Advance preparation

• Free Heroku account (only email address required. Credit card registration is not required and the threshold is relatively low)
• Java 8
• Maven 3

Below, there is an installation procedure in the procedure

What I did and what I did

Follow the steps on the official website above to complete the following 15 steps You can do it without difficulty if you follow the procedure I'm rather embarrassed to fail twice (described later) ...

1. Introduction

Preparation contents


2. Set up

Heroku command line installation (git is installed with it)

After installation, log in with the Heroku command

$ heroku login
Enter your Heroku credentials.
Email: [email protected]
Password:

3. Prepare the app

git clone the prepared sample program and prepare it locally

$ git clone https://github.com/heroku/java-getting-started.git
$ cd java-getting-started

4. Deploy the app

Deploy and launch sample program on Heroku

$ heroku create
$ git push heroku master
$ heroku ps:scale web=1
$ heroku open

5. View logs

Explanation of log confirmation method

$ heroku logs --tail

6. Define a Procfile

Procfile description

Heroku seems to specify the type of application in this Procfile


7. Scale the app

Explanation of the concept of Dyno that runs the application and explanation of the above free frame

Dyno seems to be lightweight, secure, virtualized Unix container


8. Declare app dependencies

Explanation of pom.xml, system.properties and preparation for operation in local environment

Specify the operation version in system.properties


Because the environment variables JAVA_HOME and MAVEN_HOME were added and the setting to PATH was omitted when installing Java and Maven

No compiler is provided in this environment. Perhaps you are running on a JRE rather than a JDK? Occurrence

Environment variables MAVEN_HOME, JAVA_HOME added, both variables added to PATH solves

9. Run the app locally

Start in local environment and check screen

Local environment access URL: http: // localhost: 5000


10. Push local changes

Explanation of sample program modification procedure and deployment of modification to Heroku

$ mvn clean install
$ heroku local web

$ git add .
$ git commit -m "Demo"
$ git push heroku master
$ heroku open hello

git commit -m "Demo" says *** Please tell me who you are.

I was in the state of heroku login, so I thought that it would be linked without permission and tried various things again ...

As a result, heroku login was completely irrelevant, so quietly execute the following command displayed after Please tell me who you are.

git config --global user.email {email address}

git config --global user.name {name}

11. Provision add-ons

add-ons seems to be convenient, but I realized that credit card authentication is required and skipped


12. Start a one-off dyno

You can execute commands on Dyno

$ heroku run bash

13. Define config vars

Explanation that config settings can be used considering the environmental differences between the local environment and Heroku environment

In the local environment, set the .env file and Heroku environment with the command

$ heroku config:set ENERGY="20 GeV"
$ heroku config

14. Use a database

Explanation of DB (PostgreSQL)

On Heroku, the sample already has a DB access part, so the operation check is completed smoothly

The DB connection settings for the Heroku environment are in config

There seems to be another procedure in the local environment (not implemented)


15. Next steps

Why don't you study this area next time? Explanation


Summary

It is convenient that if you modify the program in about 2 hours in the future, you can easily publish it with just the following procedure I'm happy to be able to use DB

1. Program modification

2. mvn clean install

3. heroku local web

4. Local operation check

5. git add .

6. git commit -m "Comment"

7. git push heroku master

8. heroku open