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In this guide, you’ll learn how to integrate Docker Hub authentication into your GitHub Actions CI/CD pipeline. By the end, your workflow will automatically build and push a Docker image once unit tests and code coverage checks have passed.

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Prerequisites

  • A GitHub repository containing your application code and a Dockerfile.
  • Unit tests and code coverage steps already configured in your workflow.
  • Docker Hub account with repository access.

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1. Existing Workflow Overview

Below is an example workflow that runs unit tests and measures code coverage on every push to main or any feature/* branch: 
name: Solar System Workflow

on:
  push:
    branches:
      - main
      - 'feature/*'
  workflow_dispatch:

env:
  MONGO_URI: 'mongodb+srv://supercluster.d83jj.mongodb.net/superData'
  MONGO_USERNAME: ${{ vars.MONGO_USERNAME }}
  MONGO_PASSWORD: ${{ secrets.MONGO_PASSWORD }}

jobs:
  unit-testing: …
  code-coverage: …

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2. Dockerfile for the Application

Ensure your repository includes a Dockerfile like this: 
FROM node:18-alpine3.17
WORKDIR /usr/app

COPY package*.json /usr/app/
RUN npm install

COPY . .
ENV MONGO_URI=uriPlaceholder
ENV MONGO_USERNAME=usernamePlaceholder
ENV MONGO_PASSWORD=passwordPlaceholder

EXPOSE 3000
CMD ["npm", "start"]

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3. Add the Containerization Job

We’ll create a new job named containerization that depends on the previous jobs. This job will:
  1. Check out the repository.
  2. Authenticate to Docker Hub.
  3. Build and push the Docker image.
jobs:
  unit-testing: …
  code-coverage: …

  containerization:
    name: Containerization
    needs: [unit-testing, code-coverage]
    runs-on: ubuntu-latest

    steps:
      - name: Checkout Repository
        uses: actions/checkout@v4

      - name: Log in to Docker Hub
        uses: docker/login-action@v2
        with:
          username: ${{ vars.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_PASSWORD }}

      - name: Build Docker Image
        run: |
          docker build -t my-app:${{ github.sha }} .
          
      - name: Push Docker Image
        run: |
          docker push my-app:${{ github.sha }}
Replace my-app with your Docker Hub repository name (e.g., username/solar-system).
You can also tag with :latest or semantic versions.

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4. Store Credentials as Variables and Secrets

To prevent exposing your Docker Hub credentials in the workflow, add them via the GitHub UI:
NameTypeLocation
DOCKERHUB_USERNAMEVariableSettings → Secrets and variables → Actions → Variables
DOCKERHUB_PASSWORDSecretSettings → Secrets and variables → Actions → Secrets
  1. Go to Settings > Secrets and variables > Actions.
  2. Under Repository variables, click New repository variable and add DOCKERHUB_USERNAME.
  3. Under Repository secrets, click New repository secret and add DOCKERHUB_PASSWORD.
Add a new secret in GitHub repository settings
Manage Actions secrets and variables in GitHub repository settings
Add a new Actions variable for Docker Hub username
Overview of Actions secrets and variables management
Never hardcode sensitive credentials in your workflow files. Always use Secrets for passwords and Variables for non-sensitive values.

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5. Commit and Push

After updating .github/workflows/ci.yml (or your workflow filename), commit your changes and push to the repository: 
git add .github/workflows/ci.yml
git commit -m "chore: add Docker login and image push"
git push

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6. Verify the Workflow Run

  1. Navigate to the Actions tab in your repository.
  2. Select the latest run of your workflow.
  3. Confirm that:
    • The containerization job starts only after unit-testing and code-coverage.
    • The Docker Hub login step completes without printing your password.
List of workflow runs in GitHub Actions
Successful containerization job with Docker Hub login step
Congratulations! You have successfully set up Docker Hub login within your GitHub Actions pipeline, enabling automatic building and publishing of your container images.

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