openworkers-runtime-wasm

WebAssembly runtime for OpenWorkers using Wasmtime Component Model.

Features

• Component Model: Type-safe host/guest communication via WIT interfaces
• WASI Support: WebAssembly System Interface (WASIp2)
• Multi-language: Write workers in Rust, Go (TinyGo), C/C++, AssemblyScript
• Secure by design: Capabilities-based sandboxing, no Spectre concerns

Architecture

┌─────────────────────────────────────────────┐
│            openworkers-runner               │
└──────────────────┬──────────────────────────┘
                   │
┌──────────────────▼──────────────────────────┐
│          openworkers-runtime-wasm           │
│  ┌───────────────────────────────────────┐  │
│  │            Wasmtime                   │  │
│  │  ┌─────────────────────────────────┐  │  │
│  │  │     WASM Component (Worker)     │  │  │
│  │  │  - handle_fetch()               │  │  │
│  │  │  - handle_scheduled()           │  │  │
│  │  └─────────────────────────────────┘  │  │
│  └───────────────────────────────────────┘  │
└─────────────────────────────────────────────┘

WIT Interface

Workers implement the handler interface defined in wit/worker.wit:

interface handler {
    handle-fetch: func(request: http-request) -> http-response;
    handle-scheduled: func(scheduled-time: u64);
}

Host provides:

• log(level, message) - Logging
• get-env(key) - Environment variables

Writing a Worker (Rust)

wit_bindgen::generate!({
    world: "worker",
    path: "wit/worker.wit",
});

use exports::openworkers::worker::handler::Guest;
use openworkers::worker::types::{HttpRequest, HttpResponse};

struct MyWorker;

impl Guest for MyWorker {
    fn handle_fetch(request: HttpRequest) -> HttpResponse {
        HttpResponse {
            status: 200,
            headers: vec![("Content-Type".into(), "text/plain".into())],
            body: Some(b"Hello from WASM!".to_vec()),
        }
    }

    fn handle_scheduled(scheduled_time: u64) {
        // Handle cron job
    }
}

export!(MyWorker);

Build:

cargo build --target wasm32-wasip2 --release

Usage

use openworkers_runtime_wasm::WasmWorker;
use openworkers_core::{Script, WorkerCode, Task};

// Load WASM component
let wasm_bytes = std::fs::read("worker.wasm")?;
let script = Script::new(WorkerCode::WebAssembly(wasm_bytes));

// Create worker
let mut worker = WasmWorker::new(script, None).await?;

// Execute task
worker.exec(task).await?;

Examples

See examples/hello-worker for a complete example.

# Build the example
cd examples/hello-worker
cargo build --target wasm32-wasip2 --release

# Run tests
cd ../..
cargo test

License

MIT