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Managing Docker Images and Registries with Harbor

Prompt Template​

"Fynix, I need to build and push a Docker image of my [Language/Framework] application to a Harbor registry. Specifically:

  1. Build a Docker image from my [Application Type, e.g., Node.js/Java/Python] application code.
  2. Tag the image using the Harbor registry URL harbor.example.com/[project]/[repository]:[tag].
  3. Log in to Harbor using docker login and push the image.
  4. Verify that the image is available in Harbor.

Please provide the complete code for the [Application File and Dockerfile], and list the steps and commands to build, run, and push the Docker image. Ensure that the code and instructions can be copied and pasted to run immediately.“

Scenario​

You have a simple Node.js application that serves a "Hello World" message, and you want to:

  1. Containerize the Application: Create a Docker image of the Node.js application.
  2. Use Harbor as a Registry: Push the created image to your Harbor registry.
  3. Manage Versions and Updates: Tag and push new versions of the image as the application evolves.

Assumptions:

  • You have Docker installed and running on your machine.
  • You have access to a Harbor registry at harbor.example.com with a project named myproject.
  • You have Harbor credentials (username/password) with push privileges to the myproject project.
  • Node.js is installed locally (to test the application before containerizing).

Project Structure

node-hello-world/
├── server.js
└── Dockerfile

Prompt to Use in Fynix​

"Fynix, I need to containerize my Node.js application and push it to a Harbor registry. Specifically

  1. Create a simple Node.js web server that returns "Hello, World!" at the root path (/).

  2. Write a Dockerfile to build a Docker image of the application.

  3. Tag the image using the Harbor registry URL harbor.example.com/myproject/node-hello-world:1.0.

  4. Provide instructions to:

    • Log in to Harbor using docker login.
    • Build the Docker image.
    • Push the image to Harbor.

  5. Ensure the code is ready to run as-is, and I can copy and paste the instructions to see output.

Please provide the complete server.js file, the Dockerfile, and all necessary commands so I can run the application locally, build the image, and push it to Harbor.“

Expected Output from Fynix​

server.js (Node.js Application):

// server.js
const http = require('http');

const PORT = 3000;
const server = http.createServer((req, res) => {
  if (req.url === '/') {
    res.writeHead(200, { 'Content-Type': 'text/plain' });
    res.end('Hello, World!\n');
  } else {
    res.writeHead(404, { 'Content-Type': 'text/plain' });
    res.end('Not Found\n');
  }
});

server.listen(PORT, () => {
  console.log(`Server running at http://localhost:${PORT}/`);
});

Dockerfile (Build Instructions for the Docker Image):

# Dockerfile

FROM node:14-alpine

# Set the working directory
WORKDIR /app

# Copy package.json and package-lock.json if needed
# In this simple example, we have no dependencies, so we skip that step.

# Copy the source code
COPY server.js /app/

# Expose the port
EXPOSE 3000

# Start the server
CMD ["node", "server.js"]

Instructions to Run and See Output​

  1. Set Up the Project Files:

    • Create a directory named node-hello-world.
    • Save server.js and Dockerfile inside this directory as shown in the project structure.

  2. Test the Application Locally (Optional):

    • Run node server.js inside the node-hello-world directory:
node server.js
  • Open your browser and navigate to http://localhost:3000 to see the "Hello, World!" message.
  • Press Ctrl+C to stop the server.

  1. Build the Docker Image:

    • Navigate to the node-hello-world directory:
cd node-hello-world
  • Build the Docker image:
docker build -t harbor.example.com/myproject/node-hello-world:1.0 .
  • This command will create a Docker image tagged as harbor.example.com/myproject/node-hello-world:1.0.

  1. Run the Docker Image Locally (Optional):

    • Run the container:
docker run -p 3000:3000 harbor.example.com/myproject/node-hello-world:1.0
  • Open http://localhost:3000 in your browser, and you should see "Hello, World!" served by the containerized application.
  • Press Ctrl+C to stop the container.

  1. Log in to Harbor:

    • Log in to your Harbor registry using your credentials:
docker login harbor.example.com
  • When prompted, enter your username and password.

  1. Push the Image to Harbor:

    • Once logged in successfully, push the image:
docker push harbor.example.com/myproject/node-hello-world:1.0
  • The image will be uploaded to the myproject project in Harbor.

  1. Verify in Harbor:

    • Go to your Harbor web UI at https://harbor.example.com/.
    • Log in and navigate to the myproject project.
    • You should see the node-hello-world repository with the 1.0 tag.