cloudflare-workers-multi-lang

# 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` | | `Cannot find module` | Python | Missing dep | Add to pyproject.toml | | `Out of memory` | All | Large WASM | Enable streaming instantiation | | `Exceeded CPU time limit` | All | Long computation | Chunk processing | | `wasm-bindgen version mismatch` | Rust | Dep conflict | Align versions in Cargo.toml | | `RuntimeError: unreachable` | Rust | Panic in WASM | Add proper error handling | | `TypeError: not a function` | Rust | Missing export | Add `#[wasm_bindgen]` attribute | | `Python worker startup timeout` | Python | Slow init | Minimize imports | | `SharedArrayBuffer not supported` | All | Security | Add COOP/COEP headers | ## Rust Quick Start ```bash # 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 ``` ```rust // 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) } ``` ## Python Quick Start (Workers for Platforms) ```toml # pyproject.toml [project] name = "my-worker" version = "0.1.0" requires-python = ">=3.12" dependencies = [] [build-system] requires = ["hatchling"] build-backend = "hatchling.build" ``` ```python # 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)) ``` ## WASM Module Integration ```typescript // 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 }); }, }; ``` ## When to Load References | 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 | ## Performance Tips 1. **WASM Initialization**: Cache instance, use streaming 2. **Memory**: Use typed arrays for data transfer 3. **Bundle Size**: Enable LTO, strip debug info 4. **Cold Starts**: Keep WASM modules small 5. **Data Transfer**: Minimize JS/WASM boundary crossings ## See Also - `workers-performance` - General optimization techniques - `workers-testing` - Testing multi-language Workers - `cloudflare-worker-base` - Basic Workers setup