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CS156

Deploying an App - How to deploy a Hello World Spring Boot app to Dokku

Is your app a simple app?

For very simple apps (no frontend, no database, no OAuth logins), use these simplified instructions instead: https://ucsb-cs156.github.io/topics/dokku/deploying_simple_app.html

This version of the instructions is for apps where any of the following is true:

  • The app has a frontend
  • The app requires a database
  • The app requires OAuth logins

Overview

Here’s an overview of the steps involved

  1. Login to your dokku machine
  2. Create the app
  3. Define Environment Variables
  4. Define Settings
  5. Create and Link Postgres Database
  6. Sync with Github Repo
  7. Build App with http
  8. Enable https
  9. Test OAuth

We’ll now cover each of these one at a time.

Step 1: Log in to your dokku machine

See: https://ucsb-cs156.github.io/topics/dokku/logging_in.html for details.

Step 2: Create the app (dokku apps:create ...)

Create the app with this command

dokku apps:create appname

where appname is typically something like one of the following:

  • jpa03-cgaucho
  • courses-qa
  • happycows-dev-cgaucho

We’ll use appname throughout the rest of these instructions without further explanation.

Step 3: Define Environment Variables (dokku config:set ...)

Each Spring Boot app that we cover in this course will have specific requirements for environment variables and settings, so you’ll need to consult the specific documentation for the app to determine which settings are needed.

But you’ll typically always need to define PRODUCTION=true as follows:

dokku config:set appname PRODUCTION=true

This command enables the frontend code to be served from the same server that serves the backend; when running on localhost, these are separate, but on dokku these are integrated into a single server.

In addition, there will be specific environment variables for such things as the following. The precise list will depend on your application, but typically include at least the following:

  • GOOGLE_CLIENT_ID
  • GOOGLE_CLIENT_SECRET
  • ADMIN_EMAILS

You’ll find the values in your .env file, where you’ve typically configured these as part of setting up your application to run on localhost, which you typically do before setting it up to run on dokku.

For each of these values, copy the value into the command below:

dokku config:set appname --no-restart VARIABLE_NAME=value

where:

  • VARIABLE_NAME is the variable name from .env
  • value is the value from .env

Step 4: Define Settings (dokku git:set ...)

Some of the code bases we work with in this course are configured based on an assumption that the .git directory is retained when dokku pulls it in to the Docker container where the app is deployed.

We configure it this way so that we can display the git branch information in the running app.

For these apps, it is necessary to do the following one time setting:

dokku git:set appname keep-git-dir true

This setting indicates that the .git directory should be retained after the repo is cloned when setting up the app.

This is done, in part, so that the git-commit-id-maven-plugin can be used to get information about the current git branch that is deployed.

Step 5: Create and Link Postgres Database (dokku postgres:create ...)

Most apps in this course will use a Postgres Database.

Postgres database configuration requires several steps, so we’ve factored it out into it’s own page.

Follow these steps before proceeding.

Step 6: Sync with Github Repo (dokku git:sync...)

Next, sync with your github repo, like this:

dokku git:sync appName https://github.com/owner/repo.git main

Where:

  • [owner](https://github.com/owner/repo.git is the https link to your repo (which should be public (for private repos see these instructions).

Step 7: Build App with http (dokku ps:rebuild ...)

Next, to build your app the first time with http, type:

dokku ps:rebuild appname

Note that:

  • you will not be able to login with OAuth when the app is served only with http
  • however, *you cannot configure the app for https until it first is running with http

So we have to enable it with http first.

Step 8: Enable https (dokku letsencrypt...)

Now enable https with these commands:

dokku letsencrypt:set appname email yourEmail@ucsb.edu
dokku letsencrypt:enable appname

Step 9: Test OAuth

You should now be able to login to your app using https, so test that you can login with OAuth.

Try logging in at:

https://appname.dokku-xx.cs.ucsb.edu

where xx is your dokku number.