Docker Introduction Assignment

Objective

In this assignment, you will work with Docker to containerize a simple Node.js web server. You will learn to:

• Build a Docker image
• Run a Docker container
• Expose ports for accessing the web server
• Persist logs from within the container

Prerequisites

Ensure you have Docker Desktop installed on your machine. If you haven’t already installed it, follow the instructions on the Docker website to do so.

Instructions

1. Fork the Repository:

   • You should have received an invitation link to this assignment. Click the link and accept the assignment.
   • After accepting, GitHub will create a personal repository based on the template. Clone your repository to your local machine:

     git clone https://github.com/YOUR-GITHUB-USERNAME/docker-introduction-assignment.git
     cd docker-introduction-assignment

2. Explore the Project Structure:

   • Inside the project, you’ll see the following structure:

     docker-introduction-assignment/
     ├── src/
     │   └── server.js
     ├── logs/
     ├── Dockerfile
     ├── package.json
     └── README.md

   • The src/ directory contains the Node.js web server.
   • The logs/ directory is where the application will store logs when running.
   • The Dockerfile defines the instructions to build and run the Docker container.

3. Understand the Web Server:

   • The web server in src/server.js listens on port 3000 and responds with "Welcome to Docker" when accessed via a browser or HTTP request.
   • The server also logs each request to the logs/access.log file inside the container.

4. Build the Docker Image:

   • Now, you will build the Docker image for this project. Run the following command to build the image:

     docker build -t simple-node-app .

   • This command uses the Dockerfile in the root directory to build the image and tag it as simple-node-app.

5. Run the Docker Container:

   • After building the image, run the Docker container, mapping port 3000 on the container to port 3000 on your local machine. Additionally, mount the logs/ directory to persist the logs on your host machine:

     docker run -d -p 3000:3000 -v $(pwd)/logs:/app/logs simple-node-app

   • This command:
     • Runs the container in detached mode (-d).
     • Maps port 3000 from the container to port 3000 on your machine (-p 3000:3000).
     • Mounts the logs directory from your machine into the container (-v $(pwd)/logs:/app/logs).

6. Test the Web Server:

   • Open your browser and navigate to http://localhost:3000, or use the following curl command to test:

     curl http://localhost:3000

   • You should see the response: Welcome to Docker.

7. Check the Logs:

   • After making a few requests, check the logs/access.log file in your project directory. You should see entries for each request made to the server, similar to:

     Request received at 2024-10-27T10:23:59.000Z
     

8. Stop the Docker Container:

   • To stop the container, find its container ID by running:

     docker ps

   • Then stop it using:

     docker stop <container-id>

9. Submit Your Work:

   • Once you’ve confirmed the container runs correctly and the logs are being written, commit and push your changes:

     git add .
     git commit -m "Completed Docker assignment"
     git push origin main

   • Your submission will be automatically graded based on the configuration set up for this assignment.

Grading Criteria (5 Points Total)

• 1 point: Dockerfile correctly exposes port 3000.
• 1 point: The Docker image builds successfully.
• 1 point: The container runs successfully and is accessible on localhost:3000.
• 2 points: The HTTP response is correctly returned as Welcome to Docker.

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