Efficient Docker Containerization
Containerizing web applications ensures build reproducibility across development and production environments.
Step 1: Write a Optimized Dockerfile
Use multi-stage builds to exclude devDependencies and source code from the final runtime image.
# Stage 1: Build phase
FROM node:20-alpine AS builder
WORKDIR /app
COPY package*.json ./
RUN npm ci
COPY . .
RUN npm run build
# Stage 2: Production runtime
FROM node:20-alpine AS runner
WORKDIR /app
ENV NODE_ENV=production
COPY --from=builder /app/package*.json ./
COPY --from=builder /app/dist ./dist
RUN npm ci --only=production
EXPOSE 3000
CMD ["node", "dist/server/entry.mjs"]
Step 2: Build & Verify Image Size
Execute the docker build command and inspect the output size:
docker build -t app:prod .
docker images app:prod
⚠️ Security Note
Always run your node application with a non-root container user (USER node) in production.