**Course Title:** Mastering Ruby on Rails: Building Scalable Web Applications **Section Title:** Version Control, Deployment, and CI/CD **Topic:** Deploy a Rails application to Heroku and configure a CI/CD pipeline for automated testing and deployment.(Lab topic) **Objective:** By the end of this topic, students will be able to deploy a Rails application to Heroku and configure a CI/CD pipeline for automated testing and deployment. **Prerequisites:** - Familiarity with Ruby on Rails and its ecosystem - Understanding of Git and GitHub for version control - Basic knowledge of CI/CD pipelines and automated testing **Materials:** - Heroku account (free tier available) - GitHub account (free tier available) - Git version control system - CI/CD tool of choice (e.g., GitHub Actions, CircleCI) - Rails application with tested and validated code **Step 1: Setting up Heroku and a New App** 1. Log in to your Heroku account and create a new app. 2. Choose the "Ruby" runtime and select the "12.2" version. 3. Click "Create" to create the new app. **Step 2: Configuring Heroku and Setting up a New Git Repository** 1. In your terminal, navigate to your Rails application's root directory. 2. Initialize a new Git repository using `git init`. 3. Add your Rails application's files to the Git repository using `git add .`. 4. Commit your changes using `git commit -m "Initial commit"`. **Step 3: Linking Heroku to Your Git Repository** 1. In your Heroku dashboard, click on "Settings" and then "Repos". 2. Click on "Add repository" and enter the URL of your Git repository. 3. Click "Add" to link your Git repository to Heroku. **Step 4: Deploying Your Rails Application to Heroku** 1. Run `git push heroku master` to deploy your Rails application to Heroku. 2. Heroku will automatically create a new dyno and provision the necessary resources for your application. **Step 5: Configuring a CI/CD Pipeline for Automated Testing and Deployment** 1. Create a new file in your GitHub repository called `.github/workflows/deploy.yml`. 2. Add the following YAML code to the file: ```yaml name: Deploy to Heroku on: push: branches: - master jobs: deploy: runs-on: ubuntu-latest steps: - name: Checkout code uses: actions/checkout@v2 - name: Install dependencies run: bundle install - name: Login to Heroku uses: heroku/heroku-cli@v2 with: api_key: ${{ secrets.HEROKU_API_KEY }} - name: Deploy to Heroku run: heroku ps:scale web=1 ``` 3. Save the file and commit the changes using `git commit -m "CI/CD pipeline for automated testing and deployment"`. **Step 6: Running the CI/CD Pipeline** 1. In your GitHub repository, click on the "Actions" tab. 2. Click on the "Run workflow" button next to the "Deploy to Heroku" workflow. 3. The CI/CD pipeline will automatically deploy your Rails application to Heroku and run any automated tests. **Key Concepts:** - Heroku and its free tier - Git and GitHub for version control - CI/CD pipelines and automated testing - Deploying Rails applications to Heroku **Practical Takeaways:** - Deploying a Rails application to Heroku is a straightforward process that requires minimal configuration. - Configuring a CI/CD pipeline for automated testing and deployment can help ensure that your application is always in a deployable state. - Using Heroku's free tier can help reduce costs and simplify the deployment process. **External Links:** - Heroku: https://www.heroku.com/ - GitHub: https://github.com/ - GitHub Actions: https://github.com/actions **Leave a comment or ask for help:** If you have any questions or need further assistance, please leave a comment below.