Continuous Integration (CI) and Continuous Delivery (CD) are essential practices in modern software development. They help ensure that your code is always in a deployable state, automate the testing process, and streamline the deployment pipeline. In this section, we will cover the following topics:

1. Introduction to CI/CD
2. Setting Up a CI/CD Pipeline
3. Using GitHub Actions for CI/CD
4. Automating Tests
5. Deploying to App Stores

Continuous Integration is a development practice where developers integrate code into a shared repository frequently, preferably several times a day. Each integration is verified by an automated build and automated tests to detect integration errors as quickly as possible.

Continuous Delivery is a software development practice where code changes are automatically prepared for a release to production. It ensures that the software can be reliably released at any time.

• Early Detection of Errors: Automated tests run on every commit, catching bugs early.
• Faster Release Cycles: Automating the build and deployment process speeds up the release cycle.
• Improved Collaboration: Developers can work on different features without worrying about integration issues.
• Consistent Builds: Automated builds ensure that the software is built in a consistent environment.

• Source Control: A version control system like Git.
• Build Server: A server that automates the build process (e.g., GitHub Actions, Jenkins).
• Test Automation: Automated tests that run on every build.
• Deployment Automation: Scripts and tools to deploy the application to various environments.

1. Code Commit: Developers commit code to the repository.
2. Build Trigger: The CI server detects the commit and triggers a build.
3. Automated Tests: The build server runs automated tests.
4. Build Artifacts: If tests pass, the build server creates build artifacts.
5. Deployment: The build artifacts are deployed to a staging environment.
6. Manual Approval: Optionally, a manual approval step before deploying to production.
7. Production Deployment: The application is deployed to the production environment.

GitHub Actions is a powerful tool for automating workflows directly in your GitHub repository. Let's set up a basic CI/CD pipeline using GitHub Actions.

1. Create a GitHub Repository:

   • Create a new repository on GitHub or use an existing one.

2. Add a Workflow File:

   • In your repository, create a .github/workflows directory.
   • Inside this directory, create a file named ci-cd.yml.

3. Define the Workflow:

   name: CI/CD Pipeline
   
   on:
     push:
       branches:
         - main
   
   jobs:
     build:
       runs-on: ubuntu-latest
   
       steps:
         - name: Checkout code
           uses: actions/checkout@v2
   
         - name: Set up Node.js
           uses: actions/setup-node@v2
           with:
             node-version: '14'
   
         - name: Install dependencies
           run: npm install
   
         - name: Run tests
           run: npm test
   
         - name: Build project
           run: npm run build
   
         - name: Deploy to staging
           run: echo "Deploying to staging environment"
   

• name: The name of the workflow.
• on: Specifies the event that triggers the workflow (e.g., push to the main branch).
• jobs: Defines the jobs to run in the workflow.
• steps: The individual steps in the job, such as checking out the code, setting up Node.js, installing dependencies, running tests, building the project, and deploying to staging.

Automated tests are crucial for ensuring the quality of your code. In a React Native project, you can use tools like Jest and Detox for testing.

Add the following step to your GitHub Actions workflow to run Jest tests:

Add the following steps to your GitHub Actions workflow to run Detox tests:

To deploy to the Apple App Store, you can use tools like fastlane.

1. Install Fastlane:

   sudo gem install fastlane -NV
   

2. Initialize Fastlane:

   fastlane init
   

3. Create a Fastlane Lane for Deployment: In your Fastfile, add a lane for deployment:

   lane :deploy do
     build_app(scheme: "YourAppScheme")
     upload_to_app_store
   end
   

4. Add Fastlane to GitHub Actions Workflow:

   - name: Install Fastlane
     run: sudo gem install fastlane -NV
   
   - name: Deploy to App Store
     run: fastlane deploy
   

To deploy to the Google Play Store, you can also use fastlane.

1. Create a Fastlane Lane for Deployment: In your Fastfile, add a lane for deployment:

   lane :deploy do
     gradle(task: "assembleRelease")
     upload_to_play_store
   end
   

2. Add Fastlane to GitHub Actions Workflow:

   - name: Install Fastlane
     run: sudo gem install fastlane -NV
   
   - name: Deploy to Google Play
     run: fastlane deploy
   

In this section, we covered the basics of Continuous Integration and Continuous Delivery, including setting up a CI/CD pipeline, using GitHub Actions, automating tests, and deploying to app stores. By implementing CI/CD practices, you can ensure that your React Native applications are always in a deployable state, leading to faster release cycles and higher code quality.

Next, we will move on to real-world projects where you can apply the concepts learned throughout this course.