Configure CI/CD for your Ruby on Rails application

Table of contents

Prerequisites

Complete all the previous sections of this guide, starting with Containerize a Ruby on Rails application. You must have a GitHub account and a Docker account to complete this section.

Overview

In this section, you'll learn how to set up and use GitHub Actions to build and test your Docker image as well as push it to Docker Hub. You will complete the following steps:

  1. Create a new repository on GitHub.
  2. Define the GitHub Actions workflow.
  3. Run the workflow.

Step one: Create the repository

Create a GitHub repository, configure the Docker Hub credentials, and push your source code.

  1. Create a new repository on GitHub.

  2. Open the repository Settings, and go to Secrets and variables > Actions.

  3. Create a new Repository variable named DOCKER_USERNAME and your Docker ID as value.

  4. Create a new Personal Access Token (PAT) for Docker Hub. You can name this token docker-tutorial. Make sure access permissions include Read and Write.

  5. Add the PAT as a Repository secret in your GitHub repository, with the name DOCKERHUB_TOKEN.

  6. In your local repository on your machine, run the following command to change the origin to the repository you just created. Make sure you change your-username to your GitHub username and your-repository to the name of the repository you created.

    $ git remote set-url origin https://github.com/your-username/your-repository.git

  7. Run the following commands to stage, commit, and push your local repository to GitHub.

    $ git add -A
$ git commit -m "my commit"
$ git push -u origin main

Step two: Set up the workflow

Set up your GitHub Actions workflow for building, testing, and pushing the image to Docker Hub.

  1. Go to your repository on GitHub and then select the Actions tab.

  2. Select set up a workflow yourself.

    This takes you to a page for creating a new GitHub actions workflow file in your repository, under .github/workflows/main.yml by default.

  3. In the editor window, copy and paste the following YAML configuration.

    name: ci

on:
  push:
    branches:
      - main

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - name: Login to Docker Hub
        uses: docker/login-action@v3
        with:
          username: ${{ vars.DOCKER_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      - name: Build and push
        uses: docker/build-push-action@v6
        with:
          push: true
          tags: ${{ vars.DOCKER_USERNAME }}/${{ github.event.repository.name }}:latest

    For more information about the YAML syntax for docker/build-push-action, refer to the GitHub Action README.

Step three: Run the workflow

Save the workflow file and run the job.

  1. Select Commit changes... and push the changes to the main branch.

    After pushing the commit, the workflow starts automatically.

  2. Go to the Actions tab. It displays the workflow.

    Selecting the workflow shows you the breakdown of all the steps.

  3. When the workflow is complete, go to your repositories on Docker Hub.

    If you see the new repository in that list, it means the GitHub Actions successfully pushed the image to Docker Hub.

Summary

In this section, you learned how to set up a GitHub Actions workflow for your Ruby on Rails application.

Related information:

Next steps

Next, learn how you can locally test and debug your workloads on Kubernetes before deploying.

Test your Ruby on Rails deployment »