Dockerfile

# syntax=docker.io/docker/dockerfile:1

FROM node:20-slim AS base

# Install dependencies only when needed
FROM base AS deps
WORKDIR /app
# Copy only the package.json (adjust the path as needed)
COPY package.json app ./
RUN npm install --legacy-peer-deps

# Rebuild the source code only when needed
FROM base AS builder
WORKDIR /app
COPY --from=deps /app/node_modules ./node_modules
# Copy the rest of the app files from the build context
COPY . .
ENV NEXT_TELEMETRY_DISABLED=1
RUN npm run build

# Production image, copy all the files and run next
FROM base AS runner
WORKDIR /app

ENV NODE_ENV=production
ENV NEXT_TELEMETRY_DISABLED=1

# Create a system group and user (Debian uses groupadd and useradd)
RUN groupadd --gid 1001 nodejs && \
    useradd --uid 1001 --gid 1001 nextjs

# Copy public assets
COPY --from=builder /app/public ./public

# Leverage Next.js output tracing to reduce image size
COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./
COPY --from=builder --chown=nextjs:nodejs /app/.next/static ./.next/static

USER nextjs

EXPOSE 3000

ENV PORT=3000
ENV HOSTNAME="0.0.0.0"

# server.js is created by next build from the standalone output
CMD ["node", "server.js"]