# Use an official Node.js runtime as a parent image
# Alpine Linux is chosen for its small size
FROM node:20-alpine

# Set the working directory in the container
WORKDIR /app

# Copy package.json and package-lock.json (if available)
COPY package*.json ./

# Install app dependencies using npm ci for faster, reliable builds
# Use --only=production to avoid installing devDependencies
RUN npm ci --only=production

# Copy the rest of the application code
COPY . .

# Make port 3000 available to the world outside this container
# This is the port our Node.js app will listen on
EXPOSE 3000

# Define the command to run your app using CMD which defines your runtime
CMD [ "node", "server.js" ]