Chapter 49: Deployment in JavaScript

Docker, systemd, Vercel, production checklist. In this chapter, you will learn deployment in depth with JavaScript code examples, explanations, and best practices.

Overview

This chapter covers deployment for Kungfu.js developers using JavaScript. We will start with the basics, move through practical examples, and end with advanced techniques and common pitfalls.

Why This Matters

Understanding deployment is essential because it is a core part of building web applications. Every real-world app needs to handle docker, systemd, vercel, production checklist. Skipping this chapter would leave a gap in your knowledge that would cause problems later.

Code Example

Here is how to handle this in JavaScript:

# Build for production
cargo build --release --features "kungfu-core/io_uring kungfu-core/simd"

# Dockerfile
FROM rust:1.96 AS builder
WORKDIR /app
COPY . .
RUN cargo build --release

FROM debian:bookworm-slim
COPY --from=builder /app/target/release/myapp /usr/local/bin/
EXPOSE 3000
CMD ["myapp"]

Deployment Checklist

• Build with --release flag for optimizations
• Enable io_uring and SIMD features on Linux
• Set acceptor_threads to the number of CPU cores
• Put behind a reverse proxy (nginx/Caddy) for TLS
• Increase file descriptor limit: ulimit -n 1048576
• Set up health checks at /health
• Configure graceful shutdown

Common Mistakes

• Not reading the documentation: Always check the API reference when something does not work as expected.
• Skipping security: Never disable the default middleware unless you have a very good reason. Security is not optional.
• Not testing: Write tests for your handlers. Kungfu.js makes this easy with the built-in test utilities.

Summary

In this chapter, you learned about deployment in JavaScript. You saw code examples, understood how things work under the hood, and learned about common mistakes to avoid.

What is Next?

In chapter 50, we will cover Build a Full-Stack App: Put it all together: a complete project.