README.md

OpenWorkers Runtime V8

V8-based JavaScript runtime for serverless workers, built on rusty_v8.

Quick Start

use openworkers_runtime_v8::{
    init_pinned_pool, execute_pinned,
    PinnedPoolConfig, PinnedExecuteRequest, RuntimeLimits,
};

// Initialize pool once at startup
init_pinned_pool(PinnedPoolConfig {
    max_per_thread: 100,
    max_per_owner: Some(10),
    max_concurrent_per_isolate: 1,
    max_cached_contexts: 5,
    limits: RuntimeLimits::default(),
});

// Execute worker
execute_pinned(PinnedExecuteRequest {
    owner_id: "tenant-1".into(),
    worker_id: "worker-1".into(),
    version: 1,
    script,
    ops,
    task: event,
    on_warm_hit: None,
    env_updated_at: None,
}).await?;

Execution Modes

Pinned Pool (Recommended)

Thread-local isolate pool with per-owner isolation and warm context caching. PinnedPoolConfig::max_concurrent_per_isolate sets how many requests an isolate serves at once: 1 gives each request the isolate to itself, and more lets requests share it through the AsyncWaiter fair FIFO queue.

Worker (Maximum Isolation)

Fresh isolate per request. No caching, no Locker. Best for debugging or maximum security.

let mut worker = Worker::new_with_ops(script, limits, ops).await?;
worker.exec(event).await?;

Performance

Mode	Cold Start	Warm Start
Pinned Pool	Tens of µs	Sub-µs
Worker	Few ms	Few ms

Features

• Isolate pooling with LRU context caching
• Streaming with ReadableStream and backpressure
• Web APIs — fetch, setTimeout, Response, Request, URL, console
• Async/await — Full Promise support
• Code cache — V8 code cache for faster cold starts

Testing

# From openworkers-runner (not this crate directly)
cargo test --features v8

License

MIT