Dockerfile

# Multi-stage build for coding interview platform
# Stage 1: Build frontend
FROM node:20-alpine AS frontend-builder

WORKDIR /app/frontend

# Copy frontend package files
COPY frontend/package*.json ./

# Install frontend dependencies (including dev dependencies for build)
RUN npm ci

# Copy frontend source
COPY frontend/ ./

# Build frontend for production
RUN npm run build

# Stage 2: Build backend
FROM node:20-alpine AS backend-builder

WORKDIR /app/backend

# Copy backend package files
COPY backend/package*.json ./
COPY backend/tsconfig.json ./

# Install backend dependencies (including dev dependencies for build)
RUN npm ci

# Copy backend source
COPY backend/src ./src

# Build backend TypeScript
RUN npm run build

# Stage 3: Production image
FROM node:20-alpine

WORKDIR /app

# Install production dependencies for backend
COPY backend/package*.json ./
RUN npm ci --only=production && npm cache clean --force

# Copy built backend from builder
COPY --from=backend-builder /app/backend/dist ./dist

# Copy built frontend from builder
COPY --from=frontend-builder /app/frontend/dist ./frontend/dist

# Set environment to production
ENV NODE_ENV=production
ENV PORT=3000

# Expose port
EXPOSE 3000

# Health check
HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
  CMD node -e "require('http').get('http://localhost:3000/api/health', (r) => {process.exit(r.statusCode === 200 ? 0 : 1)})"

# Start the application
CMD ["node", "dist/server.js"]