From Flask App to CI/CD Pipeline with GitHub Actions & Docker Hub

DevOps is all about bridging development and operations. For this project, I decided to get hands on by containerizing a simple web application and automating its deployment pipeline.

Here’s how I built a complete CI/CD workflow from scratch using

• 
  Python + Flask for the web app


• 
  Docker for containerization


• 
  GitHub for version control


• 
  GitHub Actions for CI/CD


• 
  Docker Hub for image hosting

✅ Step 1: Create a Simple Flask Application

1.1 Set up a project folder

1.2 Create a virtual environment and install Flask

1.3 Create your Flask app

Create a file called app.py and paste this in:

1.4 Run the app locally

Then open your browser and go to http://localhost:5000

✅ Step 2: Containerize the Application

2.1 Create a Dockerfile

Create a file called Dockerfile (no extension) in the root folder:

2.2 Create .dockerignore

Create a file named .dockerignore:

2.3 Build the Docker image

2.4 Run the container

Open http://localhost:5000 in your browser again. You should see Hello DevOps!

✅ Step 3: Set Up Version Control

Next, I pushed the project to GitHub to manage changes and integrate CI/CD workflows.

git init

git add .

git commit -m "Run"

git remote add origin https://github.com/adeleke123/flask-devops-app.git

git push -u origin main

🔁 Step 4: Implement CI/CD with GitHub Actions

This is the fun part — automating the build and deployment using GitHub Actions and pushing the Docker image to Docker Hub.

4.1 🔐 Set Up Docker Hub Secrets in GitHub

I created a personal access token in Docker Hub, then added the following secrets to GitHub:

• 
  DOCKER_USERNAME – my Docker Hub username


• 
  DOCKER_TOKEN – Docker Hub access token

Location: GitHub Repo → Settings → Secrets and variables → Actions

4.2 🛠 Created the GitHub Actions Workflow

Once I pushed the workflow file, the GitHub Action triggered automatically, built my Docker image and pushed it to Docker Hub.

🐳 Final Result

You can find the container image here on Docker Hub:

🔗 https://hub.docker.com/repository/docker/bakare1234844/flask-devops-app

And the source code on GitHub:

🔗 https://github.com/adeleke123/flask-devops-app