Dockerfile

# node:20-slim
FROM node:20-slim@sha256:1e85773c98c31d4fe5b545e4cb17379e617b348832fb3738b22a08f68dec30f3 AS base

FROM base AS deps
WORKDIR /app
COPY package.json package-lock.json ./
RUN npm ci

FROM base AS builder
WORKDIR /app
COPY --from=deps /app/node_modules ./node_modules
COPY . .
ENV NEXT_TELEMETRY_DISABLED=1
RUN npm run build

FROM base AS runner
WORKDIR /app
ENV NODE_ENV=production
ENV NEXT_TELEMETRY_DISABLED=1
RUN addgroup --system --gid 1001 nodejs && \
    adduser --system --uid 1001 nextjs
COPY --from=builder /app/public ./public
COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./
COPY --from=builder --chown=nextjs:nodejs /app/.next/static ./.next/static

# Writable cache dir for --read-only filesystem compatibility
RUN mkdir -p /app/.next/cache && chown nextjs:nodejs /app/.next/cache

USER nextjs
EXPOSE 3000
ENV PORT=3000
ENV HOSTNAME=0.0.0.0

HEALTHCHECK --interval=30s --timeout=5s --start-period=10s --retries=3 \
  CMD node -e "fetch('http://localhost:3000/').then(r => {if(!r.ok) process.exit(1)}).catch(() => process.exit(1))"

CMD ["node", "server.js"]