pplx/hello-app repository overview

⁠Hello App - Docker Documentation

🐳 Docker Hub Repository: pplx/hello-app

A containerized Node.js Express application providing a simple welcome service with health monitoring capabilities.

⁠📦 Docker Image Information

• Base Image: node:24-alpine
• Exposed Port: 8080
• Image Size: ~50MB (Alpine-based)
• Architecture: Multi-platform (linux/amd64, linux/arm64)

⁠🚀 Quick Start with Docker

⁠Pull and Run from Docker Hub

# Pull the latest image
docker pull pplx/hello-app

# Run the container
docker run -d -p 8080:8080 --name hello-app pplx/hello-app

# Access the application
curl http://localhost:8080

⁠Run with Custom Configuration

# Run with custom name
docker run -d -p 8080:8080 -e NAME="Docker User" --name hello-app pplx/hello-app

# Run with custom port mapping
docker run -d -p 3000:8080 --name hello-app pplx/hello-app

⁠🔧 Environment Variables

⁠🏗️ Building from Source

⁠Prerequisites

• Docker Desktop or Docker Engine
• Git (to clone the repository)

⁠Build Steps

1. Clone the repository

   git clone https://github.com/VishwaGullapalli/hello-app.git
   cd hello-app
   

   Copy

2. Build the Docker image

   # Build with default tag
   docker build -t hello-app .
   
   # Build with custom tag
   docker build -t myusername/hello-app:v1.0.0 .
   

   Copy

3. Run the built image

   docker run -p 8080:8080 hello-app
   

   Copy

⁠📋 Dockerfile Explanation

FROM node:24-alpine    # Lightweight Alpine Linux base with Node.js 24
EXPOSE 8080           # Expose port 8080 for external access
WORKDIR /app          # Set working directory
COPY package*.json ./  # Copy package files for dependency installation
RUN npm install      # Install dependencies
COPY . .             # Copy application source code
ENV PORT=8080        # Set default port
ENV NAME=""          # Set default empty name
CMD ["npm", "start"] # Start the application

⁠🔍 Health Monitoring

The container includes a built-in health check endpoint:

# Check application health
curl http://localhost:8080/health

# Expected response:
# {"status":"OK","message":"Application is running"}

⁠Docker Health Check

Add health check to your docker run command:

docker run -d \
  --name hello-app \
  --health-cmd="curl -f http://localhost:8080/health || exit 1" \
  --health-interval=30s \
  --health-retries=3 \
  --health-start-period=5s \
  -p 8080:8080 \
  pplx/hello-app

⁠📊 Container Management

⁠Basic Commands

# View running containers
docker ps

# View container logs
docker logs hello-app

# Execute commands in running container
docker exec -it hello-app sh

# Stop the container
docker stop hello-app

# Remove the container
docker rm hello-app

# Remove the image
docker rmi pplx/hello-app

⁠🔧 Troubleshooting

⁠Common Issues

1. Port Already in Use

   # Use different port mapping
   docker run -p 8081:8080 username/hello-app
   

   Copy

2. Container Won't Start

   # Check logs
   docker logs hello-app
   
   # Check if image exists
   docker images | grep hello-app
   

   Copy

3. Cannot Access Application

   # Verify port mapping
   docker port hello-app
   
   # Check container status
   docker ps -a
   

   Copy

⁠📞 Support

• Docker Hub: https://hub.docker.com/r/pplx/hello-app⁠
• Source Code: https://github.com/VishwaGullapalli/hello-app.git⁠
• Issues: https://github.com/VishwaGullapalli/hello-app/issues⁠

⁠📝 Version History

🐳 Ready to containerize your applications? Pull this image and see Docker in action!