cloudflare-workers-multi-lang

secondsky/claude-skillsCloud PlatformsReview advisedSnapshot 7280cd6e1856

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Summary

Multi-language Workers development with Rust, Python, and WebAssembly. Use when building Workers in languages other than JavaScript/TypeScript, or when integrating WASM modules for performance-critical code.

SKILL.md

Multi-Language Workers Development

Build Cloudflare Workers using Rust, Python, or WebAssembly for performance-critical operations.

Language Comparison

Feature	JavaScript/TS	Rust	Python
Startup	Fast	Fastest (WASM)	Moderate
CPU Perf	Good	Excellent	Good
Memory	Higher	Lower	Higher
Bundle Size	Smaller	Medium	Larger
Type Safety	Optional (TS)	Strict	Optional
Best For	General apps	CPU-intensive	Data/ML

Quick Decision

Need maximum performance? → Rust/WASM
Heavy computation (crypto, image processing)? → Rust/WASM
Data processing, ML inference? → Python
General web apps? → JavaScript/TypeScript

Top 10 Multi-Lang Errors

Error	Language	Cause	Solution
`WebAssembly.instantiate() failed`	Rust	Invalid WASM	Check wasm-pack build output
`Module parse failed: Unexpected token`	Rust	ESM/CJS mismatch	Use

--target bundler

# Install tools
cargo install wasm-pack

# Create project
cargo new --lib my-worker
cd my-worker

# Add to Cargo.toml
cat >> Cargo.toml << 'EOF'
[lib]
crate-type = ["cdylib"]

[dependencies]
wasm-bindgen = "0.2"
worker = "0.3"
console_error_panic_hook = "0.1"

[profile.release]
opt-level = "s"
lto = true
EOF

// src/lib.rs
use worker::*;

#[event(fetch)]
async fn fetch(req: Request, env: Env, _ctx: Context) -> Result<Response> {
    console_error_panic_hook::set_once();

    Router::new()
        .get("/", |_, _| Response::ok("Hello from Rust!"))
        .get("/compute", |_, _| {
            // CPU-intensive computation
            let result = heavy_computation();
            Response::ok(format!("Result: {}", result))
        })
        .run(req, env)
        .await
}

fn heavy_computation() -> u64 {
    (1..1_000_000).filter(|n| is_prime(*n)).count() as u64
}

fn is_prime(n: u64) -> bool {
    if n < 2 { return false; }
    (2..=(n as f64).sqrt() as u64).all(|i| n % i != 0)
}

# pyproject.toml
[project]
name = "my-worker"
version = "0.1.0"
requires-python = ">=3.12"
dependencies = []

[build-system]
requires = ["hatchling"]
build-backend = "hatchling.build"

# src/entry.py
from js import Response, Headers

async def on_fetch(request, env):
    url = request.url

    if "/compute" in url:
        result = heavy_computation()
        return Response.new(f"Result: {result}")

    return Response.new("Hello from Python!")

def heavy_computation():
    """CPU-intensive computation"""
    return sum(1 for n in range(2, 100000) if is_prime(n))

def is_prime(n):
    if n < 2:
        return False
    return all(n % i != 0 for i in range(2, int(n**0.5) + 1))

// Load and use WASM module in TypeScript Worker
import wasmModule from './pkg/my_lib_bg.wasm';
import { init, process_data } from './pkg/my_lib';

let wasmInstance: WebAssembly.Instance;

export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    // Initialize WASM once
    if (!wasmInstance) {
      wasmInstance = await WebAssembly.instantiate(wasmModule);
      init();
    }

    // Use WASM function
    const result = process_data(inputData);

    return Response.json({ result });
  },
};

Reference	Load When
`references/rust-workers.md`	Building Workers with Rust/WASM
`references/python-workers.md`	Using Python on Workers for Platforms
`references/wasm-integration.md`	Integrating WASM modules in any Worker

cloudflare-workers-multi-lang

Summary

SKILL.md

Multi-Language Workers Development

Language Comparison

Quick Decision

Top 10 Multi-Lang Errors

Rust Quick Start

Python Quick Start (Workers for Platforms)

WASM Module Integration

When to Load References

Performance Tips

See Also

Related skills