Dockerfile

# This file tells Docker how to build a container image for our app.
# It has two stages: first we build the app, then we copy just the
# finished result into a clean, smaller image to actually run it.

# ---------- STAGE 1: Build the app ----------
FROM node:20-alpine AS builder

# This is the folder inside the container where our files will live
WORKDIR /app

# Copy just the package files first. Docker is smart about caching --
# if these files don't change, it won't need to reinstall everything
# again next time we build.
COPY package.json package-lock.json* ./

# Install all the packages our app needs
RUN npm install

# Now copy the rest of our project files into the container
COPY . .

# Prisma needs this step to generate its database client before building
RUN npx prisma generate

# Build the Next.js app for production
RUN npm run build

# ---------- STAGE 2: Run the app ----------
# We start fresh with a clean, small image. We only copy over the
# finished build, not all our source code or dev dependencies.
FROM node:20-alpine AS runner

WORKDIR /app

# Tell Next.js it's running in production mode
ENV NODE_ENV=production

# Copy the built app from the first stage
COPY --from=builder /app/public ./public
COPY --from=builder /app/.next/standalone ./
COPY --from=builder /app/.next/static ./.next/static
COPY --from=builder /app/prisma ./prisma

# Our app listens on port 3000 inside the container
EXPOSE 3000

# This is the command that starts the app
CMD ["node", "server.js"]