Dockerfile

# Use the official Node.js image as base
FROM node:20-alpine AS base

# Install dependencies only when needed
FROM base AS deps
# Check https://github.com/nodejs/docker-node/tree/b4117f9333da4138b03a546ec926ef50a31506c3#nodealpine to understand why libc6-compat might be needed.
RUN apk add --no-cache libc6-compat
WORKDIR /app

# Copy package files and install all dependencies for building
COPY package.json package-lock.json* ./
RUN npm ci

# Rebuild the source code only when needed
FROM base AS builder
WORKDIR /app
COPY --from=deps /app/node_modules ./node_modules
COPY . .

# Build the application
RUN npm run build

# Production dependencies
FROM base AS prod-deps
RUN apk add --no-cache libc6-compat
WORKDIR /app
COPY package.json package-lock.json* ./
RUN npm ci --only=production && npm cache clean --force

# Production image, copy all the files and run the app
FROM base AS runner
RUN apk add --no-cache wget
WORKDIR /app

# Create a non-root user
RUN addgroup --system --gid 1001 nodejs
RUN adduser --system --uid 1001 sveltekit

# Copy the built application
COPY --from=builder /app/build ./build
COPY --from=builder /app/package.json ./package.json
COPY --from=prod-deps /app/node_modules ./node_modules

# Change ownership to the non-root user
RUN chown -R sveltekit:nodejs /app
USER sveltekit

# Expose the port the app runs on
EXPOSE 3000

# Set environment variables
ENV NODE_ENV=production
ENV PORT=3000
ENV HOST=0.0.0.0

# Add health check
HEALTHCHECK --interval=30s --timeout=10s --start-period=30s --retries=3 \
  CMD wget --no-verbose --tries=1 --spider http://localhost:3000/ || exit 1

# Start the application
CMD ["node", "build"]