# ---- Dependency install stage ----
FROM node:20-alpine AS deps
WORKDIR /app
COPY package.json ./
RUN npm install --omit=dev

# ---- Runtime stage ----
FROM node:20-alpine
WORKDIR /app

# Non-root user
RUN addgroup -S appgroup && adduser -S appuser -G appgroup
USER appuser

COPY --from=deps /app/node_modules ./node_modules
COPY package.json ./
COPY src/ ./src/

EXPOSE 3000

HEALTHCHECK --interval=30s --timeout=5s --start-period=15s --retries=3 \
    CMD wget -qO- http://localhost:3000/health | grep -q 'UP' || exit 1

CMD ["node", "src/index.js"]