Dockerfile

# syntax=docker/dockerfile:1.5

########################
# 🔧 Base image for building
########################
FROM --platform=$BUILDPLATFORM node:20-slim AS base
WORKDIR /app

# Install libc compatibility for native modules like sharp and update all packages
RUN apt-get update && \
    apt-get upgrade -y && \
    apt-get install -y --no-install-recommends libc6 && \
    rm -rf /var/lib/apt/lists/*

########################
# 📦 Install dependencies (cached)
########################
FROM base AS deps
WORKDIR /app

COPY app/package.json app/package-lock.json* ./
RUN npm ci

########################
# 🛠 Build the Next.js app
########################
FROM base AS builder
WORKDIR /app

COPY --from=deps /app/node_modules ./node_modules
COPY app .

ENV NODE_ENV=production
RUN npm run build

########################
# 🚀 Production image
########################
FROM node:20-slim AS runner
WORKDIR /app

ARG BUILD_TIMESTAMP
LABEL org.opencontainers.image.created=$BUILD_TIMESTAMP

ENV NODE_ENV=production
ENV PORT=3000

COPY --from=deps /app/node_modules ./node_modules
COPY --from=builder /app/.next ./.next
COPY --from=builder /app/public ./public
COPY --from=builder /app/package.json ./package.json

# Generate runtime env file at container start
COPY app/scripts/generate-runtime-env.js ./scripts/generate-runtime-env.js

EXPOSE 3000

ENTRYPOINT ["sh", "-c", "node ./scripts/generate-runtime-env.js && npx next start"]