Dockerfile

# ── Stage 1: Build ────────────────────────────────────────────────────────────
# Uses full Node image to compile TypeScript → JavaScript
FROM node:20-alpine AS builder

WORKDIR /app

# Install deps first (layer cached unless package.json changes)
COPY package*.json ./
RUN npm ci --ignore-scripts

# Copy source and compile
COPY tsconfig*.json ./
COPY src/ ./src/
RUN npm run build

# ── Stage 2: Production ───────────────────────────────────────────────────────
# Lean image — only compiled JS + production deps, no TypeScript, no devDeps
FROM node:20-alpine AS production

WORKDIR /app

ENV NODE_ENV=production

# Install only production dependencies
COPY package*.json ./
RUN npm ci --omit=dev --ignore-scripts && npm cache clean --force

# Copy compiled output from builder stage
COPY --from=builder /app/dist ./dist

# Run as non-root user (security best practice)
RUN addgroup -g 1001 -S nodejs && adduser -S appuser -u 1001
USER appuser

EXPOSE 5000

HEALTHCHECK --interval=30s --timeout=3s --start-period=10s --retries=3 \
  CMD node -e "require('http').get('http://localhost:5000/health', r => process.exit(r.statusCode === 200 ? 0 : 1))"

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