Write A Short Dockerfile And Docker Image

Step 1: Set Up Project Directory/Folder Create a directory for your project files.

                   mkdir myapp
                   cd myapp

Step 2: Create Application (Example: Simple Node.js App) Create a server.js file for a basic web server. you can use vs code.

                   // server.js
                   const http = require('http');
                   const port = 3000;
                   http.createServer((req, res) => res.end('Hello from Docker!')).listen(port);

Step 3: Create package.json This file manages dependencies for Node.js. Create it in the same directory as server.js.

                   {
                      "name": "myapp",
                      "version": "1.0.0",
                      "main": "server.js",
                      "scripts": {
                      "start": "node server.js"
                      }
                    }

Step 4: Create Dockerfile In the same directory (all file create same folder), create a file called Dockerfile with the following contents:

               # Use the official Node.js base image

               FROM node:14 

               # Set the working directory inside the container 

               WORKDIR /usr/src/app

               # Copy package.json and install dependencies

               COPY package*.json ./
               RUN npm install

              # Copy the rest of the application files

               COPY . . 

               # Expose the app's port

               EXPOSE 3000

              # Run the app

              CMD ["npm", "start"]

Step 5: Build Docker Image In your terminal (Command Prompt or Terminal or VS Code Terminal), run:

 docker build -t myapp .

Step 6: Run the Docker Container Run the container using the following command:

 docker run -p 3000:3000 myapp

Step 7: View the Result Open your browser and go to http://localhost:3000. You should see:

 Hello from Docker!